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Title: The Works of William Harvey M.D. - Translated from the Latin with a life of the author
Author: Harvey, William Fryer
Language: English
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                           SYDENHAM SOCIETY




                     PRINTED BY C. AND J. ADLARD,
                          BARTHOLOMEW CLOSE.

                               THE WORKS


                         WILLIAM HARVEY, M.D.

                     TO THE COLLEGE OF PHYSICIANS

                       TRANSLATED FROM THE LATIN


                         A LIFE OF THE AUTHOR


                          ROBERT WILLIS, M.D.

                               ETC. ETC.





When, at the instance of the governing body of the Sydenham Society, I
undertook to edit the Works of the immortal Discoverer of the
Circulation of the Blood, in English, I believed that the chief of these
Works were already extant in our language, in such a shape as would make
little more from an editor necessary than a careful revision of the
text. I had unwarily adopted the idea, very gratuitously originated by
Aubrey, that Harvey was what is called an indifferent scholar, and that
the English versions of his writings were the proper originals, the
Latin versions the translations. Having access to the handsome edition
of Harvey’s Works in Latin, revised by Drs. Lawrence and Mark Akenside,
and published by the College of Physicians in 1766, I had always
referred to that when the course of my studies led me to consult Harvey.
Of the English versions, or any other edition, I knew little or nothing.
On proceeding to my new duty of English editor, however, I immediately
saw that the masterwork of Harvey on the MOTIONS of the HEART and BLOOD,
far from having the character of an originally English writing, must
have been rendered into English by one but little conversant with the
subject, that it was both extremely rebutting in point of style and full
of egregious errors, and that nothing short of an entirely new
translation could do justice to this admirable treatise, or secure for
it, at the present day, the attention it deserved. Full of zeal, and
making of my task a labour of love, I had soon completed a new
translation of the Exercises on the Heart and Blood, with equal pleasure
and profit to myself.

The work on GENERATION came next under review. The English version of
this I had heard it positively asserted was the original, was Harvey’s
own; here therefore my business of editor would properly begin. But I
had not gone through a couple of pages of the text, before difficulties
like those already experienced met me again. That the statement above
referred to was erroneous, speedily became apparent; and a little
inquiry enabled me to discover that the English version of the Exercises
on Generation was the work of a physician named Llewellen. Though not
incorrect generally, there was, nevertheless, a great deal that I wished
had been otherwise rendered; and then the scientific and professional
language of two centuries back looked strangely when examined by the
eye, and had an unusual sound when tried upon the ear. Only anxious to
present to my brethren in the most appropriate and attractive form
possible, the writings of him who had still met me in his Works and with
his contemplative look in his Portrait as a kind of divinity in
medicine, I even girded myself up for the long and laborious enterprise
of translating anew into our mother tongue the work on Generation, and
at length achieved my task, not without difficulty.

The short paper on the ANATOMY of THOMAS PARR appears in the
Philosophical Transactions in English; but it stands there as a
translation; and having now translated so much myself, I even thought it
would be well to translate that also, and so it was achieved.

The LETTERS, though frequently quoted, have never appeared in English
before. They will be found both highly interesting and important. To
render them was a light and pleasant task.--In a word, the English
reader is now presented with an entirely new translation of the writings
of William Harvey; everything of our illustrious countryman worthy of
publication that has come down to us, being here included.[1]

The reader will perceive that I have abstained from annotation and
commentary in the course of my labour. The purpose of the Council of the
Sydenham Society, as I understood it, was to give the Works of William
Harvey in English now, as he himself gave them in Latin two centuries
ago. Entirely approving of this intention, I felt that anything like
corrections of statements and opinions, which could so readily have been
made under the lights of modern physiology, would have been
impertinencies, and I therefore abstained from them. To have carried out
and completed the history of Harvey’s two grand subjects, would also
have been easy; but this would have been almost as obviously out of
place as commentary, and the inclination towards such an agreeable
undertaking was also resisted.

It appeared, nevertheless, that the Works of our great physiological
discoverer might be advantageously prefaced by some account of his Life
and Writings. One great motive with me, indeed, for undertaking the
office of Editor of the Works of Harvey was, that I might thus find a
fitting opportunity for writing his life, a task which, in other
circumstances than those that now surround me, it had still been a
cherished purpose with me to perform. The Life of Harvey, by one who had
maintained a familiarity with anatomy and physiology, had always seemed
to me a desideratum in our medical literature.

This portion of my work I have only achieved with an effort, and at
something like disadvantage. Incessantly engaged by night and by day in
the laborious and responsible duties of a country practice, enjoying
nothing of learned leisure, but snatching from the hours that should
rightfully be given to rest, the time that was necessary to composition,
remote too from means of information which I must nevertheless send for
and consult--for I could not draw entirely upon memory and old
recollections of Harvey, I have been much longer about this work than
its length might indicate. In spite of many disadvantages, however, I
trust it will be found that I have included everything of moment in my
narrative of the life of Harvey; that I have set his claims to the whole
and sole merit of the discovery of the Circulation in a new and clearer
light than they have yet been seen; and that I have done more than any
preceding biographer in exhibiting his moral nature; for truly he was as
noble in nature as he was intellectually great.

The Wills of great men have always been looked on as calculated to throw
light on the character of their authors; and I have, therefore, great
pleasure in presenting to the medical world, for the first time, the
Will of William Harvey.

It only remains for me, in conclusion, to explain and to apologise for
the long delay that has taken place in the appearance of this volume.
The work was, in fact, nearly three-fourths done more than a year ago;
but with the change made in my sphere of action about that time, all
aptitude for literary labour seemed to forsake me,--the bow, to use a
common metaphor, became unbent, and for a while resisted every effort to
string it anew; and, then, when restrung at length, how constantly was I
hindered in my purpose to use it! With this brief explanation, which
will be so well appreciated by the great majority of my fellow members
of the Sydenham Society, I confidently throw myself on their kind
consideration, and pray them to pardon the delay that has occurred.

                                                             R. WILLIS.


_Feb. 15th, 1847_.



Preface                                                                v

Life of William Harvey                                                xv

Last Will and Testament of William Harvey                          lxxxv


Dedication                                                             3

Introduction                                                           9


I. The author’s motives for writing                                   19

II. Of the Motions of the Heart, as seen in the Dissection of
Living Animals                                                        21

III. Of the Motions of Arteries, as seen in the Dissection of
Living Animals                                                        24

IV. Of the Motion of the Heart and its Auricles, as seen in the Bodies
of Living Animals                                                     26

V. Of the Motion, Action, and Office of the Heart                     31

VI. Of the Course by which the Blood is carried from the Vena Cava
into the Arteries, or from the Right into the Left Ventricle of
the Heart                                                             35

VII. The Blood percolates the Substance of the Lungs from the Right
Ventricle of the Heart into the Pulmonary Veins and Left
Ventricle                                                             40

VIII. Of the Quantity of Blood passing through the Heart from the
Veins to the Arteries; and of the Circular Motion of the
Blood                                                                 45

IX. That there is a Circulation of the Blood is confirmed from the
first proposition                                                     48

X. The First Position: of the Quantity of Blood passing from the
Veins to the Arteries. And that there is a Circuit of the
Blood, freed from objections, and farther confirmed by Experiment     52

XI. The Second Position is demonstrated                               54

XII. That there is a Circulation of the Blood is shown from the
Second Position demonstrated                                          60

XIII. The Third Position is confirmed: and the Circulation of the
Blood is demonstrated from it                                         62

XIV. Conclusion of the Demonstration of the Circulation               68

XV. The Circulation of the Blood is further confirmed by probable
reasons      ib.

XVI. The Circulation of the Blood is further proved from certain
consequences                                                          71

XVII. The Motion and Circulation of the Blood are confirmed from the
particulars apparent in the Structure of the Heart, and from
those things which Dissection unfolds                                 75

OF THE BLOOD, ADDRESSED TO JOHN RIOLAN                                89

ARE REFUTED                                                          109



Dedication                                                           145

Introduction                                                         151

Of the manner and order of acquiring knowledge                       154

Of the same matters, according to Aristotle                          158

Of the method to be pursued in studying Generation                   163


Wherefore we begin with the history of the hen’s egg                 169

Of the seat of generation                                            171

Of the upper part of the hen’s uterus, or the ovary                  172

Of the infundibulum                                                  179

Of the external portion of the uterus of the common fowl             180

Of the uterus of the fowl                                            190

Of the abdomen of the common fowl and of other birds                 195

Of the situation and structure of the remaining parts of the
fowl’s uterus                                                        198

Of the extrusion of the egg, or parturition of the fowl, in general  201

Of the increase and nutrition of the egg                             202

Of the covering or shell of the egg                                  204

Of the remaining parts of the egg                                    211

Of the diversities of eggs                                           216

Of the production of the chick from the egg of the hen               225

The first examination of the egg; or of the effect of the first
day’s incubation upon the egg                                        228

Second inspection of the egg                                         232

The third inspection of the egg                                      234

The fourth inspection of the egg                                     243

The fifth inspection of the egg                                      252

The sixth inspection                                                 256

The inspection after the tenth day                                   257

The inspection after the fourteenth day                              259

Of the exclusion of the chick, or the birth from the egg             264

Of twin-bearing eggs                                                 268

Certain deductions from the preceding history of the egg             270

Of the nature of the egg                                              ib.

The egg is not the product of the uterus, but of the vital
principle                                                            279

The egg is not produced without the hen                              284

Of the manner, according to Aristotle, in which a perfect and
fruitful egg is produced by the male and female fowl                 287

Of the uses of this disquisition on fecundity                        291

The egg is not produced by the cock and hen in the way Aristotle
would have it                                                        293

Nor in the manner imagined by physicians                             294

The male and the female are alike efficient in the business of
generation                                                           296

Of the matter of the egg, in opposition to the Aristotelians and
the medical writers                                                  297

In how far is the fowl efficient in the generation of the egg,
according to Aristotle? And wherefore is the concurrence of the
male required?                                                       300

The perfect hen’s egg is of two colours                              303

Of the manner in which the egg is increased by the albumen           305

Of what the cock and hen severally contribute to the production of
the egg                                                              307

Of the cock and the particulars most remarkable in his constitution  309

Of the hen                                                           313

Of the sense in which the hen may be called the “prime efficient:”
and of her parturition                                               318

Of the manner in which the generation of the chick takes place from
the egg                                                              323

In how many ways the chick may be said to be formed from the egg     325

Fabricius is mistaken with regard to the matter of the generation
of the chick in ovo                                                  327

What is the material of the chick, and how it is formed in the egg   333

Of the efficient cause of the generation of the chick and fœtus      340

Of the manner in which the efficient cause of the chick acts,
according to Aristotle                                               344

The opinion of Fabricius on the efficient cause of the chick

is refuted                                                           350

The inquiry into the efficient cause of the chick is one of
great difficulty                                                     355

Of the efficient cause of animals, and its conditions                360

Of the order of generation; and, first, of the primary genital
particle                                                             372

Of the blood as prime element in the body                            379

Of the inferences deducible from the course of the umbilical
vessel in the egg                                                    392

Of the order of the parts in generation from an egg, according to
Fabricius                                                            397

Of the order of the parts according to Aristotle                     407

Of the order of the parts in generation as it appears from
observation                                                          414

Of certain paradoxes and problems to be considered in connexion
with this subject                                                    423

Of the nutrition of the chick in ovo                                 434

Of the uses of the entire egg                                        442

Of the uses of the yelk and albumen                                  444

Of the uses of the other parts of the egg                            454

An egg is the common origin of all animals                           456

Of the generation of viviparous animals                              461

The generation of viviparous animals in general is illustrated from
the history of that of the hind and doe, and the reason of this
selection                                                            466

Of the uterus of the hind and doe                                    467

Of the intercourse of the hind and doe                               474

Of the constitution or change that takes place in the uterus of the
deer in the course of the month of September                         476

Of what takes place in the month of October                          478

Of what takes place in the uterus of the doe during the month of
November                                                             482

Of the conception of the deer in the course of the month of
December                                                             492

Of the innate heat                                                   501

Of the primigenial moisture                                          513

ON PARTURITION                                                       521

OF THE UTERINE MEMBRANES AND HUMOURS                                 551

Of the Humours                                                       557

Of the Membranes                                                     560

Of the Placenta                                                      563

Of the Acetabula                                                     566

Of the Umbilical Cord                                                567

ON CONCEPTION                                                        573




To Caspar Hofmann, M.D.                                              595

To Paul Marquard Slegel, of Hamburg                                  596

To the very excellent John Nardi, of Florence                        603

In reply to R. Morison, M.D., of Paris                               604

To the most excellent and learned John Nardi, of Florence            610

To John Daniel Horst, principal Physician of Hesse-Darmstadt         612

To the distinguished and learned John Dan. Horst, principal
Physician at the Court of Hesse-Darmstadt                            613

To the very learned John Nardi, of Florence, a man distinguished
alike for his virtues, life, and erudition                           615

To the distinguished and accomplished John Vlackveld, Physician of
Harlem                                                               616


William Harvey, the immortal discoverer of the Circulation of the Blood,
was the eldest son of Thomas Harvey and Joan Halke, of Folkstone, in
Kent, where he was born on the 1st of April, 1578.[3] Of the parents of
Harvey, little is known. His father, in our printed accounts, is
generally designated Gentleman,[4] and must have been in easy
circumstances; inasmuch as he had a numerous family, consisting of seven
sons and two daughters, all the males of which he felt himself competent
to launch upon life in courses that imply the possession of money
wealth. William, the first-born, adopted the profession of physic. Five
of his brothers,--Thomas, Daniel, Eliab, Michael, and Matthew--were
merchants, and not merchants in a small and niggardly way--non tenues et
sordidi, as Dr. Lawrence has it in his Life of Harvey,[5] but of weight
and substance--magni et copiosi, trading especially with Turkey or the
Levant, then the main channel through which the wealth of the East
flowed into Europe. The Harveys were undoubtedly men of consideration in
the city of London, and several of them, in the end, became possessed
of the most ample independent fortunes.[6] The son, whose name does not
appear in the list given above, was John, the immediate junior to
William. He, too, was a man of note in his day, having been one of the
King’s receivers for Lincolnshire, having sat as member of parliament
for Hythe, and for some time held the office of King’s footman. Of the
two sisters--Sarah died young; of the fate of Anne, or Amy, nothing is

Great men seem, in almost all authenticated instances, to have had
noble-minded women for their mothers. We have not a word of his age or
generation to assist us in forming an estimate of Harvey’s male
progenitor; but the inscription on his mother’s monumental tablet, in
Folkstone church, assures us that she, at least, was a woman of such
mark and likelihood, that it was held due to her memory to leave her
moral portrait to posterity in these beautiful words, penned, it may be,
by her illustrious eldest son:

    “A.D. 1605, Nov. 8th, dyed in yᵉ 50th yeere of her age,
JOAN, Wife of THO: HARVEY. Mother of 7 Sones & 2 Daughters.
      A Godly harmles Woman: A chaste loveing Wife:
    A charitable quiet Neighbour: A co~fortable frendly Matron:
  A p~ovident diligent Huswyfe: A careful te~der-harted Mother.
      Deere to her Husband; Reverensed of her Children:
        Beloved of her Neighbours: Elected of God.
      Whose Soule Rest in Heaven: her Body in this Grave:
    To Her a Happy Advantage: to Hers an Unhappy Loss.”

Epitaphs may not always be authorities implicitly to be relied on; but
we unhesitatingly accept of everything to the credit of William Harvey’s
mother as a portion of our faith.

At ten years of age, Harvey was put to the grammar school of Canterbury,
having, doubtless, already imbibed the rudiments of his English
education at home under the eye of his excellent mother. In the grammar
school of Canterbury he was, of course, initiated into a knowledge of
the Latin and Greek languages--the routine practice then as now; and
there he seems to have remained until he was about fifteen years of age.
At sixteen he was removed to Caius-Gonvil College, Cambridge,[7] where
he spent from three to four years in the study of classics, dialectics,
and physics, such discipline being held peculiarly calculated to fit the
mind of the future physician for entering on the study of the difficult
science of medicine. At nineteen (1597) he took his degree of B.A. and
quitted the University. Cambridge, in Harvey’s time, was a school of
logic and divinity rather than of physic. Then, even as at the present
day, the student of physic obtained the principal part of his medical
education from another than his alma mater. In the 16th and 17th
centuries, France and Italy boasted medical schools of higher repute
than any in Europe; and to one or other of these must the young
Englishman who dedicated himself to physic repair, in order to furnish
himself with the lore that was indispensable in his profession. Harvey
chose Italy; and Padua, about the year 1598, numbering such men as
Fabricius of Aquapendente, Julius Casserius, and Jo. Thomas Minadous
among its professors, Harvey’s preference of that school was well
founded. There, then, it was, under these and other able masters, that
our Harvey drank in the elementary knowledge which served him as a
foundation for that induction which has made his name immortal; for
without detracting from the glory of Harvey, but merely in recognizing
the means to an end, we may admit that, but for the lessons of his
master, Fabricius, Harvey might have passed through life, not unnoticed,
indeed,--for such as Harvey was in himself, he must still have been
remarkable,--but his name unconnected with one of the most admirable and
useful inferences ever given to the world.

Having passed five years at Padua, Harvey, then in the twenty-fourth
year of his age (1602), finally obtained his diploma as doctor of
physic, with licence to practise and to teach arts and medicine in every
land and seat of learning. Having returned to England in the course of
the same year, and submitted to the requisite forms, he also received
his doctor’s degree from his original University of Cambridge; and then
coming to London, and taking to himself a wife in his six and twentieth
year, he entered on the practice of his profession.

History is all but silent in regard to the woman of our great
anatomist’s choice. We only know that she was the daughter of a
physician of the day, Dr. Lancelot Browne, and that Harvey’s union with
her proved childless. He himself mentions his wife incidentally as
having a remarkable pet parrot, which must also, if we may infer so much
from the pains he takes in specifying its various habits and
accomplishments, have been a particular favorite of his own.[8]

In 1604, Harvey joined the College of Physicians, his name appearing on
the roll of candidates for the fellowship in that year; and three years
afterwards, 1607, the term of his probation having passed, he was duly
admitted to the distinction to which he aspired.

We do not now lose sight of Harvey for any length of time: for a number
of years, in the beginning of his career, he was probably occupied, like
young physicians of the present day, among the poor in circumstance and
afflicted in body, taking vast pains without prospect of pecuniary
reward, but actuated by the ennobling sense of lightening the sum of
human misery, and carried away, uncaring personal respects, by that
ardent love of his profession which distinguishes every true votary of
the art medical. Harvey, however, had not only zeal, talents, and
accomplishments; he had, what was no less needful to success: powerful
friends, united brothers, with the will and the ability to help him
forward in the career he had chosen.

In the beginning of 1609, he made suit for the reversion of the office
of physician to St. Bartholomew’s Hospital, then held by Dr. Wilkinson,
and backing his suit by such powerful missives as the king’s letters
recommendatory to the governors of the house, and farther, producing
testimonials of competency from Dr. Adkinson, President of the College
of Physicians, and others, his petition was granted, and he was
regularly chosen physician in futuro of St. Bartholomew’s Hospital. Dr.
Wilkinson having died in the course of the year, Harvey was first
appointed to discharge the physician’s duties ad interim, and by and by
he was formally elected to the vacant office, 14th October, 1609.

In his new position Harvey must have found ample scope for acquiring
tact and readiness in the practical details of his profession; though
St. Bartholomew’s Hospital in his day appears to have borne a nearer
resemblance to the dispensary of these times than to the hospital as we
now understand the term. Harvey was now in his thirty-second year, and,
brought before the public at so suitable an age, in an office of such
responsibility, he must soon have risen into eminence as a physician
and come into practice. Harvey, indeed, appears subsequently to have
been physician to many of the most distinguished men of his age, among
others to the Lord Chancellor Bacon, to Thomas Howard, Earl of Arundel,

In the year 1615, Harvey, then in the thirty-seventh year of his age,
was happily chosen to deliver the lectures on anatomy and surgery at the
College of Physicians, founded by Dr. Richard Caldwal, and it is
generally allowed that in the very first course he gave, which commenced
in the month of April of the following year, he presented a detailed
exposition of the views concerning the circulation of the blood, which
have made his name immortal. Long years had indeed been labouring at the
birth which then first saw the light; civilized Europe, ancient and
modern, had been slowly contributing and accumulating materials for its
production; Harvey at length appeared, and the idea took fashion in his
mind and emerged complete, like Pallas, perfect from the brain of Jove.

The circulation, it would seem, continued to form one of the subjects in
the lectures on anatomy, which Harvey went on delivering for many years
afterwards at the College of Physicians; but it was not till 1628 that
he gave his views to the world at large in his celebrated treatise on
the ‘Motion of the Heart and Blood,’[9] having already, as he tells us
in his preface, for nine years and more, gone on demonstrating the
subject before his learned auditory, illustrating it by new and
additional arguments, and freeing it from the objections raised by the
skilful among anatomists.

Some few years after his appointment as their lecturer by the College of
Physicians, Harvey must have been chosen one of the physicians
extraordinary to the reigning sovereign, James I. The fame of Harvey’s
new views of the motions of the heart and blood could not but speedily
have reached the wide-open ears of King James, and this of itself, to
lay no stress on the powerful city interest of the illustrious
anatomist, might suffice to ensure him such a mark of distinction as
that just named. Of the precise date of his appointment as physician
extraordinary to the king we are not informed; but in the letter of
James bearing date the 3d of February, 1623, it is spoken of as a thing
foregone--that had taken place some time ago; for in this letter Doctor
Harvey is charged in common with the physicians in ordinary, with the
care of the king’s health; and he is further guaranteed the reversion of
the office of ordinary physician whenever, by death or otherwise, a
vacancy should occur. To the promised dignity, however, Harvey did not
attain for several years, not till after the demise of James, and when
Charles had already occupied the throne of his father for some five or
six years.

Harvey may now be said to have become rather closely connected with the
court; but whether this connexion proved truly advantageous to him as a
philosopher and physiologist may fairly be questioned. The time and
service which the court physician must necessarily give to royalty and
greatness interfere materially with the leisure and privacy that are
indispensable to study and meditation. But Harvey, who appears to have
been a man of singular self-possession, not to be diverted from his
purpose by trifling or merely ceremonial considerations, always speaks
of his master Charles in terms of unfeigned love and respect; and
everything induces us to believe that Charles in turn loved and honoured
his physician. The sovereign seems even to have taken a remarkable
interest in the inquiries of the physiologist; to have had several
exhibitions prepared of the punctum saliens in the embryo chick and
deer, and to have witnessed the dissections of many of the does which he
so liberally placed at Harvey’s disposal whilst the anatomist was
prosecuting his inquiries into the subject of generation. Whatever the
defects in Charles’s public and political character, he must always be
admitted to have been a man of elegant tastes, and of amiable temper and
refined manners in private. It was certainly worthy of the Prince who
appreciated, whilst he commanded, the talents of a Vandyke and a Rubens,
that he also prized and encouraged the less brilliant, but not less
useful genius of a Harvey.

Harvey, as a physician, must now have been at the zenith of his
reputation; he was physician in ordinary to the king, and we have seen
him in the same position towards some of the foremost men of the age.
His general practice, too, must have been extensive, and, if we look at
the sum he is stated to have left behind him in money, his emoluments
large. But he had not any lengthened harvest for all his early pains;
his connexion with the court by and by came in the way of his continuing
to improve his position; and then, grievous to relate, the appearance of
the admirable Exercises on the Heart and Blood gave a decided and severe
check to his professional prosperity. John Aubrey tells us he had “heard
him (Harvey) say, that after his book on the ‘Circulation of the Blood’
came out, he fell mightily in his practice; ’twas believed by the vulgar
that he was crack-brained, and all the physitians were against him.”[10]
Writing many years afterwards, when the causes particularly indicated
above had conspired to make Harvey’s practice less, Aubrey informs us
further, that “though all his profession would allow him to be an
excellent anatomist, I never heard any that admired his therapeutique
way. I knew several practitioners in this town that would not have given
threepence for one of his bills (prescriptions), and [who said] that a
man could hardly tell by his bills what he did aim at.”[11] So has it
mostly been with those who have added to the sum of human knowledge!
The empiric under the title of the practical man, in his unsuspecting
ignorance, sets himself up and is admitted as arbiter wherever there is
difficulty: blind himself, he leads the blinded multitude the way he
lists. He who laid the foundation of modern medical science lost his
practice for his pains, and the routineer, with an appropriate salve for
every sore, a pill and potion for each particular ache and ail, would
not give threepence for one of his prescriptions! did not admire his
therapeutique way!! and could not tell what he did aim at!!! Ignorance
and presumption have never hesitated to rend the veil that science and
modesty, all in supplying the means, have still owned their inability to
raise. If Harvey faltered, who of his contemporaries could rightfully
presume to walk secure? And yet did each and all of them, unconscious of
the darkness, tread their twilight paths assuredly; whilst he, the
divinity among them, with his eyes unsealed, felt little certain of his
way. So has it still been with medicine; and the world must make many a
lusty onward stride in knowledge before it can be otherwise.

The first interruption to his ordinary professional pursuits and
avocations which Harvey seems to have suffered through his connexion
with the court, occurred in the beginning of 1630, when he was engaged
“to accompany the young Duke of Lenox in his travels beyond seas.” In
anticipation of a removal from London, apparently, Harvey had already,
in December 1629, resigned his office of treasurer to the College of
Physicians, which he seems to have filled for several years.

Of the course of Harvey’s travels with the Duke of Lenox we have not
been able to gain any information. Their way probably led them to the
Continent, and it may have been on this occasion and in this company
that he visited Venice, as we know from himself that he did in the
course of one of his journeys. Harvey must have been in England again in
1632 and 1633; for in the former year he was formally chosen physician
to Charles, and in the latter we find his absence, “by reason of his
attendance on the king’s majesty,” from St. Bartholomew’s Hospital
complained of by the surgeons of that institution, and Dr. Andrews
appointed by the governors as his substitute, but “without prejudice to
him in his yearly fee or in any other respect.”[12] Such considerate
treatment satisfies us of the esteem in which Harvey was held.

In the early part of 1633 Charles determined to visit his ancient
kingdom of Scotland, for the ostensible purpose of being crowned King of
Scots. Upon this occasion Harvey accompanied him, as matter of course,
we may presume. But the absence of the court from London was not of long
duration; and in the early autumn of the same year we are pleased to
find Harvey again at his post in St. Bartholomew’s Hospital, engaged in
his own province and propounding divers rules and regulations for the
better government of the house and its officers,[13] which of themselves
give us an excellent insight into the state of the hospital, as well as
of the relative positions of the several departments of the healing art
two centuries ago. The doctor’s treatment of the poor chirurgeons in
these rules is sufficiently despotic it must be admitted; but the
chirurgeons in their acquiescence showed that they merited no better
handling. The only point on which they proved restive, indeed, was the
revealment of their SECRETS to the physician; a great outrage in days
when every man had his secrets, and felt fully justified in keeping them
to himself. But surgery in the year 1633 had not shown any good title to
an independent existence. The surgeon of those days was but the hand or
instrument of the physician; the dignitary mostly applied to his famulus
when he required a wen removed, or a limb lopped, or a broken head
plastered; though Harvey it seems did not feel himself degraded by
taking up the knife or practising midwifery.[14] Nevertheless, in these
latter days Royal Colleges of Physicians have been seen arrogating
superiority over Royal Colleges of Surgeons, and Royal Colleges both of
Physicians and Surgeons combining to keep the practitioner of obstetrics

From the year 1633 Harvey appears to have devoted much of his time to
attendance upon the king and retainers of the court, so that we have
little or no particular information of his movements for several years.
We know, however, from Aubrey, that he accompanied Thomas Howard, Earl
of Arundel, whose physician he was, in his extraordinary embassy to the
emperor, in the year 1636.[15] In the course of this journey, Harvey had
an opportunity of visiting several of the principal cities of Germany,
and of making the acquaintance of many of the leading medical men of the
time. The place of date of one of Harvey’s letters, that namely to
Caspar Hofmann, from Nuremberg, in the month of May, 1636, has not been
noticed; but his presence with the Earl of Arundel at once accounts for
it; and we therefore see that Harvey’s offer to demonstrate to the
distinguished professor of Nuremberg, the anatomical particulars which
made the circulation of the blood a necessary conclusion was no vain
boast, made at a distance, but a substantial proposition in presence of
his opponent, and which there is tradition at least to assure us he was
called upon to fulfil.--Harvey is reported to have made a public
demonstration of his anatomical views at Nuremberg, satisfactory to all
present save Caspar Hofmann himself; to whom, as he still continued to
urge objections, the futile nature of which we in these days can readily
understand, Harvey is further related to have deigned no other answer
than by laying down the scalpel and retiring, conduct which we find in
entire conformity with our estimate of the character of the man.[16]

On his return to England, in the winter of 1636, Harvey must have
resumed his place near the person of the sovereign, and by and by, as in
duty bound, accompanied him on his first hostile expedition into
Scotland in 1639, when matters were happily accommodated between the
King and his Scottish subjects, whom he had driven to take up arms so
righteously in defence of their religious liberties. Harvey, as
physician to the person, may be further presumed to have been with
Charles when he marched towards the Border the following year, so
memorable in the annals of English history, when the war with the Scots
was renewed, when the king’s authority received the first check at the
battle of Newbury, and when Charles, returning to his capital after his
defeat, encountered the still more formidable opposition of the English

Harvey may now be said to have become fairly involved with the Court.
From the total absence of his name in the transactions of the times, it
is nevertheless interesting to observe how completely he kept himself
aloof from all the intrigues and dealings of the party with which he
was connected. He must have held himself exclusively to the discharge of
his professional duties. In the course of these he doubtless attended
Charles in his third visit to Scotland in the summer of 1641, when he
essayed the arts of diplomacy with little better effect than he had
already attempted the weight of prerogative in the first, and the force
of arms in the second visit.

On returning to London in the autumn of the same year, Charles soon
brought matters to a crisis between himself and his English subjects, in
the persons of their representatives, and nothing soon remained for him
but to unfurl his standard and proclaim himself at war with his people.
This was accordingly done in the course of the ensuing summer. But the
Parliament did not yet abandon a seeming care of the royal person, and
Harvey informs us himself, that he now attended the king, not only with
the consent, but by the desire, of the parliament. The battle of
Edge-hill, which followed, and in which the sun of fortune shone with a
partial and fitful gleam upon the royal arms, is especially interesting
to us from our Harvey having been present, though he still took no part
in the affair, and seems indeed to have felt very little solicitude
either about its progress or its issue, if the account of Aubrey may be
credited. “When King Charles,” says Aubrey, “by reason of the tumults,
left London, he (Harvey) attended him, and was at the fight of Edge-hill
with him; and during the fight the Prince and Duke of York were
committed to his care. He told me that he withdrew with them under a
hedge, and tooke out of his pockett a booke and read. But he had not
read very long before a bullet of a great gun grazed on the ground neare
him, which made him remove his station.”[17] The act of reading a book
pending an important battle, the result of which was greatly to
influence his master’s fortunes, certainly shows a wonderful degree of
coolness and a remarkable indifference to everything like military
matters. Harvey’s own candid character, and the confidence so obviously
reposed in him when he was intrusted with the care of the Prince and the
Duke of York, forbid us to interpret the behaviour into any lukewarmness
or indifference as to the issue; but Harvey, throughout his whole
career, was a most peaceful man: he never had the least taste for
literary controversy, and can scarcely be said to have replied to any of
those who opposed his views; and in his indifference about the fight of
Edge-hill he only further shows us that he was not

    “Of those who build their faith upon
     The holy text of pike and gun,
     And prove their doctrine orthodox
     By apostolic blows and knocks.”

With his fine understanding and freedom from party and sectarian views
of every kind, he probably saw that an appeal to arms was not the way
for political right to be elicited, or for a sovereign to settle matters
with his subjects. Harvey had certainly no turn for politics,[18] and
when we refer to Aubrey we find that the fight of Edge-hill was hardly
ended before our anatomist had crept back into his shell, and become
absorbed in the subjects that formed the proper business of his life. “I
first saw him (Harvey) at Oxford, 1642, after Edge-hill fight,” says our
authority, “but was then too young to be acquainted with so great a
doctor. I remember he came several times to our college (Trin.) to
George Bathurst, B.D., who had a hen to hatch eggs in his chamber, which
they opened dayly to see the progress and way of generation.” The
zealous political partisan would have found no leisure for researches
like these in such stirring times as marked the outbreak of the civil
war in England; the politician had then other than pullets’ eggs to

The king’s physician, not to speak of the author of a new doctrine of
the motions of the heart and blood, was sure to find favour in the eyes
of the high church dignitaries of Oxford; and we accordingly find that,
besides being everywhere handsomely received and entertained, Harvey had
the honorary degree of Doctor of Physic conferred on him. Oxford,
indeed, when the king and court were driven from the metropolis, which
was now wholly in the hands of the popular party, became the
head-quarters of the royal army and principal residence of the king for
several years. And here Harvey seems to have quietly settled himself
down and again turned his attention to his favorite subjects. Nor was
the honorary distinction of doctor of physic from the university, which
has been mentioned, the only mark of favour he received. Sir Nathaniel
Brent, Warden of Merton College, yielding to his natural bias, forsook
Oxford when it was garrisoned by the king, and began to take a somewhat
active part in the proceedings of the popular party; he came forward in
especial as a witness against Archbishop Laud, on the trial of that
dignitary. Merton College being thus left without a head, upon the
suggestion, as it is said, of the learned antiquary and mathematician,
John Greaves, and in virtue of a letter of the king, Harvey was elected
warden some time in the course of 1645. This appointment was doubtless
merited by Harvey for his constant and faithful service to Charles; but
it may also have been bestowed in some measure as a retort upon the
Parliament, which, the year before, had entertained a motion for the
supercession of Harvey in his office of physician to St. Bartholomew’s
Hospital.[19] Harvey, however, did not long enjoy his new office or its
emoluments; for Oxford having surrendered to the Parliamentary forces
under Fairfax the following year, Harvey, of course, resigned his
charge, and immediately afterwards betook himself to London. Sir
Nathaniel Brent, on the contrary, returned to Oxford; and the star of
the Parliamentarians being now in the ascendant, Merton College was not
slow to reinstate its old Presbyterian warden in the room of its late
royalist head.[20]

From the date of the surrender of Oxford (July, 1646), Harvey followed
the fortunes of Charles no longer. Of his reasons for quitting the
service of his old master we know nothing. He probably felt anxious for
repose; at sixty-eight, which was Harvey’s age, a man begins to find
that an easy chair is a fitter resting-place than the bare ground, a
ceiled roof more suitable covering than the open sky--prospects which a
continuance of the strife held out. Harvey, besides, as we have seen,
had no stomach for contention in any shape or form, not even in the
literary arena; and he now probably resolved himself to follow the
advice he had once given to his young friend Charles Scarborough, “to
leave off gunning,”[21] and dedicate himself wholly to more congenial
pursuits. And then Charles had long made it apparent, even to the most
ardent of his adherents, that no faith was to be put in his promise, no
trust to be reposed in his royal word. The wise old man, verging on the
age of threescore years and ten, doubtless saw that it was better for
him to retire from a responsible office, now become most irksome and
thankless, and seek privacy and leisure for the remainder of his days.
These Harvey found awaiting him in the houses of his affectionate
brothers--now in the house of Eliab, in the City, or at Roehampton, and
then in the house of Daniel, in the ‘suburban’ village of Lambeth, or at
Combe near Croydon in Surrey, in each of which Harvey had his own
apartments. The Harveys appear to have been united from first to last in
the closest bonds of brotherly love,[22] and to have had a common
interest in many of their undertakings; and Eliab, as we shall see,
employed the small capital, which his brother William must have
accumulated before the civil wars broke out, to such purpose, that the
doctor actually died a rich man. With his brothers, then, retreating now
to the “leads” of the house in the heart of the metropolis, now to the
“caves” of the one at Combe, did Harvey continue to pass his days--but
not in idleness; for the work on Generation, with the subject of which
we saw him busied at Oxford several years before, must have found him in
ample occupation. Nor was the love of ease so great in William Harvey,
even at the advanced age of seventy-one, if we may credit some of the
accounts, as to hinder him from again visiting the Continent, and making
his way as far as Italy, a journey in which it is said he was attended
by his friend the accomplished scholar and gentleman, Dr. Ent.[23]

In the beginning of 1651 appeared the second of Harvey’s great works,
that, namely, On Animal Generation.[24] In this publication we have
abundant proof of our author’s unabated industry and devotion to
physiological science; and in the long and admirable letter to P. M.
Slegel, of Hamburg, written shortly after the appearance of the work, we
have pleasing evidence of the integrity of Harvey’s faculties at the
advanced age of seventy-three.

The year after the publication of the work on Generation, i. e. 1652,
when Harvey was looked up to by common consent as the most distinguished
anatomist and physician of his age, the College of Physicians came to
the resolution of placing his statue in their hall then occupying a site
at Amen-corner; and measures being immediately taken in conformity with
this purpose, it was carried into effect by the end of the year, when
the statue, with the following complimentary inscription on the
pedestal, was displayed:

        Viro monumentis suis immortali
Hoc insuper Collegium Medicorum Londinense
          Qui enim Sanguini motum
                  ut et
          Animalibus ortum dedit,
                Meruit esse
            Stator Perpetuus.[25]

Harvey, in acknowledgment, it may have been, of the distinguished honour
done him by his friends and colleagues, appears about this time to have
commenced the erection at his own cost of a handsome addition to the
College of Physicians. It was, as Aubrey informs us, “a noble building
of Roman architecture (of rustic work, with Corinthian pilasters),
comprising a great parlour, a kind of convocation house for the fellows
to meet in below, and a library above. On the outside, on the frieze, in
letters three inches long, was this inscription: Suasu et cura Fran.
Prujeani, Præsidis, et Edmundi Smith, elect. inchoata et perfecta est
hæc fabrica, An. MDCLIII.”[26] Nor was Harvey content merely to erect
this building; he, further, furnished the library with books, and the
museum with numerous objects of curiosity and a variety of surgical
instruments. On the ceremony of this handsome addition to the College of
Physicians being opened, which took place on the 2d of February, 1653, a
sumptuous entertainment was provided at Harvey’s expense, at which he
received the president and fellows, and made over to them, on the spot,
his whole interest in the structure.

Dr. Prujean, the president of the college, going out of office, as
usual, at Michaelmas the next year (1654), Harvey was unanimously chosen
to fill the vacant chair. Having been absent when the election took
place, a deputation proceeded to his apartments to apprize him of the
honour his colleagues had done themselves and him, and to say that they
awaited his answer on the following day. Every act of Harvey’s public
life that has come down to us is marked not merely by propriety but by
grace. He attended the comitia or assembly of the college next day;
thanked his colleagues for the distinguished honour of which they had
thought him worthy--the honour, as he said, of filling the foremost
place among the physicians of England; but the concerns of the college,
he proceeded, were too weighty to be intrusted to one like him, laden
with years and infirm in health; and if he might be acquitted of
arrogance in presuming to give advice in such circumstances, he would
say that the college could not do better than reinstate in the authority
which he had but just laid down, their late president, Dr. Prujean,
under whose prudent management and fostering care the affairs of the
college had greatly prospered. This noble counsel had fitting response:
Harvey’s advice being adopted by general consent, Dr. Prujean was
forthwith re-elected president.

The College of Physicians were justly proud of their great associate,
and Harvey, in his turn, was undoubtedly attached to the college. Here,
indeed, as their lecturer on anatomy and surgery, he had first
propounded the views which had won him such distinguished credit in his
life, and which have left his name as a deathless word on the lips of
men; here he consorted with his nearest and dearest friends, receiving
from all those remarks of respectful consideration that were so justly
his due; and here, in fine, the first place among the first men of his
profession had been tendered to him, and gracefully declined. To a mind
like Harvey’s, and with the opportunity afforded him of making so
graceful a concession, the foremost place was certainly a higher
distinction unaccepted, than it had been enjoyed.--The excuse for
declining the office of president was not merely personal: it was not
alone that he was an old man, infirm in health, and incompetent for so
great a trust; but, the affairs of the college had greatly thriven under
the prudent management and constant care of the late president, and it
was no more than right that he who had but just laid down should be
re-established in authority.

Harvey, we have said, was childless; his wife, though we have not the
date of her death, he had certainly lost by this time. His only
surviving brother Eliab was rich; his nephews were prosperous merchants
and on the road to the independence and titles which several of them
afterwards achieved: he, therefore, determined to make the College of
Physicians not only heirs to his paternal estate, worth, at that time,
56_l._ per annum, but to bestow it on them in free gift during his life.
This purpose he carried into effect by means of a formal instrument,
which he delivered to the college in the month of July, 1656; the
special provisions in the deed settling one sum, by way of salary for
the librarian, and another sum, for the delivery of a solemn oration
annually, in commemoration of those who had approved themselves
benefactors to the college, and, by extension, who had added aught to
the sum of medical science in the course of the bygone year.[27]

Having thus accompanied Harvey over so much of the way in his mortal
career, let us, before proceeding further, briefly advert to his
WRITINGS, to the influence they had in the republic of letters during
his life-time, to the fruits they have since produced, and to the
impression still made on the mind that holds communion through their
means with the mind that dictated them so many years ago.--The
intellectual endowment of a man necessarily appears in his writings; it
is not always from them that so true a conception of his moral character
can be formed. Harvey, however, though in his long life he accomplished
but a small fraction of all his literary designs, has still left us
sufficient from which to form an estimate of him as a philosopher, as a
physiologist, and it may also be said as a man. Let us take a brief
survey of his writings, then, and wind up our account of his life with
such personal notices as we can gather from contemporaries, or as we can
infer from his own conduct and written word.


Harvey’s great work, though by no means the largest in bulk, is the one
on the Motions of the Heart and Blood. It has been said, happily, by a
recent critical writer, that “men were already practising what Bacon
came to inculcate,” viz. induction upon data carefully collected and
considered; and it would not be easy to adduce a more striking example
of the way in which ultimate rational truth is arrived at by a
succession of inferences than is contained in Harvey’s Essay on the
Heart and Blood. Had Bacon written his Novum Organum from Harvey’s work
as a text, he would scarcely have expressed himself otherwise than as he
has done, or given different rules for philosophizing than those which
he has laid down in his celebrated treatise.[28]

In his introduction, and by way of clearing the ground, Harvey exposes
the views of preceding physiologists, ancient and modern, in regard to
the motions of the heart, lungs, and blood, to the state of the
arteries, &c.--in short, he gives the accredited physiology of the
thoracic viscera, with comments, which prove it a mass of unintelligible
and irreconcilable confusion. There is room, therefore, for another
interpretation, consonant with reason and with anatomical fact, and
susceptible of demonstration by the senses. When he first essayed
himself to comprehend the motions of the heart, and to make out the uses
of the organ from the dissection of living animals, he found the subject
so beset with difficulties that he was almost inclined at one time to
say with Fracastorius, that these motions and their purpose could be
comprehended by God alone. By degrees, however, by repeating his
observations, using greater care, and giving more concentrated
attention, he at last discovers a way out of the labyrinth, and a means
of explaining simply all that had previously appeared so obscure. Hence
the occasion of his writing. Such is the burthen of the proem and first
chapter. With Harvey’s admirable work now put in an accessible shape
into his hands, we should (did we proceed with an analysis) but
anticipate the intelligent reader in the great pleasure he will have in
following the author through the different steps of his argument until
the conclusion is reached, and the inference presents itself as
inevitable, namely, that the blood must circle round and round in one
determinate course, in the body as in the lungs, incessantly. For
Harvey, it must be here observed, left the doctrine of the circulation
as an inference or induction only, not as a sensible demonstration. He
adduced certain circumstances, and quoted various anatomical facts which
made a continuous transit of the blood from the arteries into the veins,
from the veins into the arteries, a necessary consequence; but he never
saw this transit; his idea of the way in which it was accomplished was
even defective; he had no notion of the one order of sanguiferous
vessels ending by uninterrupted continuity, or by an intermediate
vascular network, in the other order. This was the demonstration of a
later day, and of one who first saw the light in the course of the very
year when Harvey’s work on the Heart was published.[29]

The appearance of Harvey’s book on the Motion of the Heart and Blood
seems almost immediately to have attracted the attention of all the
better intellects among the medical men of Europe. The subject was not
one, indeed, greatly calculated to interest the mass of mere
practitioners; had it been a book of receipts it would have had a better
chance with them; but the anatomists and physiologists and scientific
physicians would seem at once to have taken it up and canvassed its
merits. The conclusions come to in the work, there can be no question,
took the medical world by surprise; it was not prepared for such a
proposition as a ceaseless circular movement of the blood, with the
heart for the propelling organ; for the latter point, be it understood,
was even as great a novelty as the former.

Coming unexpectedly, and differing so widely from the ancient and
accepted notions, we cannot wonder that Harvey’s views were at first
rejected almost universally. The older intellects, in possession of the
seats and places of authority, regarded them as idle dreams; and upon
the faith of this conclusion, their author was set down and treated by
the vulgar as a crackbrained innovator. Two years, however, elapsed
before aught in contravention of the new doctrines saw the light, and
this came at length not from any of the more mature anatomists of
Europe--their minds were made up, the thing was absurd--but from a young
physician, of the name of Primerose, of Scottish descent, but French by
birth. Primerose had been a pupil of Joannes Riolanus, professor of
anatomy in the University of Paris; he had doubtless listened to his
master’s demonstration of the absurdity of the Harveian doctrine of the
circulation, and by and by he set himself down, by way apparently of
exercising his ingenuity, to try the question, not by fact and
experiment, but by the precepts he had imbibed from his teacher and the
texts of the ancients. The essay of Primerose[30] may be regarded as a
defence of the physiological ideas of Galen against the innovations of
Harvey. It is remarkable for any characteristic rather than that of a
candid spirit in pursuit of truth; it abounds in obstinate denials, and
sometimes in what may be termed dishonest perversions of simple matters
of fact, and in its whole course appeals not once to experiment as a
means of investigation.--Harvey, having already, and in the very outset
of his work, demonstrated the notions untenable which it was Primerose’s
purpose to reassert and defend, of course deigned him no reply; he could
never dream of going over the barren ground he had already trodden, in
the hope of convincing such an antagonist.

Æmylius Parisanus, a physician of Venice, was the next to assail the
Harveian doctrine of the circulation,[31] and still with the old
instruments,--the authority of Galen and the ancients generally.
Parisanus perceived Harvey’s views as directly contravening an
hypothesis to which he had formerly committed himself, namely, that the
spleen was the organ of sanguification and the furnisher of nutriment to
the heart; on this ground may Parisanus have been led to enter the lists
against the new opinions. But he proved a most flimsy antagonist.
Ignorant of some of the commonest points of anatomy, and frequently
misinterpreting the writer he combats, writing himself in a style the
most elaborately involved, and consequently obscure, it is frequently
difficult even to guess at his meaning. Like his countryman of the poet,
Signor Gratiano, he

     “Speaks an infinite deal of nothing; more than any man in all
     Venice: his reasons are two grains of wheat hid in two bushels of
     chaff; you shall seek all day ere you find them; and when you have
     them they are not worth the search.”

Had not Dr. Ent, in his Apology for the Circulation, given the name a
place on his title-page, Parisanus’s opposition would scarcely have
merited mention here.

Nearly at the same time with Parisanus, Caspar Hofmann, the learned and
laborious professor of Nuremberg, attracted particular attention, both
in his teaching and his writings, as the opponent of the Harveian
doctrine. The opposition here is the more remarkable from Hofmann’s
having shaken himself wholly free from the authority of Galen, and, as
Slegel says, even admitted the lesser circulation of the blood through
the lungs; but this must have been at a later period of his life, for in
his works, up to Harvey’s time, the idea he had of the motion of the
blood may be gathered from his likening it to a lake or sea agitated by
the wind, the veins being the conduits of the nutrient blood, the
arteries of the vital spirits. Hofmann was an adversary whom Harvey held
worthy of notice; and accordingly we have seen that our immortal
countryman took advantage of the opportunity, whilst attending the Earl
of Arundel and his party, to visit Hofmann at Nuremberg, and make a
demonstration of the new views before him. Unhappily this was done in
vain, for Hofmann continued unconvinced, though, towards the end of his
very long life, he did show some signs of yielding.[32]

Joannes Veslingius, professor in the University of Padua, and one of the
best anatomists of the age, about this time, addressed two letters to
Harvey, in which he politely but candidly states his objections to the
new doctrine. One great difficulty with Veslingius was the remarkable
difference between the colour of the arterial and the venous blood. It
did not seem possible to him that the fluid, which was of a bright
scarlet in the arteries, could be the same as the dark-coloured fluid
which is found in the veins. In the course of his letter, Veslingius
takes occasion to animadvert on the uncivil tone and indifferent style
of the productions of Primerose and Parisanus.[33]

But the theory of the double circulation was not now to meet with
opposition only; the comprehensive intellect that had seized and worked
that theorem to a rational demonstration was no longer to be left alone
against the world in its defence. Roger Drake, a young Englishman, had
the honour of appearing in his inaugural dissertation, proposed under
the auspices of Joannes Walæus, the distinguished professor of Leyden,
in 1639, as the enlightened advocate of the Harveian views; and in the
course of the same year, H. Regius (Leroy) also came forward at Utrecht
with certain Theses favorable to the doctrine of the circulation. Ten
years had not lessened Primerose’s enmity to Harvey and his views; for,
on the appearance of these academical essays, he speedily showed himself
again in the field as their opponent, publishing distinct
animadversions upon each of the inaugural dissertations in the course
of the year.[34] Regius (Leroy), a man of much less mind and information
than Drake, if we may decide from their works, was, in turn, not slow to
encounter Primerose;[35] and the spirit in which he did so, as well as
the temper and taste of the reply which Primerose, true to his
controversial nature, very soon produced,[36] may, to a certain extent,
be imagined from the titles of their several productions, which are
given below.

Still more illustrious advocates of the Harveian circulation presented
themselves in Werner Rolfink,[37] professor of anatomy at Jena, and the
celebrated Renatus Descartes. Rolfink, from his position and his
popularity as a teacher, had immense influence in disseminating the new
doctrine over Europe; and Descartes, under the ægis of his powerful
name, was no less effective by means of his writings.[38] Opposed in his
advocacy of the Harveian views by Vopiscus Fortunatus Plempius,
professor of Louvain, Descartes made himself still more thoroughly
master of the subject, and when he next appears as its advocate, which
he does by and by, he even appeals to the experiments he had made on
living animals in support of his convictions and conclusions.

The controversy on the circulation had been carried on up to this time
abroad rather than at home; Harvey seems to have won over to his side
all the men of his own country who, by their education and acquirements,
might have been fitted to array themselves against him: his lectures at
the College of Physicians had apparently satisfied all his
contemporaries. But now one of Harvey’s own countrymen made his
appearance as the vindicator of the circulation from the
misrepresentations and misapprehensions of its adversaries. This was Dr.
afterwards Sir George Ent, a good scholar, a respectable anatomist,
conversant with physical science generally, a gentleman by his position
and profession, acquainted with all the leading men of letters and
science of his time, and in particular, enjoying the friendship of
William Harvey. Ent’s work is entitled ‘An Apology for the Circulation
of the Blood, with a Reply to Æmylius Parisanus.’[39] In his letter to
Harvey, which stands in front of the work, Ent lets it appear that he
was anxious to come before the world as the advocate of the circulation;
he first thought of making Primerose the particular object of his
animadversions, but as this opponent had already been very effectually
handled by Henry Leroy, he preferred taking Parisanus to task, the
rather as in dealing with him he could also controvert Primerose where
it was necessary.--Ent’s Apology is, undoubtedly, a learned, though
perhaps a somewhat pompous and pedantic book; still the writer
occasionally shows both wit and fancy in handling his antagonist, and
always learning enough in dealing with his subject. “Nothing, indeed,”
to quote Dr. Lawrence,[40] “can be more unlike than Parisanus and Ent;
and it is not wonderful, therefore, that one utterly ignorant of
physical science confronted by one thoroughly conversant therein--that
one, without power of utterance, opposed by one gifted with
eloquence--that one, sluggish and inert, in the hands of one active and
full of energy, should be effectually vanquished and overcome.” We may
imagine, nay, we may be certain, that Harvey was not unacquainted with
Ent’s purpose to appear as the advocate of his discovery, nor with the
Apology before it saw the light.

Having observed the appearance of certain academical dissertations in
defence of the circulation, we perceive the apostles of all new truths,
namely, the youthful, at work. Were there not successive generations of
men, the world would stand still; the death of the individual was not
merely a necessary condition to the enjoyment of life by successive
generations, but essential also to the onward progress of mankind. No
man who had attained to the age of 40 years, it is said, was found to
adopt the doctrine of the circulation; it had to win its way under the
safeguard of the Drakes and Leroys especially, that is to say, of the
youthful and unprejudiced spirits of the age.

Twenty years after the publication of the ‘Exercitatio de Motu Cordis et
Sanguinis,’ Joannes Riolanus, the younger, was delivered of his
‘Encheiridium Anatomicum’ (8vo. Lugd. Batav. 1648), in which he makes a
vain attempt to supplant the Harveian doctrine by a new and most
extraordinary one of his own, so incongruous and unlikely, that in these
days we are irresistibly led to form no very high estimate of the
intellect that could have engendered it. It looks to us, indeed, at this
time, like condescension on the part of the great English anatomist,
that he noticed the abortion of such a tyro in animal physics as the
French professor here approves himself. Harvey’s genius could surely
have felt no real respect for the illogical intellect of Riolan. But
Harvey, when he noticed Riolan’s publication, was in want of a good
occasion for a farther development of his own views; and so he seized on
the Parisian professor, respectable from his position in the university,
and as physician to the queen mother of France, and made him his
vehicle--his placard bearer. Harvey, besides, was personally acquainted
with Riolan, who had accompanied Mary de Medicis to England on a visit
to her daughter the Queen of Charles the First; on which occasion Harvey
and Riolan had even held conversations on the subject of the
circulation, to which it is said that Riolan when face to face with the
propounder, made no objection.

Riolan is by no means totally opposed to a circulation of the blood; he
would only limit it to certain arbitrary regions, into which he divides
the body: whilst it goes forward in one, it has no existence in another.
The nature of his ideas can be gathered from Harvey’s comments on them
in his First Disquisition, addressed to the Coryphæus of Anatomists, as
he politely designates the Parisian professor.

Having disposed of the original notions of the author of the
‘Encheiridium Anatomicum,’ in this first disquisition, Harvey, in his
second, returns to his own views, which he proceeds still further to
illustrate and confirm by additional arguments, observations, and
experiments. In this admirable essay, we obtain innumerable glimpses of
the clearness of Harvey’s judgment, of his admirable powers of
observation, and the diligent and excellent use he made of them; we at
the same time become aware of the great loss we have sustained through
the destruction of his Medical Observations. Riolan, in his
Encheiridium, proposed to point out in the structure of the healthy body
the seats of the various diseases, and to discuss their nature in
conformity with the opinions that had been entertained of them. This was
obviously at once a barren and an impracticable route: the matters he
had in hand could never have been other than abstractions, and his own
observations criticisms on opinions, never on facts. How much more
natural and judicious the course which Harvey proposes to himself, when
he informs us that in his ‘Medical Anatomy’ he meant, “from the many
dissections he had made of the bodies of persons worn out by serious and
strange affections, to relate how and in what way the internal organs
were changed in their situation, size, structure, figure, consistency,
and other sensible qualities, from their natural forms and appearances,
such as they are usually described by anatomists; and in what various
and remarkable ways they were affected. For even as the dissection of
healthy and well-constituted bodies contributes essentially to the
advancement of philosophy and sound physiology, so does the inspection
of diseased and cachectic subjects powerfully assist philosophical
pathology.” This was precisely what Morgagni lived, in some considerable
measure, to achieve, and it is that which it has been the business of
modern pathology, through the illustrious line of the Baillies,
Laennecs, Andrals, Louis, Cruveilhiers, Carswells, Richard Brights, and
many others, to render more and more complete.

Riolan never replied to Harvey; but neither did the Parisian Professor
attempt to vindicate his views, nor did he exhibit such candour as to
own himself otherwise convinced or converted. His doctrine had no
abettors, and never bore fruit; it stood a barren ear amidst the lusty,
green, and copious harvest, that had already sprung up and overspread
the lands.

Harvey must now, indeed, have seen his views assured of general
reception at no distant date. The same year in which he himself answered
Riolan, Dr. James de Back, of Amsterdam, published his work on the
Heart,[41] which is written entirely in harmony with the Harveian
doctrines, and the celebrated Lazarus Riverius, Professor of Medicine in
the University of Montpellier, publicly defended and taught the
circulation of the blood.[42] The following year, Paul Marquard Siegel,
of Hamburg, produced his commentary on the Motion of the Blood,[43] in
which he addresses himself particularly to a refutation of Riolanus,
whose scholar he had been, and at the same time shows himself so
thoroughly at home in the general question, that he is able to throw
additional light on it by new and ingenious considerations and

Harvey appears to have been pleased with Slegel’s production; for by and
by he sends the Hamburger his new work on Generation, accompanied by an
admirable letter, which has happily been preserved.[44] No one in
reading that remarkable epistle could suppose that the pen which set it
down was in the hand of a man in the 75th year of his age.

The young men of 1628 and 1630, who had been educated in unbelief of the
circulation, were now coming into possession of professorial chairs and
places of distinction; and having long escaped from leading-strings and
made inquiry for themselves, were beginning in many of the European
universities to proclaim the better faith through further knowledge that
had sprung up within them. Harvey had himself received the seeds of his
discovery in Italy; but the fructifying mother was slow to recognize him
whom she had so powerfully concurred to form. It was not till 1651 that
Harvey’s views were in any way admitted beyond the Alps, when Trullius,
a Roman professor, expounded and taught them. About the same time, John
Pecquet,[45] of Dieppe, and Thomas Bartholin, the Dane,[46] men of
original mind in the one case, of extensive learning and great research
in the other, gave in their adhesion to the new doctrine, and spread it
far and near by their writings. The victory for the circulation may
finally be said to have been won, when Plempius, of Louvain, the old
antagonist of Descartes on the subject, retracted all he had formerly
written against it, convinced of its truth, as he so candidly informs
us, by the very pains, he took to satisfy himself of its erroneousness,
and publicly proclaimed his conversion: “Primum mihi hoc inventum non
placuit,” says the worthy Plempius--“This discovery did not please me at
all at first, as I publicly testified both by word of mouth and in my
writings; but by and by, when I gave myself up with firmer purpose to
refute and expose it, lo! I refute and expose myself, so convincing, not
to say merely persuasive, are the arguments of the author: I examine the
whole thing anew and with greater care, and having at length made the
dissection of a few live dogs, I find that all his statements are most

From the first promulgation of the doctrine of the circulation, its
progress towards ultimate general acknowledgment can scarcely be said
for a moment to have been interrupted. The hostility of the Primeroses
and Parisanuses and Riolans never interfered with it in fact; the more
candid spirits were rather led to inquire, by the virulence of these
weak and inconsistent opponents, who thus hastened the catastrophe of
their own discomfiture, and the triumph of the truth. If men’s minds
were once in danger of being led astray, it was only for an instant, and
not so much through the opposition of enemies, as by an erroneous
generalization, which a short interval of time sufficed to correct.
Cæcilius Folius, a Venetian physician, having met with one of those
anomalous instances of pervious foramen ovale in an adult, immediately
and without looking farther, jumped to the conclusion that this
structure or arrangement was normal, and that the blood passed in all
cases by the route he had discovered, from the right to the left side of
the heart. Many Italians received with favour the account which Folius
immediately published of his discovery;[48] and the natural philosopher,
Gassendi, having about the same period had another instance of the kind
which Folius encountered, shown to him, concurred with this writer in
his views, and by a variety of arguments and objections, strove to
damage, and did temporarily damage, the Harveian doctrine.[49] But this
was only for a brief season; for Domenic de Marchettis[50] soon after
showed that Folius had mistaken an extremely rare occurrence for a
general fact, and that if the open foramen ovale might afford a passage
from the right to the left side of the heart in one case, closed it
would suffer no such transit in hundreds of other instances. Gassendi,
moreover, by getting still more out of his depth, soon afterwards showed
that familiarity with general physics did not imply a particular
knowledge of anatomy, nor give the power of reasoning sagely on subjects
of special physiology; so that in his eagerness to assail Harvey he did
injury in the end only to his own reputation. In short, Harvey in his
lifetime had the high satisfaction of witnessing his discovery generally
received, and inculcated as a canon in most of the medical schools of
Europe; he is, therefore, one of the few--his friend Thomas Hobbes says,
he was the only one within his knowledge--“Solus quod sciam,”[51] who
lived to see the new doctrine which he had promulgated victorious over
opposition, and established in public opinion. Harvey’s views, then,
were admitted; the circulation of the blood, through the action of the
heart, was received as an established fact; but envy and detraction now
began their miserable work. The fact was so; but it was none of Harvey’s
discovering; the fact was so, but it was of no great moment in itself,
and the merit of arriving at it was small; the way had been amply
prepared for such a conclusion.

Let us look as impartially as we may at each of these statements.

They who deny the originality of Harvey’s induction, very commonly
confound the idea of a Motion of the blood, with the idea of a
Continuous Motion in a Circle. It would seem that even from remote
antiquity, and by common consent, mankind had recognized the blood to be
in motion. We have this fact declared to us by all antiquity, and it is
even particularly referred to in various passages of the grand observer
of his age, the depositary of the popular science of all preceding
ages--Shakespeare. Brutus speaks thus to Portia:

    “You are my true and honourable wife;
     As dear to me as are the ruddy drops
     That visit my sad heart;”

language not more touching and beautiful than physiologically correct.
And again, with more of involution and ellipsis, yet with a meaning that
is unmistakable, Warwick, by the bedside of the murdered Gloster,

    “See how the blood is settled in his face!
   --Oft have I seen a timely-parted ghost,
      Of ashy semblance, meagre, pale and bloodless,
   --Being all descended to the labouring heart,
      Who in the conflict that he holds with death,
      Attracts the same for aidance gainst the enemy;
      Which with the heart there cools, and ne’er returneth
      To blush and beautify the cheek again--
   --But see, his face is black and full of blood,” &c.

These passages have actually been cited, to prove that Shakespeare was
not unacquainted with the circulation; and there have not been wanting
some[52] who have even argued that Shakespeare had his knowledge direct
from the fountain-head--from Harvey himself, with whom, for several
years at least, he was contemporaneous.[53]

The passages quoted above are referred to all the more willingly, from
their having preceded the teaching of Harvey by a few years only; but
Shakespeare probably referred to nothing more than the accredited
opinion that the blood was in motion within the vessels, particularly
the veins of the body. In ancient times, indeed, the veins were
regarded, as they are esteemed by the vulgar at the present hour, as the
principal vessels of the body; they only were once believed to contain
true blood; the arteries were held to contain at best but a little
blood, different from that of the veins, and mixed accidentally in some
sort with the vital spirits, of which they were the proper conduits.

In former times, farther,--times anterior to Harvey whether more
remotely or more nearly,--the liver, as the organ of the hæmapoësis, was
regarded as the source of all the veins, i. e. of all the proper
blood-vessels; the heart, as the generator of heat and the vital
spirits, was viewed as the mere cistern of the blood, whence it was
propelled by the act of inspiration, and whither it reverted during the
act of expiration, its flow to this part of the body or to that, being
mainly determined by certain excitations there inherent or specially set
up. By and by, however, the liver was given up as the origin of the
venous system generally; but such anatomists as Jacobus Sylvius, Realdus
Columbus, Bartholomæus Eustachius, and Gabriel Fallopius, may be found
opposing Vesalius in regard to the origin of the vena cava, and
asserting that it takes its rise from the liver, not from the heart, as
the great reformer in modern anatomy had maintained.

In the progress of anatomical investigation, the valves in the interior
of the heart, at the roots of the two great cardiac arterial trunks, and
in the course of the veins at large, were perceived and their probable
uses and actions canvassed. The general and prevalent notion was that
they served to break or moderate the force of the current in the
interior of the vessels or parts where they were encountered; though
Berengarius of Carpi,[54] in describing the cardiac valves, had already
said that the effect of the tricuspid valves, between the right auricle
and ventricle, must be to prevent the blood in the former cavity from
escaping into the latter; whilst the office of the semilunar valves, at
the origins of the pulmonic artery and aorta, he declared, from their
position, must be to prevent the entrance of the blood of the great
arterial trunks into the heart. Fabricius, the master of Harvey, may be
said to have perfected anatomical knowledge in regard to the valves of
the veins--for he by no means first directed attention to their
existence, or discovered them, as is generally asserted. Fabricius
believed that their function was to act as obstacles to congestions of
blood, as strengtheners of the veins and preventives to their becoming

Another long and much agitated point in the anatomy of the sanguiferous
system, was the state of the septum ventriculorum of the heart, in
respect of permeability or impermeability. The reason of the vast
importance attached to this point was connected with the ancient, and,
in Harvey’s time, generally accredited hypothesis of the Three
Spirits--the natural, the vital, and the animal. The hypothesis to be
brought into play, was presumed to require the intermixture in the heart
of the two kinds of blood that were held appropriate to the two
ventricles and to the arteries and veins respectively, and that were
farther believed to meet in the cavities of the cranium, thorax, and
abdomen, from which they returned to the heart by the way they came, for
a fresh supply of the spirits (now exhausted or enfeebled), under the
agency of which all the important operations of the body were believed
to be accomplished.

Now, Galen, the author of this hypothesis, in order to obtain an
admixture of the two kinds of blood, feigned and described the partition
between the two ventricles, either as perforated like a sieve, or as
filled with depressions of depth sufficient to entitle them to be viewed
as constituting a kind of third ventricle--the last assumption doubtless
to accommodate each order of spirits with its own particular officine or
workshop. With the revival of anatomical knowledge in modern Europe,
however, the partition of the ventricles was soon perceived not to be
porous or cribriform, but, as was first said, to be so nearly solid that
any filtration of blood through it was well nigh impossible
(Berengarius, 1521), and next, to be so completely solid that all
permeation of blood was impossible (Vesalius, 1555), and another means
must therefore be found for securing the necessary admixture of the two
kinds of blood in order to effect the engenderment of the natural,
animal, and vital spirits.

Such was the state of anatomical science and physiological belief on
this particular point when Michael Servetus came upon the stage, and
suggested the transit of the blood through the lungs from the right side
of the heart to the left, with a view of meeting the difficulty which
the undeniable solidity of the septum ventriculorum opposed to the
presumed necessary admixture of the two kinds of blood. Servetus’s idea,
consequently--if at the distance of three hundred years we may presume
to follow the mental process that led to the penning of the remarkable
and often-quoted passage which occurs in his works--appears to be
nothing more than a suggestion or proposition as a means of meeting a
difficulty; it is very much as though he had said: If you cannot go
straight through, you must even go round about. To so much and to no
more, do Servetus’s claims to be considered a discoverer, in the sense
we would attach to that word, amount. The passage from the ‘Restitutio
Christianismi’ of Servetus, 1553, if viewed from the point proposed,
will not fail to set his title to be regarded as the discoverer of the
lesser circulation in its true light--in a light under which it has not
yet been seen. We translate so much of the passage as bears on the
question under review. “The vital spirit has its origin in the left
ventricle, the lungs assisting especially in its generation. It is a
subtile spirit * * * It is engendered from the mixture that takes place
in the lungs of the inspired air with the elaborated subtile blood
which the right ventricle of the heart communicates to the left. But
this communication takes place, not by the middle septum of the heart,
as is commonly believed, but by a remarkable artifice; the subtile blood
of the right side of the heart is agitated in a lengthened course
through the lungs, whereby it is elaborated, from which it is thrown of
a crimson colour, and from the vena arteriosa (pulmonary artery) is
transfused into the arteria venosa (pulmonary veins); it is then mixed
in the arteria venosa itself with the inspired air, and by the act of
expiration is purified from fuliginous vapours, when, having become the
fit recipient of the vital spirit, it is at length attracted by the
diastole. Now, that the communication and preparation take place as
stated through the lungs, is proclaimed by the various conjunctions and
communications of the arterial vein with the venous artery. The
remarkable size of the arterial vein (pulmonary artery) confirms this, a
vessel which could neither have its actual constitution nor dimensions,
nor transmit such a quantity of the purest blood direct from the heart
itself, for the mere nourishment of the lungs. Neither would the heart
supply the lungs in such proportion, (especially when we see the lungs
in the embryo nourished from another source) by reason of those
membranes or valves which remain unopened until the hour of birth, as
Galen teaches. The blood, consequently, from the moment of birth, is
sent, and in such quantity is sent, for another purpose from the heart
into the lungs; from the lungs also it is not simple air that is sent to
the heart, but air mixed with blood is transmitted through the arteria
venosa (pulmonary vein). In the lungs consequently does the mixture take
place. The crimson colour is imparted to the spirituous blood by the
lungs, not by the heart. There is not room enough in the left ventricle
of the heart for so important and so great an admixture; neither is
there space there for the elaboration into the crimson colour. Finally,
the septum medium, seeing that it is without vessels and properties, is
not adapted to accomplish that communication and elaboration, although
something may transude through it.”

The discussion in this passage from Servetus obviously concerns the
generation of the vital spirit, not the pulmonic circulation properly so
called--that is altogether secondary and subordinate. His mention of
“numerous communications between the vena arteriosa and the arteria
venosa,” is plainly conjectural; neither he, nor any one else for a
century after him, saw such communications. The course through the
lungs, then, as suggested by Servetus, was a mere hypothetical proposal
for getting over the difficulty of the solid, or nearly solid, septum
ventriculorum. As to the means by which such a transfusion as he
suggests, is effected, Servetus, as he was profoundly ignorant himself,
so does he leave his readers entirely in the dark. The transmission of
the blood from the right to the left side of the heart, which Servetus
proposed, is in fact, no great improvement on the old efflux and reflux,
like the tides of Euripus, betwixt Attica and Eubœa. He had no
conception of a circle of the blood beginning and ending in the heart.
On the contrary, he regarded the liver as the fountain-head of the
blood; and if he has any reference to a moving power in connexion with
the heart, it is nothing more than the diastole or dilatation of the
organ that is named--a passive state therefore considered as an active
and efficient cause, which is absurd.

The first modern anatomist of high repute, who treats particularly of
the motion of the blood, may be said to be Realdus Columbus;[55] for
Servetus, though educated to the medical profession, had long forsaken
it for divinity, and only uses his old anatomical knowledge as a means
of illustrating a theological dogma. Columbus, in treating of the heart
and lungs, has certainly much that is remarkable, and much that is
true; and had he said nothing more than we find in single detached
sentences or paragraphs of his book, he must have been regarded as
having gone a great length in the right direction. The blood, he says,
once it has entered the right ventricle from the vena cava, can in no
way again get back; for the tricuspid valves are so placed that whilst
they give a ready passage to the stream inwards, they effectually oppose
its return. The blood continuing to advance from the right ventricle
into the vena arteriosa or pulmonary artery, once there cannot flow back
upon the ventricle, for it is opposed by the sigmoid valves situate at
the root of the vessel. The blood, therefore, agitated and mixed with
the air in the lungs, and having thus in some sort acquired the nature
of spirit, is carried by the arteria venosa or pulmonary vein into the
left ventricle, from whence, being received into the aorta, it is, by
the ramifications of this vessel, transmitted to all parts of the body.

This much taken by itself looks very like an exposition of the
circulation of the blood as understood at the present time, though we
still see that the blood must be made to participate in the nature of
spirit before it enters the arteries, and is not the blood which is
contained in the veins, and which nourishes the body; but when we go
farther and turn to other parts of his writings, we see that Columbus
could never have conceived any proper idea of the circulation. For
example, he continues, with Galen, to regard the liver as the origin of
all the veins. The vena portæ, he says, arising by innumerable roots
from the concavity of the liver, proceeds to carry blood from this organ
by different branches to the stomach, spleen, and intestines, to the end
that it may convey nourishment in the first case, black bile in the
second, and in the third serve a double function--viz. supply
nourishment to the intestines at once, and by a kind of imbibition,
obtain nutritive matter, which is forthwith sent back to the liver for
elaboration into blood. The vena cava again, he describes as arising
from the convex aspect of the liver, whence, by its ramifications, it
carries the blood that is requisite to nourish and maintain every part
of the body.

This of itself is enough. But when, in addition, we find that Columbus
denies the muscular nature of the heart, we are fully qualified to form
a true estimate of the conception which he could have had of the motion
of the blood, and of his right to be regarded as the discoverer of its
ceaseless circular movement.

The next who is brought upon the scene with the imputed honour of having
had a knowledge, not only of the lesser, but of the greater or systemic
circulation also, is Andreas Cæsalpinus,[56] of Arezzo. The account
which this celebrated peripatetic philosopher gives of the passage of
the blood from the right to the left side of the heart is essentially
the same as that given by Columbus. From the right ventricle the blood
passes into the pulmonic artery, and from this, by numerous anastomoses,
into the pulmonic veins, which transmit it to the left ventricle.
Cæsalpinus says well that it is absurd to call the pulmonary artery by
the name of vena arteriosa, on the mere ground of its taking its
departure, like the vena cava, from the right ventricle; it is a true
artery, and is, in all respects, analogous to the aorta. The title of
arteria venosa, again, given to the pulmonic vein is not less
ridiculous; inasmuch as this vessel, though it end in the left
ventricle, has all the properties of the veins at large.

So far it looks as if Cæsalpinus had an exact idea of the pulmonary
circulation; indeed, he uses the word Circulation in reference to the
transit of the blood through the lungs; but when we discover him still
speaking of the permeation of the septum ventriculorum by the blood, our
faith in the extent and accuracy of his knowledge begins to waver.

With reference to the greater or systemic circulation, again,
Cæsalpinus speaks of the swelling of the veins between the circle of
pressure and the extremities of the vessels, when a ligature is thrown
round a limb; and he even goes so far as to state that the common
opinion which admitted a progressive motion--i. e. a motion from trunks
to branches--of the blood in the veins was erroneous. Did we go no
farther we should be led to conclude, as in Columbus’s case, that
Cæsalpinus believed in the continuous movement of the blood in the veins
in one direction only; and, as he has already spoken of the exit of the
blood from the left ventricle, and of its reception by the aorta for
general distribution, it might forthwith be inferred that, possessed of
the essential elements of the greater circulation, he must, as matter of
course, have been familiar with this as an ultimate result. And such an
inference has indeed been drawn for him by high authority; but
Cæsalpinus came not himself to any such conclusion; it was arrived at by
others in his behalf, and after the lapse of almost a century from the
date of his first publication. When we find Cæsalpinus, in other and
closely connected passages of his writings, singing the old cuckoo note
about a flux and reflux of the blood in the veins, and even using the
accredited word--Euripus--to express his idea of its tide-like nature;
when we further perceive that he was ignorant of the existence of the
valves of the veins, and finally arrive at his explanation of the cause
of the swelling which takes place in the veins of an extremity beyond a
ligature,--the cause with him consisting in an effort of the blood to
get back to the focus or centre, lest, through the compression of the
veins, it should be cut off and suffocated,--we not only feel that we
were warranted in entertaining a wholesome scepticism of the conclusion
come to by the admirers of Cæsalpinus in regard to his knowledge of a
circulation of the blood; but waxing in our infidelity as we become
farther acquainted with his thoughts on the constitution of the blood,
we find everything opposed to the likelihood of his having arrived at
the same result as Harvey; and, at length, we discover that he neither
had nor could have had any true knowledge of the circulation. Starting
from the Aristotelian doctrines of growth and nutrition (of which so
much will be found in Harvey’s work on Generation), Cæsalpinus held that
there were two kinds of blood, one for the growth, another for the
nourishment of the body. The blood which went to augment the body, and
which he designated alimentum auctivum, or aliment of increase, flowed
from the liver into the vena cava, which he seems to have thought was
connected with the heart only, ut inde virtus omnis a corde
descendat--that a sufficiency of virtue might be thereby communicated to
it. The auctive blood, he farther thought, was attracted into the
ventricles of the heart by the inherent heat of the organ. The
dilatation of the heart and arteries he imagined to be due to “an
effervescence of the spirit;” and the cause of their “collapse”--not
systole, be it observed, in the active sense--was the appropriation by
the parts of the body of the nutritive and augmentative matter. Again,
though Cæsalpinus speaks of the intercommunication of the minute
arteries and veins, he still thought that it was only during sleep that
the blood mixed with the spirits passed from the former into the latter
class of vessels; for it is during sleep, he says, that the veins become
distended, whilst the pulsations of the arteries are then moderated. He
plainly sees no connexion between a delivery by the artery and a filling
by the vein. It is along with all this, and as if to settle the question
of the kind of knowledge Cæsalpinus had of the movement of the blood,
that he uses the old word Euripus, to express his idea of its
alternating or tide-like motion.

Cæsalpinus, let us add, had no conception of the heart as the efficient
cause of any motion which the blood might have. In the often-quoted
passage from the work ‘De Plantis,’[57] it is still the spirit inherent
in, or associated with, the blood, that is the cause of its motion.

Cæsalpinus, consequently, tried by a very moderately searching
criticism, presents himself to us as but very little farther advanced
than the ancients in his ideas on the motion of the blood.--The
interpretation which successive generations of men give to a passage in
a writer, some century or two old, is very apt to be in consonance with
the state of knowledge at the time, in harmony with the prevailing ideas
of the day, and, doubtless, often differs signally from the meaning that
was in the mind of the man who composed it. The world saw nothing of the
circulation of the blood in Servetus, Columbus, Cæsalpinus,
or--Shakespeare, until after William Harvey had taught and written.

The truth is, that some of the foremost grounds of Harvey’s claims to
rank as a discoverer are very commonly overlooked. We always associate
his name and fame with the development of the ultimate fact of the
circulation of the blood. But Harvey, as a step to this conclusion,
first demonstrated the heart as the means by which the circulation was
effected; and he farther showed that there was but _one_ kind of blood,
common to both the arteries and the veins. Up to his time the heart was
regarded as the passive cistern of the blood, and the elaboratory of the
vital spirits; it was not known as the moving instrument in any efflux
or reflux of the blood, or even of any lesser circulation that had been
previously asserted or conjectured. The moving power was still the
respiratory act. Harvey may be said to have first broached, as he also
essentially completed the physiology of the heart’s actions. The
circular motion of the blood followed as a necessary corollary from
these. The “motion of the heart” has even precedence in the title of his
immortal work; the chapter in which he first enters properly on his
subject (Chap. 2), is devoted to its consideration. And then, no
physiologist up to Harvey’s time had questioned the existence of two
kinds of blood, one appropriate to each order of vessels, and answering
different ends in the economy.

The only name still wanting in this historical sketch, till we come to
Harvey, is that of Fabricius of Aquapendente, his teacher in anatomy.
Fabricius had given particular attention, among other subjects, to the
anatomy of the valves of the veins, which he entitled ostila venarum.
Fabricius, indeed, possessed so thorough a knowledge of the valvular
elements of the vascular system, that it is really astonishing, as an
able writer[58] has remarked, that he should not have had clearer ideas
on the functions, among other things, of the pulmonary veins, and should
have continued a rigid adherent to the prejudices which prevailed before
his time. Fabricius could observe, and he could describe; but he wanted
the combining intellect that infers, the imagination that leads to new
ideas--to discovery. Though he did little himself, however, to advance
the sum of human knowledge, he proved a tooth in the wheel that has
since put in motion the whole machinery of modern medical science. He it
was who sowed the seed, little dreaming of its kind, which, finding one
spot of congenial soil, sprung up a harvest that has continued to
nurture the world of physiological science to the present hour.[59]

Having now disposed of the claims that have been set up in behalf of one
or another as the discoverer of the circulation, and shown, we trust
satisfactorily, that these are all alike untenable, we should now
proceed to discuss the question of the cui bono?--but this meets us in
so forbidding an aspect, brimful as is our mind with a sense of the
all-importance of the knowledge we had from Harvey, and seems so little
to belong to our subject, that we gladly pass it by unnoticed; though it
be only to find ourselves encountered by that other topic, but little
more congenial to our mood of mind and intimate persuasion: The merit of
Harvey as a discoverer. Few, very few have been found to question this;
but as one man of undeniable learning and eminence in his
profession,[60] has very strangely, as it seems to us, been led to do
so, it will not be impertinent if we cast away a few words on this

Discovery is of several, particularly of two kinds: one sensible or
perceptive; another rational or inductive; the former an act of simple
consciousness through an impression made on one or more of the senses;
the latter a conclusion come to by the higher powers of the
understanding dealing with data previously acquired by the senses and
perceptive faculties.--We look through a telescope, for example, and we
perceive a star which no one else had seen before; we note the fact, and
so become discoverers of a new star. The merit here is not, surely, very
great, though the added fact may be highly important. Again, one of the
planets is subject to such perturbations in its course that to compose
exact tables of its orbit is held impossible. These perturbations are
referable to none of the known perturbing causes. A great astronomer
suggests the influence of an exterior and unknown planet as their cause.
A consummate mathematician and physical astronomer makes trial of this
suggestion: he assumes the ascertained perturbations as elements, he
combines these under the guidance of knowledge and reason, and at length
he says, if the cause suggested be well founded, there or thereabouts
must it exist; and lo! on turning the far-seeing tube to the point in
space which he had indicated, there in verity gleams a new world, then
first seen, though launched by God from Eternity to circle on the verge
of our creation; and he who bade us look becomes the discoverer of a new
planet. Who will dispute the merit here? Truly, man does show the God
within him when he uses his faculties--God-like in themselves--in such
God-like fashion. But Harvey’s merit, according to our idea, was of the
selfsame description in another sphere. The facts he used were
familiarly known, most of them to his predecessors for nearly a century,
all of them to his teachers and immediate contemporaries; yet did no
one, mastering these facts in their connexion and sequence, rising
superior to prejudice, groundless hypothesis, and erroneous reasoning,
draw the inference that now meets the world as irresistible, until the
combining mind of Harvey gave it shape and utterance. To our
apprehension Harvey was as far above his fellows as the eye of poetic
intelligence, that exultingly absorbs the beauties of the starry sky and
the green earth, is above the mere physical sense that distinguishes
light from dark. The late Dr. Barclay, a fervent admirer of Harvey,
whose name he never uttered without the epithet immortal, has put the
question of Harvey’s merit both happily and eloquently, and it affords
us pleasure to quote the passage from the writings of our old and
honoured teacher in anatomy. “The late Dr. Hunter,” says Dr.
Barclay,[61] “has rather invidiously introduced Harvey along with
Copernicus and Columbus, to show that his merit as a discoverer was
comparatively low. But what did Copernicus, and what did Columbus? Not
in possession of more numerous facts than their contemporaries, but
endowed with nobler and more vigorous intellects, the one developed the
intricate system of the heavenly bodies and the other discovered an
unheard-of continent. Was it not in the same way, by the exertion of
superior intellect, that Harvey made his immortal discovery? I know not
what has happened in the world unseen; but if I may judge from the
records of history and the annals of fame, the spirit of Bacon, the
spirits of Columbus, Copernicus and Newton have not been ashamed to
welcome and associate with the congenial spirit of Harvey.” To this fine
passage there is little to be added: Harvey’s discovery was of the
rational and inductive and therefore higher class, according to our
estimate; it was made in virtue of the intellectual powers which
peculiarly distinguish man, possessed in a state of the highest


In our account of Harvey’s public career we found him busy with the
subject of Generation at Oxford in 1642; but he had certainly turned his
attention that way at a much earlier period, for one of the chief causes
of his regret, as expressed to Dr. Ent, for the destruction of his
papers during the civil war, is the loss of his Observations on the
Generation of Insects, which could only have been made and reduced to
form many years previously, probably before his engagement to accompany
the Duke of Lennox on his travels. And then we see that all his notes on
the gestation of the hind or doe were made in the palmy days of the
first Charles, before the differences between him and the people of
these countries had come to the arbitrement of arms. Harvey probably
occupied a good deal of his leisure in arranging and writing the work on
Generation, after quitting the service of Charles in 1646; his practice
at this period was not extensive, and he seems to have passed much of
his time in the country. Harvey appears to have been little inclined to
the publication of this work, and only to have ventured it out of his
hands with reluctance. Without the solicitations of Ent, indeed, it
would certainly have been left unpublished during his lifetime. Ent,
however, succeeded in carrying off the prize which his illustrious
friend had showed him, and lost no time in getting it into types, taking
on himself the task of correcting the press, and sending it forth
according to his own ideas in fitting form, with a frontispiece, and a
highflown dedication to the President and Fellows of the College of
Physicians. Ent’s account of his interview with Harvey on the occasion
of obtaining his consent to the publication, though highly theatrical,
is still extremely interesting. Saluting the great anatomist, and asking
if all were well with him, Harvey answers, somewhat impatiently as it
seems: “How can it, whilst the Commonwealth is full of distractions, and
I myself am still in the open sea? And truly,” he continues, “did I not
find solace in my studies, and a balm for my spirit in the memory of my
observations of former years, I should feel little desire for longer
life.” (p. 145.) Let the reader turn to the page from which the above
quotation is taken, and to the one which follows it, for thoughts and
views that clearly bespeak the greatness of intellect, the nobleness of
sentiment that distinguished William Harvey. When Ent proceeds to say
that the learned world, aware of his indefatigable industry, were
eagerly looking for other works at his hands, the fervid genius of the
poet or discoverer still appears in his reply: “And would you be the
man,” said Harvey, smiling, “who should recommend me to quit the
peaceful haven, where I now pass my life, and launch again upon the
faithless sea? You know full well what a storm my former lucubrations
raised. Much better is it oftentimes to grow wise at home and in
private, than by publishing what you have amassed with infinite labour,
to stir up tempests that may rob you of peace and quiet for the rest of
your days.” (p. 147.) By and by, however, he produces his Exercises on
the Generation of Animals, and though he makes many difficulties at
first, urging, among other things, that the work must be held
incomplete, as containing nothing on the generation of insects, Ent,
nevertheless, prevails in the end, and receives the papers with full
authority, either speedily to commit them to the press, or to delay
their publication to a future time. Ent set about his office of midwife,
as he has it, forthwith, and the following year (1651) saw the birth of
the work on Generation.

Physiological science generally was not sufficiently advanced in
Harvey’s time to admit of a truly great and enduring work being produced
on a subject so abstruse, and involving so many particulars as that of
Generation. On the doctrine of the circulation the dawn had long been
visible; Harvey came and the sun arose. On the subject of animal
reproduction, all was night and darkness two centuries ago; and though
the light has still been waxing in strength since Harvey wrote, it is
only in these times that we have seen it brightening into something like
the day. In Harvey’s time the very means and instruments that were
indispensable to the investigation were not yet known, or were used of
powers inadequate to bring the prime facts within the cognizance of the
senses. Harvey doubtless did as much as any man living could have
accomplished when he wrote. He announced the general truth: Omne animal
ex ovo; he showed the cicatricula of the egg as the point where the
reproductive process begins; he corrected numerous errors into which his
master Fabricius had fallen; he further pointed out the path of
observation and experiment as the only one that could lead to
satisfactory results in the investigation of a subject which gradually
displayed itself as one of natural history; and, it may be added, by his
wanderings in the labyrinth of the metaphysics of physiological
science, he did enough to deter any one from attempting to tread such
barren ground again. In his work on the Heart and Blood, Harvey had all
the essential facts of the subject clearly before him, and he used them
at once in such masterly-wise, that he left little or nothing for
addition either by himself or others. Secure of his footing here, he
could well dispense with “vital spirits,” “innate heat,” and other
inscrutable agencies, he could leave “adequate and efficient causes,”
and other metaphysical phantoms on one side--it was physics that he was
dealing with, and the physician was at home. With the information we now
possess, we see clearly how indifferently weaponed was the physiologist
of the year 1647 for encountering such a subject as Animal Generation; a
Leeuwenhoek and a De Graaf, a Spallanzani and a Haighton, a Wolff, a
Purkinje, a Von Baer, a Valentin, a Rudolph Wagner, a Bischoff, and many
more, had successively to appear, before the facts of the subject could
be ascertained, and a Schleiden and a Schwann were further necessary as
ultimate interpreters of the things observed before they could be either
rightly or wholly understood. No wonder then that The Physiologist of
the 17th century, meets us in the guise of one rather puzzled with the
burthen he has made up his mind to bear, and, contrary to his former
wont, eking out the lack of positive knowledge by reiterated
disquisitions on topics where certainty is unattainable.

It is rather curious, moreover, to find Harvey, in his work on
Generation, not entirely escaping the pitfall of which he was so well
aware, and which he shunned so successfully in his earlier production.
In the work on the Heart, he sets out with the certainty that the whole
of the notions of the ancients on the heart and blood are untenable; and
then, taking Nature for his guide, his fine intellect never once suffers
him to stray from the right path. In the book on Generation, on the
other hand, he begins by putting himself in some sort into the harness
of Aristotle, and taking the bit of Fabricius between his teeth; and
then, either assuming the ideas of the former as premises, or those of
the latter as topics of discussion or dissent, he labours on
endeavouring to find Nature in harmony with the Stagyrite, or at
variance with the professor of Padua--for, in spite of many expressions
of respect and deference for his old master, Harvey evidently delights
to find Fabricius in the wrong. Finally, so possessed is he by
scholastic ideas, that he winds up some of his opinions upon animal
reproduction by presenting them in the shape of logical syllogisms.

The age of Harvey, then, was not competent to produce a work on
generation,--it was still an impossible undertaking. Yet has Harvey
written a remarkable book; one that teems with interesting observation,
and that presents the author to us in the character of the elegant
writer, the scholar, and the poet as well as the discoverer--if, indeed,
poet and discoverer, though variously applied, be not identical terms.
Besides the points already referred to, as immediately connected with
his subject, we here find Harvey anticipating modern surgery, by
applying a ligature to the main artery of a tumour which he wished to
extirpate, and so making its subsequent removal much more easy. Here,
too, we find him, a century and a half before his contemporaries, in the
most rapidly progressive period in the history of human knowledge,
throwing out the first hint of the true use of the lungs. Hitherto the
lungs had been regarded as surrounding the heart for the purpose of
ventilating the blood and tempering or moderating its heat, the heart
being viewed as the focus or hearth of the innate heat; and Harvey
himself generally uses language in harmony with these ideas; but in one
instance, the lightning of genius giving him a glimpse of the truth, he
says, “Air is given neither for the cooling nor the nutrition of animals
* * * it is as if heat were rather enkindled within the fœtus [at
birth] than repressed by the influence of the air.”[62]

Had William Harvey possessed this idea in his earlier years, and pursued
it as he did that of the blood never moving in the veins but in one
recurrent course, he would at least have prepared the way for another
grand discovery in physiology: demonstrating the erroneousness of the
current physiological notions on the use of the lungs, he would have led
the van in the investigation of their proper office; and, had everything
else permitted, he might even have anticipated Joseph Black in
explaining the source of animal heat. But this was an impossibility at
the time: chemistry, in Harvey’s day, mostly in the hands of adepts and
charlatans, transmuters of the base metals, and searchers after the
philosopher’s stone and the elixir of life, could have no attractions
for the clear intellect of the demonstrator of the circulation of the
blood. No wonder, therefore, that Harvey “did not care for chymistrey,”
or that “he was wont to speak against the chymists” (Aubrey, l. c. p.
385); this anecdote is but another proof of Harvey’s sagacity. Harvey
then could only show himself in advance of his age by questioning its
opinions on the office of the lungs as he does; the state of chemical
science in the middle of the 17th century did not admit of his doing
more. Harvey, however, well knew the vivifying force of heat: he saw it
the immediate indispensable agent in the reproduction of a living
sentient being, as it is probably employed by the Creator as mainspring
in the elaborate mechanism of the automatic animal body.

       *       *       *       *       *

The short piece on the ANATOMY of THOMAS PARR, is interesting in itself;
and in giving us a glimpse of Harvey’s style of pathological reasoning,
confirms us in our faith in the great physiologist as a practitioner of
medicine. If knowledge will not help, how should the want of it avail?

       *       *       *       *       *

The LETTERS of Great men generally serve to make us more intimately
acquainted with them than without such aid we could have become. This is
more especially the case as respects the letters that are written in the
ease and confidence of private friendship. It is greatly to be regretted
that so few of the letters of this description that flowed from the pen
of Harvey should have come down to us. Those addressed to Giovanni
Nardi, however, show us what an affectionate and elegant mind our Harvey
possessed; how mindful he always appears of former kindnesses to himself
and to those that were near to him; how anxious that he should be
cherished in the memory of his friends, even as he cherishes them in his

The other letters we possess are mostly upon professional--physiological
topics; though the one addressed from Nuremberg to Caspar Hofmann may,
perhaps, be held an exception; for in this letter the manly and candid
character of Harvey displays itself conspicuously. In his own city he
challenges the Nuremberg professor to the proof. “If you would see with
your own eyes the things I assert of the circulation, I promise to show
them to you with the opportunity afforded me.” We have seen that Harvey
accompanied the Earl of Arundel in his extraordinary embassy to the
Emperor, in 1636, and may probably have been one of the party of which
three members were barbarously murdered on their way, from Nuremberg to
Ratisbon, as Crowne[63] informs us. Hence the solicitude which Hollar,
the artist, who also accompanied the ambassador, informed Aubrey the
Earl of Arundel expressed for his physician’s safety: “For he would
still be making of excursions into the woods, making observations of
strange trees, plants, earths, &c., and sometimes like to be lost; so
that my lord ambassador would be really angry with him, for there was
not only danger of wild beasts but of thieves.”[64]

The burthen of the long and able letter to Siegel, of Hamburg, is still
the Circulation. The one addressed to Morison, and the two to Horst,
treat of the discovery of the receptaculum chyli and thoracic duct by
Pecquet. Harvey has been held wanting to his greatness in having refused
his assent to the facts of the distinct existence and special office of
the lymphatic system. But, non omnia possumus omnes; Harvey had his own
work laid out for him, and the lymphatic system was not a part of it.
Aselli’s book on the ‘Lacteal Viens,’[65] was even published before
Harvey’s own Exercises on the Heart and Blood had appeared, and must
have been familiar to our physiologist; but that he failed to perceive
the import of that discovery, and never inquired particularly into it,
cannot surely be rightly laid to him as a charge; and then, when the
newly-discovered system of vessels acquired extension from the
researches of Pecquet, Rudbeck, and Bartholin, Harvey felt that he was
both too old and too infirm to enter on the examination of so extensive
and delicate an anatomical question. In entire consistency with his
noble nature, however, and in striking contrast with his own opponents,
he nowhere formally denies the existence of the new lymphatic vessels;
nor does he once oppose the authority of his name to the investigation
of the truth. On the contrary, he states his objections, “not as being
obstinately wedded to his own opinion, but that he may show what can
readily be urged in opposition to the advocates of the new ideas. Nor do
I doubt,” he proceeds, “but that many things now hidden in the well of
Democritus, will by and by be drawn up into day by the ceaseless
industry of a coming age.”[66]

The letter to Vlackveld was written the very year, within a few weeks
indeed, of his death. It is even touching--it is in vain, he says, to
his correspondent, that he would apply the spur; he has already felt his
right to demand his release from duty; yet would he still be honorably
considered by his contemporaries, and he begs his friend Vlackveld to
love him to the last.

       *       *       *       *       *

We have taken occasion from time to time in the course of our narrative,
to glance at the mental and moral constitution, and also at the personal
character, of Harvey, principally by way of inference from his conduct
on particular occasions, and from what appears in his writings. Happily
we have in addition a few particulars from the pen of a contemporary,
John Aubrey,[67] which, though perchance they do not harmonize in every
respect with the facts in his public life and the portrait he gives us
of himself in his works, are nevertheless extremely interesting, and
cannot be left unnoticed in a Life of Harvey.

“In person,” Aubrey informs us, “Harvey was not tall, but of the lowest
stature; round faced; olivaster (like wainscot) complexion; little eye,
round, very black, full of spirit; his hair black as a raven, but quite
white 20 years before he died.” The portrait we have of Harvey by
Cornelius Jansen, in the library of the Royal College of Physicians, as
well as of one, we presume by Bemmel, now in the possession of Dr.
Richard Bright, corresponds with this account: the temperament is
nervous-bilious; the forehead is compact and square, and of greater
width than usual between the temples; the expression is highly
intellectual, contemplative, and manly.

“In temper,” Aubrey says, “he was like the rest of his brothers, very
choleric, and, in his younger days, he wore a dagger, as the fashion
then was, which he would be apt to draw out upon every occasion.” We
cannot suppose that this was offensively, but merely in the way of
gesticulation, and to lend force to his words; for in his public and
literary life, Harvey showed everything but a choleric nature: he seems,
indeed, at all times to have had his temper under entire control. The
way in which Harvey himself speaks of the robbery of his apartments and
the destruction of his papers, has nothing of bitterness or acrimony in
it. With the opportunity presenting itself to him--as when he sends
Nardi the books on the Troubles in England--he is not tempted to utter
even a splenetic word against the party which had been all along opposed
to his friends, and by which he had suffered so severely. Harvey was,
probably, a marked man by Cromwell and his adherents; but had he been so
disposed he could have indulged in a little vituperation without risk of
molestation. The government of England in the Protector’s time was still
no tyranny.

Harvey appears not to have esteemed the fair sex very highly. He would
say, that “we Europeans knew not how to order or govern our women, and
that the Turks were the only people who used them wisely.” But, indeed,
if Aubrey may be trusted, he did not think very much of mankind in
general: he was wont to say, that “man was but a great mischievous
baboon.” Harvey, however, wived young, and in his age he seems still to
have thought that the old man was best tended by the gentle hand of a
woman not too far stricken in years.[68]

Harvey, in his own family circle, must have been affectionate and
kind,--characteristics of all his brothers--who appear as we have said
to have lived together through their lives in perfect amity and peace.
But our Harvey’s sympathies were not limited to his immediate relatives:
attachment, friendship was an essential ingredient in his nature. His
will from first to last is a piece of beautiful humanity, and more than
one widow and helpless woman is there provided for. He seems to have
been very anxious to live in the memory of his sisters-in-law and of his
nephews and nieces, whose legacies are mostly given to the end that they
may buy something to keep in remembrance of him. To Dr. Ent he was much
attached, and, besides his bookcases, there are ‘five pounds to buy a
ring.’ Dr. Scarborough, who also stood high in Harvey’s favour, has his
‘silver instruments of surgery and his best velvet gown.’

We cannot fancy that Harvey was at any time very eager in the pursuit of
wealth. Aubrey tells us that, “For twenty years before he died, he took
no care of his worldly concerns; but his brother Eliab, who was a very
wise and prudent manager, ordered all, not only faithfully, but better
than he could have done for himself.” The effect of this good management
was that Harvey lived, towards the end of his life, in very easy
circumstances. Having no costly establishment to maintain, for he always
lived with one or other of his brothers in his latter days, and no
family to provide for, he could afford to be munificent, as we have seen
him, to the College of Physicians, and at his death he is reported to
have left as much as 20,000_l._ to his faithful steward and kind brother
Eliab, who always meets us as the guardian angel of our anatomist, in a
worldly and material point of view. Honoured be the name and the memory
of Eliab Harvey for his good offices to one so worthy!

Though of competent estate, in the enjoyment of the highest reputation,
and trusted by two sovereign Princes in succession, Harvey never
suffered his name to be coupled with any of those lower-grade titles
that were so freely conferred in the time of both the First and Second
Charles. When we associate Harvey’s name with a title at all, it is with
the one he fairly won from his masters of Padua: by his contemporaries
he is always spoken of as Dr. Harvey; we in the present day rightly
class him with our Shakespeares, and our Miltons, and speak of him as
Harvey. Harvey, indeed, had no love of ostentation or display. The very
buildings he erected, were built “at the suggestion and under the
auspices” of others.

Harvey’s mind was largely imbued with the imaginative faculty: how
finely he brings in the classical allusion to “the Sicilian sea, dashing
among the rocks around Charybdis, hissing and foaming and tossed hither
and thither,” in illustration of those who reason against the evidence
of their senses, (p. 130.) And then what unbounded confidence he has in
Nature (p. 153), and how keenly alive he is to her beauties in every
sphere: Nature has not been sedulous to deck out animals only with
ornaments; she has further thrown an infinite variety of beautiful dyes
over the lowly and insensate herbs and flowers. (p. 426.)

In Harvey the religious sentiments appear to have been active; the
exordium to his will is unusually solemn and grand. He also evinces true
and elevated piety throughout the whole course of his work on
Generation, and seizes every opportunity of giving utterance to his
sense of the immediate agency and omnipotence of Deity. He appears, with
the ancient philosophers, to have regarded the universe and its parts as
actuated by a Supreme and all-pervading Intelligence. He was a great
admirer of Virgil, whose works were frequently in his hands, and whose
religious philosophy he seems also, in a great measure, to have adopted.
The following beautiful and often-quoted passage of his favorite author
may be said to embody his ideas on this subject, as they appear
repeatedly in the course of the work on Generation:--

    “Principio cœlum ac terras camposque liquentes,
     Lucentemque globum lunæ, Titaniaque astra,
     Spiritus intus alit, totamque infusa per artus
     Mens agitat molem, et magno se corpore miscet.”

   --The heavens and earth, and ocean’s liquid plains,
     The moon’s bright orb, and the Titanian stars,
     Are fed by intrinsic spirit: deep infused
     Through all, mind mingles with and actuates the mass.

Upon the purely Deistic notions of antiquity, however, Harvey
unquestionably ingrafted the special faith in Christianity. In connexion
with the subject of the “term utero-gestation,” he adduces the highest
recorded examples as the rule, and speaks of “Christ, our Saviour, of
men the most perfect;”[69] in the will he farther “most humbly renders
his soul to Him that gave it, and to his blessed Lord and Saviour Christ

Harvey was very inquisitive into natural things and natural phenomena.
When he accompanied the Earl of Arundel, we have seen that he would
still be wandering in the woods, making observations on the strange
trees and herbs, and minerals he encountered. His industry in collecting
facts was unwearied, and the accuracy with which he himself observed
appears in every page of his writings; though we sometimes meet him
amiably credulous in regard to the observations of others,--as in that
instance where he suffers himself to be imposed upon by the traveller’s
tale of the “Genus humanum caudatum”--the race of the human kind with
tails.[70] Harvey was the first English comparative anatomist; in other
words, he was the first physiologist England produced whom superiority
of natural endowment led to perceive the relations between the meanest
and the highest of created things, and who made the simplicity of
structure and of function in the one, a means of explaining the
complexity of structure and of function in the other. “Had anatomists,”
he says, “only been as conversant with the dissection of the lower
animals as they are with that of the human body, many matters that have
hitherto kept them in a perplexity of doubt would, in my opinion, have
met them freed from every kind of difficulty.” (On the Heart, p. 35.)
Harvey makes frequent and most effectual use of his knowledge of
comparative anatomy in his earlier work; and if the reader will turn to
the one on Generation (p. 423), and peruse what is said on the subject
of ‘parts not essential to the being of the individual,’ and will then
visit the Hunterian Museum in Lincoln’s Inn Fields, he will find that
the great comparative anatomist and physiologist of the 19th century had
a herald in the great comparative anatomist and physiologist of the 17th
century. Aubrey mentions particularly Harvey’s having “often said that
of all the losses he sustained, no grief was so crucifying to him as the
loss of his papers (containing notes of his dissections of the frog,
toad, and other animals,) which, together with his goods in his lodgings
at Whitehall, were plundered at the beginning of the rebellion.”
Harvey’s store of individual knowledge must have been great; and he
seems never to have flagged in his anxiety to learn more. He made
himself master of Oughtred’s ‘Clavis Mathematica’ in his old age,
according to Aubrey, who found him “perusing it, and working problems
not long before he dyed.”

Aubrey says “he understood Greek and Latin pretty well, but was no
critique, and he wrote very bad Latin. The Circuitus Sanguinis was, as I
take it, done into Latin by Sir George Ent, as also his booke de
Generatione Animalium; but a little booke, in 12mo, against Riolan (I
thinke) wherein he makes out his doctrine clearer, was writ by himself,
and that, as I take it, at Oxford.”[71] Aubrey, in his gossiping, is
doing injustice both to the scholarship and to the candour of Harvey. He
heard or knew that Harvey wrote an indifferent hand, and this forsooth
he turns into writing indifferent Latin. Everything points to the year
1619 as the period when the book De Motu Cordis et Sanguinis (Aubrey
does not even know the title!) was written; Ent, born in 1603, was then
a lad of sixteen, and in all likelihood had never heard of Harvey’s
name; in 1628, when the work came forth at Frankfort, he was but
twenty-five, and scarcely emancipated from the leading strings of his
instructors. The Exercises to Riolan, which Aubrey cites as a specimen
of Harvey’s own latinity, are at least as well written as the Exercises
on the Heart. And then our authority evidently speaks at random in
regard to the time and place when these Exercises were composed. Harvey
never resided at Oxford after 1646, and Riolan’s Encheiridium
Anatomicum, to which Harvey’s Two Exercises were an answer, did not
appear till 1648! Harvey’s reply could not have been written by
anticipation. It came out at Cambridge the year after Riolan’s work--in

With regard to the work on Generation, again, had Ent received it in
English and turned it into Latin, this fact would certainly have been
stated; whereas, there is only the information that he played the
midwife’s part, and overlooked the press. More than this, from what Ent
says, it is evident that the printer worked from Harvey’s own MS. “As
our author writes a bad hand,” says Ent, “which no one without practice
can easily read, I have taken some pains to prevent the printer
committing any very grave blunders through this,--a point which, I
observe, has not been sufficiently attended to in a small work of his
(The Exercitatio ad Riolanum) which lately appeared.”[72] Harvey was a
man of the most liberal education, and lived in an age when every man of
liberal education wrote and conversed in Latin with ease at least, if
not always with elegance. Harvey’s Latin is generally easy, often
elegant, and not unfrequently copious and imaginative; he never seems to
feel in the least fettered by the language he is using.

Harvey, if eager in the acquirement of knowledge, was also ready at all
times to communicate what he knew, “and,” as Aubrey has it, “to instruct
any that were modest and respectful to him. In order to my journey (I
was at that time bound for Italy) he dictated to me what to see, what
company to keep, what bookes to read, how to manage my studies--in
short, he bid me go to the fountain head and read Aristotle, Cicero,
Avicenna, and did call the Neoteriques s--t-breeches.”[73]

Harvey was not content merely to gather knowledge; he digested and
arranged it under the guidance of the faculties which compare and
reason. “He was always very contemplative,” pursues Aubrey, “and was
wont to frequent the leads of Cockaine-house, which his brother Eliab
had bought, having there his several stations in regard to the sun and
the wind, for the indulgence of his fancy. At the house at Combe, in
Surrey,” which, by the way, appears to have been purchased of Mr.
Cockaine, as well as the mansion in the city, “he had caves made in the
ground, in which he delighted in the summer time to meditate. He also
loved darkness,” telling Aubrey, “‘that he could then best contemplate.’
His thoughts working, would many times keep him from sleeping, in which
case his way was to rise from his bed and walk about his chamber in his
shirt, till he was pretty cool, and then return to his bed and sleep
very comfortably.” He treated the principal bodily ailment with which he
was afflicted (gout) somewhat in the same manner. The fever of the mind
being subdued by the application of cold air to the body at large, the
fever in the blood, induced by gout, was abated by the use of cold water
to the affected member: “He would then sitt with his legges bare, though
it were frost, on the leads of Cockaine-house, putt them into a payle of
water till he was almost dead with cold, and betake himself to his
stove, and so ’twas gone.”[74]

Harvey, besides being physician to the king and household, held the same
responsible situation in the families of many of the most distinguished
among the nobles and men of eminence of his time--among others to the
Lord Chancellor Bacon, whom, Aubrey informs us, “ he esteemed much for
his witt and style, but would not allow to be a great philosopher. Said
he to me, ‘He writes philosophy like a Lord Chancellor’--speaking in
derision.” Harvey’s penetration never failed him: the philosopher of
fact cared not for the philosopher of prescription; he who was dealing
with the Things, and, through his own inherent powers, exhibiting the
Rule, thought little of him who was at work upon abstractions, and who
only inculcated the Rule from the use which he saw others making of it.
Bacon has many admirers, but there are not wanting some in these present
times who hold, with his illustrious contemporary, that “he wrote
philosophy like a Lord Chancellor.”

Harvey was also acquainted with all the men of letters and science of
his age--with Hobbes, Dryden, Cowley, Boyle, and the rest. Dryden, in
his metrical epistle to Dr. Charleton, has these lines, of no great
merit or significance:--

    “The circling streams once thought but pools of blood,
     (Whether life’s fuel or the body’s food,)
     From dark oblivion Harvey’s name shall save.”

Cowley is more happy in his ode on Dr. Harvey:--

      “Thus Harvey sought for truth in Truth’s own book
   --Creation--which by God himself was writ;
    And wisely thought ’twas fit
    Not to read comments only upon it,
      But on th’ original itself to look.
    Methinks in Art’s great circle others stand
    Lock’d up together hand in hand:
      Every one leads as he is led,
      The same bare path they tread,
    A dance like that of Fairies, a fantastic round,
    With neither change of motion nor of ground.
      Had Harvey to this road confined his wit,
      His noble circle of the blood had been untrodden yet.”

Cowley and Harvey must often have encountered; both had the confidence
of the king, but in very different ways: Cowley lent himself to the
privacies and intrigues of the royal family and its adherents, for whom
he even consented to play the base part of spy upon their opponents. He
was also the cypher-letter writer, and the decypherer of the royal
correspondence, and thus mixed up with all the littlenesses of the court
party, by whom he must have been, as matter of course, despised, as he
was subsequently neglected. Harvey was a man of another stamp, composed
of a different clay; and it gives us a high sense of his independence
and true nobility of nature that in the midst of faction and intrigue,
he is never found associated with aught that is unworthy of the name of
man in his best estate. The war of party and the work of destruction
might be going on around; Harvey, under a hedge, and within reach of
shot, was cooly engaged with his book, or in the chamber of his friend
Dr. Bathurst, wrapt in contemplation of the mysteries of Generation.

Harvey appears to have possessed, in a remarkable degree, the power of
persuading and conciliating those with whom he came in contact. In the
whole course of his long life we hear nothing either of personal enemies
or personal enmities; “Man” he says “comes into the world naked and
unarmed, as if nature had destined him for a social creature and
ordained that he should live under equitable laws and in peace; as if
she had desired that he should be guided by reason rather than be driven
by force.”[75] The whole of the opposition to his new views on the
circulation was got up at a distance; all within his own sphere were of
his way of thinking. His brethren of the College of Physicians appear to
have revered him. The congregated fellows must have risen to their feet
by common consent as he came among them on the memorable occasion after
they had elected him their president.

Among other tastes or habits which Harvey had, Aubrey informs us that
“he was wont to drink coffee, which he and his brother Eliab did before
coffee-houses were in fashion in London.”[76] This was probably a
cherished taste with Harvey. In his will he makes a special reservation
of his “coffey-pot;”--his niece Mary West and her daughter have all his
plate except this precious utensil, which, with the residue, he
evidently desired should descend to his brother Eliab as a memorial
doubtless of the pleasure they had often enjoyed together over its
contents--the brewage from the ‘sober berry.’

In visiting his patients, Harvey “rode on horseback with a foot-cloath,
his men following on foot, as the fashion then was, which was very
decent, now quite discontinued. The judges rode also with their
foot-cloathes to Westminster Hall, which ended at the death of Sir
Robert Hyde, Lord Chief Justice; Anthony Earl of Shaftesbury would have
revived it, but several of the judges being old and ill horsemen would
not agree to it.”[77]

Harvey appears to have preserved his faculties unimpaired to the very
last. Aubrey, as we have seen, found the anatomist perusing Oughtred’s
‘Clavis Mathematica,’ and working the problems not long before he died;
and the registers of the College of Physicians further assure us that
Harvey, when very far stricken in years, still lost little or nothing of
his old activity of mind. He continued to deliver his lectures till
within a year or two of his death, when he was succeeded by his friend
Sir Charles Scarborough, and he never failed at the comitia of the
college when anything of moment was under consideration.

Accumulating years, however, and repeated attacks of gout, to which
Harvey had long been a martyr, at length asserted their mastery over the
declining body, and William Harvey, the great in intellect, the noble in
nature, finally ceased to be, on the 3d of June, 1657, in the eightieth
year of his age. About ten o’clock in the morning, as Aubrey tells us,
on attempting to speak, he found that he had lost the power of
utterance, that, in the language of the vulgar, he had the dead palsy in
his tongue. He did not lose his other faculties, however; but knowing
that his end was approaching, he sent for his nephews, to each of whom
he gave some token of remembrance,--his watch to one, his signet ring to
another, and so on. He farther made signs to Sambroke, his apothecary,
to let him blood in the tongue; but this did little or no good, and by
and by, in the evening of the day on which he was stricken, he died;
“the palsy,” as Aubrey has it, “giving him an easy passport.”[78]

The funeral took place a few days afterwards, the body being attended
far beyond the walls of the city by a long train of his friends of the
College of Physicians, and the remains were finally deposited “in a
vault at Hempstead, in Essex, which his brother Eliab had built; he was
lapt in lead, and on his breast, in great letters, his name--DR. WILLIAM
HARVEY. * * * I was at his funeral,” continues Aubrey, “and helpt to
carry him into the vault.” And there, at this hour, he lies, the lead
that laps him little changed, and showing indistinctly the outline of
the form within; for he lies not in an ordinary coffin, but the
cerements that surround the body immediately invested in their turn by
the lead.

So lived, so died one of the great men whom God, in virtue of his
eternal laws, bids to appear on earth from time to time to enlighten,
and to ennoble mankind.[79]


_Extracted from the Registry of the Prerogative Court of Canterbury._

In the name of the Almighty and Eternal God Amen I WILLIAM HARVEY of
London Doctor of Physicke doe by these presents make and ordaine this my
last Will and testament in manner and forme following Revoking hereby
all former and other wills and testaments whatsoever Imprimis I doe most
humbly render my soule to Him that gave it and to my blessed Lord and
Saviour Christ Jesus and my bodie to the Earth to be buried at the
discretion of my executor herein after named The personall estate which
at the time of my decease I shalbe in any way possessed of either in Law
or equitie be it in goods householdstuffe readie moneys debts duties
arrearages of rents or any other wayes whatsoever and whereof I shall
not by this present will or by some Codicill to be hereunto annexed make
a particular gift and disposition I doe after my debts Funeralls and
Legacies paid and discharged give and bequeath the same vnto my loving
brother Mr. Eliab Harvey merchant of London whome I make Executor of
this my last will and testament And whereas I have lately purchased
certaine lands in Northamptonshire or thereabouts commonly knowne by the
name of Oxon grounds and formally belonging vnto to the Earl of
Manchester and certaine other grounds in Leicestershire commonly called
or knowne by the name of Baron Parke and sometime heretofore belonging
vnto Sir Henry Hastings Knight both which purchases were made in the
name of several persons nominated and trusted by me and by two severall
deeds of declaracon vnder the hands and seales of all persons any waye
parties or privies to the said trusts are declared to be first vpon
trust and to the intent that I should be permitted to enioye all the
rents and profits and the benefit of the collaterall securitie during my
life and from and after my decease Then upon trust and for the benefit
of such person and persons and of and for such estate and estates and
Interests And for raysing and payment of such summe and summes of Money
Rents Charges Annuities and yearly payments to and for such purposes as
from time to time by any writing or writings to be by me signed and
sealed in the presence of Two or more credible witnesses or by my last
will and testament in writing should declare limit direct or appoint And
further in trust that the said Mannors and lands and everie part thereof
together with the Collaterall securitie should be assigned conveyed and
assured vnto such persons and for suche Estates as the same should by me
be limited and directed charged and chargeable nevertheles with all
Annuities rents and summes of money by me limited and appointed if any
such shalbe And in default of such appointment then to Eliab Harvey his
heires executors and Assignes or to such as he or they shall nominate as
by the said two deeds of declaracon both of them bearing date the tenth
day of July in the year of our Lord God one Thousand sixe hundred Fiftie
and one more at large it doth appeare I doe now hereby declare limit
direct and appoint that with all convenient speed after my decease there
shalbe raised satisfied and paid these severall summes of money Rents
Charges and Annuities herein after expressed and likewise all such other
summes of Money Rents Charges or Annuities which at any time hereafter
in any Codicill to be hereunto annexed shall happen to be limited or
expressed And first I appoint so much money to be raised and laid out
vpon that building which I have already begun to erect within the
Colledge of Physicians in London as will serve to finish the same
according to the designe already made Item I give and bequeath vnto my
lo sister in Law Mrs Eliab Harvey one hundred pounds to buy something to
keepe in remembrance of me   Item   I give to my Niece Mary Pratt all
that Linnen householdstuffe and furniture which I have at Coome neere
Croydon for the vse of Will Foulkes and to whom his keeping shalbe
assigned after her death or before me at any time   Item   I give vnto
my Niece Mary West and her daughter Amy West halfe the Linnen I shall
leave at London in my chests and Chambers together with all my plate
excepting my Coffey pot   Item   I give to my lo sister Eliab all the
other halfe of my Linnen which I shall leave behind me   Item   I give
to my lo sister Daniell at Lambeth and to everie one of her children
severally the summe of fiftie pounds   Item   I give to my lo Coosin Mr
Heneage Finch for his paines counsell and advice about the contriving of
this my will one hundred pounds   Item   I give to all my little
Godchildren Nieces and Nephews severally to everie one Fiftie pounds
  Item   I give and bequeath to the towne of Foulkestone where I was
borne two hundred pounds to be bestowed by the advice of the Mayor
thereof and my Executor for the best vse of the poore   Item   I give to
the poore of Christ hospitall in Smithfield thirtie pounds Item I give
to Will Harvey my godsonne the sonne of my brother Mich Harvey deceased
one hundred pounds and to his brother Michaell Fiftie pounds   Item   I
give to my Nephew Tho Cullen and his children one hundred pounds and to
his brother my godsonne Will Cullen one hundred pounds Item I give to my
Nephew Jhon Harvey the sonne of my lo brother Tho Harvey deceased two
hundred pounds   Item   I give to my Servant John Raby for his diligence
in my service and sicknesse twentie pounds And to Alice Garth my
Servant Tenne pounds over and above what I am already owing unto her by
my bill which was her mistresses legacie   Item   I give among the poor
children of Amy Rigdon daughter of my lo vncle Mr Tho Halke twentie
pounds   Item   among other my poorest kindred one hundred pounds to be
distributed at the appointment of my Executor   Item   I give among the
servants of my sister Dan at my Funeralls Five pounds And likewise among
the servants of my Nephew Dan Harvey at Coome as much   Item   I give to
my Cousin Mary Tomes Fifty pounds Item I give to my lo Friend Mr
Prestwood one hundred pounds   Item   I give to everie one of my lo
brother Eliab his sonnes and daughters severally Fiftie pounds apiece
All which legacies and gifts aforesaid are chiefly to buy something to
keepe in remembrance of me   Item   I give among the servants of my
brother Eliab which shalbe dwelling with him at the time of my decease
tenne pounds Furthermore I give and bequeath vnto my Sister Eliabs
Sister Mrs Coventrey a widowe during her natural life the yearly rent or
summe of twentie pounds   Item   I give to my Niece Mary West during her
naturall life the yearly rent or summe of Fortie pounds   Item   I give
for the vse and behoofe and better ordering of Will Foulkes for and
during the term of his life vnto my Niece Mary Pratt the yearly rent of
tenne pounds which summe if it happen my said Niece shall dye before him
I desire may be paid to them to whome his keeping shalbe appointed
  Item   I will that the twentie pounds which I yearly allowe him my
brother Galen Browne may be continued as a legacie from his sister
during his naturall life   Item   I will that the payments to Mr Samuel
Fentons children out of the profits of Buckholt Lease be orderly
performed as my deere deceased lo wife gave order so long as that lease
shall stand good   Item   I give vnto Alice Garth during her naturall
life the yearly rent or summe of twentie pounds   Item   To John Raby
during his naturall life sixteene pounds yearly rent All which yearly
rents or summes to be paid halfe yearly at the two most vsuall feasts in
the yeare viz Michaelmas and our Lady day without any deduction for or
by reason of any manner of taxes to be any way hereafter imposed The
first payment of all the said rents or Annuities respectively to beginne
at such of those feasts which shall first happen next after my decease
Thus I give the remainder of my lands vnto my lo brother Eliab and his
heires All my legacies and gifts &c. being performed and discharged
Touching my bookes and householdstuffe Pictures and apparell of which I
have not already disposed I give to the Colledge of Physicians all my
bookes and papers and my best Persia long Carpet and my blue sattin
imbroyedyed Cushion one paire of brasse Andirons with fireshovell and
tongues of brasse for the ornament of the meeting roome I have erected
for that purpose   Item   I give my velvet gowne to my lo friend Mr
Doctor Scarbrough desiring him and my lo friend Mr Doctor Ent to looke
over those scattered remnant of my poore Librarie and what bookes papers
or rare collections they shall thinke fit to present to the Colledge and
the rest to be Sold and with the money buy better And for their paines I
give to Mr Doctor Ent all the presses and shelves he please to make use
of and five pounds to buy him a ring to keepe or weare in remembrance of
me And to Doctor Scarbrough All my little silver instruments of surgerie
Item I give all my Chamber furniture tables bed bedding hangings which I
have at Lambeth to my Sister Dan and her daughter Sarah And all that at
London to my lo Sister Eliab and her daughter or my godsonne Eliab as
she shall appoint   Lastly   I desire my executor to assigne over the
custode of Will Fowkes after the death of my Niece Mary Pratt if she
happen to dye before him vnto the Sister of the said William my Niece
Mary West Thus I have finished my last Will in three pages two of them
written with own hand and my name subscribed to everie one with my hand
and seal to the last

                                                            WILL HARVEY

Signed sealed and published as the last will and testament of me William
Harvey In the presence of us Edward Dering Henneage Finch Richard Flud
Francis Finche Item I have since written a Codicill with my owne hand in
a sheet of paper to be added hereto with my name thereto subscribed and
my seale.

ITEM I will that the sumes and charges here specified be added and
annexed vnto my last will and testament published heretofore in the
presence of Sir Edward Dering and Mr Henneage Finch and others and as a
Codicill by my Executor in like manner to be performed whereby I will
and bequeath to John Denn sonne of Vincent Denne the summe of thirtie
pounds. Item to my good friend Mr Tho Hobbs to buy something to keepe in
remembrance of me tenne pounds and to Mr Kennersley in like manner
twentie pounds Item what moneys shalbe due to me from Mr Hen Thompson
his fees being discharged I give to my friend Mr Prestwood Item what
money is of mine viz one hundred pounds in the hands of my Cosin Rigdon
I give halfe thereof to him towards the marriage of his niece and the
other halfe to be given to Mrs Coventrey for her sonne Walter when he
shall come of yeares and for vse my Cosin Rigdon giving securitie I
would he should pay none Item what money shalbe due to me and Alice
Garth my servant on a pawne now in the hands of Mr Prestwood I will
after my decease shall all be given my said servant for her diligence
about me in my siknesse and service both interest and principall Item if
in case it so fall out that my good friend Mrs Coventrey during her
widowhood shall not dyet on freecost with my brother or Sister Eliab
Harvey Then I will and bequeath to her one hundred marke yearly daring
her widowhood Item I will and bequeath to my loving Cosin Mr Henneage
Finch (more than heretofore) to be for my godsonne Will Finche one
hundred pounds Item I will and bequeath yearly during her life a rent of
thirtie pounds vnto Mrs Jane Nevison Widdowe in case she shall not
preferre her selfe in marriage to be paid quarterly by even porcons the
first to beginn at Christmas Michaelmas or Lady day or Midsummer which
first happens after my decease Item I give to my Goddaughter Mrs Eliz
Glover daughter of my Cosin Toomes the yearly rent of tenne pounds from
my decease vnto the end of five years Item to her brother Mr Rich Toomes
thirty pounds as a legacie Item I give to John Cullen sonne of Tho
Cullen deceased all what I have formerly given his father and more one
hundred pounds Item I will that what I have bequeathed to my Niece Mary
West be given to her husband my Cosin Rob West for his daughter Amy West
Item what should have bene to my Sister Dan deceased I will be given my
lo Niece her daughter in Law Item I give my Cosin Mrs Mary Ranton fortie
pounds to buy something to keep in remembrance of me Item to my nephews
Michaell and Will the sonnes of my brother Mich one hundred pounds to
either of them Item all the furniture of my chamber and all the hangings
I give to my godsonne Mr Eliab Harvey at his marriage and all my red
damaske furniture and plate to my Cosin Mary Harvey Item I give my best
velvet gowne to Doctor Scarbrowe.

                                                           WILL HARVEY.

Memorandum that upon Sunday the twentie eighth day of December in the
yeare of our Lord one thousand sixe hundred fiftie sixe I did againe
peruse my last will which formerly conteined three pages and hath now
this fourth page added to it And I doe now this present Sunday December
28 1656 publish and declare these foure pages whereof the three last are
written with my owne hand to be my last will In the presence of Henneage
Finch John Raby.

       *       *       *       *       *

THIS WILL with the Codicill annexed was proved at London on the second
day of May In the yeare of our Lord God one Thousand six hundred fiftie
nine before the Judge for probate of wills and granting Adcons lawfully
authorized By the oath of Eliab Harvey the Brother and sole executor
therein named To whom Administracon of all and singular the goods
Chattells and debts of the said deceased was granted and committed He
being first sworne truely to administer.[80]

                            CHAS. DYNELEY }
                            JOHN IGGULDEN } _Deputy_
                            W. F. GOSTLING} _Registers._









The heart of animals is the foundation of their life, the sovereign of
everything within them, the sun of their microcosm, that upon which all
growth depends, from which all power proceeds. The King, in like manner,
is the foundation of his kingdom, the sun of the world around him, the
heart of the republic, the fountain whence all power, all grace doth
flow. What I have here written of the motions of the heart I am the more
emboldened to present to your Majesty, according to the custom of the
present age, because almost all things human are done after human
examples, and many things in a King are after the pattern of the heart.
The knowledge of his heart, therefore, will not be useless to a Prince,
as embracing a kind of Divine example of his functions,--and it has
still been usual with men to compare small things with great. Here, at
all events, best of Princes, placed as you are on the pinnacle of human
affairs, you may at once contemplate the prime mover in the body of man,
and the emblem of your own sovereign power. Accept therefore, with your
wonted clemency, I most humbly beseech you, illustrious Prince, this, my
new Treatise on the Heart; you, who are yourself the new light of this
age, and indeed its very heart; a Prince abounding in virtue and in
grace, and to whom we gladly refer all the blessings which England
enjoys, all the pleasure we have in our lives.

Your Majesty’s most devoted servant,

                                                        WILLIAM HARVEY.



     To his very dear Friend, DOCTOR ARGENT, the excellent and
     accomplished President of the Royal College of Physicians, and to
     other learned Physicians, his most esteemed Colleagues.

I have already and repeatedly presented you, my learned friends, with my
new views of the motion and function of the heart, in my anatomical
lectures; but having now for nine years and more confirmed these views
by multiplied demonstrations in your presence, illustrated them by
arguments, and freed them from the objections of the most learned and
skilful anatomists, I at length yield to the requests, I might say
entreaties, of many, and here present them for general consideration in
this treatise.

       *       *       *       *       *

Were not the work indeed presented through you, my learned friends, I
should scarce hope that it could come out scatheless and complete; for
you have in general been the faithful witnesses of almost all the
instances from which I have either collected the truth or confuted
error; you have seen my dissections, and at my demonstrations of all
that I maintain to be objects of sense, you have been accustomed to
stand by and bear me out with your testimony. And as this book alone
declares the blood to course and revolve by a new route, very different
from the ancient and beaten pathway trodden for so many ages, and
illustrated by such a host of learned and distinguished men, I was
greatly afraid lest I might be charged with presumption did I lay my
work before the public at home, or send it beyond seas for impression,
unless I had first proposed its subject to you, had confirmed its
conclusions by ocular demonstrations in your presence, had replied to
your doubts and objections, and secured the assent and support of our
distinguished President. For I was most intimately persuaded, that if I
could make good my proposition before you and our College, illustrious
by its numerous body of learned individuals, I had less to fear from
others; I even ventured to hope that I should have the comfort of
finding all that you had granted me in your sheer love of truth,
conceded by others who were philosophers like yourselves. For true
philosophers, who are only eager for truth and knowledge, never regard
themselves as already so thoroughly informed, but that they welcome
further information from whomsoever and from whencesoever it may come;
nor are they so narrow-minded as to imagine any of the arts or sciences
transmitted to us by the ancients, in such a state of forwardness or
completeness, that nothing is left for the ingenuity and industry of
others; very many, on the contrary, maintain that all we know is still
infinitely less than all that still remains unknown; nor do philosophers
pin their faith to others’ precepts in such wise that they lose their
liberty, and cease to give credence to the conclusions of their proper
senses. Neither do they swear such fealty to their mistress Antiquity,
that they openly, and in sight of all, deny and desert their friend
Truth. But even as they see that the credulous and vain are disposed at
the first blush to accept and to believe everything that is proposed to
them, so do they observe that the dull and unintellectual are indisposed
to see what lies before their eyes, and even to deny the light of the
noonday sun. They teach us in our course of philosophy as sedulously to
avoid the fables of the poets and the fancies of the vulgar, as the
false conclusions of the sceptics. And then the studious, and good, and
true, never suffer their minds to be warped by the passions of hatred
and envy, which unfit men duly to weigh the arguments that are advanced
in behalf of truth, or to appreciate the proposition that is even fairly
demonstrated; neither do they think it unworthy of them to change their
opinion if truth and undoubted demonstration require them so to do; nor
do they esteem it discreditable to desert error, though sanctioned by
the highest antiquity; for they know full well that to err, to be
deceived, is human; that many things are discovered by accident, and
that many may be learned indifferently from any quarter, by an old man
from a youth, by a person of understanding from one of inferior

       *       *       *       *       *

My dear colleagues, I had no purpose to swell this treatise into a large
volume by quoting the names and writings of anatomists, or to make a
parade of the strength of my memory, the extent of my reading, and the
amount of my pains; because I profess both to learn and to teach
anatomy, not from books but from dissections; not from the positions of
philosophers but from the fabric of nature; and then because I do not
think it right or proper to strive to take from the ancients any honour
that is their due, nor yet to dispute with the moderns, and enter into
controversy with those who have excelled in anatomy and been my
teachers. I would not charge with wilful falsehood any one who was
sincerely anxious for truth, nor lay it to any one’s door as a crime
that he had fallen into error. I avow myself the partisan of truth
alone; and I can indeed say that I have used all my endeavours, bestowed
all my pains on an attempt to produce something that should be agreeable
to the good, profitable to the learned, and useful to letters.

                    Farewell, most worthy Doctors,

                  And think kindly of your Anatomist,

                            WILLIAM HARVEY.





As we are about to discuss the motion, action, and use of the heart and
arteries, it is imperative on us first to state what has been thought of
these things by others in their writings, and what has been held by the
vulgar and by tradition, in order that what is true may be confirmed,
and what is false set right by dissection, multiplied experience, and
accurate observation.

Almost all anatomists, physicians, and philosophers, up to the present
time, have supposed, with Galen, that the object of the pulse was the
same as that of respiration, and only differed in one particular, this
being conceived to depend on the animal, the respiration on the vital
faculty; the two, in all other respects, whether with reference to
purpose or to motion, comporting themselves alike. Whence it is
affirmed, as by Hieronymus Fabricius of Aquapendente, in his book on
‘Respiration,’ which has lately appeared, that as the pulsation of the
heart and arteries does not suffice for the ventilation and
refrigeration of the blood, therefore were the lungs fashioned to
surround the heart. From this it appears, that whatever has hitherto
been said upon the systole and diastole, on the motion of the heart and
arteries, has been said with especial reference to the lungs.

But as the structure and movements of the heart differ from those of the
lungs, and the motions of the arteries from those of the chest, so seems
it likely that other ends and offices will thence arise, and that the
pulsations and uses of the heart, likewise of the arteries, will differ
in many respects from the heavings and uses of the chest and lungs. For
did the arterial pulse and the respiration serve the same ends; did the
arteries in their diastole take air into their cavities, as commonly
stated, and in their systole emit fuliginous vapours by the same pores
of the flesh and skin; and further, did they, in the time intermediate
between the diastole and the systole, contain air, and at all times
either air, or spirits, or fuliginous vapours, what should then be said
to Galen, who wrote a book on purpose to show that by nature the
arteries contained blood, and nothing but blood; neither spirits nor
air, consequently, as may be readily gathered from the experiments and
reasonings contained in the same book? Now if the arteries are filled in
the diastole with air then taken into them (a larger quantity of air
penetrating when the pulse is large and full), it must come to pass,
that if you plunge into a bath of water or of oil when the pulse is
strong and full, it ought forthwith to become either smaller or much
slower, since the circumambient bath will render it either difficult or
impossible for the air to penetrate. In like manner, as all the
arteries, those that are deep-seated as well as those that are
superficial, are dilated at the same instant, and with the same
rapidity, how were it possible that air should penetrate to the deeper
parts as freely and quickly through the skin, flesh, and other
structures, as through the mere cuticle? And how should the arteries of
the fœtus draw air into their cavities through the abdomen of the mother
and the body of the womb? And how should seals, whales, dolphins and
other cetaceans, and fishes of every description, living in the depths
of the sea, take in and emit air by the diastole and systole of their
arteries through the infinite mass of waters? For to say that they
absorb the air that is infixed in the water, and emit their fumes into
this medium, were to utter something very like a mere figment. And if
the arteries in their systole expel fuliginous vapours from their
cavities through the pores of the flesh and skin, why not the Spirits,
which are said to be contained in these vessels, at the same time, since
spirits are much more subtile than fuliginous vapours or smoke? And
further, if the arteries take in and cast out air in the systole and
diastole, like the lungs in the process of respiration, wherefore do
they not do the same thing when a wound is made in one of them, as is
done in the operation of arteriotomy? When the windpipe is divided, it
is sufficiently obvious that the air enters and returns through the
wound by two opposite movements; but when an artery is divided, it is
equally manifest that blood escapes in one continuous stream, and that
no air either enters or issues. If the pulsations of the arteries fan
and refrigerate the several parts of the body as the lungs do the heart,
how comes it, as is commonly said, that the arteries carry the vital
blood into the different parts, abundantly charged with vital spirits,
which cherish the heat of these parts, sustain them when asleep, and
recruit them when exhausted? and how should it happen that, if you tie
the arteries, immediately the parts not only become torpid, and frigid,
and look pale, but at length cease even to be nourished? This, according
to Galen, is because they are deprived of the heat which flowed through
all parts from the heart, as its source; whence it would appear that the
arteries rather carry warmth to the parts than serve for any fanning or
refrigeration. Besides, how can the diastole [of the arteries] draw
spirits from the heart to warm the body and its parts, and, from
without, means of cooling or tempering them? Still further, although
some affirm that the lungs, arteries, and heart have all the same
offices, they yet maintain that the heart is the workshop of the
spirits, and that the arteries contain and transmit them; denying,
however, in opposition to the opinion of Columbus, that the lungs can
either make or contain spirits; and then they assert, with Galen,
against Erasistratus, that it is blood, not spirits, which is contained
in the arteries.

These various opinions are seen to be so incongruous and mutually
subversive, that every one of them is not unjustly brought under
suspicion. That it is blood and blood alone which is contained in the
arteries is made manifest by the experiment of Galen, by arteriotomy,
and by wounds; for from a single artery divided, as Galen himself
affirms in more than one place, the whole of the blood may be withdrawn
in the course of half an hour, or less. The experiment of Galen alluded
to is this: “If you include a portion of an artery between two
ligatures, and slit it open lengthways, you will find nothing but
blood;” and thus he proves that the arteries contain blood only. And we
too may be permitted to proceed by a like train of reasoning: if we find
the same blood in the arteries that we find in the veins, which we have
tied in the same way, as I have myself repeatedly ascertained, both in
the dead body and in living animals, we may fairly conclude that the
arteries contain the same blood as the veins, and nothing but the same
blood. Some, whilst they attempt to lessen the difficulty here,
affirming that the blood is spirituous and arterious, virtually concede
that the office of the arteries is to carry blood from the heart into
the whole of the body, and that they are therefore filled with blood;
for spirituous blood is not the less blood on that account. And then no
one denies that the blood as such, even the portion of it which flows in
the veins, is imbued with spirits. But if that portion which is
contained in the arteries be richer in spirits, it is still to be
believed that these spirits are inseparable from the blood, like those
in the veins; that the blood and spirits constitute one body (like whey
and butter in milk, or heat [and water] in hot water), with which the
arteries are charged, and for the distribution of which from the heart
they are provided, and that this body is nothing else than blood. But if
this blood be said to be drawn from the heart into the arteries by the
diastole of these vessels, it is then assumed that the arteries by their
distension are filled with blood, and not with the ambient air, as
heretofore; for if they be said also to become filled with air from the
ambient atmosphere, how and when, I ask, can they receive blood from the
heart? If it be answered: during the systole; I say, that seems
impossible; the arteries would then have to fill whilst they contracted;
in other words, to fill, and yet not become distended. But if it be
said: during the diastole, they would then, and for two opposite
purposes, be receiving both blood and air, and heat and cold; which is
improbable. Further, when it is affirmed that the diastole of the heart
and arteries is simultaneous, and the systole of the two is also
concurrent, there is another incongruity. For how can two bodies
mutually connected, which are simultaneously distended, attract or draw
anything from one another; or, being simultaneously contracted, receive
anything from each other? And then, it seems impossible that one body
can thus attract another body into itself, so as to become distended,
seeing that to be distended is to be passive, unless, in the manner of a
sponge, previously compressed by an external force, whilst it is
returning to its natural state. But it is difficult to conceive that
there can be anything of this kind in the arteries. The arteries dilate,
because they are filled like bladders or leathern bottles; they are not
filled because they expand like bellows. This I think easy of
demonstration; and indeed conceive that I have already proved it.
Nevertheless, in that book of Galen headed ‘Quod Sanguis continetur in
Arteriis,’ he quotes an experiment to prove the contrary: An artery
having been exposed, is opened longitudinally, and a reed or other
pervious tube, by which the blood is prevented from being lost, and the
wound is closed, is inserted into the vessel through the opening. “So
long,” he says, “as things are thus arranged, the whole artery will
pulsate; but if you now throw a ligature about the vessel and tightly
compress its tunics over the tube, you will no longer see the artery
beating beyond the ligature.” I have never performed this experiment of
Galen’s, nor do I think that it could very well be performed in the
living body, on account of the profuse flow of blood that would take
place from the vessel which was operated on; neither would the tube
effectually close the wound in the vessel without a ligature; and I
cannot doubt but that the blood would be found to flow out between the
tube and the vessel. Still Galen appears by this experiment to prove
both that the pulsative faculty extends from the heart by the walls of
the arteries, and that the arteries, whilst they dilate, are filled by
that pulsific force, because they expand like bellows, and do not dilate
because they are filled like skins. But the contrary is obvious in
arteriotomy and in wounds; for the blood spurting from the arteries
escapes with force, now farther, now not so far, alternately, or in
jets; and the jet always takes place with the diastole of the artery,
never with the systole. By which it clearly appears that the artery is
dilated by the impulse of the blood; for of itself it would not throw
the blood to such a distance, and whilst it was dilating; it ought
rather to draw air into its cavity through the wound, were those things
true that are commonly stated concerning the uses of the arteries. Nor
let the thickness of the arterial tunics impose upon us, and lead us to
conclude that the pulsative property proceeds along them from the heart.
For in several animals the arteries do not apparently differ from the
veins; and in extreme parts of the body, where the arteries are minutely
subdivided, as in the brain, the hand, &c., no one could distinguish the
arteries from the veins by the dissimilar characters of their coats; the
tunics of both are identical. And then, in an aneurism proceeding from a
wounded or eroded artery, the pulsation is precisely the same as in the
other arteries, and yet it has no proper arterial tunic. This the
learned Riolanus testifies to, along with me, in his Seventh Book.

Nor let any one imagine that the uses of the pulse and the respiration
are the same, because under the influence of the same causes, such as
running, anger, the warm bath, or any other heating thing, as Galen
says, they become more frequent and forcible together. For, not only is
experience in opposition to this idea, though Galen endeavours to
explain it away, when we see that with excessive repletion the pulse
beats more forcibly, whilst the respiration is diminished in amount; but
in young persons the pulse is quick, whilst respiration is slow. So is
it also in alarm, and amidst care, and under anxiety of mind; sometimes,
too, in fevers, the pulse is rapid, but the respiration is slower than

These and other objections of the same kind may be urged against the
opinions mentioned. Nor are the views that are entertained of the
offices and pulse of the heart, perhaps, less bound up with great and
most inextricable difficulties. The heart, it is vulgarly said, is the
fountain and workshop of the vital spirits, the centre from whence life
is dispensed to the several parts of the body; and yet it is denied that
the right ventricle makes spirits; it is rather held to supply
nourishment to the lungs; whence it is maintained that fishes are
without any right ventricle (and indeed every animal wants a right
ventricle which is unfurnished with lungs), and that the right ventricle
is present solely for the sake of the lungs.

1. Why, I ask, when we see that the structure of both ventricles is
almost identical, there being the same apparatus of fibres, and braces,
and valves, and vessels, and auricles, and in both the same infarction
of blood, in the subjects of our dissections, of the like black colour,
and coagulated--why, I say, should their uses be imagined to be
different, when the action, motion, and pulse of both are the same? If
the three tricuspid valves placed at the entrance into the right
ventricle prove obstacles to the reflux of the blood into the vena cava,
and if the three semilunar valves which are situated at the commencement
of the pulmonary artery be there, that they may prevent the return of
the blood into the ventricle; wherefore, when we find similar structures
in connexion with the left ventricle, should we deny that they are
there for the same end, of preventing here the egress, there the
regurgitation of the blood?

2. And again, when we see that these structures, in point of size, form,
and situation, are almost in every respect the same in the left as in
the right ventricle, wherefore should it be maintained that things are
here arranged in connexion with the egress and regress of spirits,
there, i.e. in the right, of blood. The same arrangement cannot be held
fitted to favour or impede the motion of blood and of spirits

3. And when we observe that the passages and vessels are severally in
relation to one another in point of size, viz., the pulmonary artery to
the pulmonary veins; wherefore should the one be imagined destined to a
private or particular purpose, that to wit, of nourishing the lungs, the
other to a public and general function?

4. And, as Realdus Columbus says, how can it be conceived that such a
quantity of blood should be required for the nutrition of the lungs; the
vessel that leads to them, the vena arteriosa or pulmonary artery being
of greater capacity than both the iliac veins?

5. And I ask further; as the lungs are so close at hand, and in
continual motion, and the vessel that supplies them is of such
dimensions, what is the use or meaning of the pulse of the right
ventricle? and why was nature reduced to the necessity of adding another
ventricle for the sole purpose of nourishing the lungs?

When it is said that the left ventricle obtains materials for the
formation of spirits, air to wit, and blood, from the lungs and right
sinuses of the heart, and in like manner sends spirituous blood into the
aorta, drawing fuliginous vapours from thence, and sending them by the
arteria venosa into the lungs, whence spirits are at the same time
obtained for transmission into the aorta, I ask how, and by what means,
is the separation effected? and how comes it that spirits and fuliginous
vapours can pass hither and thither without admixture or confusion? If
the mitral cuspidate valves do not prevent the egress of fuliginous
vapours to the lungs, how should they oppose the escape of air? and how
should the semilunars hinder the regress of spirits from the aorta upon
each supervening diastole of the heart? and, above all, how can they say
that the spirituous blood is sent from the arteria venalis (pulmonary
veins) by the left ventricle into the lungs without any obstacle to its
passage from the mitral valves, when they have previously asserted that
the air entered by the same vessel from the lungs into the left
ventricle, and have brought forward these same mitral valves as
obstacles to its retrogression? Good God! how should the mitral valves
prevent regurgitation of air and not of blood?

Further, when they dedicate the vena arteriosa (or pulmonary artery), a
vessel of great size, and having the tunics of an artery, to none but a
kind of private and single purpose, that, namely, of nourishing the
lungs, why should the arteria venalis (or pulmonary vein), which is
scarcely of similar size, which has the coats of a vein, and is soft and
lax, be presumed to be made for many--three or four, different uses? For
they will have it that air passes through this vessel from the lungs
into the left ventricle; that fuliginous vapours escape by it from the
heart into the lungs; and that a portion of the spirituous or
spiritualized blood is distributed by it to the lungs for their

If they will have it that fumes and air--fumes flowing from, air
proceeding towards the heart--are transmitted by the same conduit, I
reply, that nature is not wont to institute but one vessel, to contrive
but one way for such contrary motions and purposes, nor is anything of
the kind seen elsewhere.

If fumes or fuliginous vapours and air permeate this vessel, as they do
the pulmonary bronchia, wherefore do we find neither air nor fuliginous
vapours when we divide the arteria venosa? why do we always find this
vessel full of sluggish blood, never of air? whilst in the lungs we find
abundance of air remaining.

If any one will perform Galen’s experiment of dividing the trachea of a
living dog, forcibly distending the lungs with a pair of bellows, and
then tying the trachea securely, he will find, when he has laid open the
thorax, abundance of air in the lungs, even to their extreme investing
tunic, but none in either the pulmonary veins, or left ventricle of the
heart. But did the heart either attract air from the lungs, or did the
lungs transmit any air to the heart, in the living dog, by so much the
more ought this to be the case in the experiment just referred to. Who,
indeed, doubts that, did he inflate the lungs of a subject in the
dissecting-room, he would instantly see the air making its way by this
route, were there actually any such passage for it? But this office of
the pulmonary veins, namely, the transference of air from the lungs to
the heart, is held of such importance, that Hieronymus Fabricius, of
Aquapendente, maintains the lungs were made for the sake of this vessel,
and that it constitutes the principal element in their structure.

But I should like to be informed wherefore, if the pulmonary vein were
destined for the conveyance of air, it has the structure of a
blood-vessel here. Nature had rather need of annular tubes, such as
those of the bronchia, in order that they might always remain open, not
have been liable to collapse; and that they might continue entirely free
from blood, lest the liquid should interfere with the passage of the
air, as it so obviously does when the lungs labour from being either
greatly oppressed or loaded in a less degree with phlegm, as they are
when the breathing is performed with a sibilous or rattling noise.

Still less is that opinion to be tolerated which (as a two-fold matter,
one aëreal, one sanguineous, is required for the composition of vital
spirits,) supposes the blood to ooze through the septum of the heart
from the right to the left ventricle by certain secret pores, and the
air to be attracted from the lungs through the great vessel, the
pulmonary vein; and which will have it, consequently, that there are
numerous pores in the septum cordis adapted for the transmission of the
blood. But, in faith, no such pores can be demonstrated, neither in fact
do any such exist. For the septum of the heart is of a denser and more
compact structure than any portion of the body, except the bones and
sinews. But even supposing that there were foramina or pores in this
situation, how could one of the ventricles extract anything from the
other--the left, e.g. obtain blood from the right, when we see that both
ventricles contract and dilate simultaneously? Wherefore should we not
rather believe that the right took spirits from the left, than that the
left obtained blood from the right ventricle, through these foramina?
But it is certainly mysterious and incongruous that blood should be
supposed to be most commodiously drawn through a set of obscure or
invisible pores, and air through perfectly open passages, at one and the
same moment. And why, I ask, is recourse had to secret and invisible
porosities, to uncertain and obscure channels, to explain the passage of
the blood into the left ventricle, when there is so open a way through
the pulmonary veins? I own it has always appeared extraordinary to me
that they should have chosen to make, or rather to imagine, a way
through the thick, hard, and extremely compact substance of the septum
cordis, rather than to take that by the open vas venosum or pulmonary
vein, or even through the lax, soft and spongy substance of the lungs at
large. Besides, if the blood could permeate the substance of the septum,
or could be imbibed from the ventricles, what use were there for the
coronary artery and vein, branches of which proceed to the septum
itself, to supply it with nourishment? And what is especially worthy of
notice is this: if in the fœtus, where everything is more lax and soft,
nature saw herself reduced to the necessity of bringing the blood from
the right into the left side of the heart by the foramen ovale, from the
vena cava through the arteria venosa, how should it be likely that in
the adult she should pass it so commodiously, and without an effort,
through the septum ventriculorum, which has now become denser by age?

Andreas Laurentius,[81] resting on the authority of Galen[82] and the
experience of Hollerius, asserts and proves that the serum and pus in
empyema, absorbed from the cavities of the chest into the pulmonary
vein, may be expelled and got rid of with the urine and fæces through
the left ventricle of the heart and arteries. He quotes the case of a
certain person affected with melancholia, and who suffered from repeated
fainting fits, who was relieved from the paroxysms on passing a quantity
of turbid, fetid, and acrid urine; but he died at last, worn out by the
disease; and when the body came to be opened after death, no fluid like
that he had micturated was discovered either in the bladder or in the
kidneys; but in the left ventricle of the heart and cavity of the thorax
plenty of it was met with; and then Laurentius boasts that he had
predicted the cause of the symptoms. For my own part, however, I cannot
but wonder, since he had divined and predicted that heterogeneous matter
could be discharged by the course he indicates, why he could not or
would not perceive, and inform us that, in the natural state of things,
the blood might be commodiously transferred from the lungs to the left
ventricle of the heart by the very same route.

Since, therefore, from the foregoing considerations and many others to
the same effect, it is plain that what has heretofore been said
concerning the motion and function of the heart and arteries must
appear obscure, or inconsistent or even impossible to him who carefully
considers the entire subject; it will be proper to look more narrowly
into the matter; to contemplate the motion of the heart and arteries,
not only in man, but in all animals that have hearts; and further, by
frequent appeals to vivisection, and constant ocular inspection, to
investigate and endeavour to find the truth.



When I first gave my mind to vivisections, as a means of discovering the
motions and uses of the heart, and sought to discover these from actual
inspection, and not from the writings of others, I found the task so
truly arduous, so full of difficulties, that I was almost tempted to
think, with Fracastorius, that the motion of the heart was only to be
comprehended by God. For I could neither rightly perceive at first when
the systole and when the diastole took place, nor when and where
dilatation and contraction occurred, by reason of the rapidity of the
motion, which in many animals is accomplished in the twinkling of an
eye, coming and going like a flash of lightning; so that the systole
presented itself to me now from this point, now from that; the diastole
the same; and then everything was reversed, the motions occurring, as it
seemed, variously and confusedly together. My mind was therefore greatly
unsettled, nor did I know what I should myself conclude, nor what
believe from others; I was not surprised that Andreas Laurentius should
have said that the motion of the heart was as perplexing as the flux and
reflux of Euripus had appeared to Aristotle.

At length, and by using greater and daily diligence, having frequent
recourse to vivisections, employing a variety of animals for the
purpose, and collating numerous observations, I thought that I had
attained to the truth, that I should extricate myself and escape from
this labyrinth, and that I had discovered what I so much desired, both
the motion and the use of the heart and arteries; since which time I
have not hesitated to expose my views upon these subjects, not only in
private to my friends, but also in public, in my anatomical lectures,
after the manner of the Academy of old.

These views, as usual, pleased some more, others less; some chid and
calumniated me, and laid it to me as a crime that I had dared to depart
from the precepts and opinion of all anatomists; others desired further
explanations of the novelties, which they said were both worthy of
consideration, and might perchance be found of signal use. At length,
yielding to the requests of my friends, that all might be made
participators in my labours, and partly moved by the envy of others,
who, receiving my views with uncandid minds and understanding them
indifferently, have essayed to traduce me publicly, I have been moved to
commit these things to the press, in order that all may be enabled to
form an opinion both of me and my labours. This step I take all the more
willingly, seeing that Hieronymus Fabricius of Aquapendente, although he
has accurately and learnedly delineated almost every one of the several
parts of animals in a special work, has left the heart alone untouched.
Finally, if any use or benefit to this department of the republic of
letters should accrue from my labours, it will, perhaps, be allowed that
I have not lived idly, and, as the old man in the comedy says:

    For never yet hath any one attained
    To such perfection, but that time, and place,
    And use, have brought addition to his knowledge;
    Or made correction, or admonished him,
    That he was ignorant of much which he
    Had thought he knew; or led him to reject
    What he had once esteemed of highest price.

So will it, perchance, be found with reference to the heart at this
time; or others, at least, starting from hence, the way pointed out to
them, advancing under the guidance of a happier genius, may make
occasion to proceed more fortunately, and to inquire more accurately.



In the first place, then, when the chest of a living animal is laid open
and the capsule that immediately surrounds the heart is slit up or
removed, the organ is seen now to move, now to be at rest;--there is a
time when it moves, and a time when it is motionless.

These things are more obvious in the colder animals, such as toads,
frogs, serpents, small fishes, crabs, shrimps, snails and shell-fish.
They also become more distinct in warm-blooded animals, such as the dog
and hog, if they be attentively noted when the heart begins to flag, to
move more slowly, and, as it were, to die: the movements then become
slower and rarer, the pauses longer, by which it is made much more easy
to perceive and unravel what the motions really are, and how they are
performed. In the pause, as in death, the heart is soft, flaccid,
exhausted, lying, as it were, at rest.

In the motion, and interval in which this is accomplished, three
principal circumstances are to be noted:

1. That the heart is erected, and rises upwards to a point, so that at
this time it strikes against the breast and the pulse is felt

2. That it is everywhere contracted, but more especially towards the
sides, so that it looks narrower, relatively longer, more drawn
together. The heart of an eel taken out of the body of the animal and
placed upon the table or the hand, shows these particulars; but the same
things are manifest in the heart of small fishes and of those colder
animals where the organ is more conical or elongated.

3. The heart being grasped in the hand, is felt to become harder during
its action. Now this hardness proceeds from tension, precisely as when
the forearm is grasped, its tendons are perceived to become tense and
resilient when the fingers are moved.

4. It may further be observed in fishes, and the colder blooded animals,
such as frogs, serpents, &c., that the heart, when it moves, becomes of
a paler colour, when quiescent of a deeper blood-red colour.

From these particulars it appeared evident to me that the motion of the
heart consists in a certain universal tension--both contraction in the
line of its fibres, and constriction in every sense. It becomes erect,
hard, and of diminished size during its action; the motion is plainly of
the same nature as that of the muscles when they contract in the line of
their sinews and fibres; for the muscles, when in action, acquire vigour
and tenseness, and from soft become hard, prominent and thickened: in
the same manner the heart.

We are therefore authorized to conclude that the heart, at the moment of
its action, is at once constricted on all sides, rendered thicker in its
parietes and smaller in its ventricles, and so made apt to project or
expel its charge of blood. This, indeed, is made sufficiently manifest
by the fourth observation preceding, in which we have seen that the
heart, by squeezing out the blood it contains becomes paler, and then
when it sinks into repose and the ventricle is filled anew with blood,
that the deeper crimson colour returns. But no one need remain in doubt
of the fact, for if the ventricle be pierced the blood will be seen to
be forcibly projected outwards upon each motion or pulsation when the
heart is tense.

These things, therefore, happen together or at the same instant: the
tension of the hearty the pulse of its apex, which is felt externally by
its striking against the chest, the thickening of its parietes, and the
forcible expulsion of the blood it contains by the constriction of its

Hence the very opposite of the opinions commonly received, appears to be
true; inasmuch as it is generally believed that when the heart strikes
the breast and the pulse is felt without, the heart is dilated in its
ventricles and is filled with blood; but the contrary of this is the
fact, and the heart, when it contracts [and the shock is given], is
emptied. Whence the motion which is generally regarded as the diastole
of the heart, is in truth its systole. And in like manner the intrinsic
motion of the heart is not the diastole but the systole; neither is it
in the diastole that the heart grows firm and tense, but in the systole,
for then only, when tense, is it moved and made vigorous.

Neither is it by any means to be allowed that the heart only moves in
the line of its straight fibres, although the great Vesalius, giving
this notion countenance, quotes a bundle of osiers bound into a
pyramidal heap in illustration; meaning, that as the apex is approached
to the base, so are the sides made to bulge out in the fashion of
arches, the cavities to dilate, the ventricles to acquire the form of a
cupping-glass and so to suck in the blood. But the true effect of every
one of its fibres is to constringe the heart at the same time that they
render it tense; and this rather with the effect of thickening and
amplifying the walls and substance of the organ than enlarging its
ventricles. And, again, as the fibres run from the apex to the base, and
draw the apex towards the base, they do not tend to make the walls of
the heart bulge out in circles, but rather the contrary; inasmuch as
every fibre that is circularly disposed, tends to become straight when
it contracts; and is distended laterally and thickened, as in the case
of muscular fibres in general, when they contract, that is, when they
are shortened longitudinally, as we see them in the bellies of the
muscles of the body at large. To all this let it be added, that not only
are the ventricles contracted in virtue of the direction and
condensation of their walls, but farther, that those fibres, or bands,
styled nerves by Aristotle, which are so conspicuous in the ventricles
of the larger animals, and contain all the straight fibres, (the
parietes of the heart containing only circular ones,) when they contract
simultaneously, by an admirable adjustment all the internal surfaces are
drawn together, as if with cords, and so is the charge of blood expelled
with force.

Neither is it true, as vulgarly believed, that the heart by any
dilatation or motion of its own, has the power of drawing the blood into
the ventricles; for when it acts and becomes tense, the blood is
expelled; when it relaxes and sinks together it receives the blood in
the manner and wise which will by and by be explained.



In connexion with the motions of the heart these things are further to
be observed having reference to the motions and pulses of the arteries:

1. At the moment the heart contracts, and when the breast is struck,
when in short the organ is in its state of systole, the arteries are
dilated, yield a pulse, and are in the state of diastole. In like
manner, when the right ventricle contracts and propels its charge of
blood, the arterial vein [the pulmonary artery] is distended at the same
time with the other arteries of the body.

2. When the left ventricle ceases to act, to contract, to pulsate, the
pulse in the arteries also ceases; further, when this ventricle
contracts languidly, the pulse in the arteries is scarcely perceptible.
In like manner, the pulse in the right ventricle failing, the pulse in
the vena arteriosa [pulmonary artery] ceases also.

3. Further, when an artery is divided or punctured, the blood is seen to
be forcibly propelled from the wound at the moment the left ventricle
contracts; and, again, when the pulmonary artery is wounded, the blood
will be seen spouting forth with violence at the instant when the right
ventricle contracts.

So also in fishes, if the vessel which leads from the heart to the gills
be divided, at the moment when the heart becomes tense and contracted,
at the same moment does the blood flow with force from the divided

In the same way, finally, when we see the blood in arteriotomy projected
now to a greater, now to a less distance, and that the greater jet
corresponds to the diastole of the artery and to the time when the heart
contracts and strikes the ribs, and is in its state of systole, we
understand that the blood is expelled by the same movement.

From these facts it is manifest, in opposition to commonly received
opinions, that the diastole of the arteries corresponds with the time of
the heart’s systole; and that the arteries are filled and distended by
the blood forced into them by the contraction of the ventricles; the
arteries, therefore, are distended, because they are filled like sacs or
bladders, and are not filled because they expand like bellows. It is in
virtue of one and the same cause, therefore, that all the arteries of
the body pulsate, viz. the contraction of the left ventricle; in the
same way as the pulmonary artery pulsates by the contraction of the
right ventricle.

Finally, that the pulses of the arteries are due to the impulses of the
blood from the left ventricle, may be illustrated by blowing into a
glove, when the whole of the fingers will be found to become distended
at one and the same time, and in their tension to bear some resemblance
to the pulse. For in the ratio of the tension is the pulse of the heart,
fuller, stronger, more frequent as that acts more vigorously, still
preserving the rhythm and volume, and order of the heart’s contractions.
Nor is it to be expected that because of the motion of the blood, the
time at which the contraction of the heart takes place, and that at
which the pulse in an artery (especially a distant one,) is felt, shall
be otherwise than simultaneous: it is here the same as in blowing up a
glove or bladder; for in a plenum, (as in a drum, a long piece of
timber, &c.) the stroke and the motion occur at both extremities at the
same time. Aristotle,[83] too, has said, “the blood of all animals
palpitates within their veins, (meaning the arteries,) and by the pulse
is sent everywhere simultaneously.” And further,[84] “thus do all the
veins pulsate together and by successive strokes, because they all
depend upon the heart; and, as it is always in motion, so are they
likewise always moving together, but by successive movements.” It is
well to observe with Galen, in this place, that the old philosophers
called the arteries veins.

I happened upon one occasion to have a particular case under my care,
which plainly satisfied me of this truth: A certain person was affected
with a large pulsating tumour on the right side of the neck, called an
aneurism, just at that part where the artery descends into the axilla,
produced by an erosion of the artery itself, and daily increasing in
size; this tumour was visibly distended as it received the charge of
blood brought to it by the artery, with each stroke of the heart: the
connexion of parts was obvious when the body of the patient came to be
opened after his death. The pulse in the corresponding arm was small, in
consequence of the greater portion of the blood being diverted into the
tumour and so intercepted.

Whence it appears that wherever the motion of the blood through the
arteries is impeded, whether it be by compression or infarction, or
interception, there do the remote divisions of the arteries beat less
forcibly, seeing that the pulse of the arteries is nothing more than the
impulse or shock of the blood in these vessels.



Besides the motions already spoken of, we have still to consider those
that appertain to the auricles.

Caspar Bauhin and John Riolan,[85] most learned men and skilful
anatomists, inform us from their observations, that if we carefully
watch the movements of the heart in the vivisection of an animal, we
shall perceive four motions distinct in time and in place, two of which
are proper to the auricles, two to the ventricles. With all deference to
such authority I say, that there are four motions distinct in point of
place, but not of time; for the two auricles move together, and so also
do the two ventricles, in such wise that though the places be four, the
times are only two. And this occurs in the following manner:

There are, as it were, two motions going on together; one of the
auricles, another of the ventricles; these by no means taking place
simultaneously, but the motion of the auricles preceding, that of the
heart itself following; the motion appearing to begin from the auricles
and to extend to the ventricles. When all things are becoming languid,
and the heart is dying, as also in fishes and the colder blooded
animals, there is a short pause between these two motions, so that the
heart aroused, as it were, appears to respond to the motion, now more
quickly, now more tardily; and at length, and when near to death, it
ceases to respond by its proper motion, but seems, as it were, to nod
the head, and is so obscurely moved that it appears rather to give signs
of motion to the pulsating auricle, than actually to move. The heart,
therefore, ceases to pulsate sooner than the auricles, so that the
auricles have been said to outlive it, the left ventricle ceasing to
pulsate first of all; then its auricle, next the right ventricle; and,
finally, all the other parts being at rest and dead, as Galen long since
observed, the right auricle still continues to beat; life, therefore,
appears to linger longest in the right auricle. Whilst the heart is
gradually dying, it is sometimes seen to reply, after two or three
contractions of the auricles, roused as it were to action, and making a
single pulsation, slowly, unwillingly, and with an effort.

But this especially is to be noted, that after the heart has ceased to
beat, the auricles however still contracting, a finger placed upon the
ventricles perceives the several pulsations of the auricles, precisely
in the same way and for the same reason, as we have said, that the
pulses of the ventricles are felt in the arteries, to wit, the
distension produced by the jet of blood. And if at this time, the
auricles alone pulsating, the point of the heart be cut off with a pair
of scissors, you will perceive the blood flowing out upon each
contraction of the auricles. Whence it is manifest how the blood enters
the ventricles, not by any attraction or dilatation of the heart, but
thrown into them by the pulses of the auricles.

And here I would observe, that whenever I speak of pulsations as
occurring in the auricles or ventricles, I mean contractions: first the
auricles _contract_, and then and subsequently the heart itself
_contracts_. When the auricles contract they are seen to become whiter,
especially where they contain but little blood; but they are filled as
magazines or reservoirs of the blood, which is tending spontaneously
and, by the motion of the veins, under pressure towards the centre; the
whiteness indicated is most conspicuous towards the extremities or edges
of the auricles at the time of their contractions.

In fishes and frogs, and other animals which have hearts with but a
single ventricle, and for an auricle have a kind of bladder much
distended with blood, at the base of the organ, you may very plainly
perceive this bladder contracting first, and the contraction of the
heart or ventricle following afterwards.

But I think it right to describe what I have observed of an opposite
character: the heart of an eel, of several fishes, and even of some [of
the higher] animals taken out of the body, beats without auricles; nay,
if it be cut in pieces the several parts may still be seen contracting
and relaxing; so that in these creatures the body of the heart may be
seen pulsating, palpitating, after the cessation of all motion in the
auricle. But is not this perchance peculiar to animals more tenacious of
life, whose radical moisture is more glutinous, or fat and sluggish, and
less readily soluble? The same faculty indeed appears in the flesh of
eels, generally, which even when skinned and embowelled, and cut into
pieces, are still seen to move.

Experimenting with a pigeon upon one occasion, after the heart had
wholly ceased to pulsate, and the auricles too had become motionless, I
kept my finger wetted with saliva and warm for a short time upon the
heart, and observed, that under the influence of this fomentation it
recovered new strength and life, so that both ventricles and auricles
pulsated, contracting and relaxing alternately, recalled as it were from
death to life.

Besides this, however, I have occasionally observed, after the heart and
even its right auricle had ceased pulsating,--when it was in articulo
mortis in short, that an obscure motion, an undulation or palpitation,
remained in the blood itself, which was contained in the right auricle,
this being apparent so long as it was imbued with heat and spirit. And
indeed a circumstance of the same kind is extremely manifest in the
course of the generation of animals, as may be seen in the course of the
first seven days of the incubation of the chick: A drop of blood makes
its appearance which palpitates, as Aristotle had already observed; from
this, when the growth is further advanced and the chick is fashioned,
the auricles of the heart are formed, which pulsating henceforth give
constant signs of life. When at length, and after the lapse of a few
days, the outline of the body begins to be distinguished, then is the
ventricular part of the heart also produced; but it continues for a time
white and apparently bloodless, like the rest of the animal; neither
does it pulsate or give signs of motion. I have seen a similar condition
of the heart in the human fœtus about the beginning of the third month,
the heart being then whitish and bloodless, although its auricles
contained a considerable quantity of purple blood. In the same way in
the egg, when the chick was formed and had increased in size, the heart
too increased and acquired ventricles, which then began to receive and
to transmit blood.

And this leads me to remark, that he who inquires very particularly into
this matter will not conclude that the heart, as a whole, is the primum
vivens, ultimum moriens--the first part to live, the last to die, but
rather its auricles, or the part which corresponds to the auricles in
serpents, fishes, &c., which both lives before the heart[86] and dies
after it.

Nay, has not the blood itself or spirit an obscure palpitation inherent
in it, which it has even appeared to me to retain after death? and it
seems very questionable whether or not we are to say that life begins
with the palpitation or beating of the heart. The seminal fluid of all
animals--the prolific spirit, as Aristotle observed, leaves their body
with a bound and like a living thing; and nature in death, as
Aristotle[87] further remarks, retracing her steps, reverts to whence
she had set out, returns at the end of her course to the goal whence she
had started; and as animal generation proceeds from that which is not
animal, entity from non-entity, so, by a retrograde course, entity, by
corruption, is resolved into non-entity; whence that in animals, which
was last created, fails first; and that which was first, fails last.

I have also observed, that almost all animals have truly a heart, not
the larger creatures only, and those that have red blood, but the
smaller, and [seemingly] bloodless ones also, such as slugs, snails,
scallops, shrimps, crabs, crayfish, and many others; nay, even in wasps,
hornets and flies, I have, with the aid of a magnifying glass, and at
the upper part of what is called the tail, both seen the heart pulsating
myself, and shown it to many others.

But in the exsanguine tribes the heart pulsates sluggishly and
deliberately, contracting slowly as in animals that are moribund, a fact
that may readily be seen in the snail, whose heart will be found at the
bottom of that orifice in the right side of the body which is seen to be
opened and shut in the course of respiration, and whence saliva is
discharged, the incision being made in the upper aspect of the body,
near the part which corresponds to the liver.

This, however, is to be observed: that in winter and the colder season,
exsanguine animals, such as the snail, show no pulsations; they seem
rather to live after the manner of vegetables, or of those other
productions which are therefore designated plant-animals.

It is also to be noted that all animals which have a heart, have also
auricles, or something analogous to auricles; and further, that wherever
the heart has a double ventricle there are always two auricles present,
but not otherwise. If you turn to the production of the chick in ovo,
however, you will find at first no more than a vesicle or auricle, or
pulsating drop of blood; it is only by and by, when the development has
made some progress, that the heart is fashioned: even so in certain
animals not destined to attain to the highest perfection in their
organization, such as bees, wasps, snails, shrimps, crayfish, &c., we
only find a certain pulsating vesicle, like a sort of red or white
palpitating point, as the beginning or principle of their life.[88]

We have a small shrimp in these countries, which is taken in the Thames
and in the sea, the whole of whose body is transparent; this creature,
placed in a little water, has frequently afforded myself and particular
friends an opportunity of observing the motions of the heart with the
greatest distinctness, the external parts of the body presenting no
obstacle to our view, but the heart being perceived as though it had
been seen through a window.

I have also observed the first rudiments of the chick in the course of
the fourth or fifth day of the incubation, in the guise of a little
cloud, the shell having been removed and the egg immersed in clear tepid
water. In the midst of the cloudlet in question there was a bloody point
so small that it disappeared during the contraction and escaped the
sight, but in the relaxation it reappeared again, red and like the
point of a pin; so that betwixt the visible and invisible, betwixt being
and not being, as it were, it gave by its pulses a kind of
representation of the commencement of life.[89]



From these and other observations of the like kind, I am persuaded it
will be found that the motion of the heart is as follows:

First of all, the auricle contracts, and in the course of its
contraction throws the blood, (which it contains in ample quantity as
the head of the veins, the store-house and cistern of the blood,) into
the ventricle, which being filled, the heart raises itself straightway,
makes all its fibres tense, contracts the ventricles, and performs a
beat, by which beat it immediately sends the blood supplied to it by the
auricle into the arteries; the right ventricle sending its charge into
the lungs by the vessel which is called vena arteriosa, but which, in
structure and function, and all things else, is an artery; the left
ventricle sending its charge into the aorta, and through this by the
arteries to the body at large.

These two motions, one of the ventricles, another of the auricles, take
place consecutively, but in such a manner that there is a kind of
harmony or rhythm preserved between them, the two concurring in such
wise that but one motion is apparent, especially in the warmer blooded
animals, in which the movements in question are rapid. Nor is this for
any other reason than it is in a piece of machinery, in which, though
one wheel gives motion to another, yet all the wheels seem to move
simultaneously; or in that mechanical contrivance which is adapted to
firearms, where the trigger being touched, down comes the flint, strikes
against the steel, elicits a spark, which falling among the powder, it
is ignited, upon which the flame extends, enters the barrel, causes the
explosion, propels the ball, and the mark is attained--all of which
incidents, by reason of the celerity with which they happen, seem to
take place in the twinkling of an eye. So also in deglutition: by the
elevation of the root of the tongue, and the compression of the mouth,
the food or drink is pushed into the fauces, the larynx is closed by its
own muscles, and the epiglottis, whilst the pharynx, raised and opened
by its muscles no otherwise than is a sac that is to be filled, is
lifted up, and its mouth dilated; upon which, the mouthful being
received, it is forced downwards by the transverse muscles, and then
carried farther by the longitudinal ones. Yet are all these motions,
though executed by different and distinct organs, performed
harmoniously, and in such order, that they seem to constitute but a
single motion and act, which we call deglutition.

Even so does it come to pass with the motions and action of the heart,
which constitute a kind of deglutition, a transfusion of the blood from
the veins to the arteries. And if any one, bearing these things in mind,
will carefully watch the motions of the heart in the body of a living
animal, he will perceive not only all the particulars I have mentioned,
viz., the heart becoming erect, and making one continuous motion with
its auricles; but farther, a certain obscure undulation and lateral
inclination in the direction of the axis of the right ventricle, [the
organ] twisting itself slightly in performing its work. And indeed every
one may see, when a horse drinks, that the water is drawn in and
transmitted to the stomach at each movement of the throat, the motion
being accompanied with a sound, and yielding a pulse both to the ear and
the touch; in the same way it is with each motion of the heart, when
there is the delivery of a quantity of blood from the veins to the
arteries, that a pulse takes place, and can be heard within the chest.

The motion of the heart, then, is entirely of this description, and the
one action of the heart is the transmission of the blood and its
distribution, by means of the arteries, to the very extremities of the
body; so that the pulse which we feel in the arteries is nothing more
than the impulse of the blood derived from the heart.

Whether or not the heart, besides propelling the blood, giving it motion
locally, and distributing it to the body, adds anything else to
it,--heat, spirit, perfection,--must be inquired into by and by, and
decided upon other grounds. So much may suffice at this time, when it is
shown that by the action of the heart the blood is transfused through
the ventricles from the veins to the arteries, and distributed by them
to all parts of the body.

So much, indeed, is admitted by all [physiologists], both from the
structure of the heart and the arrangement and action of its valves. But
still they are like persons purblind or groping about in the dark; and
then they give utterance to diverse, contradictory, and incoherent
sentiments, delivering many things upon conjecture, as we have already
had occasion to remark.

The grand cause of hesitation and error in this subject appears to me to
have been the intimate connexion between the heart and the lungs. When
men saw both the vena arteriosa [or pulmonary artery] and the arteriæ
venosæ [or pulmonary veins] losing themselves in the lungs, of course it
became a puzzle to them to know how or by what means the right ventricle
should distribute the blood to the body, or the left draw it from the
venæ cavæ. This fact is borne witness to by Galen, whose words, when
writing against Erasistratus in regard to the origin and use of the
veins and the coction of the blood, are the following:[90] “You will
reply,” he says, “that the effect is so; that the blood is prepared in
the liver, and is thence transferred to the heart to receive its proper
form and last perfection; a statement which does not appear devoid of
reason; for no great and perfect work is ever accomplished at a single
effort, or receives its final polish from one instrument. But if this be
actually so, then show us another vessel which draws the absolutely
perfect blood from the heart, and distributes it as the arteries do the
spirits over the whole body.” Here then is a reasonable opinion not
allowed, because, forsooth, besides not seeing the true means of
transit, he could not discover the vessel which should transmit the
blood from the heart to the body at large!

But had any one been there in behalf of Erasistratus, and of that
opinion which we now espouse, and which Galen himself acknowledges in
other respects consonant with reason, to have pointed to the aorta as
the vessel which distributes the blood from the heart to the rest of
the body, I wonder what would have been the answer of that most
ingenious and learned man? Had he said that the artery transmits spirits
and not blood, he would indeed sufficiently have answered Erasistratus,
who imagined that the arteries contained nothing but spirits; but then
he would have contradicted himself, and given a foul denial to that for
which he had keenly contended in his writings against this very
Erasistratus, to wit, that blood in substance is contained in the
arteries, and not spirits; a fact which he demonstrated not only by many
powerful arguments, but by experiments.

But if the divine Galen will here allow, as in other places he does,
“that all the arteries of the body arise from the great artery, and that
this takes its origin from the heart; that all these vessels naturally
contain and carry blood; that the three semilunar valves situated at the
orifice of the aorta prevent the return of the blood into the heart, and
that nature never connected them with this, the most noble viscus of the
body, unless for some most important end;” if, I say, this father of
physic admits all these things,--and I quote his own words,--I do not
see how he can deny that the great artery is the very vessel to carry
the blood, when it has attained its highest term of perfection, from the
heart for distribution to all parts of the body. Or would he perchance
still hesitate, like all who have come after him, even to the present
hour, because he did not perceive the route by which the blood was
transferred from the veins to the arteries, in consequence, as I have
already said, of the intimate connexion between the heart and the lungs?
And that this difficulty puzzled anatomists not a little, when in their
dissections they found the pulmonary artery and left ventricle full of
thick, black, and clotted blood, plainly appears, when they felt
themselves compelled to affirm that the blood made its way from the
right to the left ventricle by sweating through the septum of the heart.
But this fancy I have already refuted. A new pathway for the blood must
therefore be prepared and thrown open, and being once exposed, no
further difficulty will, I believe, be experienced by any one in
admitting what I have already proposed in regard to the pulse of the
heart and arteries, viz. the passage of the blood from the veins to the
arteries, and its distribution to the whole of the body by means of
these vessels.



Since the intimate connexion of the heart with the lungs, which is
apparent in the human subject, has been the probable cause of the errors
that have been committed on this point, they plainly do amiss who,
pretending to speak of the parts of animals generally, as anatomists for
the most part do, confine their researches to the human body alone, and
that when it is dead. They obviously act no otherwise than he who,
having studied the forms of a single commonwealth, should set about the
composition of a general system of polity; or who, having taken
cognizance of the nature of a single field, should imagine that he had
mastered the science of agriculture; or who, upon the ground of one
particular proposition, should proceed to draw general conclusions.

Had anatomists only been as conversant with the dissection of the lower
animals as they are with that of the human body, the matters that have
hitherto kept them in a perplexity of doubt would, in my opinion, have
met them freed from every kind of difficulty.

And, first, in fishes, in which the heart consists of but a single
ventricle, they having no lungs, the thing is sufficiently manifest.
Here the sac, which is situated at the base of the heart, and is the
part analogous to the auricle in man, plainly throws the blood into the
heart, and the heart, in its turn, conspicuously transmits it by a pipe
or artery, or vessel analogous to an artery; these are facts which are
confirmed by simple ocular inspection, as well as by a division of the
vessel, when the blood is seen to be projected by each pulsation of the

The same thing is also not difficult of demonstration in those animals
that have either no more, or, as it were, no more than a single
ventricle to the heart, such as toads, frogs, serpents, and lizards,
which, although they have lungs in a certain sense, as they have a
voice, (and I have many observations by me on the admirable structure of
the lungs of these animals, and matters appertaining, which, however, I
cannot introduce in this place,) still their anatomy plainly shows that
the blood is transferred in them from the veins to the arteries in the
same manner as in higher animals, viz., by the action of the heart; the
way, in fact, is patent, open, manifest; there is no difficulty, no room
for hesitating about it; for in them the matter stands precisely as it
would in man, were the septum of his heart perforated or removed, or one
ventricle made out of two; and this being the case, I imagine that no
one will doubt as to the way by which the blood may pass from the veins
into the arteries.

But as there are actually more animals which have no lungs than there
are which be furnished with them, and in like manner a greater number
which have only one ventricle than there are which have two, it is open
to us to conclude, judging from the mass or multitude of living
creatures, that for the major part, and generally, there is an open way
by which the blood is transmitted from the veins through the sinuses or
cavities of the heart into the arteries.

I have, however, cogitating with myself, seen further, that the same
thing obtained most obviously in the embryos of those animals that have
lungs; for in the fœtus the four vessels belonging to the heart, viz.,
the vena cava, the vena arteriosa or pulmonary artery, the arteria
venalis or pulmonary vein, and the arteria magna or aorta, are all
connected otherwise than in the adult; a fact sufficiently known to
every anatomist. The first contact and union of the vena cava with the
arteria venosa or pulmonary veins, which occurs before the cava opens
properly into the right ventricle of the heart, or gives off the
coronary vein, a little above its escape from the liver, is by a lateral
anastomosis; this is an ample foramen, of an oval form, communicating
between the cava and the arteria venosa, or pulmonary vein, so that the
blood is free to flow in the greatest abundance by that foramen from the
vena cava into the arteria venosa or pulmonary vein, and left auricle,
and from thence into the left ventricle; and farther, in this foramen
ovale, from that part which regards the arteria venosa, or pulmonary
vein, there is a thin tough membrane, larger than the opening, extended
like an operculum or cover; this membrane in the adult blocking up the
foramen, and adhering on all sides, finally closes it up, and almost
obliterates every trace of it. This membrane, however, is so contrived
in the fœtus, that falling loosely upon itself, it permits a ready
access to the lungs and heart, yielding a passage to the blood which is
streaming from the cava, and hindering the tide at the same time from
flowing back into that vein. All things, in short, permit us to believe
that in the embryo the blood must constantly pass by this foramen from
the vena cava into the arteria venosa, or pulmonary vein, and from
thence into the left auricle of the heart; and having once entered
there, it can never regurgitate.

Another union is that by the vena arteriosa, or pulmonary artery, and is
effected when that vessel divides into two branches after its escape
from the right ventricle of the heart. It is as if to the two trunks
already mentioned a third were superadded, a kind of arterial canal,
carried obliquely from the vena arteriosa, or pulmonary artery, to
perforate and terminate in the arteria magna or aorta. In the embryo,
consequently, there are, as it were, two aortas, or two roots of the
arteria magna, springing from the heart. This canalis arteriosus shrinks
gradually after birth, and is at length and finally almost entirely
withered, and removed, like the umbilical vessels.

The canalis arteriosus contains no membrane or valve to direct or impede
the flow of the blood in this or in that direction: for at the root of
the vena arteriosa, or pulmonary artery, of which the canalis arteriosus
is the continuation in the fœtus, there are three sigmoid or semilunar
valves, which open from within outwards, and oppose no obstacle to the
blood flowing in this direction or from the right ventricle into the
pulmonary artery and aorta; but they prevent all regurgitation from the
aorta or pulmonic vessels back upon the right ventricle; closing with
perfect accuracy, they oppose an effectual obstacle to everything of the
kind in the embryo. So that there is also reason to believe that when
the heart contracts, the blood is regularly propelled by the canal or
passage indicated from the right ventricle into the aorta.

What is commonly said in regard to these two great communications, to
wit, that they exist for the nutrition of the lungs, is both improbable
and inconsistent; seeing that in the adult they are closed up,
abolished, and consolidated, although the lungs, by reason of their heat
and motion, must then be presumed to require a larger supply of
nourishment. The same may be said in regard to the assertion that the
heart in the embryo does not pulsate, that it neither acts nor moves, so
that nature was forced to make these communications for the nutrition of
the lungs. This is plainly false; for simple inspection of the incubated
egg, and of embryos just taken out of the uterus, shows that the heart
moves precisely in them as in adults, and that nature feels no such
necessity. I have myself repeatedly seen these motions, and Aristotle is
likewise witness of their reality. “The pulse,” he observes, “inheres in
the very constitution of the heart, and appears from the beginning, as
is learned both from the dissection of living animals, and the formation
of the chick in the egg.”[91] But we further observe, that the passages
in question are not only pervious up to the period of birth in man, as
well as in other animals, as anatomists in general have described them,
but for several months subsequently, in some indeed for several years,
not to say for the whole course of life; as, for example, in the goose,
snipe, and various birds, and many of the smaller animals. And this
circumstance it was, perhaps, that imposed upon Botallus, who thought he
had discovered a new passage for the blood from the vena cava into the
left ventricle of the heart; and I own that when I met with the same
arrangement in one of the larger members of the mouse family, in the
adult state, I was myself at first led to something of a like

From this it will be understood that in the human embryo, and in the
embryos of animals in which the communications are not closed, the same
thing happens, namely, that the heart by its motion propels the blood by
obvious and open passages from the vena cava into the aorta through the
cavities of both the ventricles; the right one receiving the blood from
the auricle, and propelling it by the vena arteriosa, or pulmonary
artery, and its continuation, named the ductus arteriosus, into the
aorta; the left, in like manner, charged by the contraction of its
auricle, which has received its supply through the foramen ovale from
the vena cava, contracting, and projecting the blood through the root of
the aorta into the trunk of that vessel.

In embryos, consequently, whilst the lungs are yet in a state of
inaction, performing no function, subject to no motion any more than if
they had not been present, nature uses the two ventricles of the heart
as if they formed but one, for the transmission of the blood. The
condition of the embryos of those animals which have lungs, whilst these
organs are yet in abeyance and not employed, is the same as that of
those animals which have no lungs.

So clearly, therefore, does it appear in the case of the fœtus, viz.,
that the heart by its action transfers the blood from the vena cava into
the aorta, and that by a route as obvious and open, as if in the adult
the two ventricles were made to communicate by the removal of their
septum. Since, then, we find that in the greater number of animals, in
all, indeed, at a certain period of their existence, the channels for
the transmission of the blood through the heart are so conspicuous, we
have still to inquire wherefore in some creatures--those, namely, that
have warm blood, and that have attained to the adult age, man among the
number--we should not conclude that the same thing is accomplished
through the substance of the lungs, which in the embryo, and at a time
when the function of these organs is in abeyance, nature effects by the
direct passages described, and which, indeed, she seems compelled to
adopt through want of a passage by the lungs; or wherefore it should be
better (for nature always does that which is best) that she should close
up the various open routes which she had formerly made use of in the
embryo and fœtus, and still uses in all other animals; not only opening
up no new apparent channels for the passage of the blood, therefore, but
even entirely shutting up those which formerly existed.

And now the discussion is brought to this point, that they who inquire
into the ways by which the blood reaches the left ventricle of the heart
and pulmonary veins from the vena cava, will pursue the wisest course if
they seek by dissection to discover the causes why in the larger and
more perfect animals of mature age, nature has rather chosen to make the
blood percolate the parenchyma of the lungs, than as in other instances
chosen a direct and obvious course--for I assume that no other path or
mode of transit can be entertained. It must be either because the larger
and more perfect animals are warmer, and when adult their heat
greater--ignited, as I might say, and requiring to be damped or
mitigated; therefore it may be that the blood is sent through the
lungs, that it may be tempered by the air that is inspired, and
prevented from boiling up, and so becoming extinguished, or something
else of the sort. But to determine these matters, and explain them
satisfactorily, were to enter on a speculation in regard to the office
of the lungs and the ends for which they exist; and upon such a subject,
as well as upon what pertains to eventilation, to the necessity and use
of the air, &c., as also to the variety and diversity of organs that
exist in the bodies of animals in connexion with these matters, although
I have made a vast number of observations, still, lest I should be held
as wandering too wide of my present purpose, which is the use and motion
of the heart, and be charged with speaking of things beside the
question, and rather complicating and quitting than illustrating it, I
shall leave such topics till I can more conveniently set them forth in a
treatise apart. And now, returning to my immediate subject, I go on with
what yet remains for demonstration, viz., that in the more perfect and
warmer adult animals, and man, the blood passes from the right ventricle
of the heart by the vena arteriosa, or pulmonary artery, into the lungs,
and thence by the arteriæ venosæ, or pulmonary veins, into the left
auricle, and thence into the left ventricle of the heart. And, first, I
shall show that this may be so, and then I shall prove that it is so in



That this is possible, and that there is nothing to prevent it from
being so, appears when we reflect on the way in which water percolating
the earth produces springs and rivulets, or when we speculate on the
means by which the sweat passes through the skin, or the urine through
the parenchyma of the kidneys. It is well known that persons who use the
Spa waters, or those of La Madonna, in the territories of Padua, or
others of an acidulous or vitriolated nature, or who simply swallow
drinks by the gallon, pass all off again within an hour or two by urine.
Such a quantity of liquid must take some short time in the concoction:
it must pass through the liver; (it is allowed by all that the juices of
the food we consume pass twice through this organ in the course of the
day;) it must flow through the veins, through the parenchyma of the
kidneys, and through the ureters into the bladder.

To those, therefore, whom I hear denying that the blood, aye the whole
mass of the blood may pass through the substance of the lungs, even as
the nutritive juices percolate the liver, asserting such a proposition
to be impossible, and by no means to be entertained as credible, I
reply, with the poet, that they are of that race of men who, when they
will, assent full readily, and when they will not, by no manner of
means; who, when their assent is wanted, fear, and when it is not, fear
not to give it.

The parenchyma of the liver is extremely dense, so is that of the
kidney; the lungs, again, are of a much looser texture, and if compared
with the kidneys are absolutely spongy. In the liver there is no
forcing, no impelling power; in the lungs the blood is forced on by the
pulse of the right ventricle, the necessary effect of whose impulse is
the distension of the vessels and pores of the lungs. And then the
lungs, in respiration, are perpetually rising and falling; motions, the
effect of which must needs be to open and shut the pores and vessels,
precisely as in the case of a sponge, and of parts having a spongy
structure, when they are alternately compressed and again are suffered
to expand. The liver, on the contrary, remains at rest, and is never
seen to be dilated and constricted. Lastly, if no one denies the
possibility of the whole of the ingested juices passing through the
liver, in man, oxen, and the larger animals generally, in order to reach
the vena cava, and for this reason, that if nourishment is to go on,
these juices must needs get into the veins, and there is no other way
but the one indicated, why should not the same arguments be held of
avail for the passage of the blood in adults through the lungs? Why not,
with Columbus, that skilful and learned anatomist, maintain and believe
the like, from the capacity and structure of the pulmonary vessels; from
the fact of the pulmonary veins and ventricle corresponding with them,
being always found to contain blood, which must needs have come from the
veins, and by no other passage save through the lungs? Columbus, and we
also, from what precedes, from dissections, and other arguments,
conceive the thing to be clear. But as there are some who admit nothing
unless upon authority, let them learn that the truth I am contending for
can be confirmed from Galen’s own words, namely, that not only may the
blood be transmitted from the pulmonary artery into the pulmonary veins,
then into the left ventricle of the heart, and from thence into the
arteries of the body, but that this is effected by the ceaseless
pulsation of the heart and the motion of the lungs in breathing.

There are, as every one knows, three sigmoid or semilunar valves
situated at the orifice of the pulmonary artery, which effectually
prevent the blood sent into the vessel from returning into the cavity of
the heart. Now Galen, explaining the uses of these valves, and the
necessity for them, employs the following language:[92] “There is
everywhere a mutual anastomosis and inosculation of the arteries with
the veins, and they severally transmit both blood and spirit, by certain
invisible and undoubtedly very narrow passages. Now if the mouth of the
vena arteriosa, or pulmonary artery, had stood in like manner
continually open, and nature had found no contrivance for closing it
when requisite, and opening it again, it would have been impossible that
the blood could ever have passed by the invisible and delicate mouths,
during the contractions of the thorax, into the arteries; for all things
are not alike readily attracted, or repelled; but that which is light is
more readily drawn in, the instrument being dilated, and forced out
again when it is contracted, than that which is heavy; and in like
manner is anything drawn more rapidly along an ample conduit, and again
driven forth, than it is through a narrow tube. But when the thorax is
contracted, the pulmonary veins, which are in the lungs, being driven
inwardly, and powerfully compressed on every side, immediately force out
some of the spirit they contain, and at the same time assume a certain
portion of blood by those subtile mouths; a thing that could never come
to pass were the blood at liberty to flow back into the heart through
the great orifice of the pulmonary artery. But its return through this
great opening being prevented, when it is compressed on every side, a
certain portion of it distils into the pulmonary veins by the minute
orifices mentioned.” And shortly afterwards, in the very next chapter,
he says: “The more the thorax contracts, the more it strives to force
out the blood, the more exactly do these membranes (viz., the sigmoid
valves) close up the mouth of the vessel, and suffer nothing to
regurgitate.” The same fact he has also alluded to in a preceding part
of the tenth chapter: “Were there no valves, a three-fold inconvenience
would result, so that the blood would then perform this lengthened
course in vain; it would flow inwards during the diastoles of the lungs,
and fill all their arteries; but in the systoles, in the manner of the
tide, it would ever and anon, like the Euripus, flow backwards and
forwards by the same way, with a reciprocating motion, which would
nowise suit the blood. This, however, may seem a matter of little
moment; but if it meantime appear that the function of respiration
suffer, then I think it would be looked upon as no trifle, &c.” And
again, and shortly afterwards: “And then a third inconvenience, by no
means to be thought lightly of, would follow, were the blood moved
backwards during the expirations, had not our Maker instituted those
supplementary membranes [the sigmoid valves].” Whence, in the eleventh
chapter, he concludes: “ That they have all a common use, (to wit, the
valves,) and that it is to prevent regurgitation or backward motion;
each, however, having a proper function, the one set drawing matters
from the heart, and preventing their return, the other drawing matters
into the heart, and preventing their escape from it. For nature never
intended to distress the heart with needless labour, neither to bring
aught into the organ which it had been better to have kept away, nor to
take from it again aught which it was requisite should be brought.
Since, then, there are four orifices in all, two in either ventricle,
one of these induces, the other educes.” And again he says: “Farther,
since there is one vessel, consisting of a simple tunic, implanted in
the heart, and another, having a double tunic, extending from it, (Galen
is here speaking of the right side of the heart, but I extend his
observations to the left side also,) a kind of reservoir had to be
provided, to which both belonging, the blood should be drawn in by the
one, and sent out by the other.”

This argument Galen adduces for the transit of the blood by the right
ventricle from the vena cava into the lungs; but we can use it with
still greater propriety, merely changing the terms, for the passage of
the blood from the veins through the heart into the arteries. From
Galen, however, that great man, that father of physicians, it clearly
appears that the blood passes through the lungs from the pulmonary
artery into the minute branches of the pulmonary veins, urged to this
both by the pulses of the heart and by the motions of the lungs and
thorax; that the heart, moreover, is incessantly receiving and expelling
the blood by and from its ventricles, as from a magazine or cistern, and
for this end is furnished with four sets of valves, two serving for the
induction and two for the eduction of the blood, lest, like the Euripus,
it should be incommodiously sent hither and thither, or flow back into
the cavity which it should have quitted, or quit the part where its
presence was required, and so the heart be oppressed with labour in
vain, and the office of the lungs be interfered with.[93] Finally, our
position that the blood is continually passing from the right to the
left ventricle, from the vena cava into the aorta, through the porous
structure of the lungs, plainly appears from this, that since the blood
is incessantly sent from the right ventricle into the lungs by the
pulmonary artery, and in like manner is incessantly drawn from the lungs
into the left ventricle, as appears from what precedes and the position
of the valves, it cannot do otherwise than pass through continuously.
And then, as the blood is incessantly flowing into the right ventricle
of the heart, and is continually passed out from the left, as appears in
like manner, and as is obvious both to sense and reason, it is
impossible that the blood can do otherwise than pass continually from
the vena cava into the aorta.

Dissection consequently shows distinctly what takes place [in regard to
the transit of the blood] in the greater number of animals, and indeed
in all, up to the period of their [fœtal] maturity; and that the same
thing occurs in adults is equally certain, both from Galen’s words, and
what has already been said on the subject, only that in the former the
transit is effected by open and obvious passages, in the latter by the
obscure porosities of the lungs and the minute inosculations of
vessels. Whence it appears that, although one ventricle of the heart,
the left to wit, would suffice for the distribution of the blood over
the body, and its eduction from the vena cava, as indeed is done in
those creatures that have no lungs, nature, nevertheless, when she
ordained that the same blood should also percolate the lungs, saw
herself obliged to add another ventricle, the right, the pulse of which
should force the blood from the vena cava through the lungs into the
cavity of the left ventricle. In this way, therefore, it may be said
that the right ventricle is made for the sake of the lungs, and for the
transmission of the blood through them, not for their nutrition; seeing
it were unreasonable to suppose that the lungs required any so much more
copious a supply of nutriment, and that of so much purer and more
spirituous a kind, as coming immediately from the ventricle of the
heart, than either the brain with its peculiarly pure substance, or the
eyes with their lustrous and truly admirable structure, or the flesh of
the heart itself, which is more commodiously nourished by the coronary



Thus far I have spoken of the passage of the blood from the veins into
the arteries, and of the manner in which it is transmitted and
distributed by the action of the heart; points to which some, moved
either by the authority of Galen or Columbus, or the reasonings of
others, will give in their adhesion. But what remains to be said upon
the quantity and source of the blood which thus passes, is of so novel
and unheard-of character, that I not only fear injury to myself from the
envy of a few, but I tremble lest I have mankind at large for my
enemies, so much doth wont and custom, that become as another nature,
and doctrine once sown and that hath struck deep root, and respect for
antiquity influence all men: Still the die is cast, and my trust is in
my love of truth, and the candour that inheres in cultivated minds. And
sooth to say, when I surveyed my mass of evidence, whether derived from
vivisections, and my various reflections on them, or from the ventricles
of the heart and the vessels that enter into and issue from them, the
symmetry and size of these conduits,--for nature doing nothing in vain,
would never have given them so large a relative size without a
purpose,--or from the arrangement and intimate structure of the valves
in particular, and of the other parts of the heart in general, with many
things besides, I frequently and seriously bethought me, and long
revolved in my mind, what might be the quantity of blood which was
transmitted, in how short a time its passage might be effected, and the
like; and not finding it possible that this could be supplied by the
juices of the ingested aliment without the veins on the one hand
becoming drained, and the arteries on the other getting ruptured through
the excessive charge of blood, unless the blood should somehow find its
way from the arteries into the veins, and so return to the right side of
the heart; I began to think whether there might not be A MOTION, AS IT
WERE, IN A CIRCLE. Now this I afterwards found to be true; and I finally
saw that the blood, forced by the action of the left ventricle into the
arteries, was distributed to the body at large, and its several parts,
in the same manner as it is sent through the lungs, impelled by the
right ventricle into the pulmonary artery, and that it then passed
through the veins and along the vena cava, and so round to the left
ventricle in the manner already indicated. Which motion we may be
allowed to call circular, in the same way as Aristotle says that the air
and the rain emulate the circular motion of the superior bodies; for the
moist earth, warmed by the sun, evaporates; the vapours drawn upwards
are condensed, and descending in the form of rain, moisten the earth
again; and by this arrangement are generations of living things
produced; and in like manner too are tempests and meteors engendered by
the circular motion, and by the approach and recession of the sun.

And so, in all likelihood, does it come to pass in the body, through the
motion of the blood; the various parts are nourished, cherished,
quickened by the warmer, more perfect, vaporous, spirituous, and, as I
may say, alimentive blood; which, on the contrary, in contact with these
parts becomes cooled, coagulated, and, so to speak, effete; whence it
returns to its sovereign the heart, as if to its source, or to the
inmost home of the body, there to recover its state of excellence or
perfection. Here it resumes its due fluidity and receives an infusion of
natural heat--powerful, fervid, a kind of treasury of life, and is
impregnated with spirits, and it might be said with balsam; and thence
it is again dispersed; and all this depends on the motion and action of
the heart.

The heart, consequently, is the beginning of life; the sun of the
microcosm, even as the sun in his turn might well be designated the
heart of the world; for it is the heart by whose virtue and pulse the
blood is moved, perfected, made apt to nourish, and is preserved from
corruption and coagulation; it is the household divinity which,
discharging its function, nourishes, cherishes, quickens the whole body,
and is indeed the foundation of life, the source of all action. But of
these things we shall speak more opportunely when we come to speculate
upon the final cause of this motion of the heart.

Hence, since the veins are the conduits and vessels that transport the
blood, they are of two kinds, the cava and the aorta; and this not by
reason of there being two sides of the body, as Aristotle has it, but
because of the difference of office; nor yet, as is commonly said, in
consequence of any diversity of structure, for in many animals, as I
have said, the vein does not differ from the artery in the thickness of
its tunics, but solely in virtue of their several destinies and uses. A
vein and an artery, both styled vein by the ancients, and that not
undeservedly, as Galen has remarked, because the one, the artery to wit,
is the vessel which carries the blood from the heart to the body at
large, the other or vein of the present day bringing it back from the
general system to the heart; the former is the conduit from, the latter
the channel to, the heart; the latter contains the cruder, effete blood,
rendered unfit for nutrition; the former transmits the digested,
perfect, peculiarly nutritive fluid.



But lest any one should say that we give them words only, and make mere
specious assertions without any foundation, and desire to innovate
without sufficient cause, three points present themselves for
confirmation, which being stated, I conceive that the truth I contend
for will follow necessarily, and appear as a thing obvious to all.
First,--the blood is incessantly transmitted by the action of the heart
from the vena cava to the arteries in such quantity, that it cannot be
supplied from the ingesta, and in such wise that the whole mass must
very quickly pass through the organ; Second,--the blood under the
influence of the arterial pulse enters and is impelled in a continuous,
equable, and incessant stream through every part and member of the body,
in much larger quantity than were sufficient for nutrition, or than the
whole mass of fluids could supply; Third,--the veins in like manner
return this blood incessantly to the heart from all parts and members of
the body. These points proved, I conceive it will be manifest that the
blood circulates, revolves, propelled and then returning, from the heart
to the extremities, from the extremities to the heart, and thus that it
performs a kind of circular motion.

Let us assume either arbitrarily or from experiment, the quantity of
blood which the left ventricle of the heart will contain when distended
to be, say two ounces, three ounces, one ounce and a half--in the dead
body I have found it to hold upwards of two ounces. Let us assume
further, how much less the heart will hold in the contracted than in the
dilated state; and how much blood it will project into the aorta upon
each contraction;--and all the world allows that with the systole
something is always projected, a necessary consequence demonstrated in
the third chapter, and obvious from the structure of the valves; and let
us suppose as approaching the truth that the fourth, or fifth, or sixth,
or even but the eighth part of its charge is thrown into the artery at
each contraction; this would give either half an ounce, or three
drachms, or one drachm of blood as propelled by the heart at each pulse
into the aorta; which quantity, by reason of the valves at the root of
the vessel, can by no means return into the ventricle. Now in the course
of half an hour, the heart will have made more than one thousand beats,
in some as many as two, three, and even four thousand. Multiplying the
number of drachms propelled by the number of pulses, we shall have
either one thousand half ounces, or one thousand times three drachms, or
a like proportional quantity of blood, according to the amount which we
assume as propelled with each stroke of the heart, sent from this organ
into the artery; a larger quantity in every case than is contained in
the whole body! In the same way, in the sheep or dog, say that but a
single scruple of blood passes with each stroke of the heart, in one
half hour we should have one thousand scruples, or about three pounds
and a half of blood injected into the aorta; but the body of neither
animal contains above four pounds of blood, a fact which I have myself
ascertained in the case of the sheep.

Upon this supposition, therefore, assumed merely as a ground for
reasoning, we see the whole mass of blood passing through the heart,
from the veins to the arteries, and in like manner through the lungs.

But let it be said that this does not take place in half an hour, but in
an hour, or even in a day; any way it is still manifest that more blood
passes through the heart in consequence of its action, than can either
be supplied by the whole of the ingesta, or than can be contained in the
veins at the same moment.

Nor can it be allowed that the heart in contracting sometimes propels
and sometimes does not propel, or at most propels but very little, a
mere nothing, or an imaginary something: all this, indeed, has already
been refuted; and is, besides, contrary both to sense and reason. For if
it be a necessary effect of the dilatation of the heart that its
ventricles become filled with blood, it is equally so that, contracting,
these cavities should expel their contents; and this not in any trifling
measure, seeing that neither are the conduits small, nor the
contractions few in number, but frequent, and always in some certain
proportion, whether it be a third or a sixth, or an eighth, to the total
capacity of the ventricles, so that a like proportion of blood must be
expelled, and a like proportion received with each stroke of the heart,
the capacity of the ventricle contracted always bearing a certain
relation to the capacity of the ventricle when dilated. And since in
dilating, the ventricles cannot be supposed to get filled with nothing,
or with an imaginary something; so in contracting they never expel
nothing or aught imaginary, but always a certain something, viz. blood,
in proportion to the amount of the contraction. Whence it is to be
inferred, that if at one stroke the heart in man, the ox or the sheep,
ejects but a single drachm of blood, and there are one thousand strokes
in half an hour, in this interval there will have been ten pounds five
ounces expelled: were there with each stroke two drachms expelled, the
quantity would of course amount to twenty pounds and ten ounces; were
there half an ounce, the quantity would come to forty-one pounds and
eight ounces; and were there one ounce it would be as much as
eighty-three pounds and four ounces; the whole of which, in the course
of one half hour, would have been transfused from the veins to the
arteries. The actual quantity of blood expelled at each stroke of the
heart, and the circumstances under which it is either greater or less
than ordinary, I leave for particular determination afterwards, from
numerous observations which I have made on the subject.

Meantime this much I know, and would here proclaim to all that the blood
is transfused at one time in larger, at another in smaller quantity; and
that the circuit of the blood is accomplished now more rapidly, now more
slowly, according to the temperament, age, &c. of the individual,
to external and internal circumstances, to naturals and
non-naturals,--sleep, rest, food, exercise, affections of the mind, and
the like. But indeed, supposing even the smallest quantity of blood to
be passed through the heart and the lungs with each pulsation, a vastly
greater amount would still be thrown into the arteries and whole body,
than could by any possibility be supplied by the food consumed; in short
it could be furnished in no other way than by making a circuit and

This truth, indeed, presents itself obviously before us when we consider
what happens in the dissection of living animals; the great artery need
not be divided, but a very small branch only, (as Galen even proves in
regard to man,) to have the whole of the blood in the body, as well
that of the veins as of the arteries, drained away in the course of no
long time--some half hour or less. Butchers are well aware of the fact
and can bear witness to it; for, cutting the throat of an ox and so
dividing the vessels of the neck, in less than a quarter of an hour they
have all the vessels bloodless--the whole mass of blood has escaped. The
same thing also occasionally occurs with great rapidity in performing
amputations and removing tumours in the human subject.

Nor would this argument lose any of its force, did any one say that in
killing animals in the shambles, and performing amputations, the blood
escaped in equal, if not perchance in larger quantity by the veins than
by the arteries. The contrary of this statement, indeed, is certainly
the truth; the veins, in fact, collapsing, and being without any
propelling power, and further, because of the impediment of the valves,
as I shall show immediately, pour out but very little blood; whilst the
arteries spout it forth with force abundantly, impetuously, and as if it
were propelled by a syringe. And then the experiment is easily tried of
leaving the vein untouched, and only dividing the artery in the neck of
a sheep or dog, when it will be seen with what force, in what abundance,
and how quickly, the whole blood in the body, of the veins as well as of
the arteries, is emptied. But the arteries receive blood from the veins
in no other way than by transmission through the heart, as we have
already seen; so that if the aorta be tied at the base of the heart, and
the carotid or any other artery be opened, no one will now be surprised
to find it empty, and the veins only replete with blood.

And now the cause is manifest, wherefore in our dissections we usually
find so large a quantity of blood in the veins, so little in the
arteries; wherefore there is much in the right ventricle, little in the
left; circumstances which probably led the ancients to believe that the
arteries (as their name implies) contained nothing but spirits during
the life of an animal. The true cause of the difference is this perhaps:
that as there is no passage to the arteries, save through the lungs and
heart, when an animal has ceased to breathe and the lungs to move, the
blood in the pulmonary artery is prevented from passing into the
pulmonary veins, and from thence into the left ventricle of the heart;
just as we have already seen the same transit prevented in the embryo,
by the want of movement in the lungs and the alternate opening and
shutting of their minute orifices and invisible pores. But the heart not
ceasing to act at the same precise moment as the lungs, but surviving
them and continuing to pulsate for a time, the left ventricle and
arteries go on distributing their blood to the body at large and sending
it into the veins; receiving none from the lungs, however, they are soon
exhausted, and left, as it were, empty. But even this fact confirms our
views, in no trifling manner, seeing that it can be ascribed to no other
than the cause we have just assumed.

Moreover it appears from this that the more frequently or forcibly the
arteries pulsate, the more speedily will the body be exhausted in an
hemorrhagy. Hence, also, it happens, that in fainting fits and in states
of alarm, when the heart beats more languidly and with less force,
hemorrhages are diminished or arrested.

Still further, it is from this that after death, when the heart has
ceased to beat, it is impossible by dividing either the jugular or
femoral veins and arteries, by any effort to force out more than one
half of the whole mass of the blood. Neither could the butcher, did he
neglect to cut the throat of the ox which he has knocked on the head and
stunned, until the heart had ceased beating, ever bleed the carcass

Finally, we are now in a condition to suspect wherefore it is that no
one has yet said anything to the purpose upon the anastomosis of the
veins and arteries, either as to where or how it is effected, or for
what purpose. I now enter upon the investigation of the subject.



So far our first position is confirmed, whether the thing be referred to
calculation or to experiment and dissection, viz., that the blood is
incessantly infused into the arteries in larger quantities than it can
be supplied by the food; so that the whole passing over in a short
space of time, it is matter of necessity that the blood perform a
circuit, that it return to whence it set out.

But if any one shall here object that a large quantity may pass through
and yet no necessity be found for a circulation, that all may come from
the meat and drink consumed, and quote as an illustration the abundant
supply of milk in the mammæ--for a cow will give three, four, and even
seven gallons and more in a day, and a woman two or three pints whilst
nursing a child or twins, which must manifestly be derived from the food
consumed; it may be answered, that the heart by computation does as much
and more in the course of an hour or two.

And if not yet convinced, he shall still insist, that when an artery is
divided a preternatural route is, as it were, opened, and that so the
blood escapes in torrents, but that the same thing does not happen in
the healthy and uninjured body when no outlet is made; and that in
arteries filled, or in their natural state, so large a quantity of blood
cannot pass in so short a space of time as to make any return
necessary;--to all this it may be answered, that from the calculation
already made, and the reasons assigned, it appears, that by so much as
the heart in its dilated state contains in addition to its contents in
the state of constriction, so much in a general way must it emit upon
each pulsation, and in such quantity must the blood pass, the body being
healthy and naturally constituted.

But in serpents, and several fishes, by tying the veins some way below
the heart, you will perceive a space between the ligature and the heart
speedily to become empty; so that, unless you would deny the evidence of
your senses, you must needs admit the return of the blood to the heart.
The same thing will also plainly appear when we come to discuss our
second position.

Let us here conclude with a single example, confirming all that has been
said, and from which every one may obtain conviction through the
testimony of his own eyes.

If a live snake be laid open, the heart will be seen pulsating quietly,
distinctly, for more than an hour, moving like a worm, contracting in
its longitudinal dimensions, (for it is of an oblong shape,) and
propelling its contents; becoming of a paler colour in the systole, of a
deeper tint in the diastole; and almost all things else by which I have
already said that the truth I contend for is established, only that
here everything takes place more slowly, and is more distinct. This
point in particular may be observed more clearly than the noon-day sun:
the vena cava enters the heart at its lower part, the artery quits it at
the superior part; the vein being now seized either with forceps or
between the finger and thumb, and the course of the blood for some space
below the heart interrupted, you will perceive the part that intervenes
between the fingers and the heart almost immediately to become empty,
the blood being exhausted by the action of the heart; at the same time
the heart will become of a much paler colour, even in its state of
dilatation, than it was before; it is also smaller than at first, from
wanting blood; and then it begins to beat more slowly, so that it seems
at length as if it were about to die. But the impediment to the flow of
blood being removed, instantly the colour and the size of the heart are

If, on the contrary, the artery instead of the vein be compressed or
tied, you will observe the part between the obstacle and the heart, and
the heart itself, to become inordinately distended, to assume a deep
purple or even livid colour, and at length to be so much oppressed with
blood that you will believe it about to be choked; but the obstacle
removed, all things immediately return to their pristine state--the
heart to its colour, size, stroke, &c.

Here then we have evidence of two kinds of death: extinction from
deficiency, and suffocation from excess. Examples of both have now been
set before you, and you have had opportunity of viewing the truth
contended for with your own eyes in the heart.



That this may the more clearly appear to every one, I have here to cite
certain experiments, from which it seems obvious that the blood enters a
limb by the arteries, and returns from it by the veins; that the
arteries are the vessels carrying the blood from the heart, and the
veins the returning channels of the blood to the heart; that in the
limbs and extreme parts of the body the blood passes either immediately
by anastomosis from the arteries into the veins, or mediately by the
pores of the flesh, or in both ways, as has already been said in
speaking of the passage of the blood through the lungs; whence it
appears manifest that in the circuit the blood moves from thence hither,
and from hence thither; from the centre to the extremities, to wit; and
from the extreme parts back again to the centre. Finally, upon grounds
of calculation, with the same elements as before, it will be obvious
that the quantity can neither be accounted for by the ingesta, nor yet
be held necessary to nutrition.

The same thing will also appear in regard to ligatures, and wherefore
they are said to _draw_; though this is neither from the heat, nor the
pain, nor the vacuum they occasion, nor indeed from any other cause yet
thought of; it will also explain the uses and advantages to be derived
from ligatures in medicine, the principle upon which they either
suppress or occasion hemorrhage; how they induce sloughing and more
extensive mortification in extremities; and how they act in the
castration of animals and the removal of warts and fleshy tumours. But
it has come to pass, from no one having duly weighed and understood the
causes and rationale of these various effects, that though almost all,
upon the faith of the old writers, recommend ligatures in the treatment
of disease, yet very few comprehend their proper employment, or derive
any real assistance from them in effecting cures.

Ligatures are either very tight or of middling tightness. A ligature I
designate as tight or perfect when it is drawn so close about an
extremity that no vessel can be felt pulsating beyond it. Such a
ligature we use in amputations to control the flow of blood; and such
also are employed in the castration of animals and the removal of
tumours. In the latter instances, all afflux of nutriment and heat being
prevented by the ligature, we see the testes and large fleshy tumours
dwindle, and die, and finally fall off.

Ligatures of middling tightness I regard as those which compress a limb
firmly all around, but short of pain, and in such a way as still suffers
a certain degree of pulsation to be felt in the artery beyond them. Such
a ligature is in use in bloodletting, an operation in which the fillet
applied above the elbow is not drawn so tight but that the arteries at
the wrist may still be felt beating under the finger.

Now let any one make an experiment upon the arm of a man, either using
such a fillet as is employed in bloodletting, or grasping the limb
lightly with his hand, the best subject for it being one who is lean,
and who has large veins, and the best time after exercise, when the body
is warm, the pulse is full, and the blood carried in larger quantity to
the extremities, for all then is more conspicuous; under such
circumstances let a ligature be thrown about the extremity, and drawn as
tightly as can be borne, it will first be perceived that beyond the
ligature, neither in the wrist nor anywhere else, do the arteries
pulsate, at the same time that immediately above the ligature the artery
begins to rise higher at each diastole, to throb more violently, and to
swell in its vicinity with a kind of tide, as if it strove to break
through and overcome the obstacle to its current; the artery here, in
short, appears as if it were preternaturally full. The hand under such
circumstances retains its natural colour and appearance; in the course
of time it begins to fall somewhat in temperature, indeed, but nothing
is _drawn_ into it.

After the bandage has been kept on for some short time in this way, let
it be slackened a little, brought to that state or term of middling
tightness which is used in bleeding, and it will be seen that the whole
hand and arm will instantly become deeply suffused and distended, and
the veins show themselves tumid and knotted; after ten or fifteen pulses
of the artery, the hand will be perceived excessively distended,
injected, gorged with blood, _drawn_, as it is said, by this middling
ligature, without pain, or heat, or any horror of a vacuum, or any other
cause yet indicated.

If the finger be applied over the artery as it is pulsating by the edge
of the fillet, at the moment of slackening it, the blood will be felt to
glide through, as it were, underneath the finger; and he, too, upon
whose arm the experiment is made, when the ligature is slackened, is
distinctly conscious of a sensation of warmth, and of something, viz., a
stream of blood suddenly making its way along the course of the vessels
and diffusing itself through the hand, which at the same time begins to
feel hot, and becomes distended.

As we had noted, in connexion with the tight ligature, that the artery
above the bandage was distended and pulsated, not below it, so, in the
case of the moderately tight bandage, on the contrary, do we find that
the veins below, never above, the fillet, swell, and become dilated,
whilst the arteries shrink; and such is the degree of distension of the
veins here, that it is only very strong pressure that will force the
blood beyond the fillet, and cause any of the veins in the upper part of
the arm to rise.

From these facts it is easy for every careful observer to learn that the
blood enters an extremity by the arteries; for when they are effectually
compressed nothing is _drawn_ to the member; the hand preserves its
colour; nothing flows into it, neither is it distended; but when the
pressure is diminished, as it is with the bleeding fillet, it is
manifest that the blood is instantly thrown in with force, for then the
hand begins to swell; which is as much as to say, that when the arteries
pulsate the blood is flowing through them, as it is when the moderately
tight ligature is applied; but where they do not pulsate, as, when a
tight ligature is used, they cease from transmitting anything; they are
only distended above the part where the ligature is applied. The veins
again being compressed, nothing can flow through them; the certain
indication of which is, that below the ligature they are much more tumid
than above it, and than they usually appear when there is no bandage
upon the arm.

It therefore plainly appears that the ligature prevents the return of
the blood through the veins to the parts above it, and maintains those
beneath it in a state of permanent distension. But the arteries, in
spite of its pressure, and under the force and impulse of the heart,
send on the blood from the internal parts of the body to the parts
beyond the bandage. And herein consists the difference between the tight
and the medium bandage, that the former not only prevents the passage of
the blood in the veins, but in the arteries also; the latter, however,
whilst it does not prevent the pulsific force from extending beyond it,
and so propelling the blood to the extremities of the body, compresses
the veins, and greatly or altogether impedes the return of the blood
through them.

Seeing, therefore, that the moderately tight ligature renders the veins
turgid, and the whole hand full of blood, I ask, whence is this? Does
the blood accumulate below the ligature coming through the veins, or
through the arteries, or passing by certain secret pores? Through the
veins it cannot come; still less can it come by any system of invisible
pores; it must needs arrive by the arteries, then, in conformity with
all that has been already said. That it cannot flow in by the veins
appears plainly enough from the fact that the blood cannot be forced
towards the heart unless the ligature be removed; when on a sudden all
the veins collapse, and disgorge themselves of their contents into the
superior parts, the hand at the same time resuming its natural pale
colour,--the tumefaction and the stagnating blood have disappeared.

Moreover, he whose arm or wrist has thus been bound for some little time
with the medium bandage, so that it has not only got swollen and livid
but cold, when the fillet is undone is aware of something cold making
its way upwards along with the returning blood, and reaching the elbow
or the axilla. And I have myself been inclined to think that this cold
blood rising upwards to the heart was the cause of the fainting that
often occurs after bloodletting: fainting frequently supervenes even in
robust subjects, and mostly at the moment of undoing the fillet, as the
vulgar say, from the turning of the blood.

Farther, when we see the veins below the ligature instantly swell up and
become gorged, when from extreme tightness it is somewhat relaxed, the
arteries meantime continuing unaffected, this is an obvious indication
that the blood passes from the arteries into the veins, and not from the
veins into the arteries, and that there is either an anastomosis of the
two orders of vessels, or pores in the flesh and solid parts generally
that are permeable to the blood. It is farther an indication that the
veins have frequent communications with one another, because they all
become turgid together, whilst under the medium ligature applied above
the elbow; and if any single small vein be pricked with a lancet, they
all speedily shrink, and disburthening themselves into this they subside
almost simultaneously.

These considerations will enable any one to understand the nature of the
attraction that is exerted by ligatures, and perchance of fluxes
generally; how, for example, the veins when compressed by a bandage of
medium tightness applied above the elbow, the blood cannot escape,
whilst it still continues to be driven in, to wit, by the forcing power
of the heart, by which the parts are of necessity filled, gorged with
blood. And how should it be otherwise? Heat and pain and the _vis vacui_
draw, indeed; but in such wise only that parts are filled, not
preternaturally distended or gorged, not so suddenly and violently
overwhelmed with the charge of blood forced in upon them, that the flesh
is lacerated and the vessels ruptured. Nothing of the kind as an effect
of heat, or pain, or the vacuum force, is either credible or

Besides, the ligature is competent to occasion the afflux in question
without either pain, or heat, or _vis vacui_. Were pain in any way the
cause, how should it happen that, with the arm bound above the elbow,
the hand and fingers should swell below the bandage, and their veins
become distended? The pressure of the bandage certainly prevents the
blood from getting there by the veins. And then, wherefore is there
neither swelling nor repletion of the veins, nor any sign or symptom of
attraction or afflux, above the ligature? But this is the obvious cause
of the preternatural attraction and swelling below the bandage, and in
the hand and fingers, that the blood is entering abundantly, and with
force, but cannot pass out again.

Now is not this the cause of all tumefaction, as indeed Avicenna has it,
and of all oppressive redundancy in parts, that the access to them is
open, but the egress from them is closed? Whence it comes that they are
gorged and tumefied. And may not the same thing happen in local
inflammations, where, so long as the swelling is on the increase, and
has not reached its extreme term, a full pulse is felt in the part,
especially when the disease is of the more acute kind, and the swelling
usually takes place most rapidly. But these are matters for after
discussion. Or does this, which occurred in my own case, happen from the
same cause. Thrown from a carriage upon one occasion, I struck my
forehead a blow upon the place where a twig of the artery advances from
the temple, and immediately, within the time in which twenty beats could
have been made, I felt a tumour the size of an egg developed, without
either heat or any great pain: the near vicinity of the artery had
caused the blood to be effused into the bruised part with unusual force
and quickness.

And now, too, we understand wherefore in phlebotomy we apply our fillet
above the part that is punctured, not below it; did the flow come from
above, not from below, the bandage in this case would not only be of no
service, but would prove a positive hinderance; it would have to be
applied below the orifice, in order to have the flow more free, did the
blood descend by the veins from superior to inferior parts; but as it is
elsewhere forced through the extreme arteries into the extreme veins,
and the return in these last is opposed by the ligature, so do they fill
and swell, and being thus filled and distended, they are made capable of
projecting their charge with force, and to a distance, when any one of
them is suddenly punctured; but the fillet being slackened, and the
returning channels thus left open, the blood forthwith no longer
escapes, save by drops; and, as all the world knows, if in performing
phlebotomy the bandage be either slackened too much or the limb be bound
too tightly, the blood escapes without force, because in the one case
the returning channels are not adequately obstructed; in the other the
channels of influx, the arteries, are impeded.



If these things be so, another point which I have already referred to,
viz., the continual passage of the blood through the heart will also be
confirmed. We have seen, that the blood passes from the arteries into
the veins, not from the veins into the arteries; we have seen, farther,
that almost the whole of the blood may be withdrawn from a puncture made
in one of the cutaneous veins of the arm if a bandage properly applied
be used; we have seen, still farther, that the blood flows so freely and
rapidly that not only is the whole quantity which was contained in the
arm beyond the ligature, and before the puncture was made, discharged,
but the whole which is contained in the body, both that of the arteries
and that of the veins.

Whence we must admit, first, that the blood is sent along with an
impulse, and that it is urged with force below the fillet; for it
escapes with force, which force it receives from the pulse and power of
the heart; for the force and motion of the blood are derived from the
heart alone. Second, that the afflux proceeds from the heart, and
through the heart by a course from the great veins [into the aorta]; for
it gets into the parts below the ligature through the arteries, not
through the veins; and the arteries nowhere receive blood from the
veins, nowhere receive blood save and except from the left ventricle of
the heart. Nor could so large a quantity of blood be drawn from one vein
(a ligature having been duly applied), nor with such impetuosity, such
readiness, such celerity, unless through the medium of the impelling
power of the heart.

But if all things be as they are now represented, we shall feel
ourselves at liberty to calculate the quantity of the blood, and to
reason on its circular motion. Should any one, for instance, in
performing phlebotomy, suffer the blood to flow in the manner it usually
does, with force and freely, for some half hour or so, no question but
that the greatest part of the blood being abstracted, faintings and
syncopes would ensue, and that not only would the arteries but the great
veins also be nearly emptied of their contents. It is only consonant
with reason to conclude that in the course of the half hour hinted at,
so much as has escaped has also passed from the great veins through the
heart into the aorta. And further, if we calculate how many ounces flow
through one arm, or how many pass in twenty or thirty pulsations under
the medium ligature, we shall have some grounds for estimating how much
passes through the other arm in the same space of time; how much through
both lower extremities, how much through the neck on either side, and
through all the other arteries and veins of the body, all of which have
been supplied with fresh blood, and as this blood must have passed
through the lungs and ventricles of the heart, and must have come from
the great veins,--we shall perceive that a circulation is absolutely
necessary, seeing that the quantities hinted at cannot be supplied
immediately from the ingesta, and are vastly more than can be requisite
for the mere nutrition of the parts.

It is still further to be observed, that the truths contended for are
sometimes confirmed in another way; for having tied up the arm properly,
and made the puncture duly, still, if from alarm or any other causes, a
state of faintness supervenes, in which the heart always pulsates more
languidly, the blood does not flow freely, but distils by drops only.
The reason is, that with the somewhat greater than usual resistance
offered to the transit of the blood by the bandage, coupled with the
weaker action of the heart, and its diminished impelling power, the
stream cannot make its way under the fillet; and farther, owing to the
weak and languishing state of the heart, the blood is not transferred in
such quantity as wont from the veins to the arteries through the sinuses
of that organ. So also, and for the same reasons, are the menstrual
fluxes of women, and indeed hemorrhagies of every kind, controlled. And
now, a contrary state of things occurring, the patient getting rid of
his fear and recovering his courage, the pulsific power is increased,
the arteries begin again to beat with greater force, and to drive the
blood even into the part that is bound; so that the blood now springs
from the puncture in the vein, and flows in a continuous stream.



Thus far have we spoken of the quantity of blood passing through the
heart and the lungs in the centre of the body, and in like manner from
the arteries into the veins in the peripheral parts and the body at
large. We have yet to explain, however, in what manner the blood finds
its way back to the heart from the extremities by the veins, and how and
in what way these are the only vessels that convey the blood from the
external to the central parts; which done, I conceive that the three
fundamental propositions laid down for the circulation of the blood will
be so plain, so well established, so obviously true, that they may claim
general credence. Now the remaining position will be made sufficiently
clear from the valves which are found in the cavities of the veins
themselves, from the uses of these, and from experiments cognizable by
the senses.

The celebrated Hieronymus Fabricius of Aquapendente, a most skilful
anatomist, and venerable old man, or, as the learned Riolan will have
it, Jacobus Silvius, first gave representations of the valves in the
veins, which consist of raised or loose portions of the inner membranes
of these vessels, of extreme delicacy, and a sigmoid or semilunar shape.
They are situated at different distances from one another, and
diversely in different individuals; they are connate at the sides of the
veins; they are directed upwards or towards the trunks of the veins; the
two--for there are for the most part two together--regard each other,
mutually touch, and are so ready to come into contact by their edges,
that if anything attempt to pass from the trunks into the branches of
the veins, or from the greater vessels into the less, they completely
prevent it; they are farther so arranged, that the horns of those that
succeed are opposite the middle of the convexity of those that precede,
and so on alternately.

The discoverer of these valves did not rightly understand their use, nor
have succeeding anatomists added anything to our knowledge: for their
office is by no means explained when we are told that it is to hinder
the blood, by its weight, from all flowing into inferior parts; for the
edges of the valves in the jugular veins hang downwards, and are so
contrived that they prevent the blood from rising upwards; the valves,
in a word, do not invariably look upwards, but always towards the trunks
of the veins, invariably towards the seat of the heart. I, and indeed
others, have sometimes found valves in the emulgent veins, and in those
of the mesentery, the edges of which were directed towards the vena cava
and vena portæ. Let it be added that there are no valves in the arteries
[save at their roots], and that dogs, oxen, &c., have invariably valves
at the divisions of their crural veins, in the veins that meet towards
the top of the os sacrum, and in those branches which come from the
haunches, in which no such effect of gravity from the erect position was
to be apprehended. Neither are there valves in the jugular veins for the
purpose of guarding against apoplexy, as some have said; because in
sleep the head is more apt to be influenced by the contents of the
carotid arteries. Neither are the valves present, in order that the
blood may be retained in the divarications or smaller trunks and minuter
branches, and not be suffered to flow entirely into the more open and
capacious channels; for they occur where there are no divarications;
although it must be owned that they are most frequent at the points
where branches join. Neither do they exist for the purpose of rendering
the current of blood more slow from the centre of the body; for it seems
likely that the blood would be disposed to flow with sufficient slowness
of its own accord, as it would have to pass from larger into
continually smaller vessels, being separated from the mass and fountain
head, and attaining from warmer into colder places.

But the valves are solely made and instituted lest the blood should pass
from the greater into the lesser veins, and either rupture them or cause
them to become varicose; lest, instead of advancing from the extreme to
the central parts of the body, the blood should rather proceed along the
veins from the centre to the extremities; but the delicate valves, while
they readily open in the right direction, entirely prevent all such
contrary motion, being so situated and arranged, that if anything
escapes, or is less perfectly obstructed by the cornua of the one above,
the fluid passing, as it were, by the chinks between the cornua, it is
immediately received on the convexity of the one beneath, which is
placed transversely with reference to the former, and so is effectually
hindered from getting any farther.

And this I have frequently experienced in my dissections of the veins:
if I attempted to pass a probe from the trunk of the veins into one of
the smaller branches, whatever care I took I found it impossible to
introduce it far any way, by reason of the valves; whilst, on the
contrary, it was most easy to push it along in the opposite direction,
from without inwards, or from the branches towards the trunks and roots.
In many places two valves are so placed and fitted, that when raised
they come exactly together in the middle of the vein, and are there
united by the contact of their margins; and so accurate is the
adaptation, that neither by the eye nor by any other means of
examination can the slightest chink along the line of contact be
perceived. But if the probe be now introduced from the extreme towards
the more central parts, the valves, like the floodgates of a river, give
way, and are most readily pushed aside. The effect of this arrangement
plainly is to prevent all motion of the blood from the heart and vena
cava, whether it be upwards towards the head, or downwards towards the
feet, or to either side towards the arms, not a drop can pass; all
motion of the blood, beginning in the larger and tending towards the
smaller veins, is opposed and resisted by them; whilst the motion that
proceeds from the lesser to end in the larger branches is favoured, or,
at all events, a free and open passage is left for it.

[Illustration: Fig. 1.]

[Illustration: Fig. 2.]

[Illustration: Fig. 3.]

[Illustration: Fig. 4.]

But that this truth may be made the more apparent, let an arm be tied up
above the elbow as if for phlebotomy (A, A, fig. 1). At intervals in the
course of the veins, especially in labouring people and those whose
veins are large, certain knots or elevations (B, C, D, E, F,) will be
perceived, and this not only at the places where a branch is received
(E, F), but also where none enters (C, D): these knots or risings are
all formed by valves, which thus show themselves externally. And now if
you press the blood from the space above one of the valves, from H to O,
(fig. 2,) and keep the point of a finger upon the vein inferiorly, you
will see no influx of blood from above; the portion of the vein between
the point of the finger and the valve O will be obliterated; yet will
the vessel continue sufficiently distended above that valve (O, G). The
blood being thus pressed out, and the vein emptied, if you now apply a
finger of the other hand upon the distended part of the vein above the
valve O, (fig. 3,) and press downwards, you will find that you cannot
force the blood through or beyond the valve; but the greater effort you
use, you will only see the portion of vein that is between the finger
and the valve become more distended, that portion of the vein which is
below the valve remaining all the while empty (H, O, fig. 3).

It would therefore appear that the function of the valves in the veins
is the same as that of the three sigmoid valves which we find at the
commencement of the aorta and pulmonary artery, viz., to prevent all
reflux of the blood that is passing over them.

Farther, the arm being bound as before, and the veins looking full and
distended, if you press at one part in the course of a vein with the
point of a finger (L, fig. 4), and then with another finger streak the
blood upwards beyond the next valve (N), you will perceive that this
portion of the vein continues empty (L N), and that the blood cannot
retrograde, precisely as we have already seen the case to be in fig. 2;
but the finger first applied (H, fig. 2, L, fig. 4), being removed,
immediately the vein is filled from below, and the arm becomes as it
appears at D C, fig. 1. That the blood in the veins therefore proceeds
from inferior or more remote to superior parts, and towards the heart,
moving in these vessels in this and not in the contrary direction,
appears most obviously. And although in some places the valves, by not
acting with such perfect accuracy, or where there is but a single valve,
do not seem totally to prevent the passage of the blood from the centre,
still the greater number of them plainly do so; and then, where things
appear contrived more negligently, this is compensated either by the
more frequent occurrence or more perfect action of the succeeding valves
or in some other way: the veins, in short, as they are the free and open
conduits of the blood returning _to_ the heart, so are they effectually
prevented from serving as its channels of distribution _from_ the heart.

But this other circumstance has to be noted: The arm being bound, and
the veins made turgid, and the valves prominent, as before, apply the
thumb or finger over a vein in the situation of one of the valves in
such a way as to compress it, and prevent any blood from passing upwards
from the hand; then, with a finger of the other hand, streak the blood
in the vein upwards till it has passed the next valve above, (N, fig.
4,) the vessel now remains empty; but the finger at L being removed for
an instant, the vein is immediately filled from below; apply the finger
again, and having in the same manner streaked the blood upwards, again
remove the finger below, and again the vessel becomes distended as
before; and this repeat, say a thousand times, in a short space of time.
And now compute the quantity of blood which you have thus pressed up
beyond the valve, and then multiplying the assumed quantity by one
thousand, you will find that so much blood has passed through a certain
portion of the vessel; and I do now believe that you will find yourself
convinced of the circulation of the blood, and of its rapid motion. But
if in this experiment you say that a violence is done to nature, I do
not doubt but that, if you proceed in the same way, only taking as great
a length of vein as possible, and merely remark with what rapidity the
blood flows upwards, and fills the vessel from below, you will come to
the same conclusion.



And now I may be allowed to give in brief my view of the circulation of
the blood, and to propose it for general adoption.

Since all things, both argument and ocular demonstration, show that the
blood passes through the lungs and heart by the action of the [auricles
and] ventricles, and is sent for distribution to all parts of the body,
where it makes its way into the veins and pores of the flesh, and then
flows by the veins from the circumference on every side to the centre,
from the lesser to the greater veins, and is by them finally discharged
into the vena cava and right auricle of the heart, and this in such a
quantity or in such a flux and reflux thither by the arteries, hither by
the veins, as cannot possibly be supplied by the ingesta, and is much
greater than can be required for mere purposes of nutrition; it is
absolutely necessary to conclude that the blood in the animal body is
impelled in a circle, and is in a state of ceaseless motion; that this
is the act or function which the heart performs by means of its pulse;
and that it is the sole and only end of the motion and contraction of
the heart.



It will not be foreign to the subject if I here show further, from
certain familiar reasonings, that the circulation is matter both of
convenience and necessity. In the first place, since death is a
corruption which takes place through deficiency of heat,[94] and since
all living things are warm, all dying things cold, there must be a
particular seat and fountain, a kind of home and hearth, where the
cherisher of nature, the original of the native fire, is stored and
preserved; whence heat and life are dispensed to all parts as from a
fountain head; whence sustenance may be derived; and upon which
concoction and nutrition, and all vegetative energy may depend. Now,
that the heart is this place, that the heart is the principle of life,
and that all passes in the manner just mentioned, I trust no one will

The blood, therefore, required to have motion, and indeed such a motion
that it should return again to the heart; for sent to the external parts
of the body far from its fountain, as Aristotle says, and without
motion, it would become congealed. For we see motion generating and
keeping up heat and spirits under all circumstances, and rest allowing
them to escape and be dissipated. The blood, therefore, become thick or
congealed by the cold of the extreme and outward parts, and robbed of
its spirits, just as it is in the dead, it was imperative that from its
fount and origin, it should again receive heat and spirits, and all else
requisite to its preservation--that, by returning, it should be
renovated and restored.

We frequently see how the extremities are chilled by the external cold,
how the nose and cheeks and hands look blue, and how the blood,
stagnating in them as in the pendent or lower parts of a corpse, becomes
of a dusky hue; the limbs at the same time getting torpid, so that they
can scarcely be moved, and seem almost to have lost their vitality. Now
they can by no means be so effectually, and especially so speedily
restored to heat and colour and life, as by a new afflux and appulsion
of heat from its source. But how can parts attract in which the heat and
life are almost extinct? Or how should they whose passages are filled
with condensed and frigid blood, admit fresh aliment--renovated
blood--unless they had first got rid of their old contents? Unless the
heart were truly that fountain where life and heat are restored to the
refrigerated fluid, and whence new blood, warm, imbued with spirits,
being sent out by the arteries, that which has become cooled and effete
is forced on, and all the particles recover their heat which was
failing, and their vital stimulus well-nigh exhausted.

Hence it is that if the heart be unaffected, life and health may be
restored to almost all the other parts of the body; but the heart being
chilled, or smitten with any serious disease, it seems matter of
necessity that the whole animal fabric should suffer and fall into
decay. When the source is corrupted, there is nothing, as Aristotle
says,[95] which can be of service either to it or aught that depends on
it. And hence, by the way, it may perchance be wherefore grief, and
love, and envy, and anxiety, and all affections of the mind of a similar
kind are accompanied with emaciation and decay, or with cacochemy and
crudity, which engender all manner of diseases and consume the body of
man. For every affection of the mind that is attended with either pain
or pleasure, hope or fear, is the cause of an agitation whose influence
extends to the heart, and there induces change from the natural
constitution, in the temperature, the pulse and the rest, which
impairing all nutrition in its source and abating the powers at large,
it is no wonder that various forms of incurable disease in the
extremities and in the trunk are the consequence, inasmuch as in such
circumstances the whole body labours under the effects of vitiated
nutrition and a want of native heat.

Moreover, when we see that all animals live through food concocted in
their interior, it is imperative that the digestion and distribution be
perfect; and, as a consequence, that there be a place and receptacle
where the aliment is perfected and whence it is distributed to the
several members. Now this place is the heart, for it is the only organ
in the body which contains blood for the general use; all the others
receive it merely for their peculiar or private advantage, just as the
heart also has a supply for its own especial behoof in its coronary
veins and arteries; but it is of the store which the heart contains in
its auricles and ventricles that I here speak; and then the heart is the
only organ which is so situated and constituted that it can distribute
the blood in due proportion to the several parts of the body, the
quantity sent to each being according to the dimensions of the artery
which supplies it, the heart serving as a magazine or fountain ready to
meet its demands.

Further, a certain impulse or force, as well as an impeller or forcer,
such as the heart, was required to effect this distribution and motion
of the blood; both because the blood is disposed from slight causes,
such as cold, alarm, horror, and the like, to collect in its source, to
concentrate like parts to a whole, or the drops of water spilt upon a
table to the mass of liquid; and then because it is forced from the
capillary veins into the smaller ramifications, and from these into the
larger trunks by the motion of the extremities and the compression of
the muscles generally. The blood is thus more disposed to move from the
circumference to the centre than in the opposite direction, were there
even no valves to oppose its motion; whence that it may leave its source
and enter more confined and colder channels, and flow against the
direction to which it spontaneously inclines, the blood requires both
force and an impelling power. Now such is the heart and the heart alone,
and that in the way and manner already explained.



There are still certain phenomena, which, taken as consequences of this
truth assumed as proven, are not without their use in exciting belief,
as it were, _a posteriore_; and which, although they may seem to be
involved in much doubt and obscurity, nevertheless readily admit of
having reasons and causes assigned for them. The phenomena alluded to
are those that present themselves in connexion with contagions, poisoned
wounds, the bites of serpents and rabid animals, lues venerea and the
like. We sometimes see the whole system contaminated, though the part
first infected remains sound; the lues venerea has occasionally made its
attack with pains in the shoulders and head, and other symptoms, the
genital organs being all the while unaffected; and then we know that the
wound made by a rabid dog having healed, fever and a train of disastrous
symptoms nevertheless supervene. Whence it appears that the contagion
impressed upon or deposited in a particular part, is by and by carried
by the returning current of blood to the heart, and by that organ is
sent to contaminate the whole body.

In tertian fever, the morbific cause seeking the heart in the first
instance, and hanging about the heart and lungs, renders the patient
short-winded, disposed to sighing, indisposed to exertion; because the
vital principle is oppressed and the blood forced into the lungs and
rendered thick, does not pass through their substance, (as I have myself
seen in opening the bodies of those who had died in the beginning of the
attack,) when the pulse is always frequent, small, and occasionally
irregular; but the heat increasing, the matter becoming attenuated, the
passages forced, and the transit made, the whole body begins to rise in
temperature, and the pulse becomes fuller, stronger--the febrile
paroxysm is fully formed, whilst the preternatural heat kindled in the
heart, is thence diffused by the arteries through the whole body along
with the morbific matter, which is in this way overcome and dissolved by

When we perceive, further, that medicines applied externally exert their
influence on the body just as if they had been taken internally, the
truth we are contending for is confirmed. Colocynth and aloes [applied
externally] move the belly, cantharides excites the urine, garlic
applied to the soles of the feet assists expectoration, cordials
strengthen, and an infinite number of examples of the same kind might be
cited. It will not, therefore, be found unreasonable perchance, if we
say that the veins, by means of their orifices, absorb some of the
things that are applied externally and carry this inwards with the
blood, not otherwise, it may be, than those of the mesentery imbibe the
chyle from the intestines and carry it mixed with the blood to the
liver. For the blood entering the mesentery by the cœliac artery, and
the superior and inferior mesenteries, proceeds to the intestines, from
which, along with the chyle that has been attracted into the veins, it
returns by their numerous ramifications into the vena portæ of the
liver, and from this into the vena cava, and this in such wise that the
blood in these veins has the same colour and consistency as in other
veins, in opposition to what many believe to be the fact. Nor indeed can
we imagine two contrary motions in any capillary system--the chyle
upwards, the blood downwards. This could scarcely take place, and must
be held as altogether improbable. But is not the thing rather arranged
as it is by the consummate providence of nature? For were the chyle
mingled with the blood, the crude with the concocted, in equal
proportions, the result would not be concoction, transmutation, and
sanguification, but rather, and because they are severally active and
passive, a mixture or combination, or medium compound of the two,
precisely as happens when wine is mixed with water and syrup. But when a
very minute quantity of chyle is mingled with a very large quantity of
circulating blood, a quantity of chyle that bears no kind of proportion
to the mass of blood, the effect is the same, as Aristotle says, as when
a drop of water is added to a cask of wine, or the contrary; the mass
does not then present itself as a mixture, but is still sensibly either
wine or water. So in the mesenteric veins of an animal we do not find
either chyme or chyle and blood, blended together or distinct, but only
blood, the same in colour, consistency, and other sensible properties,
as it appears in the veins generally. Still as there is a certain though
small and inappreciable proportion of chyle or unconcocted matter
mingled with this blood, nature has interposed the liver, in whose
meandering channels it suffers delay and undergoes additional change,
lest arriving prematurely and crude at the heart, it should oppress the
vital principle. Hence in the embryo, there is almost no use for the
liver, but the umbilical vein passes directly through, a foramen or
anastomosis existing from the vena portæ, so that the blood returns from
the intestines of the fœtus, not through the liver, but into the
umbilical vein mentioned, and flows at once into the heart, mingled with
the natural blood which is returning from the placenta; whence also it
is that in the development of the fœtus the liver is one of the organs
that is last formed; I have observed all the members perfectly marked
out in the human fœtus, even the genital organs, whilst there was yet
scarcely any trace of the liver. And indeed at the period when all the
parts, like the heart itself in the beginning, are still white, and save
in the veins there is no appearance of redness, you shall see nothing in
the seat of the liver but a shapeless collection, as it were, of
extravasated blood, which you might take for the effects of a contusion
or ruptured vein.

But in the incubated egg there are, as it were, two umbilical vessels,
one from the albumen passing entire through the liver, and going
straight to the heart; another from the yelk, ending in the vena portæ;
for it appears that the chick, in the first instance, is entirely formed
and nourished by the white; but by the yelk after it has come to
perfection and is excluded from the shell; for this part may still be
found in the abdomen of the chick many days after its exclusion, and is
a substitute for the milk to other animals.

But these matters will be better spoken of in my observations on the
formation of the fœtus, where many propositions, the following among the
number, will be discussed: Wherefore is this part formed or perfected
first, that last?--and of the several members: what part is the cause of
another? And many points having special reference to the heart, such as:
Wherefore does it first acquire consistency, and appear to possess life,
motion, sense, before any other part of the body is perfected, as
Aristotle says in his third book, De partibus Animalium? And so also of
the blood: Wherefore does it precede all the rest? And in what way does
it possess the vital and animal principle? And show a tendency to
motion, and to be impelled hither and thither, the end for which the
heart appears to be made? In the same way, in considering the pulse:
Wherefore one kind of pulse should indicate death, another recovery? And
so of all the other kinds of pulse, what may be the cause and indication
of each. So also in the consideration of crises and natural critical
discharges; of nutrition, and especially the distribution of the
nutriment; and of defluxions of every description. Finally, reflecting
on every part of medicine, physiology, pathology, semeiotics,
therapeutics, when I see how many questions can be answered, how many
doubts resolved, how much obscurity illustrated, by the truth we have
declared, the light we have made to shine, I see a field of such vast
extent in which I might proceed so far, and expatiate so widely, that
this my tractate would not only swell out into a volume, which was
beyond my purpose, but my whole life, perchance, would not suffice for
its completion.

In this place, therefore, and that indeed in a single chapter, I shall
only endeavour to refer the various particulars that present themselves
in the dissection of the heart and arteries to their several uses and
causes; for so I shall meet with many things which receive light from
the truth I have been contending for, and which, in their turn, render
it more obvious. And indeed I would have it confirmed and illustrated by
anatomical arguments above all others.

There is but a single point which indeed would be more correctly placed
among our observations on the use of the spleen, but which it will not
be altogether impertinent to notice in this place incidentally. From the
splenic branch which passes into the pancreas, and from the upper part,
arise the posterior coronary, gastric, and gastroepiploic veins, all of
which are distributed upon the stomach in numerous branches and twigs,
just as the mesenteric vessels are upon the intestines; in like manner,
from the inferior part of the same splenic branch, and along the back of
the colon and rectum proceed the hemorrhoidal veins. The blood returning
by these veins, and bringing the cruder juices along with it, on the one
hand from the stomach, where they are thin, watery, and not yet
perfectly chylified; on the other thick and more earthy, as derived from
the fæces, but all poured into this splenic branch, are duly tempered by
the admixture of contraries; and nature mingling together these two
kinds of juices, difficult of coction by reason of most opposite
defects, and then diluting them with a large quantity of warm blood,
(for we see that the quantity returned from the spleen must be very
large when we contemplate the size of its arteries,) they are brought to
the porta of the liver in a state of higher preparation; the defects of
either extreme are supplied and compensated by this arrangement of the



I do not find the heart as a distinct and separate part in all animals;
some, indeed, such as the zoophytes, have no heart; this is because
these animals are coldest, of no great bulk, of soft texture or of a
certain uniform sameness or simplicity of structure; among the number I
may instance grubs and earthworms, and those that are engendered of
putrefaction and do not preserve their species. These have no heart, as
not requiring any impeller of nourishment into the extreme parts; for
they have bodies which are connate and homogeneous, and without limbs;
so that by the contraction and relaxation of the whole body they assume
and expel, move and remove the aliment. Oysters, mussels, sponges, and
the whole genus of zoophytes or plant-animals have no heart; for the
whole body is used as a heart, or the whole animal is a heart. In a
great number of animals, almost the whole tribe of insects, we cannot
see distinctly by reason of the smallness of the body; still in bees,
flies, hornets, and the like, we can perceive something pulsating with
the help of a magnifying glass; in pediculi, also, the same thing may be
seen, and as the body is transparent, the passage of the food through
the intestines, like a black spot or stain, may be perceived by the aid
of the same magnifying glass.

In some of the bloodless[96] and colder animals, further, as in snails,
whelks, shrimps, and shell-fish, there is a part which pulsates--a kind
of vesicle or auricle without a heart--slowly indeed, and not to be
perceived save in the warmer season of the year. In these creatures this
part is so contrived that it shall pulsate, as there is here a necessity
for some impulse to distribute the nutritive fluid, by reason of the
variety of organic parts, or of the density of the substance; but the
pulsations occur unfrequently, and sometimes in consequence of the cold
not at all, an arrangement the best adapted to them as being of a
doubtful nature, so that sometimes they appear to live, sometimes to
die; sometimes they show the vitality of an animal, sometimes of a
vegetable. This seems also to be the case with the insects which conceal
themselves in winter, and lie, as it were, defunct, or merely
manifesting a kind of vegetative existence. But whether the same thing
happens in the case of certain animals that have red blood, such as
frogs, tortoises, serpents, swallows, may be made a question without any
kind of impropriety.

In all the larger and warmer, because [red-]blooded animals, there was
need of an impeller of the nutritive fluid, and that perchance
possessing a considerable amount of power. In fishes, serpents, lizards,
tortoises, frogs, and others of the same kind there is a heart present,
furnished with both an auricle and a ventricle, whence it is perfectly
true, as Aristotle has observed,[97] that no [red-]blooded animal is
without a heart, by the impelling power of which the nutritive fluid is
forced, both with greater vigour and rapidity to a greater distance; it
is not merely agitated by an auricle as it is in lower forms. And then
in regard to animals that are yet larger, warmer, and more perfect, as
they abound in blood, which is ever hotter and more spirituous, and
possess bodies of greater size and consistency, they require a larger,
stronger, and more fleshy heart, in order that the nutritive fluid may
be propelled with yet greater force and celerity. And further, inasmuch
as the more perfect animals require a still more perfect nutrition, and
a larger supply of native heat, in order that the aliment may be
thoroughly concocted and acquire the last degree of perfection, they
required both lungs and a second ventricle, which should force the
nutritive fluid through them.

Every animal that has lungs has therefore two ventricles to its heart,
one right, another left; and wherever there is a right, there also is
there a left ventricle; but the contrary of this does not hold good:
where there is a left there is not always a right ventricle. The left
ventricle I call that which is distinct in office, not in place from the
other, that one namely which distributes the blood to the body at large,
not to the lungs only. Hence the left ventricle seems to form the
principal part of the heart; situated in the middle, more strongly
marked, and constructed with greater care, the heart seems formed for
the sake of the left ventricle, and the right but to minister to it; for
the right neither reaches to the apex of the heart, nor is it nearly of
such strength, being three times thinner in its walls, and in some sort
jointed on to the left, (as Aristotle says;) though indeed it is of
greater capacity, inasmuch as it has not only to supply material to the
left ventricle, but likewise to furnish aliment to the lungs.

It is to be observed, however, that all this is otherwise in the embryo,
where there is not such a difference between the two ventricles; but as
in a double nut, they are nearly equal in all respects, the apex of the
right reaching to the apex of the left, so that the heart presents
itself as a sort of double-pointed cone. And this is so, because in the
fœtus, as already said, whilst the blood is not passing through the
lungs from the right to the left cavities of the heart, but flowing by
the foramen ovale and ductus arteriosus, directly from the vena cava
into the aorta, whence it is distributed to the whole body, both
ventricles have in fact the same office to perform, whence their
equality of constitution. It is only when the lungs come to be used,
and it is requisite that the passages indicated should be blocked up,
that the difference in point of strength and other things between the
two ventricles begin to be apparent: in the altered circumstances the
right has only to throw the blood through the lungs, whilst the left has
to impel it through the whole body.

There are further within the heart numerous braces, so to speak, fleshy
columns and fibrous bands, which Aristotle, in his third book on
Respiration, and the Parts of Animals, entitles nerves. These are
variously extended, and are either distinct or contained in grooves in
the walls and partition, where they occasion numerous pits or
depressions. They constitute a kind of small muscles, which are
superadded and supplementary to the heart, assisting it to execute a
more powerful and perfect contraction, and so proving subservient to the
complete expulsion of the blood. They are in some sort like the
elaborate and artful arrangement of ropes in a ship, bracing the heart
on every side as it contracts, and so enabling it more effectually and
forcibly to expel the charge of blood from its ventricles. This much is
plain, at all events, that some animals have them strongly marked,
others have them less so; and, in all that have them, they are more
numerous and stronger in the left than in the right ventricle; and
whilst some have them in the left, there are yet none present in the
right ventricle. In the human subject, again, these fleshy columns and
braces are more numerous in the left than in the right ventricle, and
they are more abundant in the ventricles than in the auricles;
occasionally, indeed, in the auricles there appear to be none present
whatsoever. In large, more muscular and hardier bodies, as of
countrymen, they are numerous; in more slender frames and in females
they are fewer.

In those animals in which the ventricles of the heart are smooth within,
and entirely without fibres or muscular bands, or anything like foveæ,
as in almost all the smaller birds, the partridge and the common fowl,
serpents, frogs, tortoises, and also fishes, for the major part, there
are no chordæ tendineæ, nor bundles of fibres, neither are there any
tricuspid valves in the ventricles.

Some animals have the right ventricle smooth internally, but the left
provided with fibrous bands, such as the goose, swan, and larger birds;
and the reason here is still the same as elsewhere: as the lungs are
spongy, and loose, and soft, no great amount of force is required to
force the blood through them; hence the right ventricle is either
without the bundles in question, or they are fewer and weaker, not so
fleshy or like muscles; those of the left ventricle, however, are both
stronger and more numerous, more fleshy and muscular, because the left
ventricle requires to be stronger, inasmuch as the blood which it
propels has to be driven through the whole body. And this, too, is the
reason why the left ventricle occupies the middle of the heart, and has
parietes three times thicker and stronger than those of the right. Hence
all animals--and among men it is not otherwise--that are endowed with
particularly strong frames, and that have large and fleshy limbs at a
great distance from the heart, have this central organ of greater
thickness, strength, and muscularity. And this is both obvious and
necessary. Those, on the contrary, that are of softer and more slender
make have the heart more flaccid, softer, and internally either sparely
or not at all fibrous. Consider farther the use of the several valves,
which are all so arranged, that the blood once received into the
ventricles of the heart shall never regurgitate, once forced into the
pulmonary artery and aorta shall not flow back upon the ventricles. When
the valves are raised and brought together they form a three cornered
line, such as is left by the bite of a leech; and the more they are
forced, the more firmly do they oppose the passage of the blood. The
tricuspid valves are placed, like gate-keepers, at the entrance into the
ventricles from the venæ cavæ and pulmonary veins, lest the blood when
most forcibly impelled should flow back; and it is for this reason that
they are not found in all animals; neither do they appear to have been
constructed with equal care in all the animals in which they are found;
in some they are more accurately fitted, in others more remissly or
carelessly contrived, and always with a view to their being closed under
a greater or a slighter force of the ventricle. In the left ventricle,
therefore, and in order that the occlusion may be the more perfect
against the greater impulse, there are only two valves, like a mitre,
and produced into an elongated cone, so that they come together and
touch to their middle; a circumstance which perhaps led Aristotle into
the error of supposing this ventricle to be double, the division taking
place transversely. For the same reason, indeed, and that the blood may
not regurgitate upon the pulmonary veins, and thus the force of the
ventricle in propelling the blood through the system at large come to be
neutralized, it is that these mitral valves excel those of the right
ventricle in size and strength, and exactness of closing. Hence, too, it
is essential that there can be no heart without a ventricle, since this
must be the source and storehouse of the blood. The same law does not
hold good in reference to the brain. For almost no genus of birds has a
ventricle in the brain, as is obvious in the goose and swan, the brains
of which nearly equal that of a rabbit in size; now rabbits have
ventricles in the brain, whilst the goose has none. In like manner,
wherever the heart has a single ventricle, there is an auricle appended,
flaccid, membranous, hollow, filled with blood; and where there are two
ventricles, there are likewise two auricles. On the other hand, however,
some animals have an auricle without any ventricle; or at all events
they have a sac analogous to an auricle; or the vein itself, dilated at
a particular part, performs pulsations, as is seen in hornets, bees, and
other insects, which certain experiments of my own enable me to
demonstrate have not only a pulse, but a respiration in that part which
is called the tail, whence it is that this part is elongated and
contracted now more rarely, now more frequently, as the creature appears
to be blown and to require a larger quantity of air. But of these
things, more in our Treatise on Respiration.

It is in like manner evident that the auricles pulsate, contract, as I
have said before, and throw the blood into the ventricles; so that
wherever there is a ventricle an auricle is necessary, not merely that
it may serve, according to the general belief, as a source and magazine
for the blood: for what were the use of its pulsations had it nothing to
do save to contain? No; the auricles are prime movers of the blood,
especially the right auricle, which is “the first to live, the last to
die;” as already said; whence they are subservient to sending the blood
into the ventricle, which, contracting incontinently, more readily and
forcibly expels the blood already in motion; just as the ball-player can
strike the ball more forcibly and further if he takes it on the rebound
than if he simply threw it. Moreover, and contrary to the general
opinion, since neither the heart nor anything else can dilate or distend
itself so as to draw aught into its cavity during the diastole, unless,
like a sponge, it has been first compressed, and as it is returning to
its primary condition; but in animals all local motion proceeds from,
and has its original in the contraction of some part: it is consequently
by the contraction of the auricles that the blood is thrown into the
ventricles, as I have already shown, and from thence, by the contraction
of the ventricles, it is propelled and distributed. Which truth
concerning local motions, and how the immediate moving organ in every
motion of an animal primarily endowed with a motive spirit (as Aristotle
has it,[98]) is contractile; and in what way the word νεῡρον is derived
from νεύω, nuto, contraho; and how Aristotle was acquainted with the
muscles, and did not unadvisedly refer all motion in animals to the
nerves, or to the contractile element, and therefore called those little
bands in the heart nerves--all this, if I am permitted to proceed in my
purpose of making a particular demonstration of the organs of motion in
animals from observations in my possession, I trust I shall be able to
make sufficiently plain.

But that we may go on with the subject we have in hand, viz., the use of
the auricles in filling the ventricles: we should expect that the more
dense and compact the heart, the thicker its parietes, the stronger and
more muscular must be the auricle to force and fill it, and _vice
versa_. Now this is actually so: in some the auricle presents itself as
a sanguinolent vesicle, as a thin membrane containing blood, as in
fishes, in which the sac that stands in lieu of the auricle, is of such
delicacy and ample capacity, that it seems to be suspended or to float
above the heart; in those fishes in which the sac is somewhat more
fleshy, as in the carp, barbel, tench, and others, it bears a wonderful
and strong resemblance to the lungs.

In some men of sturdier frame and stouter make, the right auricle is so
strong, and so curiously constructed within of bands and variously
interlacing fibres, that it seems to equal the ventricle of the heart in
other subjects; and I must say that I am astonished to find such
diversity in this particular in different individuals. It is to be
observed, however, that in the fœtus the auricles are out of all
proportion large, which is because they are present before the heart
[the ventricular portion] makes its appearance or suffices for its
office even when it has appeared, and they therefore have, as it were,
the duty of the whole heart committed to them, as has already been
demonstrated. But what I have observed in the formation of the fœtus as
before remarked (and Aristotle had already confirmed all in studying the
incubated egg,) throws the greatest light and likelihood upon the point.
Whilst the fœtus is yet in the guise of a soft worm, or, as is commonly
said, in the milk, there is a mere bloody point or pulsating vesicle, a
portion apparently of the umbilical vein, dilated at its commencement or
base; by and by, when the outline of the fœtus is distinctly indicated,
and it begins to have greater bodily consistence, the vesicle in
question having become more fleshy and stronger, and changed its
position, passes into the auricles, over or upon which the body of the
heart begins to sprout, though as yet it apparently performs no duty;
but when the fœtus is farther advanced, when the bones can be
distinguished from the soft parts, and movements take place, then it has
also a heart internately which pulsates, and, as I have said, throws
blood by either ventricle from the vena cava into the arteries.

Thus nature, ever perfect and divine, doing nothing in vain, has neither
given a heart where it was not required, nor produced it before its
office had become necessary; but by the same stages in the development
of every animal, passing through the constitutions of all, as I may say
(ovum, worm, fœtus), it acquires perfection in each. These points will
be found elsewhere confirmed by numerous observations on the formation
of the fœtus.

Finally, it was not without good grounds that Hippocrates, in his book,
‘De Corde,’ intitles it a muscle; as its action is the same, so is its
function, viz., to contract and move something else, in this case, the
charge of blood.

Farther, as in muscles at large, so can we infer the action and use of
the heart from the arrangement of its fibres and its general structure.
All anatomists admit with Galen that the body of the heart is made up of
various courses of fibres running straight, obliquely, and transversely,
with reference to one another; but in a heart which has been boiled the
arrangement of the fibres is seen to be different: all the fibres in the
parietes and septum are circular, as in the sphincters; those, again,
which are in the columnæ extend lengthwise, and are oblique
longitudinally; and so it comes to pass, that when all the fibres
contract simultaneously, the apex of the cone is pulled towards its base
by the columnæ, the walls are drawn circularly together into a globe,
the whole heart in short is contracted, and the ventricles narrowed; it
is therefore impossible not to perceive that, as the action of the organ
is so plainly contraction, its function is to propel the blood into the

Nor are we the less to agree with Aristotle in regard to the sovereignty
of the heart; nor are we to inquire whether it receives sense and motion
from the brain? whether blood from the liver? whether it be the origin
of the veins and of the blood? and more of the same description. They
who affirm these propositions against Aristotle, overlook, or do not
rightly understand the principal argument, to the effect that the heart
is the first part which exists, and that it contains within itself
blood, life, sensation, motion, before either the brain or the liver
were in being, or had appeared distinctly, or, at all events, before
they could perform any function. The heart, ready furnished with its
proper organs of motion, like a kind of internal creature, is of a date
anterior to the body: first formed, nature willed that it should
afterwards fashion, nourish, preserve, complete the entire animal, as
its work and dwelling place: the heart, like the prince in a kingdom, in
whose hands lie the chief and highest authority, rules over all; it is
the original and foundation from which all power is derived, on which
all power depends in the animal body.

And many things having reference to the arteries farther illustrate and
confirm this truth. Why does not the arteria venosa pulsate, seeing that
it is numbered among the arteries? Or wherefore is there a pulse in the
vena arteriosa? Because the pulse of the arteries is derived from the
impulse of the blood. Why does an artery differ so much from a vein in
the thickness and strength of its coats? Because it sustains the shock
of the impelling heart and streaming blood. Hence, as perfect nature
does nothing in vain, and suffices under all circumstances, we find that
the nearer the arteries are to the heart, the more do they differ from
the veins in structure; here they are both stronger and more
ligamentous, whilst in extreme parts of the body, such as the feet and
hands, the brain, the mesentery, and the testicles, the two orders of
vessels are so much alike that it is impossible to distinguish between
them with the eye. Now this is for the following very sufficient
reasons: for the more remote vessels are from the heart, with so much
the less force are they impinged upon by the stroke of the heart, which
is broken by the great distance at which it is given. Add to this, that
the impulse of the heart exerted upon the mass of blood, which must
needs fill the trunks and branches of the arteries, is diverted,
divided, as it were, and diminished at every subdivision; so that the
ultimate capillary divisions of the arteries look like veins, and this
not merely in constitution but in function; for they have either no
perceptible pulse, or they rarely exhibit one, and never save where the
heart beats more violently than wont, or at a part where the minute
vessel is more dilated or open than elsewhere. Hence it happens that at
times we are aware of a pulse in the teeth, in inflammatory tumours, and
in the fingers; at another time we feel nothing of the sort. Hence, too,
by this single symptom I have ascertained for certain that young
persons, whose pulses are naturally rapid, were labouring under fever;
in like manner, on compressing the fingers in youthful and delicate
subjects during a febrile paroxysm, I have readily perceived the pulse
there. On the other hand, when the heart pulsates more languidly, it is
often impossible to feel the pulse not merely in the fingers, but at the
wrist, and even at the temple; this is the case in persons afflicted
with lipothymiæ and asphyxia, and hysterical symptoms, as also in
persons of very weak constitution and in the moribund.

And here surgeons are to be advised that, when the blood escapes with
force in the amputation of limbs, in the removal of tumours, and in
wounds, it constantly comes from an artery; not always per saltum,
however, because the smaller arteries do not pulsate, especially if a
tourniquet has been applied.

And then the reason is the same wherefore the pulmonary artery has not
only the structure of an artery, but wherefore it does not differ so
widely in the thickness of its tunics from the veins as the aorta: the
aorta sustains a more powerful shock from the left ventricle than the
pulmonary artery does from the right; and the tunics of this last vessel
are thinner and softer than those of the aorta in the same proportion as
the walls of the right ventricle of the heart are weaker and thinner
than those of the left ventricle; and in like manner, in the same degree
in which the lungs are softer and laxer in structure than the flesh and
other constituents of the body at large, do the tunics of the branches
of the pulmonary artery differ from the tunics of the vessels derived
from the aorta. And the same proportion in these several particulars is
universally preserved. The more muscular and powerful men are, the
firmer their flesh, the stronger, thicker, denser, and more fibrous
their heart, in the same proportion are the auricles and arteries in all
respects thicker, closer, and stronger. And again, and on the other
hand, in those animals the ventricles of whose heart are smooth within,
without villi or valves, and the walls of which are thinner, as in
fishes, serpents, birds, and very many genera of animals, in all of them
the arteries differ little or nothing in the thickness of their coats
from the veins.

Farther, the reason why the lungs have such ample vessels, both arteries
and veins, (for the capacity of the pulmonary veins exceeds that of both
the crural and jugular vessels,) and why they contain so large a
quantity of blood, as by experience and ocular inspection we know they
do, admonished of the fact indeed by Aristotle, and not led into error
by the appearances found in animals which have been bled to death,--is,
because the blood has its fountain, and storehouse, and the workshop of
its last perfection in the heart and lungs. Why, in the same way we find
in the course of our anatomical dissections the arteria venosa and left
ventricle so full of blood, of the same black colour and clotted
character, too, as that with which the right ventricle and pulmonary
artery are filled, inasmuch as the blood is incessantly passing from one
side of the heart to the other through the lungs. Wherefore, in fine,
the pulmonary artery or vena arteriosa has the constitution of an
artery, and the pulmonary veins or arteriæ venosæ have the structure of
veins; because, in sooth, in function and constitution, and everything
else, the first is an artery, the others are veins, in opposition to
what is commonly believed; and why the pulmonary artery has so large an
orifice, because it transports much more blood than is requisite for the
nutrition of the lungs.

All these appearances, and many others, to be noted in the course of
dissection, if rightly weighed, seem clearly to illustrate and fully to
confirm the truth contended for throughout these pages, and at the same
time to stand in opposition to the vulgar opinion; for it would be very
difficult to explain in any other way to what purpose all is constructed
and arranged as we have seen it to be.











Some few months ago there appeared a small anatomical and pathological
work from the pen of the celebrated Riolanus, for which, as sent to me
by the author himself, I return him my grateful thanks.[99] I also
congratulate this author on the highly laudable undertaking in which he
has engaged. To demonstrate the seats of all diseases is a task that can
only be achieved under favour of the highest abilities; for surely he
enters on a difficult province who proposes to bring under the
cognizance of the eyes those diseases which almost escape the keenest
understanding. But such efforts become the prince of anatomists; for
there is no science which does not spring from preexisting knowledge,
and no certain and definite idea which has not derived its origin from
the senses. Induced therefore by the subject itself, and the example of
so distinguished an individual, which makes me think lightly of the
labour, I also intend putting to press my Medical Anatomy, or Anatomy in
its Application to Medicine. Not with the purpose, like Riolanus, of
indicating the seats of diseases from the bodies of healthy subjects,
and discussing the several diseases that make their appearance there,
according to the views which others have entertained of them; but that I
may relate from the many dissections I have made of the bodies of
persons diseased, worn out by serious and strange affections, how and in
what way the internal organs were changed in their situation, size,
structure, figure, consistency, and other sensible qualities, from their
natural forms and appearances, such as they are usually described by
anatomists; and in what various and remarkable ways they were affected.
For even as the dissection of healthy and well-constituted bodies
contributes essentially to the advancement of philosophy and sound
physiology, so does the inspection of diseased and cachectic subjects
powerfully assist philosophical pathology. And, indeed, the
physiological consideration of the things which are according to nature
is to be first undertaken by medical men; since that which is in
conformity with nature is right, and serves as a rule both to itself and
to that which is amiss; by the light it sheds, too, aberrations and
affections against nature are defined; pathology then stands out more
clearly; and from pathology the use and art of healing, as well as
occasions for the discovery of many new remedies, are perceived. Nor
could any one readily imagine how extensively internal organs are
altered in diseases, especially chronic diseases, and what monstrosities
among internal parts these diseases engender. So that I venture to say,
that the examination of a single body of one who has died of tabes or
some other disease of long standing, or poisonous nature, is of more
service to medicine than the dissection of the bodies of ten men who
have been hanged.

I would not have it supposed by this that I in any way disapprove of the
purpose of Riolanus, that learned and skilful anatomist; on the
contrary, I think it deserving of the highest praise, as likely to be
extremely useful to medicine, inasmuch as it illustrates the
physiological branch of this science; but I have thought that it would
scarcely turn out less profitable to the art of healing, did I place
before the eyes of my readers not only the places, but the affections of
these places, illustrating them as I proceed with observations, and
recording the results of my experience derived from my numerous

But it is imperative on me first to dispose of those observations
contained in the work referred to, which bear upon the circulation of
the blood as discovered by me, and which seem to require especial notice
at my hands. For the judgment of such a man, who is indeed the prince
and leader of all the anatomists of the present age, in such a matter,
is not to be lightly esteemed, but is rather to be held of greater
weight and authority, either for praise or blame, than the commendations
or censure of all the world besides.

Riolanus, then, admits our motion of the blood in animals,[100] and
falls in with our conclusions in regard to the circulation; yet not
entirely and avowedly; for he says[101] that the blood contained in the
vena portæ does not circulate like that in the vena cava; and again he
states[102] that there is some blood which circulates, and that the
circulatory vessels are the aorta and vena cava; but then he denies that
the continuations of these trunks have any circulation, “because the
blood is effused into all the parts of the second and third regions,
where it remains for purposes of nutrition; nor does it return to any
greater vessels, unless forcibly drawn back when there is a great lack
of blood in the main channels, or driven by a fit of passion when it
flows to the greater circulatory vessels;” and shortly afterwards:
“thus, as the blood of the veins naturally ascends incessantly or
returns to the heart, so the blood of the arteries descends or departs
from the heart; still, if the smaller veins of the arms and legs be
empty, the blood filling the empty channels in succession, may descend
in the veins, as I have clearly shown,” he says, “against Harvey and
Walæus.” And as the authority of Galen and daily experience confirm the
anastomoses of the arteries and veins, and the necessity of the
circulation of the blood, “you perceive,” he continues, “how the
circulation is effected, without any perturbation or confusion of fluids
and the destruction of the ancient system of medicine.”

These words explain the motives by which this illustrious anatomist was
actuated when he was led partly to admit, partly to deny the circulation
of the blood; and why he only ventures on an undecided and inconclusive
opinion of the subject; his fear is lest it destroy the ancient
medicine. Not yielding implicitly to the truth, which it appears he
could not help seeing, but rather guided by caution, he fears speaking
plainly out, lest he offend the ancient physic, or perhaps seem to
retract the physiological doctrines he supports in his Anthropology. The
circulation of the blood does not shake, but much rather confirms the
ancient medicine; though it runs counter to the physiology of
physicians, and their speculations upon natural subjects, and opposes
the anatomical doctrine of the use and action of the heart and lungs,
and rest of the viscera. That this is so shall readily be made to
appear, both from his own words and avowal, and partly also from what I
shall supply; viz., that the whole of the blood, wherever it be in the
living body, moves and changes its place, not merely that which is in
the larger vessels and their continuations, but that also which is in
their minute subdivisions, and which is contained in the pores or
interstices of every part; that it flows from and back to the heart
ceaselessly and without pause, and could not pause for ever so short a
time without detriment, although I admit that occasionally, and in some
places, its motion is quicker or slower.[103]

In the first place, then, our learned anatomist only denies that the
contents of the branches in continuation of the vena portæ circulate;
but he could neither oppose nor deny this, did he not conceal from
himself the force of his own arguments; for he says in his Third Book,
chap. viii, “If the heart at each pulsation admits a drop of blood which
it throws into the aorta, and in the course of an hour makes two
thousand beats, it is a necessary consequence that the quantity of blood
transmitted must be great.” He is farther forced to admit as much in
reference to the mesentery, when he sees that far more than single drops
of blood are sent into the cœliac and mesenteric arteries at each
pulsation; so that there must either be some outlet for the fluid, of
magnitude commensurate with its quantity, or the branches of the vena
portæ must give way. Nor can the explanation that is had recourse to
with a view of meeting the difficulty, viz., that the blood of the
mesentery ebbs and flows by the same channels, after the manner of
Euripus, be received as either probable or possible. Neither can the
reflux from the mesentery be effected by those passages and that system
of translation, by which he will have it to disgorge itself into the
aorta; this were against the force of the existing current, and by a
contrary motion; nor can anything like pause or alternation be admitted,
where there is very certainly an incessant influx: the blood sent into
the mesentery must as inevitably go elsewhere as that which is poured
into the heart. And this is obvious; were it otherwise, indeed,
everything like a circulation might be overturned upon the same showing
and by the same subterfuge; it might just as well be said that the blood
contained in the left ventricle of the heart is propelled into the aorta
during the systole, and flows back to it during the diastole, the aorta
disgorging itself into the ventricle, precisely as the ventricle has
disgorged itself into the aorta. There would thus be circulation neither
in the heart nor in the mesentery, but an alternate flux and reflux,--a
useless labour, as it seems. If, therefore, and for the reason assigned
and approved by him, a circulation through the heart be argued for as a
thing necessary, the argument has precisely the same force when applied
to the mesentery: if there be no circulation in the mesentery, neither
is there any in the heart; for both affirmations, this in reference to
the heart, that in reference to the mesentery, merely changing the
words, stand or fall together, by force of the very same arguments.

He says: “The sigmoid valves prevent regurgitation into the heart; but
there are no valves in the mesentery.” To this I reply, that the thing
is not so; for there is a valve in the splenic vein, and sometimes also
in other veins. And besides, valves are not met with universally in
veins; there are few or none in the deep-seated veins of the
extremities, but many in the subcutaneous branches. For where the blood
is flowing naturally from smaller into greater branches, into which it
is disposed to enter, the pressure of the circumjacent muscles is
enough, and more than enough to prevent all retrograde movement, and it
is forced on where the way lies open; in such circumstances, what use
were there for valves? But the quantity of blood that is forced into the
mesentery by each stroke of the heart, may be estimated in the same way
as you estimate the quantity impelled into the hand when you bind a
ligature with medium tightness about the wrist: if in so many beats the
vessels of the hand become distended, and the whole extremity swells,
you will find, that much more than a single drop of blood has entered
with each pulse, and which cannot return, but must remain to fill the
hand and increase its size. But analogy permits us to say, that the same
thing takes place in reference to the mesentery and its vessels, in an
equal degree at least, if not in a greater degree, seeing that the
vessels of the mesentery are considerably larger than those of the
carpus. And if any one will but think on the difficulty that is
experienced with all the aid supplied by compresses, bandages, and a
multiplied apparatus, in restraining the flow of blood from the smallest
artery when wounded, with what force it overcomes all obstacles and
soaks through the whole apparatus, he will scarcely, I imagine, think it
likely that there can be any retrograde motion against such an impulse
and influx of blood, any retrograde force to meet and overcome a direct
force of such power. Turning over these things in his mind, I say, no
one will ever be brought to believe that the blood from the branches of
the vena portæ can possibly make its way by the same channels against an
influx by the artery of such impetuosity and force, and so unload the

Moreover, if the learned anatomist does not think that the blood is
moved and changed by a circular motion, but that the same fluid always
stagnates in the channels of the mesentery, he appears to suppose that
there are two descriptions of blood, serving different uses and ends;
that the blood of the vena portæ, and that of the vena cava are
dissimilar in constitution, seeing that the one requires a circulation
for its preservation, the other requires nothing of the kind; which
neither appears on the face of the thing, nor is its truth demonstrated
by him. Our author then refers to “A fourth order of mesenteric vessels,
the lacteal vessels, discovered by Asellius;0”[104] and having mentioned
these, he seems to infer that they extract all the nutriment from the
intestines, and transfer this to the liver, the workshop of the blood,
whence, having been concocted and changed into blood, (so he says in his
third book, chapter the 8th), the blood is transferred from the liver to
the right ventricle of the heart. “Which things premised,” he
continues,[105] “all the difficulties which were formerly experienced in
regard to the distribution of the chyle and blood by the same channel
come to an end; for the lacteal veins carry the chyle to the liver, and
as these canals are distinct, so may they be severally obstructed.” But
truly I would here ask: how this milky fluid can be poured into and pass
through the liver, and how from thence gain the vena cava and the
ventricle of the heart? when our author denies that the blood of the
vena portæ passes through the liver, and that so a circulation is
established. I pause for a reply. I would fain know how such a thing can
be shown to be probable; especially when the blood appears to be both
more spirituous or subtile and penetrating than the chyle or milk
contained in these lacteal vessels, and is further impelled by the
pulsations of the arteries that it may find a passage by other channels.

Our learned author mentions a certain tract of his on the Circulation of
the Blood: I wish I could obtain a sight of it; perhaps I might retract.
But had the learned writer been so disposed, I do not see but that
having admitted the circular motion of the blood,[106] all the
difficulties which were formerly felt in connexion with the distribution
of the chyle and the blood by the same channels are brought to an
equally satisfactory solution; so much so indeed that there would be no
necessity for inquiring after or laying down any separate vessels for
the chyle. Even as the umbilical veins absorb the nutritive juices from
the fluids of the egg and transport them for the nutrition and growth of
the chick, in its embryo state, so do the meseraic veins suck up the
chyle from the intestines and transfer it to the liver; and why should
we not maintain that they perform the same office in the adult? For all
the mooted difficulties vanish when we cease to suppose two contrary
motions in the same vessels, and admit but one and the same continuous
motion in the mesenteric vessels from the intestines to the liver.

I shall elsewhere state my views of the lacteal veins when I treat of
the milk found in different parts of new-born animals, especially of the
human subject; for it is met with in the mesentery and all its glands,
in the thymus, in the axillæ, also in the breasts of infants. This milk
the midwifes are in the habit of pressing out, for the health, as they
believe, of the infants. But it has pleased the learned Riolanus, not
only to take away circulation from the blood contained in the mesentery;
he affirms that neither do the vessels in continuation of the vena cava,
nor the arteries, nor any of the parts of the second and third regions,
admit of circulation, so that he entitles and enumerates as circulating
vessels the vena cava and aorta only. For this he appears to me to give
a very indifferent reason:[107] “The blood,” he says, “effused into all
the parts of the second and third regions, remains there for their
nutrition; nor does it return to the great vessels, unless forcibly
drawn back by an extreme dearth of blood in the great vessels, nor,
unless carried by an impulse, does it flow to the circulatory vessels.”

That so much of the blood must remain as is appropriated to the
nutrition of the tissues, is matter of necessity; for it cannot nourish
unless it be assimilated and become coherent, and form substance in lieu
of that which is lost; but that the whole of the blood which flows into
a part should there remain, in order that so small a portion should
undergo transformation, is nowise necessary; for no part uses so much
blood for its nutrition as is contained in its arteries, veins, and
interstices. Nor because the blood is continually coming and going is it
necessary to suppose that it leaves nothing for nutriment behind it.
Consequently it is by no means necessary that the whole remain in order
that nutrition be effected. But our learned author, in the same book,
where he affirms so much, appears almost everywhere else to assert the
contrary. In that paragraph especially where he describes the
circulation in the brain, he says: “And the brain by means of the
circulation sends back blood to the heart, and thus refrigerates the
organ.” And in the same way are all the more remote parts said to
refrigerate the heart; thus in fevers, when the præcordia are scorched
and burn with febrile heat, patients baring their limbs and casting off
the bedclothes, seek to cool their heart; and the blood generally,
tempered and cooled down, as our learned author states it to be with
reference to the brain in particular, returns by the veins and
refrigerates the heart. Our author, therefore, appears to insinuate a
certain necessity for a circulation from every part, as well as from the
brain, in opposition to what he had before said in very precise terms.
But then he cautiously and ambiguously asserts, that the blood does not
return from the parts composing the second and third regions, unless, as
he says, it is drawn by force, and through a signal deficiency of blood
in the larger vessels, &c., which is most true if these words be rightly
understood; for by the larger vessels, in which the deficiency is said
to cause the reflux, I think he must be held to mean the veins not the
arteries; for the arteries are never emptied, save into the veins or
interstices of parts, but are incessantly filled by the strokes of the
heart; but in the vena cava and other returning channels, in which the
blood glides rapidly on, hastening to the heart, there would speedily
be a great deficiency of blood did not every part incessantly restore
the blood that is incessantly poured into it. Add to this, that by the
impulse of the blood which is forced with each stroke into every part of
the second and third regions, that which is contained in the pores or
interstices is urged into the smaller veins, from which it passes into
larger vessels, its motion assisted besides by the motion and pressure
of circumjacent parts; for from every containing thing compressed and
constringed, contained matters are forced out. And thus it is that by
the motions of the muscles and extremities, the blood contained in the
minor vessels is forced onwards and delivered into the larger trunks.
But that the blood is incessantly driven from the arteries into every
part of the body, there gives a pulse and never flows back in these
channels, cannot be doubted, if it be admitted that with each pulse of
the heart all the arteries are simultaneously distended by the blood
sent into them; and as our learned author himself allows that the
diastole of the arteries is occasioned by the systole of the heart, and
that the blood once out of the heart can never get back into the
ventricles by reason of the opposing valves; if I say, our learned
author believes that these things are so, it will be as manifestly true
with regard to the force and impulse by which the blood contained in the
vessels is propelled into every part of every region of the body. For
wheresoever the arteries pulsate, so far must the impulse and influx
extend, and therefore is the impulse felt in every part of each several
region; for there is a pulse everywhere, to the very points of the
fingers and under the nails, nor is there any part of the body where the
shooting pain that accompanies each pulse of the artery, and the effort
made to effect a solution of the continuity is not experienced when it
is the seat of a phlegmon or furuncle.

But, further, that the blood contained in the pores of the living
tissues returns to the heart, is manifest from what we observe in the
hands and feet. For we frequently see the hands and feet, in young
persons especially, during severe weather, become so cold that to the
touch they feel like ice, and they are so benumbed and stiffened that
they seem scarcely to retain a trace of sensibility or to be capable of
any motion; still are they all the while surcharged with blood, and look
red or livid. Yet can the extremities be warmed in no way, save by
circulation; the chilled blood, which has lost its spirit and heat,
being driven out, and fresh, warm, and vivified blood flowing in by the
arteries in its stead, which fresh blood cherishes and warms the parts,
and restores to them sense and motion; nor could the extremities be
restored by the warmth of a fire or other external heat, any more than
those of a dead body could be so recovered: they are only brought to
life again, as it were, by an influx of internal warmth. And this indeed
is the principal use and end of the circulation; it is that for which
the blood is sent on its ceaseless course, and to exert its influence
continually in its circuit, to wit, that all parts dependent on the
primary innate heat may be retained alive, in their state of vital and
vegetative being, and apt to perform their functions; whilst, to use the
language of physiologists, they are sustained and actuated by the
inflowing heat and vital spirits. Thus, by the aid of two extremes, viz.
cold and heat, is the temperature of the animal body retained at its
mean. For as the air inspired tempers the too great heat of the blood in
the lungs and centre of the body, and effects the expulsion of
suffocating fumes, so in its turn does the hot blood, thrown by the
arteries into all parts of the body, cherish and nourish and keep them
in life, defending them from extinction through the power of external

It would, therefore, be in some sort unfair and extraordinary did not
every particle composing the body enjoy the advantages of the
circulation and transmutation of the blood; the ends for which the
circulation was mainly established by nature would no longer be
effected. To conclude then: you see how circulation may be accomplished
without confusion or admixture of humours, through the whole body, and
each of its individual parts, in the smaller as well as in the larger
vessels; and all as matter of necessity and for the general advantage;
without circulation, indeed, there would be no restoration of chilled
and exhausted parts, no continuance of these in life; since it is
apparent enough that the whole influence of the preservative heat comes
by the arteries, and is the work of the circulation.

It, therefore, appears to me that the learned Riolanus speaks rather
expediently than truly, when in his Enchiridion he denies a circulation
to certain parts; it would seem as though he had wished to please the
mass, and oppose none; to have written with such a bias rather than
rigidly and in behalf of the simple truth. This is also apparent when he
would have the blood to make its way into the left ventricle through the
septum of the heart, by certain invisible and unknown passages, rather
than through those ample and abundantly pervious channels, the pulmonary
vessels, furnished with valves, opposing all reflux or regurgitation. He
informs us that he has elsewhere discussed the reasons of the
impossibility or inconvenience of this: I much desire to see his
disquisition. It would be extraordinary, indeed, were the aorta and
pulmonary artery, with the same dimensions, properties, and structure,
not to have the same functions. But it would be more wonderful still
were the whole tide of the blood to reach the left ventricle by a set of
inscrutable passages of the septum, a tide which, in quantity must
correspond, first to the influx from the vena cava into the right side
of the heart, and next to the efflux from the left, both of which
require such ample conduits. But our author has adduced these matters
inconsistently, for he has established the lungs as an emunctory or
passage from the heart;[108] and he says: “The lung is affected by the
blood which passes through it, the sordes flowing along with the blood.”
And, again: “The lungs receive injury from distempered and
ill-conditioned viscera; these deliver an impure blood to the heart,
which it cannot correct except by multiplied circulations.” In the same
place, he further proceeds, whilst speaking against Galen of
bloodletting in peripneumonia and the communication of the veins: “Were
it true that the blood naturally passed from the right ventricle of the
heart to the lungs, that it might be carried into the left ventricle and
from thence into the aorta; and were the circulation of the blood
admitted, who does not see that in affections of the lungs the blood
would flow to them in larger quantity and would oppress them, unless it
were taken away, first, freely, and then in repeated smaller quantities
in order to relieve them, which indeed was the advice of Hippocrates,
who, in affections of the lungs takes away blood from every part--the
head, nose, tongue, arms and feet, in order that its quantity may be
diminished and a diversion effected from the lungs; he takes away blood
till the body is almost bloodless. Now admitting the circulation, the
lungs are most readily depleted by opening a vein; but rejecting it, I
do not see how any revulsion of the blood can be accomplished by this
means; for did it flow back by the pulmonary artery upon the right
ventricle, the sigmoid valves would oppose its entrance, and any escape
from the right ventricle into the vena cava is prevented by the
tricuspid valves. The blood, therefore, is soon exhausted when a vein is
opened in the arm or foot, if we admit the circulation; and the opinion
of Fernelius is at the same time upset by this admission, viz. that in
affections of the lungs it is better to bleed from the right than the
left arm; because the blood cannot flow backwards into the vena cava
unless the two barriers situated in the heart be first broken down.”

He adds yet further in the same place:[109] “If the circulation of the
blood be admitted, and it be acknowledged that this fluid generally
passes through the lungs, not through the middle partition of the heart,
a double circulation becomes requisite; one effected through the lungs,
in the course of which the blood quitting the right ventricle of the
heart passes through the lungs in order that it may arrive at the left
ventricle; leaving the heart on the one hand, therefore, the blood
speedily returns to it again; another and longer circulation proceeding
from the left ventricle of the heart performs the circuit of the whole
body by the arteries, and by the veins returns to the right side of the

The learned anatomist might here have added a third and extremely short
circulation, viz.--from the left to the right ventricle of the heart,
with that blood which courses through the coronary arteries and veins,
and by their ramifications is distributed to the body, walls, and septum
of the heart.

“He who admits one circulation,” proceeds our author, “cannot repudiate
the other;” and he might, as it appears, have added, “the third.” For
why should the coronary arteries of the heart pulsate, if it were not to
force on the blood by their pulsations? and why should there be coronary
veins, the end and office of all veins being to receive the blood
brought by the arteries, were it not to deliver and discharge the blood
sent into the substance of the heart? In this consideration let it be
remembered that a valve is very commonly found at the orifice of the
coronary vein, as our learned author himself admits,[110] preventing all
ingress, but offering no obstacle to the egress of the blood. It
therefore seems that he cannot do otherwise than admit this third
circulation, who acknowledges a general circulation through the body,
and that the blood also passes through the lungs and the brain.[111]
Nor, indeed, can he deny a similar circulation to every other part of
every other region. The blood flowing in under the influence of the
arterial pulse, and returning by the veins, every particle of the body
has its circulation.

From the words of our learned writer quoted above, consequently, his
opinion may be gathered both of the general circulation, and then of the
circulation through the lungs and the several parts of the body; for he
who admits the first, manifestly cannot refuse to acknowledge the
others. How indeed could he who has repeatedly asserted a circulation
through the general system and the greater vessels, deny a circulation
in the branches continuous with these vessels, or in the several parts
of the second and third regions? as if all the veins, and those he calls
greater circulatory vessels, were not enumerated by every anatomist, and
by himself, as being within the second region of the body. Is it
possible that there can be a circulation which is universal, and which
yet does not extend through every part? Where he denies it, then, he
does so hesitatingly, and vaccillates between negations, giving us mere
words. Where he asserts the circulation, on the contrary, he speaks out
heartily, and gives sufficient reasons, as becomes a philosopher; and
then, when he relies on this opinion in a particular instance, he
delivers himself like an experienced physician and honest man, and, in
opposition to Galen and his favorite Fernelius, advises bloodletting as
the chief remedy in dangerous diseases of the lungs.

No learned man and Christian, having doubts in such a case, would have
recommended his experience to posterity, to the imminent risk, and even
loss of human life; neither would he without very sufficient reasons,
have repudiated the authority of Galen and Fernelius, which has usually
such weight with him. Whatever he has denied in the circulation of the
blood, therefore, whether with reference to the mesentery or any other
part, and with an eye to the lacteal veins or the ancient system of
physic, or any other consideration, must be ascribed to his courtesy and
modesty, and is to be excused.

Thus far, I think, it appears plain enough, from the very words and
arguments of our author, that there is a circulation everywhere; that
the blood, wherever it is, changes its place, and by the veins returns
to the heart; so that our learned author seems to be of the same opinion
as myself. It would therefore be labour in vain, did I here quote at
greater length the various reasons which I have consigned in my work on
the Motion of the Blood, in confirmation of my opinions, and which are
derived from the structure of the vessels, the position of the valves,
and other matters of experience and observation; and this the more, as I
have not yet seen the treatise on the Circulation of the Blood of the
learned writer; nor, indeed, have I yet met with a single argument of
his, or more than his simple negation, which would lead me to see
wherefore he should reject a circulation which he admits as universal,
in certain parts, regions, and vessels.

It is true that by way of subterfuge he has recourse to an anastomosis
of the vessels on the authority of Galen, and the evidence of daily
experience. But so distinguished a personage, an anatomist so expert, so
inquisitive, and careful, should first have shown anastomoses between
the larger arteries and larger veins, and these, both obvious and ample,
having mouths in relation with such a torrent as is constituted by the
whole mass of the blood, and larger than the capacity of the continuous
branches, (from which he takes away all circulation,) before he had
rejected those that are familiarly known, that are more likely and more
open; he ought to have clearly shown us where these anastomoses are, and
how they are fashioned, whether they be adapted only to permit the
access of the blood into the veins, and not to allow of its
regurgitation, in the same way as we see the ureters connected with the
urinary bladder, or in what other manner things are contrived. But--and
here I speak over boldly perhaps--neither our learned author himself,
nor Galen, nor any experience, has ever succeeded in making such
anastomoses as he imagines, sensible to the eye.

I have myself pursued this subject of the anastomosis with all the
diligence I could command, and have given not a little both of time and
labour to the inquiry; but I have never succeeded in tracing any
connexion between arteries and veins by a direct anastomosis of their
orifices. I would gladly learn of those who give so much to Galen, how
they dare swear to what he says. Neither in the liver, spleen, lungs,
kidneys, nor any other viscus, is such a thing as an anastomosis to be
seen; and by boiling, I have rendered the whole parenchyma of these
organs so friable that it could be shaken like dust from the fibres, or
picked away with a needle, until I could trace the fibres of every
subdivision, and see every capillary filament distinctly. I can
therefore boldly affirm, that there is neither any anastomosis of the
vena portæ with the cava, of the arteries with the veins, or of the
capillary ramifications of the biliary ducts, which can be traced
through the entire liver, with the veins. This alone may be observed in
the recent liver: all the branches of the vena cava ramifying through
the convexity of the liver, have their tunics pierced with an infinity
of minute holes, as is a sieve, and are fashioned to receive the blood
in its descent. The branches of the porta are not so constituted, but
simply spread out in subdivisions; and the distribution of these two
vessels is such, that whilst the one runs upon the convexity, the other
proceeds along the concavity of the liver to its outer margin, and all
the while without anastomosing.

In three places only do I find anything that can be held equivalent to
an anastomosis. From the carotids, as they are creeping over the base of
the brain, numerous interlaced fibres arise, which afterwards form the
choroid plexus, and passing through the lateral ventricles, finally
unite and terminate in the third sinus, which performs the office of a
vein. In the spermatic vessels, commonly called vasa præparantia,
certain minute arteries proceeding from the great artery adhere to the
venæ præparantes, which they accompany, and are at length taken in and
included within their coats, in such a way that they seem to have a
common ending, so that where they terminate on the upper portion of the
testis, on that cone-shaped process called the corpus varicosum et
pampiniforme, it is altogether uncertain whether we are to regard their
terminations as veins, or as arteries, or as both. In the same way are
the ultimate ramifications of the arteries which run to the umbilical
vein, lost in the tunics of this vessel.

What doubt can there be, if by such channels the great arteries,
distended by the stream of blood sent into them, are relieved of so
great and obvious a torrent, but that nature would not have denied
distinct and visible passages, vortices, and estuaries, had she intended
to divert the whole current of the blood, and had wished in this way to
deprive the lesser branches and the solid parts of all the benefit of
the influx of that fluid?

Finally, I shall quote this single experiment, which appears to me
sufficient to clear up all doubts about the anastomoses, and their uses,
if any exist, and to set at rest the question of a passage of the blood
from the veins to the arteries, by any special channels, or by

Having laid open the thorax of an animal, and tied the vena cava near
the heart, so that nothing shall pass from that vessel into its
cavities, and immediately afterwards, having divided the carotid
arteries on both sides, the jugular veins being left untouched; if the
arteries be now perceived to become empty but not the veins, I think it
will be manifest that the blood does nowhere pass from the veins into
the arteries except through the ventricles of the heart. Were it not so,
as observed by Galen, we should see the veins as well as the arteries
emptied in a very short time, by the efflux from their corresponding

For what further remains, oh Riolanus! I congratulate both myself and
you: myself, for the opinion with which you have graced my circulation;
and you, for your learned, polished, and terse production, than which
nothing more elegant can be imagined. For the favour you have done me in
sending me this work, I feel most grateful, and I would gladly, as in
duty bound, proclaim my sense of its merits, but I confess myself
unequal to the task; for I know that the Enchiridion bearing the name of
Riolanus inscribed upon it, has thereby more of honour conferred upon it
than it can derive from any praise of mine, which nevertheless I would
yield without reserve. The famous book will live for ever; and when
marble shall have mouldered, will proclaim to posterity the glory that
belongs to your name. You have most happily conjoined anatomy with
pathology, and have greatly enriched the subject with a new and most
useful osteology. Proceed in your worthy career, most illustrious
Riolanus, and love him who wishes that you may enjoy both happiness and
length of days, and that all your admirable works may conduce to your
eternal fame.

                                                        WILLIAM HARVEY.









It is now many years, most learned Riolanus, since, with the aid of the
press, I published a portion of my work. But scarce a day, scarce an
hour, has passed since the birth-day of the Circulation of the blood,
that I have not heard something for good or for evil said of this my
discovery. Some abuse it as a feeble infant, and yet unworthy to have
seen the light; others, again, think the bantling deserves to be
cherished and cared for; these oppose it with much ado, those patronize
it with abundant commendation; one party holds that I have completely
demonstrated the circulation of the blood by experiment, observation,
and ocular inspection, against all force and array of argument; another
thinks it scarcely yet sufficiently illustrated--not yet cleared of all
objections. There are some, too, who say that I have shown a
vainglorious love of vivisections, and who scoff at and deride the
introduction of frogs and serpents, flies, and others of the lower
animals upon the scene, as a piece of puerile levity, not even
refraining from opprobrious epithets.

To return evil speaking with evil speaking, however, I hold to be
unworthy in a philosopher and searcher after truth; I believe that I
shall do better and more advisedly if I meet so many indications of ill
breeding with the light of faithful and conclusive observation. It
cannot be helped that dogs bark and vomit their foul stomachs, or that
cynics should be numbered among philosophers; but care can be taken that
they do not bite or inoculate their mad humours, or with their dogs’
teeth gnaw the bones and foundations of truth.

Detractors, mummers, and writers defiled with abuse, as I resolved with
myself never to read them, satisfied that nothing solid or excellent,
nothing but foul terms, was to be expected from them, so have I held
them still less worthy of an answer. Let them consume on their own ill
nature; they will scarcely find many well-disposed readers, I imagine,
nor does God give that which is most excellent and chiefly to be
desired--wisdom, to the wicked; let them go on railing, I say, until
they are weary, if not ashamed.

If for the sake of studying the meaner animals you should even enter the
bakehouse with Heraclitus, as related in Aristotle, I bid you approach;
for neither are the immortal Gods absent here, and the great and
almighty Father is sometimes most visible in His lesser, and to the eye
least considerable works.[112]

In my book on the Motion of the Heart and Blood in Animals, I have only
adduced those facts from among many other observations, by which either
errors were best refuted, or truth was most strongly supported; I have
left many proofs, won by dissection and appreciable to sense, as
redundant and unnecessary; some of these, however, I now supply in brief
terms, for the sake of the studious, and those who have expressed their
desire to have them.

The authority of Galen is of such weight with all, that I have seen
several hesitate greatly with that experiment before them, in which the
artery is tied upon a tube placed within its cavity; and by which it is
proposed to prove that the arterial pulse is produced by a power
communicated from the heart through the coats of the arteries, and not
from the shock of the blood contained within them; and thence, that the
arteries dilate as bellows, are not filled as sacs. This experiment is
spoken of by Vesalius, the celebrated anatomist; but neither Vesalius
nor Galen says that he had tried the experiment, which, however, I did.
Vesalius only prescribes, and Galen advises it, to those anxious to
discover the truth, and for their better assurance, not thinking of the
difficulties that attend its performance, nor of its futility when done;
for indeed, although executed with the greatest skill, it supplies
nothing in support of the opinion which maintains that the coats of the
vessel are the cause of the pulse; it much rather proclaims that this is
owing to the impulse of the blood. For the moment you have thrown your
ligature around the artery upon the reed or tube, immediately, by the
force of the blood thrown in from above, it is dilated beyond the circle
of the tube, by which the flow is impeded, and the shock is broken; so
that the artery which is tied only pulsates obscurely, being now cut off
from the full force of the blood that flows through it, the shock being
reverberated, as it were, from that part of the vessel which is above
the ligature; but if the artery below the ligature be now divided, the
contrary of what has been maintained will be apparent, from the spurting
of the blood impelled through the tube; just as happens in the cases of
aneurism, referred to in my book on the Motion of the Blood, which arise
from an erosion of the coats of the vessel, and when the blood is
contained in a membranous sac, formed not by the coats of the vessel
dilated, but preternaturally produced from the surrounding tissues and
flesh. The arteries beyond an aneurism of this kind will be felt beating
very feebly, whilst in those above it and in the swelling itself the
pulse will be perceived of great strength and fulness. And here we
cannot imagine that the pulsation and dilatation take place by the coats
of the arteries, or any power communicated to the walls of the sac; they
are plainly due to the shock of the blood.

But that the error of Vesalius, and the inexperience of those who assert
their belief that the part below the tube does not pulsate when the
ligature is tied, may be made the more apparent, I can state, after
having made the trial, that the inferior part will continue to pulsate
if the experiment be properly performed; and whilst they say that when
you have undone the ligature the inferior arteries begin again to
pulsate, I maintain that the part below beats less forcibly when the
ligature is untied than it did when the thread was still tight. But the
effusion of blood from the wound confuses everything, and renders the
whole experiment unsatisfactory and nugatory, so that nothing certain
can be shown, by reason, as I have said, of the hemorrhage. But if, as I
know by experience, you lay bare an artery, and control the divided
portion by the pressure of your fingers, you may try many things at
pleasure by which the truth will be made to appear. In the first place,
you will feel the blood coming down in the artery at each pulsation,
and visibly dilating the vessel. You may also at will suffer the blood
to escape, by relaxing the pressure, and leaving a small outlet; and you
will see that it jets out with each stroke, with each contraction of the
heart, and with each dilatation of the artery, as I have said in
speaking of arteriotomy, and the experiment of perforating the heart.
And if you suffer the efflux to go on uninterruptedly, either from the
simple divided artery or from a tube inserted into it, you will be able
to perceive by the sight, and if you apply your hand, by the touch
likewise, every character of the stroke of the heart in the jet; the
rhythm, order, intermission, force, &c., of its pulsations, all becoming
sensible there, no otherwise than would the jets from a syringe, pushed
in succession and with different degrees of force, received upon the
palm of the hand, be obvious to sight and touch. I have occasionally
observed the jet from a divided carotid artery to be so forcible, that,
when received on the hand, the blood rebounded to the distance of four
or five feet.

But that the question under discussion, viz.--that the pulsific power
does not proceed from the heart by the coats of the vessels, may be set
in yet a clearer light, I beg here to refer to a portion of the
descending aorta, about a span in length, with its division into the two
crural trunks, which I removed from the body of a nobleman, and which is
converted into a bony tube; by this hollow tube, nevertheless, did the
arterial blood reach the lower extremities of this nobleman during his
life, and cause the arteries in these to beat; and yet the main trunk
was precisely in the same condition as is the artery in the experiment
of Galen, when it is tied upon a hollow tube; where it was converted
into bone it could neither dilate nor contract like bellows, nor
transmit the pulsific power from the heart to the inferior vessels; it
could not convey a force which it was incapable of receiving through the
solid matter of the bone. In spite of all, however, I well remember to
have frequently noted the pulse in the legs and feet of this patient
whilst he lived, for I was myself his most attentive physician, and he
my very particular friend. The arteries in the inferior extremities of
this nobleman must therefore and of necessity have been dilated by the
impulse of the blood like flaccid sacs, and not have expanded in the
manner of bellows through the action of their tunics. It is obvious,
that whether an artery be tied over a hollow tube, or its tunics be
converted into a bony and unyielding canal, the interruption to the
pulsific power in the inferior part of the vessel must be the same.

I have known another instance in which a portion of the aorta near the
heart was found converted into bone, in the body of a nobleman, a man of
great muscular strength. The experiment of Galen, therefore, or, at all
events, a state analogous to it, not effected on purpose but encountered
by accident, makes it sufficiently to appear, that compression or
ligature of the coats of an artery does not interfere with the pulsative
properties of its derivative branches; and indeed, if the experiment
which Galen recommends were properly performed by any one, its results
would be found in opposition to the views which Vesalius believed they
would support.

But we do not therefore deny everything like motion to the tunics of the
arteries; on the contrary, we allow them the same motions which we
concede to the heart, viz., a diastole, and a systole or return from the
distended to the natural state; this much we believe to be effected by a
power inherent in the coats themselves. But it is to be observed, that
they are not both dilated and contracted by the same, but by different
causes and means; as may be observed of the motions of all parts, and of
the ventricle of the heart itself, which is distended by the auricle,
contracted by its own inherent power; so, the arteries are dilated by
the stroke of the heart, but they contract or collapse of

You may also perform another experiment at the same time: if you fill
one of two basins of the same size with blood issuing per saltum from an
artery, the other with venous blood from a vein of the same animal, you
will have an opportunity of perceiving by the eye, both immediately and
by and by, when the blood in either vessel has become cold, what
differences there are between them. You will find that it is not as they
believe who fancy that there is one kind of blood in the arteries and
another in the veins, that in the arteries being of a more florid
colour, more frothy, and imbued with an abundance of I know not what
spirits, effervescing and swelling, and occupying a greater space, like
milk or honey set upon the fire. For were the blood which is thrown from
the left ventricle of the heart into the arteries, fermented into any
such frothy and flatulent fluid, so that a drop or two distended the
whole cavity of the aorta; unquestionably, upon the subsidence of this
fermentation, the blood would return to its original quantity of a few
drops; (and this, indeed, is the reason that some assign for the usually
empty state of the arteries in the dead body;) and so should it be with
the arterial blood in the cup, for so it is with boiling milk and honey
when they come to cool. But if in either basin you find blood nearly of
the same colour, not of very different consistency in the coagulated
state, forcing out serum in the same manner, and filling the cups to the
same height when cold that it did when hot, this will be enough for any
one to rest his faith upon, and afford argument enough, I think, for
rejecting the dreams that have been promulgated on the subject. Sense
and reason alike assure us that the blood contained in the left
ventricle is not of a different nature from that in the right. And then,
when we see that the mouth of the pulmonary artery is of the same size
as the aorta, and in other respects equal to that vessel, it were
imperative on us to affirm that the pulmonary artery was distended by a
single drop of spumous blood, as well as the aorta, and so that the
right as well as the left side of the heart was filled with a brisk or
fermenting blood.

The particulars which especially dispose men’s minds to admit diversity
in the arterial and venous blood are three in number: one, because in
arteriotomy the blood that flows is of a more florid hue than that which
escapes from a vein; a second, because in the dissection of dead bodies
the left ventricle of the heart, and the arteries in general, are mostly
found empty; a third, because the arterial blood is believed to be more
spirituous, and being replete with spirit is made to occupy a much
larger space. The causes and reasons, however, wherefore all these
things are so, present themselves to us when we ask after them.

1st. With reference to the colour it is to be observed, that wherever
the blood issues by a very small orifice, it is in some measure
strained, and the thinner and lighter part, which usually swims on the
top and is the most penetrating, is emitted. Thus, in phlebotomy, when
the blood escapes forcibly and to a distance, in a full stream, and from
a large orifice, it is thicker, has more body, and a darker colour; but,
if it flows from a small orifice, and only drop by drop, as it usually
does when the bleeding fillet is untied, it is of a brighter hue; for
then it is strained as it were, and the thinner and more penetrating
portion only escapes; in the same way, in the bleeding from the nose, in
that which takes place from a leech-bite, or from scarifications, or in
any other way by diapedesis or transudation, the blood is always seen to
have a brighter cast, because the thickness and firmness of the coats of
the arteries render the outlet or outlets smaller, and less disposed to
yield a ready passage to the outpouring blood; it happens also that when
fat persons, are let blood, the orifice of the vein is apt to be
compressed by the subcutaneous fat, by which the blood is made to appear
thinner, more florid, and in some sort arterious. On the other hand, the
blood that flows into a basin from a large artery freely divided, will
look venous. The blood in the lungs is of a much more florid colour than
it is in the arteries, and we know how it is strained through the
pulmonary tissue.

2d. The emptiness of the arteries in the dead body, which probably
misled Erasistratus in supposing that they only contained aereal
spirits, is caused by this, that when respiration ceases the lungs
collapse, and then the passages through them are closed; the heart,
however, continues for a time to contract upon the blood, whence we find
the left auricle more contracted, and the corresponding ventricle, as
well as the arteries at large, appearing empty, simply because there is
no supply of blood flowing round to fill them. In cases, however, in
which the heart has ceased to pulsate and the lungs to afford a passage
to the blood simultaneously, as in those who have died from drowning or
syncope, or who die suddenly, you will find the arteries, as well as the
veins, full of blood.

3d. With reference to the third point, or that of the spirits, it may be
said that, as it is still a question what they are, how extant in the
body, of what consistency, whether separate and distinct from the blood
and solids, or mingled with these,--upon each and all of these points
there are so many and such conflicting opinions, that it is not
wonderful that the spirits, whose nature is thus left so wholly
ambiguous, should serve as the common subterfuge of ignorance. Persons
of limited information, when they are at a loss to assign a cause for
anything, very commonly reply that it is done by the spirits; and so
they bring the spirits into play upon all occasions; even as indifferent
poets are always thrusting the gods upon the stage as a means of
unravelling the plot, and bringing about the catastrophe.

Fernelius, and many others, suppose that there are aereal spirits and
invisible substances. Fernelius proves that there are animal spirits, by
saying that the cells in the brain are apparently unoccupied, and as
nature abhors a vacuum, he concludes that in the living body they are
filled with spirits, just as Erasistratus had held that, because the
arteries were empty of blood, therefore they must be filled with
spirits. But Medical Schools admit three kinds of spirits: the natural
spirits flowing through the veins, the vital spirits through the
arteries, and the animal spirits through the nerves; whence physicians
say, out of Galen, that sometimes the parts of the brain are oppressed
by sympathy, because the faculty with the essence, i. e., the spirit, is
overwhelmed; and sometimes this happens independently of the essence.
Farther, besides the three orders of influxive spirits adverted to, a
like number of implanted or stationary spirits seem to be acknowledged;
but we have found none of all these spirits by dissection, neither in
the veins, nerves, arteries, nor other parts of living animals. Some
speak of corporeal, others of incorporeal spirits; and they who advocate
the corporeal spirits will have the blood, or the thinner portion of the
blood, to be the bond of union with the soul, the spirit being contained
in the blood as the flame is in the smoke of a lamp or candle, and held
admixed by the incessant motion of the fluid; others, again, distinguish
between the spirits and the blood. They who advocate incorporeal spirits
have no ground of experience to stand upon; their spirits indeed are
synonymous with powers or faculties, such as a concoctive spirit, a
chylopoietic spirit, a procreative spirit, &c.--they admit as many
spirits, in short, as there are faculties or organs.

But then the schoolmen speak of a spirit of fortitude, prudence,
patience, and the other virtues, and also of a most holy spirit of
wisdom, and of every divine gift; and they besides suppose that there
are good and evil spirits that roam about or possess the body, that
assist or cast obstacles in the way. They hold some diseases to be owing
to a Cacodæmon or evil spirit, as there are others that are due to a
cacochemy or defective assimilation.

Although there is nothing more uncertain and questionable, then, than
the doctrine of spirits that is proposed to us, nevertheless physicians
seem for the major part to conclude, with Hippocrates, that our body is
composed or made up of three elements, viz., containing parts, contained
parts, and causes of action, spirits being understood by the latter
term. But if spirits are to be taken as synonymous with causes of
activity, whatever has power in the living body and a faculty of action
must be included under the denomination. It would appear, therefore,
that all spirits were neither aereal substances, nor powers, nor habits;
and that all were not incorporeal.

But keeping in view the points that especially interest us, others, as
leading to tediousness, being left unnoticed, it seems that the spirits
which flow by the veins or the arteries are not distinct from the blood,
any more than the flame of a lamp is distinct from the inflammable
vapour that is on fire; in short, that the blood and these spirits
signify one and the same thing, though different,--like generous wine
and its spirit; for as wine, when it has lost all its spirit, is no
longer wine, but a vapid liquor or vinegar; so blood without spirit is
not blood, but something else--clot or cruor; even as a hand of stone,
or of a dead body, is no hand in the most complete sense, neither is
blood void of the vital principle proper blood; it is immediately to be
held as corrupt when deprived of its spirit. The spirit therefore which
inheres in the arteries, and especially in the blood which fills them,
is to be regarded either as its act or agent, in the same way as the
spirit of wine in wine, and the spirit of aqua vitæ in brandy, or as a
flame kindled in alcohol, which lives and feeds on, or is nourished by
itself. The blood consequently, though richly imbued with spirits, does
not swell, nor ferment, nor rise to a head through them, so as to
require and occupy a larger space,--a fact that may be ascertained
beyond the possibility of question by the two cups of equal size; it is
to be regarded as wine, possessed of a large amount of spirits, or, in
the Hippocratic sense, of signal powers of acting and effecting.

It is therefore the same blood in the arteries that is found in the
veins, although it may be admitted to be more spirituous, possessed of
higher vital force in the former than in the latter; but it is not
changed into anything more vaporous, or more aereal, as if there were no
spirits but such as are aereal, and no cause of action or activity that
is not of the nature of flatus or wind. But neither the animal, natural,
nor vital spirits which inhere in the solids, such as the ligaments and
nerves (especially if they be of so many different species), and are
contained within the viewless interstices of the tissues, are to be
regarded as so many different aereal forms, or kinds of vapour.

And here I would gladly be informed by those who admit corporeal
spirits, but of a gaseous or vaporous consistency, in the bodies of
animals, whether or not they have the power of passing hither and
thither, like distinct bodies independently of the blood? Or whether the
spirits follow the blood in its motions, either as integral parts of the
fluid or as indissolubly connected with it, so that they can neither
quit the tissues nor pass hither nor thither without the influx and
reflux, and motion of the blood? For if the spirits exhaling from the
blood, like the vapour of water attenuated by heat, exist in a state of
constant flow and succession as the pabulum of the tissues, it
necessarily follows that they are not distinct from this pabulum, but
are incessantly disappearing; whereby it seems that they can neither
have influx nor reflux, nor passage, nor yet remain at rest without the
influx, the reflux, the passage [or stasis] of the blood, which is the
fluid that serves as their vehicle or pabulum.

And next I desire to know of those who tell us that the spirits are
formed in the heart, being compounded of the vapours or exhalations of
the blood (excited either by the heat of the heart or the concussion)
and the inspired air, whether such spirits are not to be accounted much
colder than the blood, seeing that both the elements of their
composition, namely, air and vapour, are much colder? For the vapour of
boiling water is much more bearable than the water itself; the flame of
a candle is less burning than the red-hot snuff, and burning charcoal
than incandescent iron or brass. Whence it would appear that spirits of
this nature rather receive their heat from the blood, than that the
blood is warmed by these spirits; such spirits are rather to be regarded
as fumes and excrementitious effluvia proceeding from the body in the
manner of odours, than in any way as natural artificers of the tissues;
a conclusion which we are the more disposed to admit, when we see that
they so speedily lose any virtue they may possess, and which they had
derived from the blood as their source,--they are at best of a very
frail and evanescent nature. Whence also it becomes probable that the
expiration of the lungs is a means by which these vapours being cast
off, the blood is fanned and purified; whilst inspiration is a means by
which the blood in its passage between the two ventricles of the heart
is tempered by the cold of the ambient atmosphere, lest, getting heated,
and blown up with a kind of fermentation, like milk or honey set over
the fire, it should so distend the lungs that the animal got suffocated;
somewhat in the same way, perchance, as one labouring under a severe
asthma, which Galen himself seems to refer to its proper cause when he
says it is owing to an obstruction of the smaller arteries, viz., the
vasa venosa et arteriosa. And I have found by experience that patients
affected with asthma might be brought out of states of very imminent
danger by having cupping-glasses applied, and a plentiful and sudden
affusion of cold water [upon the chest]. Thus much--and perhaps it is
more than was necessary--have I said on the subject of spirits in this
place, for I felt it proper to define them, and to say something of
their nature in a physiological disquisition.

I shall only further add, that they who descant on the calidum innatum
or innate heat, as an instrument of nature available for every purpose,
and who speak of the necessity of heat as the cherisher and retainer in
life of the several parts of the body, who at the same time admit that
this heat cannot exist unless connected with something, and because they
find no substance of anything like commensurate mobility, or which might
keep pace with the rapid influx and reflux of this heat (in affections
of the mind especially), take refuge in spirits as most subtile
substances, possessed of the most penetrating qualities, and highest
mobility--these persons see nothing less than the wonderful and almost
divine character of the natural operations as proceeding from the
instrumentality of this common agent, viz., the calidum innatum; they
farther regard these spirits as of a sublime, lucid, ethereal,
celestial, or divine nature, and the bond of the soul; even as the
vulgar and unlettered, when they do not comprehend the causes of various
effects, refer them to the immediate interposition of the Deity. Whence
they declare that the heat perpetually flowing into the several parts is
in virtue of the influx of spirits through the channels of the arteries;
as if the blood could neither move so swiftly, nor penetrate so
intimately, nor cherish so effectually. And such faith do they put in
this opinion, such lengths are they carried by their belief, that they
deny the contents of the arteries to be blood! And then they proceed
with trivial reasonings to maintain that the arterial blood is of a
peculiar kind, or that the arteries are filled with such aereal spirits,
and not with blood; all the while, in opposition to everything which
Galen has advanced against Erasistratus, both on grounds of experiment
and of reason. But that arterial blood differs in nothing essential from
venous blood has been already sufficiently demonstrated; and our senses
likewise assure us that the blood and spirits do not flow in the
arteries separately and disjoined, but as one body.

We have occasion to observe so often as our hands, feet, or ears have
become stiff and cold, that as they recover again by the warmth that
flows into them, they acquire their natural colour and heat
simultaneously; that the veins which had become small and shrunk, swell
visibly and enlarge, so that when they regain their heat suddenly they
become painful; from which it appears, that that which by its influx
brings heat is the same which causes repletion and colour; now this can
be and is nothing but blood.

When an artery and a vein are divided, any one may clearly see that the
part of the vein towards the heart pours out no blood, whilst that
beyond the wound gives a torrent; the divided artery, on the contrary,
(as in my experiment on the carotids,) pours out a flood of pure blood
from the orifice next the heart, and in jets as if it were forced from a
syringe, whilst from the further orifice of the divided artery little or
no blood escapes. This experiment therefore plainly proves in what
direction the current sets in either order of vessels--towards the heart
in the veins, from the heart in the arteries; it also shows with what
velocity the current moves, not gradually and by drops, but even with
violence. And lest any one, by way of subterfuge, should take shelter in
the notion of invisible spirits, let the orifice of the divided vessel
be plunged under water or oil, when, if there be any air contained in
it, the fact will be proclaimed by a succession of visible bubbles.
Hornets, wasps, and other insects of the same description plunged in
oil, and so suffocated, emit bubbles of air from their tail whilst they
are dying; whence it is not improbable that they thus respire when
alive; for all animals submerged and drowned, when they finally sink to
the bottom and die, emit bubbles of air from the mouth and lungs. It is
also demonstrated by the same experiment, that the valves of the veins
act with such accuracy, that air blown into them does not penetrate;
much less then can blood make its way through them:--it is certain, I
say, that neither sensibly nor insensibly, nor gradually and drop by
drop, can any blood pass from the heart by the veins.

And that no one may seek shelter in asserting that these things are so
when nature is disturbed and opposed, but not when she is left to
herself and at liberty to act; that the same things do not come to pass
in morbid and unusual states as in the healthy and natural condition;
they are to be met by saying, that if it were so, if it happened that so
much blood was lost from the farther orifice of a divided vein because
nature was disturbed, still that the incision does not close the nearer
orifice, from which nothing either escapes or can be expressed, whether
nature be disturbed or not. Others argue in the same way, maintaining
that, although the blood immediately spurts out in such profusion with
every beat, when an artery is divided near the heart, it does not
therefore follow that the blood is propelled by the pulse when the heart
and artery are entire. It is most probable, however, that every stroke
impels something; and that there would be no pulse of the container,
without an impulse being communicated to the thing contained, seems
certain. Yet some, that they may seize upon a farther means of defence,
and escape the necessity of admitting the circulation, do not fear to
affirm that the arteries in the living body and in the natural state are
already so full of blood, that they are incapable of receiving another
drop; and so also of the ventricles of the heart. But it is indubitable
that, whatever the degree of distension and the extent of contraction
of the heart and arteries, they are still in a condition to receive an
additional quantity of blood forced into them, and that this is far more
than is usually reckoned in grains or drops, seems also certain. For if
the ventricles become so excessively distended that they will admit no
more blood, the heart ceases to beat, (and we have occasional
opportunities of observing the fact in our vivisections,) and,
continuing tense and resisting, death by asphyxia ensues.

In the work on the Motion of the Heart and Blood, I have already
sufficiently discussed the question as to whether the blood in its
motion was attracted, or impelled, or moved by its own inherent nature.
I have there also spoken at length of the action and office, of the
dilatation and contraction of the heart, and have shown what these truly
are, and how the heart contracts during the diastole of the arteries; so
that I must hold those who take points for dispute from among them as
either not understanding the subject, or as unwilling to look at things
for themselves, and to investigate them with their own senses.[114]

For my part, I believe that no other kind of attraction can be
demonstrated in the living body save that of the nutriment, which
gradually and incessantly passes on to supply the waste that takes place
in the tissues; in the same way as the oil rises in the wick of a lamp
to be consumed by the flame. Whence I conclude that the primary and
common organ of all sensible attraction and impulsion is of the nature
of sinew (nervus), or fibre, or muscle, and this to the end that it may
be contractile, that contracting it may be shortened, and so either
stretch out, draw towards, or propel. But these topics will be better
discussed elsewhere, when we speak of the organs of motion in the animal

To those who repudiate the circulation because they neither see the
efficient nor final cause of it, and who exclaim, cui bono? I have yet
to reply, having hitherto taken no note of the ground of objection which
they take up. And first I own I am of opinion that our first duty is to
inquire whether the thing be or not, before asking wherefore it is? for
from the facts and circumstances which meet us in the circulation
admitted, established, the ends and objects of its institution are
especially to be sought. Meantime I would only ask, how many things we
admit in physiology, pathology, and therapeutics, the causes of which
are unknown to us? That there are many, no one doubts--the causes of
putrid fevers, of revulsions, of the purgation of excrementitious
matters, among the number.

Whoever, therefore, sets himself in opposition to the circulation,
because, if it be acknowledged, he cannot account for a variety of
medical problems, nor in the treatment of diseases and the
administration of medicines, give satisfactory reasons for the phenomena
that appear; or who will not see that the precepts he has received from
his teachers are false; or who thinks it unseemly to give up accredited
opinions; or who regards it as in some sort criminal to call in question
doctrines that have descended through a long succession of ages, and
carry the authority of the ancients;--to all of these I reply: that the
facts cognizable by the senses wait upon no opinions, and that the works
of nature bow to no antiquity; for indeed there is nothing either more
ancient or of higher authority than nature.

To those who object to the circulation as throwing obstacles in the way
of their explanations of the phenomena that occur in medical cases (and
there are persons who will not be content to take up with a new system,
unless it explains everything, as in astronomy), and who oppose it with
their own erroneous assumptions, such as that, if it be true, phlebotomy
cannot cause revulsion, seeing that the blood will still continue to be
forced into the affected part; that the passage of excrementitious
matters and foul humours through the heart, that most noble and
principal viscus, is to be apprehended; that an efflux and excretion,
occasionally of foul and corrupt blood, takes place from the same body,
from different parts, even from the same part and at the same time,
which, were the blood agitated by a continuous current, would be shaken
and effectually mixed in passing through the heart, and many points of
the like kind admitted in our medical schools, which are seen to be
repugnant to the doctrine of the circulation,--to them I shall not
answer farther here, than that the circulation is not always the same in
every place, and at every time, but is contingent upon many
circumstances: the more rapid or slower motion of the blood, the
strength or weakness of the heart as the propelling organ, the quantity
and quality or constitution of the blood, the rigidity or laxity of the
tissues, and the like. A thicker blood, of course, moves more slowly
through narrower channels; it is more effectually strained in its
passage through the substance of the liver than through that of the
lungs. It has not the same velocity through flesh and the softer
parenchymatous structures and through sinewy parts of greater
compactness and consistency: for the thinner and purer and more
spirituous part permeates more quickly, the thicker more earthy and
indifferently concocted portion moves more slowly, or is refused
admission. The nutritive portion, or ultimate aliment of the tissues,
the dew or cambium, is of a more penetrating nature, inasmuch as it has
to be added everywhere, and to everything that grows and is nourished in
its length and thickness, even to the horns, nails, hair and feathers;
and then the excrementitious matters have to be secreted in some places,
where they accumulate, and either prove a burthen or are concocted. But
I do not imagine that the excrementitious fluids or bad humours when
once separated, nor the milk, the phlegm, and the spermatic fluid, nor
the ultimate nutritive part, the dew or cambium, necessarily circulate
with the blood: that which nourishes every part adheres and becomes
agglutinated to it. Upon each of these topics and various others
besides, to be discussed and demonstrated in their several places, viz.,
in the physiology and other parts of the art of medicine, as well as of
the consequences, advantages or disadvantages of the circulation of the
blood, I do not mean to touch here; it were fruitless indeed to do so
until the circulation has been established and conceded as a fact. And
here the example of astronomy is by no means to be followed, in which
from mere appearances or phenomena that which is in fact, and the reason
wherefore it is so, are investigated. But as he who inquires into the
cause of an eclipse must be placed beyond the moon if he would ascertain
it by sense, and not by reason, still, in reference to things sensible,
things that come under the cognizance of the senses, no more certain
demonstration or means of gaining faith can be adduced than examination
by the senses, than ocular inspection.

There is one remarkable experiment which I would have every one try who
is anxious for truth, and by which it is clearly shown that the arterial
pulse is owing to the impulse of the blood. Let a portion of the dried
intestine of a dog or wolf, or any other animal, such as we see hung up
in the druggists’ shops, be taken and filled with water, and then
secured at both ends like a sausage: by tapping with the finger at one
extremity, you will immediately feel a pulse and vibration in any other
part to which you apply the fingers, as you do when you feel the pulse
at the wrist. In this way, indeed, and also by means of a distended
vein, you may accurately either in the dead or living body, imitate and
show every variety of the pulse, whether as to force, frequency, volume,
rhythm, &c. Just as in a long bladder full of fluid, or in an oblong
drum, every stroke upon one end is immediately felt at the other; so
also in a dropsy of the belly and in abscesses under the skin, we are
accustomed to distinguish between collections of fluid and of air,
between anasarca and tympanites in particular. If a slap or push given
on one side is clearly felt by a hand placed on the other side, we judge
the case to be tympanites[?]; not, as falsely asserted, because we hear
a sound like that of a drum, and this produced by flatus, which never
happens[?]; but because, as in a drum, every the slightest tap passes
through and produces a certain vibration on the opposite side; for it
indicates that there is a serous and ichorous substance present, of such
a consistency as urine, and not any sluggish or viscid matter as in
anasarca, which when struck retains the impress of the blow or pressure,
and does not transmit the impulse.

Having brought forward this experiment I may observe, that a most
formidable objection to the circulation of the blood rises out of it,
which, however, has neither been observed nor adduced by any one who has
written against me. When we see by the experiment just described, that
the systole and diastole of the pulse can be accurately imitated without
any escape of fluid, it is obvious that the same thing may take place in
the arteries from the stroke of the heart, without the necessity for a
circulation, but like Euripus, with a mere motion of the blood
alternately backwards and forwards. But we have already satisfactorily
replied to this difficulty; and now we venture to say that the thing
could not be so in the arteries of a living animal; to be assured of
this it is enough to see that the right auricle is incessantly injecting
the right ventricle of the heart with blood, the return of which is
effectually prevented by the tricuspid valves; the left auricle in like
manner filling the left ventricle, the return of the blood there being
opposed by the mitral valves; and then the ventricles in their turn are
propelling the blood into either great artery, the reflux in each being
prevented by the sigmoid valves in its orifice. Either, consequently,
the blood must move on incessantly through the lungs, and in like manner
within the arteries of the body, or stagnating and pent up, it must
rupture the containing vessels, or choke the heart by over distension,
as I have shown it to do in the vivisection of a snake, described in my
book on the Motion of the Blood. To resolve this doubt I shall relate
two experiments among many others, the first of which, indeed, I have
already adduced, and which show with singular clearness that the blood
flows incessantly and with great force and in ample abundance in the
veins towards the heart. The internal jugular vein of a live fallow deer
having been exposed, (many of the nobility and his most serene majesty
the king, my master, being present,) was divided; but a few drops of
blood were observed to escape from the lower orifice rising up from
under the clavicle; whilst from the superior orifice of the vein and
coming down from the head, a round torrent of blood gushed forth. You
may observe the same fact any day in practising phlebotomy: if with a
finger you compress the vein a little below the orifice, the flow of
blood is immediately arrested; but the pressure being removed, forthwith
the flow returns as before.

From any long vein of the forearm get rid of the blood as much as
possible by holding the hand aloft and pressing the blood towards the
trunk, you will perceive the vein collapsed and leaving, as it were, in
a furrow of the skin; but now compress the vein with the point of a
finger, and you will immediately perceive all that part of it which is
towards the hand, to enlarge and to become distended with the blood that
is coming from the hand. How comes it when the breath is held and the
lungs thereby compressed, a large quantity of air having been taken in,
that the vessels of the chest are at the same time obstructed, the blood
driven into the face, and the eyes rendered red and suffused? Why is it,
as Aristotle asks in his problems, that all the actions are more
energetically performed when the breath is held than when it is given?
In like manner, when the frontal and lingual veins are incised, the
blood is made to flow more freely by compressing the neck and holding
the breath. I have several times opened the breast and pericardium of a
man within two hours after his execution by hanging, and before the
colour had totally left the face, and in presence of many witnesses,
have demonstrated the right auricle of the heart and the lungs distended
with blood; the auricle in particular of the size of a large man’s fist,
and so full of blood that it looked as if it would burst. This great
distension, however, had disappeared next day, the body having stiffened
and become cold, and the blood having made its escape through various
channels. These and other similar facts, therefore, make it sufficiently
certain that the blood flows through the whole of the veins of the body
towards the base of the heart, and that unless there was a further
passage afforded it, it would be pent up in these channels, or would
oppress and overwhelm the heart; as on the other hand, did it not flow
outwards by the arteries, but was found regurgitating, it would soon be
seen how much it would oppress.

I add another observation. A noble knight, Sir Robert Darcy, an ancestor
of that celebrated physician and most learned man, my very dear friend
Dr. Argent, when he had reached to about the middle period of life, made
frequent complaint of a certain distressing pain in the chest,
especially in the night season; so that dreading at one time syncope, at
another suffocation in his attacks he led an unquiet and anxious life.
He tried many remedies in vain, having had the advice of almost every
medical man. The disease going on from bad to worse, he by and by became
cachectic and dropsical, and finally, grievously distressed, he died in
one of his paroxysms. In the body of this gentleman, at the inspection
of which there were present Dr. Argent, then president of the College of
Physicians, and Dr. Gorge, a distinguished theologian and preacher, who
was pastor of the parish, we found the wall of the left ventricle of the
heart ruptured, having a rent in it of size sufficient to admit any of
my fingers, although the wall itself appeared sufficiently thick and
strong; this laceration had apparently been caused by an impediment to
the passage of the blood from the left ventricle into the arteries.

I was acquainted with another strong man, who having received an injury
and affront from one more powerful than himself, and upon whom he could
not have his revenge, was so overcome with hatred and spite and passion,
which he yet communicated to no one, that at last he fell into a strange
distemper, suffering from extreme oppression and pain of the heart and
breast, and the prescriptions of none of the very best physicians
proving of any avail, he fell in the course of a few years into a
scorbutic and cachectic state, became tabid and died. This patient only
received some little relief when the whole of his chest was pummelled or
kneaded by a strong man, as a baker kneads dough. His friends thought
him poisoned by some maleficent influence, or possessed with an evil
spirit. His jugular arteries, enlarged to the size of the thumb, looked
like the aorta itself, or they were as large as the descending aorta;
they had pulsated violently, and appeared like two long aneurisms. These
symptoms had led to trying the effects of arteriotomy in the temples,
but with no relief. In the dead body I found the heart and aorta so much
gorged and distended with blood, that the cavities of the ventricles
equalled those of a bullock’s heart in size. Such is the force of the
blood pent up, and such are the effects of its impulse.

We may therefore conclude, that although there may be impulse without
any exit, as illustrated in the experiment lately spoken of, still that
this could not take place in the vessels of living creatures without
most serious dangers and impediments. From this, however, it is manifest
that the blood in its course does not everywhere pass with the same
celerity, neither with the same force in all places and at all times,
but that it varies greatly according to age, sex, temperament, habit of
body, and other contingent circumstances, external as well as internal,
natural or non-natural. For it does not course through intricate and
obstructed passages with the same readiness that it does through
straight, unimpeded, and pervious channels. Neither does it run through
close, hard, and crowded parts, with the same velocity as through
spongy, soft, and permeable tissues. Neither does it flow and penetrate
with such swiftness when the impulse [of the heart] is slow and weak, as
when this is forcible and frequent, in which case the blood is driven
onwards with vigour and in large quantity. Nor is the same blood, when
it has become more consistent or earthy, so penetrative as when it is
more serous and attenuated or liquid. And then it seems only reasonable
to think that the blood in its circuit passes more slowly through the
kidneys than through the substance of the heart; more swiftly through
the liver than through the kidneys; through the spleen more quickly than
through the lungs, and through the lungs more speedily than through any
of the other viscera or the muscles, in proportion always to the
denseness or sponginess of the tissue of each.

We may be permitted to take the same view of the influence of age, sex,
temperament, and habit of body, whether this be hard or soft; of that of
the ambient cold which condenses bodies, and makes the veins in the
extremities to shrink and almost to disappear, and deprives the surface
both of colour and heat; and also of that of meat and drink which render
the blood more watery, by supplying fresh nutritive matter. From the
veins, therefore, the blood flows more freely in phlebotomy when the
body is warm than when it is cold. We also observe the signal influence
of the affections of the mind when a timid person is bled and happens to
faint: immediately the flow of blood is arrested, a deadly pallor
overspreads the surface, the limbs stiffen, the ears sing, the eyes are
dazzled or blinded, and, as it were, convulsed. But here I come upon a
field where I might roam freely and give myself up to speculation. And,
indeed, such a flood of light and truth breaks in upon me here; occasion
offers of explaining so many problems, of resolving so many doubts, of
discovering the causes of so many slighter and more serious diseases,
and of suggesting remedies for their cure, that the subject seems almost
to demand a separate treatise. And it will be my business in my ‘Medical
Observations,’ to lay before my reader matter upon all these topics
which shall be worthy of the gravest consideration.

And what indeed is more deserving of attention than the fact that in
almost every affection, appetite, hope, or fear, our body suffers, the
countenance changes, and the blood appears to course hither and thither.
In anger the eyes are fiery and the pupils contracted; in modesty the
cheeks are suffused with blushes; in fear, and under a sense of infamy
and of shame, the face is pale, but the ears burn as if for the evil
they heard or were to hear; in lust how quickly is the member distended
with blood and erected! But, above all, and this is of the highest
interest to the medical practitioner,--how speedily is pain relieved or
removed by the detraction of blood, the application of cupping-glasses,
or the compression of the artery which leads to a part? It sometimes
vanishes as if by magic. But these are topics that I must refer to my
‘Medical Observations,’ where they will be found exposed at length and

Some weak and inexperienced persons vainly seek by dialectics and
far-fetched arguments, either to upset or establish things that are only
to be founded on anatomical demonstration, and believed on the evidence
of the senses. He who truly desires to be informed of the question in
hand, and whether the facts alleged be sensible, visible, or not, must
be held bound either to look for himself, or to take on trust the
conclusions to which they have come who have looked; and indeed there is
no higher method of attaining to assurance and certainty. Who would
pretend to persuade those who had never tasted wine that it was a drink
much pleasanter to the palate than water? By what reasoning should we
give the blind from birth to know that the sun was luminous, and far
surpassed the stars in brightness? And so it is with the circulation of
the blood, which the world has now had before it for so many years,
illustrated by proofs cognizable by the senses, and confirmed by various
experiments. No one has yet been found to dispute the sensible facts,
the motion, efflux and afflux of the blood, by like observations based
on the evidence of sense, or to oppose the experiments adduced, by other
experiments of the same character; nay, no one has yet attempted an
opposition on the ground of ocular testimony.

There have not been wanting many who, inexperienced and ignorant of
anatomy, and making no appeal to the senses in their opposition, have,
on the contrary, met it with empty assertions, and mere suppositions,
with assertions derived from the lessons of teachers and captious
cavillings; many, too, have vainly sought refuge in words, and these not
always very nicely chosen, but reproachful and contumelious; which,
however, have no farther effect than to expose their utterer’s vanity
and weakness, and ill breeding and lack of the arguments that are to be
sought in the conclusions of the senses, and false sophistical
reasonings that seem utterly opposed to sense. Even as the waves of the
Sicilian sea, excited by the blast, dash against the rocks around
Charybdis, and then hiss and foam, and are tossed hither and thither; so
do they who reason against the evidence of their senses.

Were nothing to be acknowledged by the senses without evidence derived
from reason, or occasionally even contrary to the previously received
conclusions of reason, there would now be no problem left for
discussion. Had we not our most perfect assurances by the senses, and
were not their perceptions confirmed by reasoning, in the same way as
geometricians proceed with their figures, we should admit no science of
any kind; for it is the business of geometry, from things sensible, to
make rational demonstration of things that are not sensible; to render
credible or certain things abstruse and beyond sense from things more
manifest and better known. Aristotle counsels us better when, in
treating of the generation of bees, he says:[115] “Faith is to be given
to reason, if the matters demonstrated agree with those that are
perceived by the senses; when the things have been thoroughly
scrutinized, then are the senses to be trusted rather than the reason.”
Whence it is our duty to approve or disapprove, to receive or reject
everything only after the most careful examination; but to examine, to
test whether anything have been well or ill advanced, to ascertain
whether some falsehood does not lurk under a proposition, it is
imperative on us to bring it to the proof of sense, and to admit or
reject it on the decision of sense. Whence Plato in his Critias, says,
that the explanation of those things is not difficult of which we can
have experience; whilst they are not of apt scientific apprehension who
have no experience.

How difficult is it to teach those who have no experience, the things of
which they have not any knowledge by their senses! And how useless and
intractable, and unimpregnable to true science are such auditors! They
show the judgment of the blind in regard to colours, of the deaf in
reference to concords. Who ever pretended to teach the ebb and flow of
the tide, or from a diagram to demonstrate the measurements of the
angles and the proportions of the sides of a triangle to a blind man, or
to one who had never seen the sea nor a diagram? He who is not
conversant with anatomy, inasmuch as he forms no conception of the
subject from the evidence of his own eyes, is virtually blind to all
that concerns anatomy, and unfit to appreciate what is founded thereon;
he knows nothing of that which occupies the attention of the anatomist,
nor of the principles inherent in the nature of the things which guide
him in his reasonings; facts and inferences as well as their sources are
alike unknown to such a one. But no kind of science can possibly flow,
save from some pre-existing knowledge of more obvious things; and this
is one main reason why our science in regard to the nature of celestial
bodies, is so uncertain and conjectural. I would ask of those who
profess a knowledge of the causes of all things, why the two eyes keep
constantly moving together, up or down, to this side or to that, and not
independently, one looking this way another that; why the two auricles
of the heart contract simultaneously, and the like? Are fevers,
pestilence, and the wonderful properties of various medicines to be
denied because their causes are unknown? Who can tell us why the fœtus
in utero, breathing no air up to the tenth month of its existence, is
yet not suffocated? born in the course of the seventh or eighth month,
and having once breathed, it is nevertheless speedily suffocated if its
respiration be interrupted. Why can the fœtus still contained within the
uterus, or enveloped in the membranes, live without respiration; whilst
once exposed to the air, unless it breathes it inevitably dies?[116]

Observing that many hesitate to acknowledge the circulation, and others
oppose it, because, as I conceive, they have not rightly understood me,
I shall here recapitulate briefly what I have said in my work on the
Motion of the Heart and Blood. The blood contained in the veins, in its
magazine, and where it is collected in largest quantity, viz., in the
vena cava, close to the base of the heart and right auricle, gradually
increasing in temperature by its internal heat, and becoming attenuated,
swells and rises like bodies in a state of fermentation, whereby the
auricle being dilated, and then contracting, in virtue of its pulsative
power, forthwith delivers its charge into the right ventricle; which
being filled, and the systole ensuing, the charge, hindered from
returning into the auricle by the tricuspid valves, is forced into the
pulmonary artery, which stands open to receive it, and is immediately
distended with it. Once in the pulmonary artery, the blood cannot
return, by reason of the sigmoid valves; and then the lungs, alternately
expanded and contracted during inspiration and expiration, afford it
passage by the proper vessels into the pulmonary veins; from the
pulmonary veins, the left auricle, acting equally and synchronously with
the right auricle, delivers the blood into the left ventricle; which
acting harmoniously with the right ventricle, and all regress being
prevented by the mitral valves, the blood is projected into the aorta,
and consequently impelled into all the arteries of the body. The
arteries, filled by this sudden push, as they cannot discharge
themselves so speedily, are distended; they receive a shock, or undergo
their diastole. But as this process goes on incessantly, I infer that
the arteries both of the lungs and of the body at large, under the
influence of such a multitude of strokes of the heart and injections of
blood, would finally become so over-gorged and distended, that either
any further injection must cease, or the vessels would burst, or the
whole blood in the body would accumulate within them, were there not an
exit provided for it.

The same reasoning is applicable to the ventricles of the heart:
distended by the ceaseless action of the auricles, did they not
disburthen themselves by the channels of the arteries, they would by and
by become over-gorged, and be fixed and made incapable of all motion.
Now this, my conclusion, is true and necessary, if my premises be true;
but that these are either true or false, our senses must inform us, not
our reason--ocular inspection, not any process of the mind.

I maintain further, that the blood in the veins always and everywhere
flows from less to greater branches, and from every part towards the
heart; whence I gather that the whole charge which the arteries receive,
and which is incessantly thrown into them, is delivered to the veins,
and flows back by them to the source whence it came. In this way,
indeed, is the circulation of the blood established: by an efflux and
reflux from and to the heart; the fluid being forcibly projected into
the arterial system, and then absorbed and imbibed from every part by
the veins, it returns through these in a continuous stream. That all
this is so, sense assures us; and necessary inference from the
perceptions of sense takes away all occasion for doubt. Lastly, this is
what I have striven, by my observations and experiments, to illustrate
and make known; I have not endeavoured from causes and probable
principles to demonstrate my propositions, but, as of higher authority,
to establish them by appeals to sense and experiment, after the manner
of anatomists.

And here I would refer to the amount of force, even of violence, which
sight and touch make us aware of in the heart and greater arteries; and
to the systole and diastole constituting the pulse in the large
warm-blooded animals, which I do not say is equal in all the vessels
containing blood, nor in all animals that have blood; but which is of
such a nature and amount in all, that a flow and rapid passage of the
blood through the smaller arteries, the interstices of the tissues, and
the branches of the veins, must of necessity take place; and therefore
there is a circulation.

For neither do the most minute arteries, nor the veins, pulsate; but the
larger arteries and those near the heart pulsate, because they do not
transmit the blood so quickly as they receive it.[117] Having exposed an
artery, and divided it so that the blood shall flow out as fast and
freely as it is received, you will scarcely perceive any pulse in that
vessel; and for the simple reason, that an open passage being afforded,
the blood escapes, merely passing through the vessel, not distending it.
In fishes, serpents, and the colder animals, the heart beats so slowly
and feebly, that a pulse can scarcely be perceived in the arteries; the
blood in them is transmitted gradually. Whence in them, as also in the
smaller branches of the arteries in man, there is no distinction between
the coats of the arteries and veins, because the arteries have to
sustain no shock from the impulse of the blood.

An artery denuded and divided in the way I have indicated, sustains no
shock, and therefore does not pulsate; whence it clearly appears that
the arteries have no inherent pulsative power, and that neither do they
derive any from the heart; but that they undergo their diastole solely
from the impulse of the blood; for in the full stream, flowing to a
distance, you may see the systole and diastole, all the motions of the
heart--their order, force, rhythm, &c.,[118] as it were in a mirror,
and even perceive them by the touch. Precisely as in the water that is
forced aloft, through a leaden pipe, by working the piston of a
forcing-pump, each stroke of which, though the jet be many feet distant,
is nevertheless distinctly perceptible,--the beginning, increasing
strength, and end of the impulse, as well as its amount, and the
regularity or irregularity with which it is given, being indicated, the
same precisely is the case from the orifice of a divided artery; whence,
as in the instance of the forcing engine quoted, you will perceive that
the efflux is uninterrupted, although the jet is alternately greater and
less. In the arteries, therefore, besides the concussion or impulse of
the blood, the pulse or beat of the artery, which is not equally
exhibited in all, there is a perpetual flow and motion of the blood,
which returns in an unbroken stream to the point from whence it
commenced--the right auricle of the heart.

All these points you may satisfy yourself upon, by exposing one of the
longer arteries, and having taken it between your finger and thumb,
dividing it on the side remote from the heart. By the greater or less
pressure of your fingers, you can have the vessel pulsating less or
more, or losing the pulse entirely, and recovering it at will. And as
these things proceed thus when the chest is uninjured, so also do they
go on for a short time when the thorax is laid open, and the lungs
having collapsed, all the respiratory motions have ceased; here,
nevertheless, for a little while you may perceive the left auricle
contracting and emptying itself, and becoming whiter; but by and by
growing weaker and weaker, it begins to intermit, as does the left
ventricle also, and then it ceases to beat altogether, and becomes
quiescent. Along with this, and in the same measure, does the stream of
blood from the divided artery grow less and less, the pulse of the
vessel weaker and weaker, until at last, the supply of blood and the
impulse of the left ventricle failing, nothing escapes from it. You may
perform the same experiment, tying the pulmonary veins, and so taking
away the pulse of the left auricle, or relaxing the ligature, and
restoring it at pleasure. In this experiment, too, you will observe what
happens in moribund animals, viz., that the left ventricle first ceases
from pulsation and motion, then the left auricle, next the right
ventricle, finally the right auricle; so that where the vital force and
pulse first begin, there do they also last fail.

All of these particulars having been recognized by the senses, it is
manifest that the blood passes through the lungs, not through the septum
[in its course from the right to the left side of the heart], and only
through them when they are moved in the act of respiration, not when
they are collapsed and quiescent; whence we see the probable reason
wherefore nature has instituted the foramen ovale in the fœtus, instead
of sending the blood by the way of the pulmonary artery into the left
auricle and ventricle, which foramen she closes when the new-born
creature begins to breathe freely. We can also now understand why, when
the vessels of the lungs become congested and oppressed, and in those
who are affected with serious diseases, it should be so dangerous and
fatal a symptom when the respiratory organs become implicated.

We perceive further, why the blood is so florid in the lungs, which is,
because it is thinner, as having there to undergo filtration.

Still further; from the summary which precedes, and by way of satisfying
those who are importunate in regard to the causes of the circulation,
and incline to regard the power of the heart as competent to
everything--as that it is not only the seat and source of the pulse
which propels the blood, but also, as Aristotle thinks, of the power
which attracts and produces it; moreover, that the spirits are
engendered by the heart, and the influxive vital heat, in virtue of the
innate heat of the heart, as the immediate instrument of the soul, or
common bond and prime organ in the performance of every act of vitality;
in a word, that the motion, perfection, heat, and every property besides
of the blood and spirits are derived from the heart, as their fountain
or original, (a doctrine as old as Aristotle, who maintained all these
qualities to inhere in the blood, as heat inheres in boiling water or
pottage,) and that the heart is the primary cause of pulsation and life;
to those persons, did I speak openly, I should say that I do not agree
with the common opinion; there are numerous particulars to be noted in
the production of the parts of the body which incline me this way, but
which it does not seem expedient to enter upon here. Before long,
perhaps, I shall have occasion to lay before the world things that are
more wonderful than these, and that are calculated to throw still
greater light upon natural philosophy.

Meantime I shall only say, and, without pretending to demonstrate it,
propound--with the good leave of our learned men, and with all respect
for antiquity--that the heart, with the veins and arteries and the blood
they contain, is to be regarded as the beginning and author, the
fountain and original of all things in the body, the primary cause of
life; and this in the same acceptation as the brain with its nerves,
organs of sense and spinal marrow inclusive, is spoken of as the one and
general organ of sensation. But if by the word heart the mere body of
the heart, made up of its auricles and ventricles, be understood, then I
do not believe that the heart is the fashioner of the blood; neither do
I imagine that the blood has powers, properties, motion, or heat, as the
gift of the heart; lastly, neither do I admit that the cause of the
systole and contraction is the same as that of the diastole or
dilatation, whether in the arteries, auricles, or ventricles; for I hold
that that part of the pulse which is designated the diastole depends on
another cause different from the systole, and that it must always and
everywhere precede any systole; I hold that the innate heat is the first
cause of dilatation, and that the primary dilatation is in the blood
itself, after the manner of bodies in a state of fermentation, gradually
attenuated and swelling, and that in the blood is this finally
extinguished; I assent to Aristotle’s example of gruel or milk upon the
fire, to this extent, that the rising and falling of the blood does not
depend upon vapours or exhalations, or spirits, or anything rising in a
vaporous or aëreal shape, nor upon any external agency, but upon an
internal principle under the control of nature.

Nor is the heart, as some imagine, anything like a chauffer or fire, or
heated kettle, and so the source of the heat of the blood; the blood,
instead of receiving, rather gives heat to the heart, as it does to all
the other parts of the body; for the blood is the hottest element in the
body; and it is on this account that the heart is furnished with
coronary arteries and veins; it is for the same reason that other parts
have vessels, viz., to secure the access of warmth for their due
conservation and stimulation; so that the warmer any part is, the
greater is its supply of blood, or otherwise; where the blood is in
largest quantity, there also is the heat highest. For this reason is the
heart, remarkable through its cavities, to be viewed as the elaboratory,
fountain, and perennial focus of heat, and as comparable to a hot
kettle, not because of its proper substance, but because of its
contained blood; for the same reason, because they have numerous veins
or vessels containing blood, are the liver, spleen, lungs, &c., reputed
hot parts. And in this way do I view the native or innate heat as the
common instrument of every function, the prime cause of the pulse among
the rest. This, however, I do not mean to state absolutely, but only
propose it by way of thesis. Whatever may be objected to it by good and
learned men, without abusive or contemptuous language, I shall be ready
to listen to--I shall even be most grateful to any one who will take up
and discuss the subject.

These then, are, as it were, the very elements and indications of the
passage and circulation of the blood, viz., from the right auricle into
the right ventricle; from the right ventricle by the way of the lungs
into the left auricle; thence into the left ventricle and aorta; whence
by the arteries at large through the pores or interstices of the tissues
into the veins, and by the veins back again with great rapidity to the
base of the heart.

There is an experiment on the veins by which any one that chooses may
convince himself of this truth: Let the arm be bound with a moderately
tight bandage, and then, by opening and shutting the hand, make all the
veins to swell as much as possible, and the integuments below the fillet
to become red; and now let the arm and hand be plunged into very cold
water, or snow, until the blood pent up in the veins shall have become
cooled down; then let the fillet be undone suddenly, and you will
perceive, by the cold blood returning to the heart, with what celerity
the current flows, and what an effect it produces when it has reached
the heart; so that you will no longer be surprised that some should
faint when the fillet is undone after venesection.[119] This experiment
shows that the veins swell below the ligature not with attenuated blood,
or with blood raised by spirits or vapours, for the immersion in the
cold water would repress their ebullition, but with blood only, and such
as could never make its way back into the arteries, either by
open-mouthed communications or by devious passages; it shows, moreover,
how and in what way those who are travelling over snowy mountains are
sometimes stricken suddenly with death, and other things of the same

Lest it should seem difficult for the blood to make its way through the
pores of the various structures of the body, I shall add one
illustration: The same thing happens in the bodies of those that are
hanged or strangled, as in the arm that is bound with a fillet: all the
parts beyond the noose,--the face, lips, tongue, eyes, and every part of
the head appear gorged with blood, swollen and of a deep red or livid
colour; but if the noose be relaxed, in whatever position you have the
body, before many hours have passed you will perceive the whole of the
blood to have quitted the head and face, and gravitated through the
pores of the skin, flesh, and other structures, from the superior parts
towards those that are inferior and dependent, until they become tumid
and of a dark colour. But if this happens in the dead body, with the
blood dead and coagulated, the frame stiffened with the chill of death,
the passages all compressed or blocked up, it is easy to perceive how
much more apt it will be to occur in the living subject, when the blood
is alive and replete with spirits, when the pores are all open, the
fluid ready to penetrate, and the passage in every way made easy.

When the ingenious and acute Descartes, (whose honourable mention of my
name demands my acknowledgments,) and others, having taken out the heart
of a fish, and put it on a plate before them, see it continuing to
pulsate (in contracting), and when it raises or erects itself and
becomes firm to the touch, they think it enlarges, expands, and that its
ventricles thence become more capacious. But, in my opinion, they do not
observe correctly; for, at the time the heart gathers itself up, and
becomes erect, it is certain that it is rather lessened in every one of
its dimensions; that it is in its systole, in short, not in its
diastole. Neither, on the contrary, when it collapses and sinks down, is
it then properly in its state of diastole and distension, by which the
ventricles become more capacious. But as we do not say that the heart is
in the state of diastole in the dead body, as having sunk relaxed after
the systole, but is then collapsed, and without all motion--in short is
in a state of rest, and not distended. It is only truly distended, and
in the proper state of diastole, when it is filled by the charge of
blood projected into it by the contraction of the auricles; a fact which
sufficiently appears in the course of vivisections. Descartes therefore
does not perceive how much the relaxation and subsidence of the heart
and arteries differ from their distension or diastole; and that the
cause of the distension, relaxation, and constriction, is not one and
the same; as contrary effects so must they rather acknowledge contrary
causes; as different movements they must have different motors; just as
all anatomists know that the flexion and extension of an extremity are
accomplished by opposite antagonist muscles, and contrary or diverse
motions are necessarily performed by contrary and diverse organs
instituted by nature for the purpose. Neither do I find the efficient
cause of the pulse aptly explained by this philosopher, when with
Aristotle he assumes the cause of the systole to be the same as that of
the diastole, viz., an effervescence of the blood due to a kind of
ebullition. For the pulse is a succession of sudden strokes and quick
percussions; but we know of no kind of fermentation or ebullition in
which the matter rises and falls in the twinkling of an eye; the heaving
is always gradual where the subsidence is notable. Besides, in the body
of a living animal laid open, we can with our eyes perceive the
ventricles of the heart both charged and distended by the contraction of
the auricles, and more or less increased in size according to the
charge; and farther, we can see that the distension of the heart is
rather a violent motion, the effect of an impulsion, and not performed
by any kind of attraction.

Some are of opinion that, as no kind of impulse of the nutritive juices
is required in vegetables, but that these are attracted by the parts
which require them, and flow in to take the place of what has been lost;
so neither is there any necessity for an impulse in animals, the
vegetative faculty in both working alike. But there is a difference
between plants and animals. In animals, a constant supply of warmth is
required to cherish the members, to maintain them in life by the
vivifying heat, and to restore parts injured from without. It is not
merely nutrition that has to be provided for.

So much for the circulation; any impediment, or perversion, or excessive
excitement of which, is followed by a host of dangerous diseases and
remarkable symptoms: in connexion with the veins--varices,
abscesses, pains, hemorrhoids, hemorrhages; in connexion with the
arteries--enlargements, phlegmons, severe and lancinating pains,
aneurisms, sarcoses, fluxions, sudden attacks of suffocation, asthmas,
stupors, apoplexies, and innumerable other affections. But this is not
the place to enter on the consideration of these; neither may I say
under what circumstances and how speedily some of these diseases, that
are even reputed incurable, are remedied and dispelled, as if by
enchantment. I shall have much to put forth in my Medical Observations
and Pathology, which, so far as I know, has as yet been observed by no

That I may afford you still more ample satisfaction, most learned
Riolanus, as you do not think there is a circulation in the vessels of
the mesentery, I shall conclude by proposing the following experiment:
throw a ligature around the porta close to the liver, in a living
animal, which is easily done. You will forthwith perceive the veins
below the ligature swelling in the same way as those of the arm when the
bleeding fillet is bound above the elbow; a circumstance which will
proclaim the course of the blood there. And as you still seem to think
that the blood can regurgitate from the veins into the arteries by open
anastomoses, let the vena cava be tied in a living animal near the
divarication of the crural veins, and immediately afterwards let an
artery be opened to give issue to the blood: you will soon observe the
whole of the blood discharged from all the veins, that of the ascending
cava among the number, with the single exception of the crural veins,
which will continue full; and this certainly could not happen were there
any retrograde passage for the blood from the veins to the arteries by
open anastomoses.








LONDON, 1651.

     To the learned and illustrious the President and Fellows of the
     College of Physicians of London.

Harassed with anxious, and in the end not much availing cares, about
Christmas last,[120] I sought to rid my spirit of the cloud that
oppressed it, by a visit to that great man, the chief honour and
ornament of our College, Dr. WILLIAM HARVEY, then dwelling not far from
the city. I found him, Democritus like, busy with the study of natural
things, his countenance cheerful, his mind serene, embracing all within
its sphere. I forthwith saluted him, and asked if all were well with
him? “How can it,” said he, “whilst the Commonwealth is full of
distractions, and I myself am still in the open sea? And truly,” he
continued, “did I not find solace in my studies, and a balm for my
spirit in the memory of my observations of former years, I should feel
little desire for longer life. But so it has been, that this life of
obscurity, this vacation from public business, which causes tedium and
disgust to so many, has proved a sovereign remedy to me.”

I answering said, “I can readily account for this: whilst most men are
learned through others’ wits, and under cover of a different diction and
a new arrangement, vaunt themselves on things that belong to the
ancients, thou ever interrogatest Nature herself concerning her
mysteries. And this line of study as it is less likely to lead into
error, so is it also more fertile in enjoyment, inasmuch as each
particular point examined often leads to others which had not before
been surmised. You yourself, I well remember, informed me once that you
had never dissected any animal--and many and many a one have you
examined,--but that you discovered something unexpected, something of
which you were formerly uninformed.”

“It is true,” said he: “the examination of the bodies of animals has
always been my delight; and I have thought that we might thence not only
obtain an insight into the lighter mysteries of nature, but there
perceive a kind of image or reflex of the omnipotent Creator himself.
And though much has already been made out by the learned men of former
times, I have still thought that much more remained behind, hidden by
the dusky night of nature, uninterrogated; so that I have oftentimes
wondered and even laughed at those who have fancied that everything had
been so consummately and absolutely investigated by an Aristotle or a
Galen, or some other mighty name, that nothing could by possibility be
added to their knowledge. Nature, however, is the best and most faithful
interpreter of her own secrets; and what she presents either more
briefly or obscurely in one department, that she explains more fully and
clearly in another. No one indeed has ever rightly ascertained the use
or function of a part who has not examined its structure, situation,
connexions by means of vessels, and other accidents, in various animals,
and carefully weighed and considered all he has seen. The ancients, our
authorities in science, even as their knowledge of geography was limited
by the boundaries of Greece, so neither did their knowledge of animals,
vegetables, and other natural objects extend beyond the confines of
their country. But to us the whole earth lies open, and the zeal of our
travellers has made us familiar not only with other countries and the
manners and customs of their inhabitants, but also with the animals,
vegetables, and minerals that are met with in each. And truly there is
no nation so barbarous which has not discovered something for the
general good, whether led to it by accident or compelled by necessity,
which had been overlooked by more civilized communities. But shall we
imagine that nothing can accrue to the wide domains of science from such
advantages, or that all knowledge was exhausted by the first ages of the
world? If we do, the blame very certainly attaches to our indolence,
nowise to nature.

“To this there is another evil added: many persons, wholly without
experience, from the presumed verisimilitude of a previous opinion, are
often led by and by to speak of it boldly, as a matter that is certainly
known; whence it comes, that not only are they themselves deceived, but
that they likewise lead other incautious persons into error.”

Discoursing in this manner, and touching upon many topics besides with
wonderful fluency and facility, as is his custom, I interposed by
observing, “How free you yourself are from the fault you indicate all
know who are acquainted with you; and this is the reason wherefore the
learned world, who are aware of your unwearied industry in the study of
philosophy, are eagerly looking for your farther experiments.”

“And would you be the man,” said Harvey, smiling, “who should recommend
me to quit the peaceful haven, where I now pass my life, and launch
again upon the faithless sea? You know full well what a storm my former
lucubrations raised. Much better is it oftentimes to grow wise at home
and in private, than by publishing what you have amassed with infinite
labour, to stir up tempests that may rob you of peace and quiet for the
rest of your days.”

“True,” said I; “it is the usual reward of virtue to have received ill
for having merited well. But the winds which raised those storms, like
the north-western blast, which drowns itself in its own rain, have only
drawn mischief on themselves.”

Upon this he showed me his ‘Exercises on the Generation of Animals,’ a
work composed with vast labour and singular care; and having it in my
hands, I exclaimed, “Now have I what I so much desired! and unless you
consent to make this work public, I must say that you will be wanting
both to your own fame and to the public usefulness. Nor let any fear of
farther trouble in the matter induce you to withhold it longer: I gladly
charge myself with the whole business of correcting the press.”

Making many difficulties at first, urging, among other things, that his
work must be held imperfect, as not containing his investigations on the
generation of insects, I nevertheless prevailed at length, and he said
to me, “I intrust these papers to your care with full authority either
speedily to commit them to the press, or to suppress them till some
future time.” Having returned him many thanks, I bade him adieu, and
took my leave, feeling like another Jason laden with the golden fleece.
On returning home I forthwith proceeded to examine my prize in all its
parts, and could not but wonder with myself that such a treasure should
have lain so long concealed; and that whilst others produce their
trifles and emptinesses with much ado, their messes twice, aye, an
hundred times, heated up, our Harvey should set so little store by his
admirable observations. And indeed, so often as he has sent forth any of
his discoveries to the world, he has not comported himself like those
who, when they publish, would have us believe that an oak had spoken,
and that they had merited the rarest honours,--a draught of hen’s milk
at the least. Our Harvey rather seems as though discovery were natural
to him, a thing of ease and of course, a matter of ordinary business;
though he may nevertheless have expended infinite labour and study on
his works. And we have evidence of his singular candour in this, that he
never hostilely attacks any previous writer, but ever courteously sets
down and comments upon the opinions of each; and indeed he is wont to
say, that it is argument of an indifferent cause when it is contended
for with violence and distemper; and that truth scarce wants an

It would have been easy for our illustrious colleague to have woven the
whole of this web from materials of his own; but to escape the charge of
envy, he has rather chosen to take Aristotle and Fabricius of
Aquapendente as his guides, and to appear as contributing but his
portion to the general fabric. Of him, whose virtue, candour, and genius
are so well known to you all, I shall say no more, lest I should seem to
praise to his face one whose singular worth has exalted him beyond the
reach of all praise. Of myself I shall only say, that I have done no
more than perform the midwife’s office in this business, ushering into
the light this product of our colleague’s genius as you see it,
consummate and complete, but long delayed, and fearing perchance some
envious blast: in other words, I have overlooked the press; and as our
author writes a hand which no one without practice can easily read (a
thing that is common among our men of letters), I have taken some pains
to prevent the printer committing any very grave blunders through
this--a point which I observe not to have been sufficiently attended to
in the small work of his which lately appeared.[121]

Here then, my learned friends, you have the cause of my addressing you
at this time, viz. that you may know that our Harvey presents an
offering to the benefit of the republic of letters, to your honour, to
his own eternal fame.

                                                 Farewell, and prosper.

                                                            GEORGE ENT.


It will not, I trust, be unwelcome to you, candid reader, if I yield to
the wishes, I might even say the entreaties, of many, and in these
Exercises on Animal Generation, lay before the student and lover of
truth what I have observed on this subject from anatomical dissections,
which turns out to be very different from anything that is delivered by
authors, whether philosophers or physicians.

Physicians, following Galen, teach that from the semen of the male and
female mingled in coition the offspring is produced, and resembles one
or other, according to the _predominance_ of this one or of that; and
farther, that in virtue of the same predominance, it is either male or
female. Sometimes they declare the semen masculinum as the _efficient
cause_, and the semen femininum as supplying the _matter_; and
sometimes, again, they advocate precisely the opposite doctrine.
Aristotle, one of Nature’s most diligent inquirers, however affirms the
_principles_ of generation to be the male and the female, she
contributing the matter, he the form; and that immediately after the
sexual act the vital principle and the first particle of the future
fœtus, viz. the heart, in animals that have red blood, are formed from
the menstrual blood in the uterus.

But that these are erroneous and hasty conclusions is easily made to
appear: like phantoms of darkness they suddenly vanish before the light
of anatomical inquiry. Nor is any long refutation necessary where the
truth can be seen with one’s proper eyes; where the inquirer by simple
inspection finds everything in conformity with reason; and where at the
same time he is made to understand how unsafe, how base a thing it is to
receive instruction from others’ comments without examination of the
objects themselves, the rather as the book of Nature lies so open and is
so easy of consultation.

What I shall deliver in these my Exercises on Animal Generation I am
anxious to make publicly known, not merely that posterity may there
perceive the sure and obvious truth, but farther, and especially, that
by exhibiting the method of investigation which I have followed, I may
propose to the studious a new and, unless I mistake, a safer way to the
attainment of knowledge.

For although it is a new and difficult road in studying nature, rather
to question things themselves than, by turning over books, to discover
the opinions of philosophers regarding them, still it must be
acknowledged that it is the more open path to the secrets of natural
philosophy, and that which is less likely to lead into error.

Nor is there any just cause wherefore the labour should deter any one,
if he will but think that he himself only lives through the ceaseless
working of his heart. Neither, indeed, would the way I propose be felt
as so barren and lonely, but for the custom, or vice rather, of the age
we live in, when men, inclined to idleness, prefer going wrong with the
many, to becoming wise with the few through dint of toil and outlay of
money. The ancient philosophers, whose industry even we admire, went a
different way to work, and by their unwearied labour and variety of
experiments, searching into the nature of things, have left us no
doubtful light to guide us in our studies. In this way it is that almost
everything we yet possess of note or credit in philosophy, has been
transmitted to us through the industry of ancient Greece. But when we
acquiesce in the discoveries of the ancients, and believe (which we are
apt to do through indolence) that nothing farther remains to be known,
we suffer the edge of our ingenuity to be taken off, and the lamp which
they delivered to us to be extinguished. No one of a surety will allow
that all truth was engrossed by the ancients, unless he be utterly
ignorant (to pass by other arts for the present) of the many remarkable
discoveries that have lately been made in anatomy, these having been
principally achieved by individuals who, either intent upon some
particular matter, fell upon the novelty by accident, or (and this is
the more excellent way) who following the traces of nature with their
own eyes, pursued her through devious but most assured ways till they
reached her in the citadel of truth. And truly in such pursuits it is
sweet not merely to toil, but even to grow weary, when the pains of
discovering are amply compensated by the pleasures of discovery. Eager
for novelty, we are wont to travel far into unknown countries, that with
our own eyes we may witness what we have heard reported as having been
seen by others, where, however, we for the most part find

   ---- minuit præsentia famam:

that the presence lessens the repute. It were disgraceful, therefore,
with this most spacious and admirable realm of nature before us, and
where the reward ever exceeds the promise, did we take the reports of
others upon trust, and go on coining crude problems out of these, and on
them hanging knotty and captious and petty disputations. Nature is
herself to be addressed; the paths she shows us are to be boldly
trodden; for thus, and whilst we consult our proper senses, from
inferior advancing to superior levels, shall we penetrate at length into
the heart of her mystery.

_Of the Manner and Order of acquiring Knowledge._

Although there is but one road to science, that to wit, in which we
proceed from things more known to things less known, from matters more
manifest to matters more obscure; and universals are principally known
to us, science springing by reasonings from universals to particulars;
still the comprehension of universals by the understanding is based upon
the perception of individual things by the senses. Both of Aristotle’s
propositions, therefore, are true: First, the one in his Physics,[122]
where he says, “The way is naturally prepared, from those things that
are more obvious and clear to us, to those things that are more obvious
and clear by nature. For, indeed, the same things are not both known to
us and extant simply: whence it is indispensable to proceed in this way,
viz. from those things that are of a more obscure nature, but to us are
more apparent, to those that are of a nature more obvious and distinct.
Now those things are, in the first instance, more perspicuous and
manifest to us that are most confused in fact; whence it is necessary to
proceed from universals to particulars; for the whole, according to the
dictates of sense, is the more obvious; and the universal is a certain
whole.” And again, that other in his Analytics,[123] where he thus
expresses himself: “Singulars are to us more known, and are the first
that exist according to the information of sense; for, indeed, there is
nothing in the understanding which was not first in the sense. And
although that reasoning is naturally prior and more known which proceeds
by syllogism, still is that more perspicuous to us which is based on
induction. And therefore do we more readily define singulars than
universals, for there is more of equivocation in universals: whence it
is advisable from singulars to pass to universals.”

All this agrees with what we have previously said, although at first
blush it may seem contradictory; inasmuch as universals are first
imbibed from particulars by the senses, and in so far are only known to
us as an universal is a certain whole and indistinct thing, and a whole
is known to us according to sense. For though in all knowledge we begin
from sense, because, as the philosopher quoted has it, sensible
particulars are better known to sense, still the sensation itself is an
universal thing. For, if you observe rightly, although in the external
sense the object perceived is singular, as, for example, the colour
which we call yellow in the eye, still when this impression comes to be
made an abstraction, and to be judged of and understood by the internal
sensorium, it is an universal. Whence it happens that several persons
abstract several species, and conceive different notions, from viewing
the same object at the same time. This is conspicuous among poets and
painters, who, although they contemplate one and the same object in the
same place at the same moment, and with all other circumstances
agreeing, nevertheless regard and describe it variously, and as each has
conceived or formed an idea of it in his imagination. In the same way,
the painter having a certain portrait to delineate, if he draw the
outline a thousand times, he will still give a different face, and each
not only differing from the other, but from the original countenance;
with such slight variety, however, that looking at them singly, you
shall conceive you have still the same portrait set before you,
although, when set side by side, you perceive how different they are.
Now the reason is this: that in vision, or the act of seeing itself,
each particular is clear and distinct; but the moment the object is
removed, as it is by merely shutting the eyes, when it becomes an
abstraction in the fancy, or is only retained in the memory, it appears
obscure and indistinct; neither is it any longer apprehended as a
particular, but as a something that is common and universal. Seneca[124]
explains this subtlety, according to Plato’s views, in very elegant
terms: “An idea,” he says, “is an eternal copy of the things that have
place in nature. I add an explanation of this definition, that the
matter may be made plainer to you. I desire to take your portrait; I
have you as the prototype of the picture, from which my mind takes a
certain impression which it transfers to the canvass. The countenance,
therefore, which teaches and directs me, and from which the imitation is
sought, is the idea.” A little farther on he proceeds: “I have but just
made use of the image which a painter forms in his mind, by way of
illustration. Now, if he would paint a likeness of Virgil, he forms an
intuitive image of his subject: the idea is the face of Virgil, the type
of his future work; and this which the artist conveys and transfers to
his work is the resemblance or portrait. What difference is there? you
ask: the one is the pattern or prototype, the other the form taken from
the pattern and fixed in the work; the artist imitates the one, he
creates the other. A statue has a certain expression of face; this is
the Eidos, the species or representation; the prototype himself has a
certain expression, which the statuary conceiving, transfers to his
statue: this is the idea. Do you desire yet another illustration of the
distinction? The Eidos is in the work; the idea without the work, and
not only without the work, but it even existed before the work was
begun.” For the things that have formerly been noted, and that by use or
wont have become firmly fixed in the mind of the artist, do, in fact,
constitute art and the artistic faculty; art, indeed, is the reason of
the work in the mind of the artist. On the same terms, therefore, as art
is attained to, is all knowledge and science acquired; for as art is a
habit with reference to things to be done, so is science a habit in
respect of things to be known: as that proceeds from the imitation of
types or forms, so this proceeds from the knowledge of natural things.
Each has its origin in sense and experience, and it is impossible that
there can rightly be either art or science without visible instance or
example. In both, that which we perceive in sensible objects differs
from the image itself which we retain in our imagination or memory. That
is the type, idea, forma informans; this is the imitation, the Eidos,
the abstract species. That is a thing natural, a real entity; this a
representation or similitude, and a thing of the reason. That is
occupied with the individual thing, and itself is single and particular;
this is a certain universal and common thing. That in the artist and man
of science is a sensible thing, clearer, more perfect; this a matter of
reason and more obscure: for things perceived by sense are more assured
and manifest than matters inferred by reason, inasmuch as the latter
proceed from and are illustrated by the former. Finally, sensible things
are of themselves and antecedent; things of intellect, however, are
consequent, and arise from the former, and, indeed, we can in no way
attain to them without the help of the others. And hence it is, that
without the due admonition of the senses, without frequent observation
and reiterated experiment, our mind goes astray after phantoms and
appearances. Diligent observation is therefore requisite in every
science, and the senses are frequently to be appealed to. We are, I say,
to strive after personal experience, not to rely on the experience of
others; without which, indeed, no one can properly become a student of
any branch of natural science, nor show himself a competent judge of
what I am about to say on the subject of generation; for without
experience and skill in anatomy, he would not better understand me than
could one born blind appreciate the nature and difference of colours, or
one deaf from birth judge of sounds. I would, therefore, have you,
gentle reader, to take nothing on trust from me concerning the
generation of animals; I appeal to your own eyes as my witnesses and
judge. For as all true science rests upon those principles which have
their origin in the operation of the senses, particular care is to be
taken that by repeated dissection the grounds of our present subject be
fully established. If we do otherwise, we shall but come to empty and
unstable opinions; solid and true science will escape us altogether:
just as commonly happens to those who form their notions of distant
countries and cities, or who pretend to get a knowledge of the parts of
the human body, from drawings and engravings, which but too frequently
present things under false and erroneous points of view. And so it is,
that in the present age we have an abundance of writers and pretenders
to knowledge, but very few who are really learned and philosophers.

Thus much have I thought good, gentle reader, to present to you, by way
of preface, that understanding the nature of the assistance to which I
have trusted, and the counsel by which I have been led in publishing
these my observations and experiments; and that you yourself in passing
over the same ground, may not merely be in a condition to judge between
Aristotle and Galen, but, quitting subtleties and fanciful conjectures,
embracing nature with your own eyes, that you may discover many things
unknown to others, and of great importance.

_Of the same matters, according to Aristotle._

There is no such thing as innate knowledge, according to Aristotle;
neither opinion, nor art, nor understanding, nor speech, nor reason
itself, inhere in us by nature and from our birth; but all of these, as
well as the qualities and habitudes, which are believed to be
spontaneous, and to lie under the control of our will, are to be
regarded as among the number of those things that reach us from without
according to nature: such as the virtues and the vices, for which men
are either praised and rewarded or reproved and punished. All our
knowledge, therefore, of every kind has to be acquired. But this is not
the place to inquire into the first principles of knowledge.

I believe, however, that it will not be useless if I premise a few words
as to whence and how our knowledge reaches us, both with a view to
rendering what I shall say on the subject of generation more readily
intelligible, and of removing any doubts that may arise out of this
opinion of the Stagirite,[125] who asserts that all doctrine and
discipline based on reason are derived from antecedent knowledge; whence
it seems to follow that there is either no first knowledge, or that this
must be innate, a conclusion which is in contradiction with what has
already been stated.

The doubt, however, is by and by resolved by Aristotle[126] himself,
when he treats of the mode in which knowledge is acquired: for after he
has taught that all certain knowledge is obtained through syllogism and
demonstration, and made it manifest that every demonstrative syllogism
proceeds from true and necessary first principles; he goes on to inquire
how principles become known, and what the faculty is that knows; at the
same time, too, he discusses the question, Whether habits, if not
innate, are engendered; and whether, being innate, they lie concealed?
“We have not,” he says, “these habits; for it happens that they are
concealed from those who acquire the most admirable kinds of knowledge
through demonstration. If, however, we receive them, not having had them
previously, how should we become informed, how learn from non-antecedent
knowledge? It is obvious, therefore, that they are neither possessed,
nor can they be engendered in the ignorant and those who are endowed
with no habit. Whence it is essential that some faculty be possessed,
not however any which were more excellent, more exquisite than they.
Now it seems a thing common to all animals, that they have a congenital
power of judging, which we call sense. Since sense is innate, then, the
things perceived by sense remain in some animals; in others they do not
remain. Those in whom they do not remain, however, have either no
knowledge at all, or at least none beyond the simple perception of the
things which do not remain; others, again, when they perceive, retain a
certain something in their soul. Now, as there are many animals of this
description, there is already a distinction between one animal and
another; and to this extent, that in some there is reason from the
memory of things; and in others there is none. Memory, therefore, as is
said, follows from sense; but from repeated recollection of the same
thing springs experience (for repeated acts of memory constitute a
single experience). From experience, however, or from the whole and
universal stored quietly in the mind, (one, to wit, in place of a
multitude--because in the whole crowd of particulars there is one and
the same universal,) is derived the principle of art and of science: of
art, if it belong to production (i. e. action); of science, if it belong
to that which is (i. e. the knowledge of entity). Consequently there are
neither any definite habits that are innate, nor any habits that are
formed from other and more known habits, but from sense.”

From which words of Aristotle it plainly appears by what order or method
any art or science is acquired, viz. The thing perceived by sense
remains; from the permanence of the thing perceived results memory; from
multiplied memory, experience; from experience, universal reason,
definitions, and maxims or common axioms, the most certain principles of
knowledge; for example, the same thing under like conditions cannot be
and not be; every affirmation or negation is either true or false; and
so on.

Wherefore, as we have said above, there is no perfect knowledge which
can be entitled ours, that is innate; none but what has been obtained
from experience, or derived in some way from our senses; all knowledge,
at all events, is examined by these, approved by them, and finally
presents itself to us firmly grounded upon some pre-existing knowledge
which we possessed: because without memory there is no experience, which
is nothing else than reiterated memory; in like manner memory cannot
exist without endurance of the things perceived, and the thing perceived
cannot remain where it has never been.

The supreme dictator in philosophy again and elsewhere expresses himself
very elegantly in the same direction:[127] “All men desire by nature to
know; the evidence of this is the pleasure they take in using their
senses, among which the sight is that which is particularly preferred,
because this especially serves us to acquire knowledge, and informs us
of the greatest number of differences. Nature, therefore, endowed
animals with sense; some of them, however, have no memory from the
operations of their senses; others, again, have memory; and this is the
reason wherefore some are more intelligent, and some more capable of
receiving instruction than others, those, namely, that want
recollection. Some show discretion independently of tuition: inasmuch as
there are many that do not hear, such as bees and others of the same
kind. But all animals which along with memory have the faculty of
hearing are susceptible of education. Other creatures, again, live
possessed of fancy and memory, but they have little store of experience;
the human kind, however, have both art and reasoning. Now experience
comes to man through memory; for many memories of the same thing have
the force of a single experience: so that experience appears to be
almost identical with certain kinds of art and science;[128] and,
indeed, men acquire both art and science by experience: for experience,
as Polus rightly remarks, begets art, inexperience is waited on by

By this he plainly tells us that no one can truly be entitled discreet
or well-informed, who does not of his own experience, i. e. from
repeated memory, frequent perception by sense, and diligent observation,
know that a thing is so in fact. Without these, indeed, we only imagine
or believe, and such knowledge is rather to be accounted as belonging to
others than to us. The method of investigating truth commonly pursued at
this time therefore is to be held as erroneous and almost foolish, in
which so many inquire what others have said, and omit to ask whether the
things themselves be actually so or not; and single universal
conclusions being deduced from several premises, and analogies being
thence shaped out, we have frequently mere verisimilitudes handed down
to us instead of positive truths. Whence it comes that pretenders to
knowledge and sophists, trimming up the discoveries of others, changing
the arrangement only, or the language, and adding a few things of no
importance, audaciously send them forth as their own, and so render
philosophy, which ought to be certain and perspicuous, obscure and
intricate. For he who reads the words of an author and fails, through
his own senses, to obtain images of the things that are conveyed in
these words, derives not true ideas, but false fancies and empty
visions; whence he conjures up shadows and chimeras, and his whole
theory or contemplation, which, however, he regards as knowledge, is
nothing more than a waking dream, or such a delirium as the sick fancy

I therefore whisper in your ear, friendly reader, and recommend you to
weigh carefully in the balance of exact experience all that I shall
deliver in these Exercises on the Generation of Animals; I would not
that you gave credit to aught they contain save in so far as you find it
confirmed and borne out by the unquestionable testimony of your own

The same course is even advised by Aristotle, who, after having gone
over a great many particulars about bees, says at length:[129] “That
the generation of bees takes place in this way appears both from reason
and from those things that are seen to occur in their kind. Still all
the incidents have not yet been sufficiently examined. And when the
investigation shall be complete, then will sense be rather to be trusted
than reason; reason, however, will also deserve credit, if the things
demonstrated accord with the things that are perceived by sense.”

_Of the Method to be pursued in studying Generation._

Since in Animal Generation, (and, indeed, in all other subjects upon
which information is desired,) inquiry must be begun from the causes,
especially the material and efficient ones, it appears advisable to me
to look back from the perfect animal, and to inquire by what process it
has arisen and grown to maturity, to retrace our steps, as it were, from
the goal to the starting place; so that when at last we can retreat no
further, we shall feel assured that we have attained to the principles;
at the same time we shall perceive from what primary matter, and from
what efficient principle, and in what way from these the plastic force
proceeds; as also what processes nature brings into play in the work.
For primary and more remote matter, by abstraction and negation (being
stripped of its garments as it were) becomes more conspicuous; and
whatever is first formed or exists primarily in generation, is the
material cause of everything that succeeds. For example, before a man
attains to maturity, he was a boy, an infant, an embryo. And then it is
indispensable to inquire further as to what he was in his mother’s womb
before he was an embryo or fœtus; whether made up of three bubbles, or a
shapeless mass, or a conception or coagulum proceeding from the mingled
seminal fluids of his parents, or what else, as we have it delivered to
us by writers. In like manner, before a fowl had attained to maturity or
perfection,--because capable of engendering its like,--it was a chicken;
previous to which it was an embryo or fœtus in the egg; and before this,
Hieronymus Fabricius, of Aquapendente, has observed rudiments of the
head, eyes, and spine. But when he asserts that the bones are formed
before the muscles, heart, liver, lungs, and precordial parts, and
contends that all the internal organs must exist before the external
ones, he follows probabilities according to previous notions rather than
inspection; and quitting the evidences of sense that rest on anatomy, he
seeks refuge in reasonings upon mechanical principles; a procedure that
is anything but becoming in a great anatomist, whose duty it was
faithfully to narrate the changes he observed taking place day by day in
the egg, up to the period when the fœtus is perfected; and this the
rather as he expressly proposed to himself to write the history of the
formation of the chick in the egg, and to exhibit in figures what
happens in the course of each successive day. It would have been in
harmony with such a design, I say, had we been informed, on the
testimony of the senses, of what parts are formed first, together, or
subsequently in the egg; and not had mere opinions or musty conjectures,
and the instances of houses and ships, adduced in illustration of the
order and mode of formation of the parts.

We, therefore, in conformity with the method proposed, shall show in the
first place in the egg, and then in the conceptions of other animals,
what parts are first, and what are subsequently formed by the great God
of Nature with inimitable providence and intelligence, and most
admirable order. Next we shall inquire into the primary matter out of
which, and the efficient cause by which generation is accomplished, and
also the order and economy of generation, as observed by us; that from
thence, from its own work, we may have some certain information of the
several faculties of the formative and vegetative soul, and of the
nature of the soul itself, judging from its members or organs, and their

This, indeed, cannot be done in all animals: first, because a sufficient
number of several of these cannot be commanded; and again, because, from
the small size of many, they escape our powers of vision. It must
suffice, therefore, that this is done in some kinds which are more
familiarly known to us, and that we refer all the rest to these as types
or standards.

We have, therefore, selected those that may tend to render our
experiments more undeniable, viz. the larger and more perfect animals,
and that are easily within reach. For in the larger animals all things
are more conspicuous; in the more perfect, they are also more distinct;
and in those that we can command, and that live with us, everything is
more readily examined: we have it in our power so often as we please to
repeat our observations, and so to free them from all uncertainty and
doubt. Now, among oviparous animals of this description, we have the
common fowl, the goose, duck, pigeon; and then we have frogs, and
serpents, and fishes; crustacea, testacea, and mollusca; among insects,
bees, wasps, butterflies, and silkworms; among viviparous creatures, we
have sheep, goats, dogs, cats, deer, and oxen; lastly, we have the most
perfect of all animals, man.

Having studied and made ourselves familiar with these, we may turn to
the consideration of the more abstruse nature of the vegetative soul,
and feel ourselves in a condition to understand the method, order, and
causes of generation in animals generally; for all animals resemble one
or other of those above mentioned, and agree with them either generally
or specifically, and are procreated in the same manner, or the mode of
their generation at least is referrible by analogy to that of one or
other of them. For Nature, perfect and divine, is ever in the same
things harmonious with herself, and as her works either agree or differ,
(viz. in genus, species, or some other proportion,) so is her agency in
these (viz. generation or development) either the same or diverse. He
who enters on this new and untrodden path, and out of the vast realm of
Nature endeavours to find the truth by means of anatomical dissections
and experiments, is met by such a multitude of facts, and these of so
unusual an aspect, that he may find it more difficult to explain and
describe to others the things he has seen, than he reckoned it labour to
make his observations; so many things are encountered that require
naming; such is the abundance of matter and the dearth of words. But if
he would have recourse to metaphors, and by means of old and familiar
terms would make known his ideas concerning the things he has newly
discovered, the reader would have little chance of understanding him
better than if they were riddles that were propounded; and of the thing
itself, which he had never seen, he could have no conception. But then,
to have recourse to new and unusual terms were less to bring a torch to
lighten, than to darken things still more with a cloud: it were to
attempt an explanation of a matter unknown by one still more unknown,
and to impose a greater toil on the reader to understand the meaning of
words than to comprehend the things themselves. And so it happens that
Aristotle is believed by the inexperienced to be obscure in many places;
and on this account, perhaps, Fabricius of Aquapendente rather intended
to exhibit the chick in ovo in his figures than to explain its formation
in words.

Wherefore, courteous reader, be not displeased with me, if, in
illustrating the history of the egg, and in my account of the generation
of the chick, I follow a new plan, and occasionally have recourse to
unusual language. Think me not eager for vainglorious fame rather than
anxious to lay before you observations that are true, and that are
derived immediately from the nature of things. That you may not do me
this injustice, I would have you know that I tread in the footsteps of
those who have already thrown a light upon this subject, and that,
wherever I can, I make use of their words. And foremost of all among the
ancients I follow Aristotle; among the moderns, Fabricius of
Aquapendente; the former as my leader, the latter as my informant of the
way. For even as they who discover new lands, and first set foot on
foreign shores, are wont to give them new names which mostly descend to
posterity, so also do the discoverers of things and the earliest writers
with perfect propriety give names to their discoveries. And now I seem
to hear Galen admonishing us, that we should but agree about the things,
and not dispute greatly about the words.




_Wherefore we begin with the history of the hen’s egg._

Hieronymus Fabricius of Aquapendente, (whom, as I have said, I have
chosen my informant of the way I am to follow,) in the beginning of his
book on the Formation of the Ovum and Chick, has these words: “My
purpose is to treat of the formation of the fœtus in every animal,
setting out from that which proceeds from the egg: for this ought to
take precedence of all discussion of the subject, both because from this
it is not difficult to make out Aristotle’s views of the matter, and
because his treatise on the Formation of the Fœtus from the egg, is by
far the fullest, and the subject is by much the most extensive and

We, however, commence with the history of the hen’s egg as well for the
reasons above assigned, as because we can thence obtain certain data
which, as more familiar to us, will serve to throw light on the
generation of other animals; for as eggs cost little, and are always to
be had, we have an opportunity from them of observing the first clear
and unquestionable commencements of generation, how nature proceeds in
the process, and with what admirable foresight she governs every part of
the work.

Fabricius proceeds: “Now that the contemplation of the formation of the
chick from the egg is of very ample scope, appears from this, that the
greater number of animals are produced from ova. Passing by almost all
insects and the whole of the less perfect animals, which are obviously
produced from eggs, the greater number of the more perfect are also
engendered from eggs.” And then he goes on to particularize: “All
feathered creatures; fishes likewise, with the single exception of the
whale tribes; crustacea, testacea, and all mollusca; among land animals,
reptiles, millepeds, and all creeping things; and among quadrupeds, the
entire tribe of lizards.”

We, however, maintain (and shall take care to show that it is so), that
all animals whatsoever, even the viviparous, and man himself not
excepted, are produced from ova; that the first conception, from which
the fœtus proceeds in all, is an ovum of one description or another, as
well as the seeds of all kinds of plants. Empedocles,[130] therefore,
spoke not improperly of the _oviparum genus arboreum_, “the egg-bearing
race of trees.” The history of the egg is therefore of the widest scope,
inasmuch as it illustrates generation of every description.

We shall, therefore, begin by showing where, whence, and how eggs are
produced; and then inquire by what means and order and successive steps
the fœtus or chick is formed and perfected in and from the egg.

Fabricius has these additional words: “The fœtus of animals is
engendered in one case from an ovum, in another from the seminal fluid,
in a third from putrefaction; whence some creatures are oviparous,
others viviparous, and yet others, born of putrefaction or by the
spontaneous act of nature, automatically.”

Such a division as this, however, does not satisfy me, inasmuch as all
animals whatsoever may be said in a certain sense to spring from ova,
and in another certain sense from seminal fluid; and they are entitled
oviparous, viviparous, or vermiparous, rather in respect of their mode
of bringing forth than of their first formation. Even the creatures that
arise spontaneously are called automatic, not because they spring from
putrefaction, but because they have their origin from accident, the
spontaneous act of nature, and are equivocally engendered, as it is
said, proceeding from parents unlike themselves. And, then, certain
other animals bring forth an egg or a worm as their conception and
semen, from which, after it has been exposed abroad, a fœtus is
produced; whence such animals are called oviparous or vermiparous.
Viviparous animals are so entitled because they retain and cherish their
conception in their interior, until from thence the fœtus comes forth
into the light completely formed and alive.


_Of the seat of generation._

“Nature,” says Fabricius, “was first solicitous about the place [where
generation should proceed], which she determined should be either within
or without the animal: within she ordained the uterus; without, the
ovum: in the uterus the blood and seminal fluid engendering; in the
ovum, however, the fluids or elements of which it consists supplying
pabulum for the production of the fœtus.”

Now, whatever is procreated of the semen properly so called originates
and is perfected either in the same place or in different places. All
viviparous creatures derive their origin and have their completion in
the uterus itself; but oviparous animals, as they have their beginning
within their parents, and there become ova, so is it beyond their
parents that they are perfected into the fœtal state. Among oviparous
animals, however, there are some that retain their ova till such time as
they are mature and perfect; such as all the feathered tribes, reptiles
and serpents. Others, again, extrude their semina in a state still
immature and imperfect, and it is without the body of the parent that
increase, maturity, and perfection, are attained. Under this head we
range frogs, many kinds of fishes, crustaceous, molluscous, and
testaceous animals, the ova of which, when first extruded, are but
beginnings, sketches, yelks which afterwards surround themselves with
whites, and attracting, concocting, and attaching nutriment to
themselves, are changed into perfect seeds or eggs. Such also are the
semina of insects (called worms by Aristotle), which, imperfect on their
extrusion and in the beginning, seek food for themselves, upon which
they are nourished, and grow from a grub into a chrysalis: from an
imperfect into a perfect egg or seed. Birds, however, and the rest of
the oviparous tribes, lay perfect eggs; whence without the uterus the
fœtus is engendered. And it was on this account that Fabricius admitted
two seats of generation: one internal, the uterus; another external, the
ovum. But he would have had more reason, in my opinion, had he called
the nest, or place where the eggs are laid, the external seat, that, to
wit, in which the extruded seed or egg is cherished, matured, and
perfected into a fœtus; for it is from the differences of this seat that
the generation of oviparous animals is principally distinguished. And it
is, indeed, a thing most worthy of admiration to see these creatures
selecting and preparing their nests with so much foresight, and
fashioning, and furnishing, and concealing them with such inimitable art
and ingenuity; so that it seems imperative on us to admit in them a
certain spark of the divine flame (as the poet said of bees); and,
indeed, we can more readily admire than imitate their untaught art and


_Of the upper part of the hen’s uterus, or the ovary._

The uterus of the fowl is divided by Fabricius into the superior and
inferior portions, and the superior portion he calls the ovary.

The ovary is situated immediately beneath the liver, close to the spine,
over the descending aorta. In this situation, in the larger animals with
red blood, the cœliac artery enters the mesentery, at the origin,
namely, of the emulgent veins, or a little lower; in the situation
moreover in which in the other red-blooded and viviparous animals the
vasa præparantia, tending to the testes, take their origin: in the same
place at which the testes of the cock-bird are situated, there is the
ovary of the hen discovered. For some animals carry their testicles
externally; others have them within the body, in the loins, in the space
midway from the origins of the vasa præparantia. But the cock has his
testicles at the very origin of these vessels, as if his spermatic fluid
needed no preparation.

Aristotle[131] says that the ovum begins at the diaphragm; “I, however,”
says Fabricius, “in my treatise on Respiration, have denied that the
feathered kinds have any diaphragm. The difficulty is resolved by
admitting that birds are not entirely destitute of a kind of diaphragm,
inasmuch as they have a delicate membrane in the place of this septum,
which Aristotle calls a cincture and septum. Still they have no
diaphragm that is muscular, and that might aid respiration, like other
animals. But, indeed, Aristotle did not know the muscles.”

Thus is the prince of philosophers accused and excused in the same
breath, his challenger being himself not free from error; because it is
certain that Aristotle both knew the muscles, as I have elsewhere shown,
and the membranes, which in birds are not only situated transversely in
the direction of the cincture of the body, but extended in the line of
the longitudinal direction of the belly, supplying the place of the
diaphragm [of quadrupeds] and being subservient to respiration, as I
have shown in the clearest manner in my disquisitions on the Respiration
of Animals. And, passing over other particulars at this time, I shall
only direct attention to the fact, that birds breathe with great
freedom, and in singing also modulate their voice in the most admirable
manner, their lungs all the while being so closely connected with their
sides and ribs, that they can neither be dilated and rise, nor suffer
contraction in any considerable degree.

The bronchia or ends of the trachea in birds, moreover, are perforate,
and open into the abdomen (and this is an observation which I do not
remember to have met with elsewhere), so that the air inspired is
received into and stored up within the cells or cavities formed by the
membranes mentioned above. In the same manner as fishes and serpents
draw air into ample bladders situated in the abdomen, and there store it
up, by which they are thought to swim more lightly; and as frogs and
toads, when in the height of summer they respire more vigorously assume
more than the usual quantity of air into their vesicular lungs, (whence
they acquire so large a size,) which they afterwards freely expire,
croaking all the while; so in the feathered tribes are the lungs rather
the route and passage for respiration than its adequate instrument.

Now, had Fabricius seen this, he would never have denied that these
membranes (with the assistance of the abdominal muscles at all events,)
could subserve respiration and perform the office of the diaphragm,
which, indeed, of itself, and without the assistance of the abdominal
muscles, were incompetent to act as an instrument of respiration. And,
then, the diaphragm has another duty to perform in those creatures in
whom it is muscular or fleshy, viz., to depress the stomach filled with
food, and the intestines distended with flatus, so that the heart and
lungs shall not be invaded, and life itself oppressed in its citadel.
But as there was no danger of anything of this kind in birds, they have
a membranous septum, perfectly well adapted to the purposes of
respiration, so that they have very properly been said to have a
diaphragm. And were birds even entirely without anything in the shape of
a diaphragm, still would Aristotle not be liable to criticism for
speaking of the ova commencing at the septum transversum, because by
this title he merely indicates the place where the diaphragm is usually
met with in other animals. In the same way we ourselves say that the
ovary is situated at the origin of the spermatic vasa præparantia,
although the hen has, in fact, no such vessels.

The perforations of the lungs discovered by me (and to which I merely
direct attention in this place,) are neither obscure nor doubtful, but,
in birds especially, sufficiently conspicuous, so that in the ostrich I
found many conduits which readily admitted the points of my fingers. In
the turkey, fowl, and, indeed, almost all birds, you will find that a
probe passed downwards by the trachea makes its way out of the lungs,
and is discovered lying naked and exposed in one or another of the
abdominal cells. Air blown into the lungs of these creatures with a pair
of bellows passes on with a certain force even into the most inferior of
these cells.

We may even be permitted to ask, whether in man, whilst he lives, there
is not a passage from openings of the same kind into the cavity of the
thorax? For how else should the pus poured out in empyema and the blood
extravasated in pleurisy make its escape? In penetrating wounds of the
chest, the lungs themselves being uninjured, air often escapes by the
wound; or liquids thrown into the cavity of the thorax, are discharged
with the expectoration. But our views of this subject will be found
fully expressed elsewhere, viz., in our disquisitions on the Causes,
Uses, and Organs of Respiration.

I return to the ovary and the upper portion of the fowl’s uterus, in
which the rudiments of the eggs are produced. These, according to
Aristotle,[132] in the first instance are small, and of a white colour;
growing larger, they subsequently become of a paler and then of a deeper

The superior uterus of Fabricius, however, has no existence until after
the hen has conceived, and contains the rudiments of ova within it; when
it may be designated as a cluster of papulæ. And he therefore observes
very properly, “The superior uterus is nothing more than an almost
infinite congeries of yelks, which appear collected as it were into a
single cluster, of a rounded form, and of every size, from that of a
grain of mustard to that almost of a walnut or medlar. This multitude of
vitelli is aggregated and conjoined very much in the manner of a bunch
of grapes, for which reason I shall constantly speak of it as the
vitellarium or raceme of yelks; a comparison which Aristotle himself
made in speaking of the soft or scaleless fishes, when he says,[133]
their ovary or roe is extruded agglutinated into a kind of raceme or
bunch of grapes. And in the same way as in a bunch of grapes the several
berries are seen to be of different sizes, some large, some small, some
of very diminutive proportions, each hanging by its several peduncle, so
do we find precisely the same thing in the vitellarium of the fowl.”

In fishes, frogs, crustacea, and testacea, however, matters are
otherwise arranged. The ovary or vitellary here contains ova of one
uniform size only, which being extruded increase, attain maturity, and
give birth to fœtuses simultaneously. But in the ovary of the common
fowl, and almost all the rest of the oviparous tribes, the yelks are
found in various stages of their growth, from dimensions that are
scarcely visible up to the full size. Nevertheless the eggs of the fowl
and other birds, (not otherwise than in those cases where the eggs are
all engendered and laid at the same moment,) ripen their fœtuses under
the influence of incubation in the same nest, and produce them perfect,
nearly at the same time. In the family of the pigeons, however, (which
lay and incubate no more than two eggs in the same nest,) I have
observed that all the ova crowded together in the ovary, with the
exception of a single pair, were of the same dimensions; this pair was
very much larger than any of the others, and already prepared to descend
into the second or lower uterus. In these creatures, therefore, the
number of young is great, not because of the multitude produced at a
time, but of the frequency with which births take place, viz., every
month. In the same way, among cartilaginous fishes, such as the skates,
dog-fishes, &c., two eggs only come to maturity together, one of which
descends from the right the other from the left corner of the uterus
into the inferior portion, where they are cherished, and where they
finally produce living fœtuses, precisely as happens among viviparous
animals; in the ovary, nevertheless, there is almost infinite store of
ova of various sizes--in the ray I have counted upwards of a hundred.

The ova of the other oviparous tribes are either perfected externally,
as in the case of fishes, or they are concocted or matured, as in the
instance of testacea, crustacea, and spiders. Testaceous animals lay
their eggs amidst froth; the crustaceous tribes, such as the shrimp,
crab, and lobster, bear them about with them, attached to certain
appendages; and the spiders carry them about and cherish them, laid up
in a kind of purse or basket, made of their web. The beetle rolls its
eggs in dung, using its hind legs in the operation, and buries them.
Now, in all these creatures the quantity of eggs is almost incredibly
great: in fishes they form two oblong bladders or follicles, as may be
seen in the carp, herring, and smelt, in all of which, as there is no
uterus, but merely an ovary present, so is this sometimes crowded with
ova to such a degree, that it comes to surpass the body in bulk.

Of such ovaries of the mullet and carp, salted and pressed, and dried in
the smoke, was prepared that article of food in such request among the
Greeks and old Italians, (called botorcha by the latter, ώά τάριχα, i.
e. salted eggs, by the former,) and very similar, we may presume, to the
masses which we find in the insides of our smoked herrings, and to the
compact granular red-coloured roe of our lobsters. The article prepared
from the salted roe of the sturgeon, which is called caviare, and
resembles black soap, is still the delight of epicures.

In those fishes that are highly prolific such a quantity of eggs is
engendered, that the whole abdomen can scarcely contain them, even when
they are first produced, still less when they have grown to any size.
In fishes, therefore, there is no part save the ovary dedicated to
purposes of reproduction. The ova of these animals continue to grow
without the body, and do not require the protection of an uterus for
their evolution. And the ovary here appears to bear an analogy to the
testicles or vesiculæ seminales, not only because it is found in the
same place as the testes in the male, (the testes in the cock being
situated, as we have said, close to the origin of the cœliac artery,
near the waist, in the very same place as the ovary in the hen,) but
because among fishes, in both sexes, as the time of spawning approaches,
two follicles, alike in situation, size, and shape, are discovered,
extending the whole length of the abdomen; which increase and become
distended at the same period: in the male with a homogeneous milky
spermatic matter, (whence the term milk or milt of fishes;) in the
female with innumerable granules, which, from their diminutive size and
close texture, in the beginning of the season, escape the powers of
vision, and present themselves as constituting an uniform body, bearing
the strongest resemblance to the milt of the male regularly coagulated.
By and by they are seen in the guise of minute grains of sand, adhering
together within their follicles.

In the smaller birds that lay but once a year, and a few eggs only, you
will scarcely discover any ovary. Still, in the place where the
testicles are situated in the male, there in the female, and not less
obviously than the testicles of the male, you will perceive three or
four vesicles (the number being in proportion to that of the eggs of
which they are the rudiments), by way of ovary.

In the cornua of the uterus of snakes (which resemble the vasa
deferentia in male animals), the first rudiments of the ova present
themselves as globules strung upon a thread, in the same way as women’s
bracelets, or like a rosary composed of amber beads.

Those ova that are found in the ovary of the fowl consequently are not
to be regarded as perfect eggs, but only as their rudiments; and they
are so arranged on the cluster, they succeed each other in such an order
and of such dimensions, that they are always ready for each day’s
laying. But none of the eggs in the ovary are surrounded with albumen;
there the yelk exists alone, and each, as it enlarges, extricates itself
from the general congeries of smaller ones, in order that it may the
more readily find space to grow. Fabricius, therefore, is right when he
says,[134] “The yelks which are on the surface of the cluster are larger
than those of the middle, which are surrounded as it were by the larger
ones. The very smallest of all the ova are situated towards the centre.”
That is to say, those that grow acquire larger dimensions and become
detached from the rest, and as this proceeds, the several yelks, besides
their tunica propria, are invested with another from the ovary, which
embraces them externally, and connects them with the base whence they
spring. This coat is, therefore, entitled the peduncle by Fabricius, and
its office is that of a foot-stalk, viz. to supply nourishment to the
ovum, in the same way as fruit is nourished through the stalk by which
it is connected with the tree. For this peduncle is a hollow membranous
bond of union, extending from the foundation of the cluster [the stroma
of the ovary] to the yelk, coming into contact with which, it is dilated
and expanded in the same way as the optic nerve in the eye, and covers
the vitellus with an external tunic. This perchance was what Aristotle
called the στόλον ὸμφαλοώδην, or umbilical appendix, and described as
forming a kind of tube. This peduncle includes numerous vessels, which
are distributed on all sides around the yelk.

So much is accurately related by Fabricius; but he errs when he says,
“This tunic does not surround the entire vitellus, but only extends upon
it a little beyond the middle, very much in the manner of an acorn
within its cup; whence it comes that the outer portion of the yelk,
which is not invested by the membrane in question, presents itself free
from vessels, and to appearance naked.” The membrane, nevertheless,
surrounds the yelk completely; but on the outer aspect it is not very
easily distinguished from the tunica propria, both of them being of
extreme delicacy. Posteriorly, however, and where the yelk is turned
towards the basis of the cluster, the tunic in question does not adhere
to the vitellus, neither does it send any vessels to this part, but
merely embraces it in the manner of a sac.

Each vitellus receives a distinct tunic from the ovarian basis; whence
this is not to be regarded as the common uterus, since nothing is
discovered here except the cluster or heap of ova, of many different
sizes, proceeding from the same foundation.

Now, this foundation or basis is a body sui generis, arising on the
spine of the feathered kinds, connected by means of large arteries and
veins, and of a loose, porous, and spongy texture, in order that
multitudes of ova may be produced from it, and that it may supply tunics
to all; which tunics, when the yelks have grown to their full size, are
distended by them, and then the tunics surround the vitelli, in the
manner of sacks with narrower necks and more capacious bellies, very
much like the flasks that are formed by the breath of the glass-blower.

Fabricius then proceeds: “The yelks, as they proceed from small
beginnings, from the size of millet or mustard seeds, and are at first
not only extremely small, but colourless, as Aristotle says, so do they
increase by degrees, and, according to Aristotle, become first of a
paler and then of a deeper yellow, until they have attained to the
dimensions familiar to all.” I, however, have observed ova vastly
smaller than millet seeds, ova which, like papulæ or sudamina, or the
finest grains of sand, (such as we have indicated as found in the roe of
fishes,) almost escaped the powers of sight; their places, indeed, were
only proclaimed by a kind of roughness of the membranes.


_Of the infundibulum._

The next succeeding portion of the uterus of the common fowl is called
the infundibulum by Fabricius. It forms a kind of funnel or tube,
extending downwards from the ovary, (which it everywhere embraces,) and
becoming gradually wider, terminates in the superior produced portion of
the uterus. This infundibulum yields a passage to the yelks when they
have broken from their foot-stalks in their descent from the ovary into
the second uterus (so it is styled by Fabricius). It resembles the
tunica vaginalis in the scrotum, and is a most delicate membrane, very
easily dilatable, fitted to receive the yelks that are daily cast loose,
and to transmit them to the uterus mentioned.

Would you have an example of these structures? Figure to yourself a
small plant, whose tuberous roots should represent the congeries of
yelks; its stalk the infundibulum. Now, as the stalk of this plant dies
in the winter and disappears, in like manner, when the fowl ceases to
lay eggs, the whole ovary, with the infundibulum, withers, shrinks, and
is annulled; the basis [stroma] and indication of the roots being still

This infundibulum seems only to discharge the office of a conduit, or
tube of passage: the yelk is never observed sticking in it; but as the
testes at times creep upwards through the tunicæ vaginales into the
groins, and in some animals--the hare and the mole--even become
concealed within the abdomen, and nevertheless again descend and show
themselves externally, so are the vitelli transmitted through the
infundibulum from the ovary into the uterus. Its office is served, and
even its form is imitated, by the funnel which we make use of when we
pour fluids from one vessel into another having a narrower mouth.


_Of the external portion of the uterus of the common fowl._

Fabricius pursues his account of the uterus after having described the
ovary, and in such an inverse order, that he premises a description of
the superior portion or appendage of the uterus before he approaches the
uterus itself. He assigns to it three turns or spirals, with somewhat
too much of precision or determinateness, and settles the respective
situations of these spirals, which are nevertheless of uncertain seat.
Here, too, he very unnecessarily repeats his definition of the
infundibulum. I would, therefore, in this place, beg to be allowed to
give my own account of the uterus of the fowl, according to the
anatomical method, which I consider the more convenient, and proceeding
from external to internal parts, in opposition to the method of

In the fowl stripped of its feathers, the fundament will be observed not
contracted circularly, as in other animals, but forming a depressed
orifice, slit transversely, and consisting of two lips lying over
against each other, the superior of the two covering and concealing the
inferior, which is puckered together. The superior labium, or velabrum,
as it is called, arises from the root of the rump, and as the upper
eyelid covers the eye, so does this cover the three orifices of the
pudenda, viz. the anus, the uterus, and the ureters, which lie concealed
under the velabrum as under a kind of prepuce; very much as in the
pudenda of the woman we have the orifice of the vulva and the meatus
urinarius concealed between the labia and the nymphæ. So that without
the use of the knife, or a somewhat forcible retraction of the velabrum
in the fowl, neither the orifice by which the fæces pass from the
intestines, nor that by which the urine issues from the ureters, nor yet
that by which the egg escapes from the uterus, can be perceived. And as
the two excrementitious discharges (the urine and the fæces) are
expelled together as from a common cloaca, the velabrum being raised at
the time, and the respective outlets exposed; so, during intercourse,
the hen on the approach of the cock uncovers the vulva, and prepares for
his reception, a circumstance observed by Fabricius in the turkey hen
when she is eager for the male. I have myself observed a female ostrich,
when her attendant gently scratched her back, which seemed to excite the
sexual appetite, to lie down on the ground, lift up the velabrum, and
exhibit and protrude the vulva, seeing which the male, straightway
inflamed with a like œstrum, mounted, one foot being kept firm on the
ground, the other set upon the back of the prostrate female; the immense
penis (you might imagine it a neat’s tongue!) vibrated backwards and
forwards, and the process of intercourse was accompanied with much ado
in murmuring and noise--the heads of the creatures being at the same
time frequently thrust out and retracted--and other indications of
enjoyment. Nor is it peculiar to birds, but common to animals at large,
that, wagging the tail and protruding the genital parts, they prepare
for the access of the male. And, indeed, the tail in the majority of
animals has almost the same office as the velabrum in the common fowl;
unless it were raised or drawn aside, it would interfere with the
discharge of the fæces and the access of the male.

In the female red-deer, fallow-deer, roe, and others of the more
temperate animals, there is a corresponding protection to their private
parts, a membranous velabrum covering the vulva and meatus urinarius,
which must be raised before the penis of the male can be introduced.

In animals that have a tail, moreover, parturition could not take place
unless this part were lifted up; and even the human female is assisted
in her labour by having the coccyx anointed and drawn outwards with the

A surgeon, a trustworthy man, and with whom I am upon intimate terms, on
his return from the East Indies informed me, in perfect sincerity, that
some inland and mountainous parts of the island of Borneo are still
inhabited by a race of caudate human beings (a circumstance of which we
also read in Pausanias), one of whom, a virgin, who had only been
captured with great difficulty, for they live in the woods, he himself
had seen, with a tail, thick, fleshy, and a span in length, reflected
between the buttocks, and covering the anus and pudenda: so regularly
has nature willed to cover these parts.

To return. The structure of the velabrum in the fowl is like that of the
upper eyelid; that is to say, it is a fleshy and muscular fold of the
skin, having fibres extending from the circumference on every side
towards the centre; its inner surface, like that of the eyelid and
prepuce, being soft. Along its margin also there is a semicircular
tarsus, after the manner of that of the eyelid; and in addition, between
the skin and fleshy membrane, an interposed cartilage, extending from
the root of the rump, the sickle-shaped tarsus being connected with it
at right angles, (very much as we observe a small tail comprehended
between the wing on either side, in bats). By this structure the
velabrum is enabled more readily to open and close the foramina pudendi
that have been mentioned.

The velabrum being now raised and removed, certain foramina are brought
into view, some of which are very distinct, others more obscure. The
more obvious are the anus and vulva, or the outlet of the fæcal matters
and the inlet to the uterus. The more obscure are, first, that by which
the urine is excreted from the kidneys, and, second, the small orifice
discovered by Fabricius, “into which,” he says, “the cock immits the
spermatic fluid,” a foramen, however, which neither Antony Ulm, a
careful dissector, has indicated in Aldrovandus, nor any one else except
Fabricius, so far as I know, has ever observed.

All these foramina are so close to one another that they seem almost to
meet in a single cavity, which, as being common to the fæces and urine,
may be called the cloaca. In this cavity, the urine, as it descends from
the kidneys, is mingled with the feculent matters of the bowels, and the
two are discharged together. Through this, too, the egg, as it is laid,
forces itself a passage.

Now, the arrangements in this cavity are such, that both excrements
descending into a common sac, the urine is made use of as a natural
clyster for their evacuation. The cloaca is therefore thicker and more
rugous than the intestine; and at the moment of laying and of coition,
it is everted, (the velabrum which covers it being raised as I have
already said,) the lower portion of the bowel being as it were
prolapsed. At this moment all the foramina that terminate in the cloaca
are conspicuous; on the return or reduction of the prolapsed portion,
however, they are concealed, being all collected together as it were
into the common purse or pouch.

The more conspicuous foramina, those, viz. of the anus and uterus, are
situated, with reference to one another, differently in birds from what
they are in other animals. In these the pudendum, or female genital
part, is situated anteriorly between the rectum and bladder; in birds,
however, the excrementitious outlet is placed anteriorly, so that the
inlet to the uterus is situated between this and the rump.

The foramen, into which Fabricius believes the cock to inject his fluid,
is discovered between the orifice of the vulva and the rump. I, however,
deny any such use to this foramen; for in young chickens it is scarcely
to be seen, and in adults it is present indifferently both in males and
females. It is obvious, therefore, that it is both an extremely small
and obscure orifice, and can have no such important function to perform:
it will scarcely admit a fine needle or a bristle, and it ends in a
blind cavity; neither have I ever been able to discover any spermatic
fluid within it, although Fabricius asserts that this fluid is stored up
there even for a whole year, and that all the eggs contained in the
ovary may be thence fecundated, as it is afterwards stated.

All birds, serpents, oviparous quadrupeds, and likewise fishes, as may
readily be seen in the carp, have kidneys and ureters through which the
urine distils, a fact which was unknown to Aristotle and philosophers up
to this time. In birds and serpents, which have spongy or largely
vesicular lungs, the quantity of urine secreted is small, because they
drink little, and that by sipping; there was, therefore, no occasion for
an urinary bladder in these creatures: the renal secretion, as already
stated, is accumulated in a common cavity or cloaca, along with the
drier intestinal excrement. Nevertheless, I do find an urinary bladder
in the carp and some other fishes.

In the common fowl the ureters descend from the kidneys, which are
situated in long and ample cavities on either side of the back, to
terminate in the common cavity or cloaca. Their terminations, however,
are so obscure and so hidden by the margin of the cavity, that to
discover them from without and pass a fine probe into them would be
found impossible. Nor is this at all surprising, because in all, even
the largest animals, the insertion of the ureters near the neck of the
bladder is so tortuous and obscure, that although the urine distils
freely from them into the bladder, and calculi even make their way out
of them, still neither fluids nor air can be made to enter them by the
use of any amount of force. On the other hand, in birds as well as other
animals, a probe or a bristle passed downwards from the kidney towards
the bladder by the ureters, readily makes its way into the cloaca or

These facts are particularly distinct in the ostrich, in which, besides
the external orifice of the common cavity which the velabrum covers, I
find another within the anus, having a round and constricted orifice,
shutting in some sort in the manner of a sphincter.

Passing by these particulars, however, let us turn to others that bear
more immediately upon our subject. The uterine outlet or vulva, then, or
the passage from the common cavity to the uterus of the fowl, is a
certain protuberance, soft, lax, wrinkled, and orbicular, resembling the
orifice of the prepuce when closed, or appearing as if formed by a
prolapse of the internal membrane of the uterus. Now this outlet is
situated, as I have said, between the anus and rump, and slightly to the
left of the middle line of the body, which Ulysses Aldrovandi imagines
to be for the purpose of “facilitating intercourse, and the entrance of
the genital organ of the cock.” I have myself observed, however,
repeatedly, that the hen turned the common orifice to the right or left
indifferently, according to the side from which the cock approached her.
Neither do I find any penis in the cock--neither, indeed, could
Fabricius,--although in the goose and duck it is very conspicuous. But
in its stead I discover an orifice in the cock, not otherwise than in
the hen, although it is smaller and more contracted in her than in him;
and in the swan, goose, and duck the same thing also appears, the penis
of the male goose and duck protruding through this orifice during

In a black drake I noticed the penis of such a length that after
intercourse it trailed on the ground, and a fowl following, pecked at it
greedily, thinking it an earth-worm, as I imagine, so that it was
retracted more quickly than usual.

In the male ostrich I have found within this pudendal orifice a very
large glans, and the red body of the penis, as we discover them within
the prepuce of the horse, resembling a deer’s or a small neat’s tongue
in form and magnitude; and I have frequently observed this organ, rigid
and somewhat hooked during the coitus, and when entered into the vulva
of the female, held for some considerable time there without any
movement: it was precisely as if the two creatures had been fastened
together with a nail. Meantime, by the gesticulations of their heads and
necks, and by their noises, they seemed to notify their nuptials, and to
express the great degree of pleasure they experienced.

I have read in a treatise of Dr. Du Val, a learned physician of Rouen,
that a certain hermaphrodite was referred to the surgeons and
accoucheurs, that they might determine whether it were a man or a woman.
They, from an examination of the genital organs, adjudged the party to
be of the feminine gender, and a dress in accordance with this decision
was ordered. By and by, however, the individual was accused of
soliciting women, and of discharging the man’s office; and then it was
found, that from a prepuce, as from the private parts of a woman, a
penis protruded, and served to perform the male’s business. I have
myself occasionally seen the penis of a certain man so greatly shrunk in
size, that, unless when excited, nothing was visible in the wrinkled
prepuce above the scrotum but the extremity of the glans.

In the horse and some other animals, the principal and ample length of
the member is protruded from its concealment. In the mole, too, which is
a small animal, there is a remarkable retraction of the penis between
the skin and muscles of the belly; and the vulva in the female of this
creature is also longer and deeper than usual.

The cock, which is without a penis, performs copulation, as I imagine,
in the same manner as the smaller birds, among which the process is
rapidly executed, and by mere contact. The orifices of the male and
female cloaca, which at the moment are protuberant externally, which,
especially in the male, become tense and injected, like the glans penis,
encounter, and coition is effected by a succession of salutes, not by
any longer intromission of parts, for I do not think that the organs of
the cock enter those of the hen at all.

In the copulation of horses, dogs, cats, and the like, the female
presents her organ rigid and injected to the penis of the male. And this
also takes place in birds which, if they be tame and suffer themselves
to be handled, when inflamed with desire present their parts, which will
then be found resisting and hard to the finger.

Birds are sometimes so lustful, that if you but stroke their backs
gently with your hand, they will immediately lie down and expose and
protrude their uterine orifice; and if this part be touched with the
finger, they will not fail to proclaim their satisfaction. And that the
females may thereby be made to lay eggs, as testified to by
Aristotle,[135] I have myself found in the case of the blackbird,
thrush, and others. I learned the fact, indeed, in former years by
accident, and to my detriment; for my wife had a beautiful parrot, a
great pet, learned and talkative enough, and so tame that it was allowed
to roam at liberty about the house: when its mistress was absent it
sought her everywhere; on her return it caressed her, and loudly
proclaimed its joy; when called to it would answer; would fly to its
mistress, and then seizing her clothes with beak and feet alternately,
it climbed to her shoulder, whence creeping down the arm, it reached her
hand, its usual seat. When ordered to speak or to sing, it would obey,
although it were the night season and quite dark. Full of play and
lasciviousness, it would frequently sit in its mistress’s lap, where it
loved to have her scratch its head and stroke its back, upon which,
fluttering with its wings and making a gentle noise, it testified the
pleasure it experienced. I believed all this to proceed from his usual
familiarity and love of being noticed; for I always regarded the
creature as a male, by reason of his proficiency in talking and singing.
For among birds, the females rarely sing or challenge one another by
their note; the males alone solace their mates by their tuneful
warblings, and call them to the rites of love. And it is on this account
that Aristotle says,[136] “If partridges be placed over against the
males, and the wind blow towards them from where the males sit, they are
impregnated and conceive. They even for the most part conceive from the
note of the male bird, if they be in season and full of desire. The
flight of the male over them will also have the same effect, the male
bird casting down a fertilizing influence upon the female.” Now this
happens especially in the spring season, whence the poet sings:[137]

    Earth teems in Spring, and craves the genial seed.
    The almighty father, Æther, then descends,
    In fertilizing showers, into the lap
    Of his rejoicing spouse, and mingling there
    In wide embrace sustains the progeny
    Innumerous that springs. The pathless woods
    Then ring with the wild bird’s song, and flocks and herds
    Disport and spend the livelong day in love.

Not long after the caressings mentioned, the parrot, which had lived in
health for many years, fell sick, and by and by being seized with
repeated attacks of convulsions, seated in the lap of its mistress, it
expired, grievously regretted. Having opened the body in search of the
cause of death, I discovered an egg, nearly perfect, in the uterus, but
in consequence of the want of a male, in a state of putrefaction; and
this, indeed, frequently happens among birds confined in cages, which
show desire for the company of the male.

These and other instances induce me to believe that the common fowl and
the pheasant do not only solace their females with their crowing, but
farther give them the faculty of producing eggs by its means; for when
the cock crows in the night some of the hens perched near him bestir
themselves, clapping their wings and shaking their heads; shuddering and
gesticulating as they are wont to do after intercourse.

A certain bird, as large again as a swan, and which the Dutch call a
cassowary, was imported no long time ago from the island of Java, in the
East Indies, into Holland. Ulysses Aldrovandus[138] gives a figure of
this bird, and informs us that it is called an emeu by the Indians. It
is not a two-toed bird, like the ostrich, but has three toes on each
foot, one of which is furnished with a spur of such length, strength,
and hardness, that the creature can easily kick through a board two
fingers’ breadth in thickness. The cassowary defends itself by kicking
forwards. In the body, legs, and thighs it resembles the ostrich; it has
not a broad bill like the ostrich however, but one that is rounded and
black. On its head, by way of crest, it has an orbicular protuberant
horn. It has no tongue, and devours everything that is presented to
it--stones, coals, even though alight, pieces of glass--all without
distinction. Its feathers sprout in pairs from each particular quill,
and are of a black colour, short and slender, approaching to hair or
down in their characters. Its wings are very short and imperfect. The
whole aspect of the creature is truculent, and it has numbers of red and
blue wattles longitudinally disposed along the neck.

This bird remained for more than seven years in Holland, and was then
sent, among other presents, by the illustrious Maurice Prince of Orange,
to his serene majesty our King James, in whose gardens it continued to
live for a period of upwards of five years. By and by, however, when a
pair of ostriches, male and female, were brought to the same place, and
the cassowary heard and saw these in a neighbouring inclosure, at their
amours, unexpectedly it began to lay eggs, excited, as I imagine,
through sympathy with the acts of an allied genus; I say unexpectedly,
for all who saw the cassowary, judging from the weapons and ornaments,
had regarded it as a male rather than a female. Of these eggs, one was
laid entire, and this I opened, and found it perfect: the yelk
surrounded by the white, the chalazæ attached on either side, and a
small cavity in the blunt end; there was also a cicatricula or macula
alba present; the shell was thick, hard, and strong; and having taken
off the top, I had it formed into a cup, in the same way as ostrichs’
eggs are commonly fashioned. This egg was somewhat less than that of an
ostrich, and, as I have said, perfect in all respects. Undoubtedly,
however, it was a sort of accidental egg, and, by reason of the absence
of the male, unfruitful. I predicated the death of the cassowary as
likely to happen soon when she began laying, moved to do so by what
Aristotle says:[139] “Birds become diseased and die unless they produce
fruitful eggs.” And my prediction came true not long afterwards. On
opening the body of the cassowary, I discovered an imperfect and putrid
egg in the upper part of the uterus, as the cause of its untimely death,
just as I had found the same thing in the parrot, and other instances

Many birds, consequently, the more salacious they are, the more fruitful
are they; and occasionally, when abundantly fed, or from some other
cause, they will even lay eggs without the access of the male. It rarely
happens, however, that the eggs so produced are either perfected or
laid; the birds are commonly soon seized with serious disorders, and at
length die. The common fowl nevertheless not only conceives eggs, but
lays them, quite perfect in appearance too; but they are always wind
eggs, and incapable of producing a chick. In like manner many insects,
among the number silkworms and butterflies, conceive eggs and lay them,
without the access of the male, but they are still adventitious and
barren. Fishes also do the same.

It is of the same significance in these animals when they conceive eggs,
as it is in young women when their uterus grows hot, their menses flow,
and their bosoms swell--in a word, when they become marriageable; and
who, if they continue too long unwedded, are seized with serious
symptoms--hysterics, furor uterinus, &c. or fall into a cachectic state,
and distemperatures of various kinds. All animals, indeed, grow savage
when in heat, and unless they are suffered to enjoy one another, become
changed in disposition. In like manner women occasionally become insane
through ungratified desire, and to such a height does the malady reach
in some, that they are believed to be poisoned, or moon-struck, or
possessed by a devil. And this would certainly occur more frequently
than it does, without the influence of good nurture, respect for
character, and the modesty that is innate in the sex, which all tend to
tranquillize the inordinate passions of the mind.


_Of the uterus of the fowl._

The passage from the external uterine orifice to the internal parts and
uterus itself, where the egg is perfected, is by that part which in
other animals is called the vagina or vulva. In the fowl, however, this
passage is so intricate, and its internal membrane is so loose and
wrinkled, that although there is a ready passage from within outwards,
and a large egg makes its way through all without much difficulty, still
it scarcely seems likely that the penis of the male could penetrate or
the spermatic fluid make its way through it; for I have found it
impossible to introduce either a probe or a bristle; neither could
Fabricius pass anything of the sort, and he says that he could not even
inflate the uterus with air. Whence he was led I fancy to give an
account of the uterus, proceeding from more internal to more external
parts. Considering this structure of the uterus also, he denies that the
spermatic fluid of the male can reach the cavity of the uterus, or go to
constitute any part of the egg.[140] To this statement I most willingly
subscribe; for, indeed, there is nothing in the fruitful egg which is
not also in the barren one; there is nothing in the way of addition or
change which indicates that the seminal fluid of the male has either
made its way into the uterus, or come into contact with the egg.
Moreover, although without the access of the cock all eggs laid are
winded and barren, still through his influence, and long after
intercourse, fruitful eggs are deposited, the rudiments or matter of
which did not exist at the time of the communication.

With a view to explaining how the spermatic fluid of the cock renders
eggs fecund, Fabricius says:[141] “Since the semen does not appear in
the egg, and yet is thrown into the uterus by the cock, it may be asked
why this is done if the fluid does not enter the egg? Farther: if not
present in the egg, how is that egg made fruitful by the spermatic fluid
of the cock which it yet does not contain? My opinion is that the semen
of the cock thrown into the commencement of the uterus, produces an
influence on the whole of the uterus, and at the same time renders
fruitful the whole of the yelks, and finally of the perfect eggs which
fall into it; and this the semen effects by its peculiar property or
irradiative spirituous substance, in the same manner as we see other
animals rendered fruitful by the testicles and semen. For if any one
will but bring to mind the incredible change that is produced by
castration, when the heat, strength, and fecundity are lost, he will
readily admit that what we have proposed may happen in reference to the
single uterus of a fowl. But that it is in all respects true, and that
the faculty of impregnating the whole of the ova, and also the uterus
itself, proceeds from the semen of the cock, appears from the custom of
those housewives who keep hens at home but no cock, that they commit
their hens for a day or two to a neighbour’s cock, and in this short
space of time the whole of the eggs that will be laid for a certain
season are rendered prolific. And this fact is confirmed by
Aristotle,[142] who will have it that, among birds, one intercourse
suffices to render almost all the eggs fruitful. For the fecundating
influence of the seminal fluid, as it cannot exhale, so is it long
retained in the uterus, to which it imparts the whole of its virtue;
nature herself stores it up, placing it in a cavity appended to the
uterus, near the fundament, furnished with an entrance only, so that,
being there laid up, its virtue is the better preserved and communicated
to the entire uterus.”

I, however, suspected the truth of the above views, all the more when I
saw that the words of the philosopher referred to were not accurately
quoted. Aristotle does not say that “Birds which have once copulated
almost all continue to lay prolific eggs,” but simply “almost all
continue to lay eggs;” the word “prolific” is an addition by Fabricius.
But it is one thing to have birds conceiving eggs after intercourse, and
another to say that these eggs are fruitful through this intercourse.
And this is the more obvious from Aristotle’s previous words, where he
says, “Nor in the family of birds can those eggs even that are produced
by intercourse acquire their full size unless the intercourse between
the sexes be continued. And the reason is, that as the menstrual
excretion in women is attracted by the intercourse of their husbands,
(for the uterus, being warmed, draws the moisture, and the passages are
opened,) so in birds it comes to pass that, as the menstruous discharge
takes place very gradually, because of its being in small quantity, it
cannot make its way externally, but is contained superiorly as high as
the waist, and only distils down into the uterus itself. For the egg is
increased by this, just as the fœtus of oviparous animals is nourished
by that which reaches it through the umbilicus. For when once birds have
copulated, almost all continue to lay eggs, but of small size and
imperfect;” and therefore unprolific, for the perfection of an egg is
its being fertile. If, therefore, without continued intercourse, not
even those eggs that were conceived in consequence of intercourse grow
to their proper size, or, as Fabricius interprets it, are “perfected,”
much less are those eggs prolific which fowls continue to lay
independently of intercourse with the male bird.

But lest any one should think that these words, “for the uterus warmed,
draws, and the passages are opened,” signify that the uterus can attract
the semen masculinum into its cavity, let them be aware that the
philosopher does not say that the uterus attracts the semen from without
into its cavity, but that in females, from the veins and passages,
opened by the heat of intercourse, the menstruous blood is attracted
from its own body; so in birds the blood is attracted to the uterus,
warmed by repeated intercourse, whereby the eggs grow, as the fœtus of
oviparous animals grows through the umbilicus.

But what Fabricius adds upon that cavity or bursa, in which he thinks
the semen of the cock may be stored up for a whole year, has been
already refuted by us, where we have stated that it contains no seminal
fluid, and that it exists in the cock as well as in the hen. Wherefore,
though I readily believed (if by fecundity we are to understand a
greater number of larger eggs), that the hens of poor people,
indifferently fed in all probability, will lay both fewer and smaller
eggs unless they have the company of a cock; agreeably to what the
philosopher quoted avers, viz.: “that hens which have once been trodden
continue to lay larger, better, and a greater number of eggs through the
whole of the year,” (a result on which the abundance and the good
quality of the food has unquestionably a great influence); still that
hens should continue for a whole year to lay prolific eggs after a few
addresses of the cock, appeared to me by no means probable: for, had a
small number of contacts sufficed for the purposes of generation during
so long a period, nature, which does nothing in vain, would have
constituted the males among birds less salacious than they are; nor
should we see the cock soliciting his hens so many times a day, even
against their inclination.

We know that the hen, as soon as she quits the nest where she has just
laid an egg, cackles loudly, and seems to entice the cock, who on his
part crowing lustily, singles her out and straightway treads her, which
surely nature had never permitted unless for purposes of procreation.

A male pheasant kept in an aviary was so inflamed with lust, that unless
he had the company of several hen-birds, six at the least, he literally
maltreated them, though his repeated addresses rather interfered with
their breeding than promoted it. I have seen a single hen-pheasant shut
up with a cock-bird (which she could in no way escape) so worn out, and
her back so entirely stript of feathers through his reiterated assaults,
that at length she died exhausted. In the body of this bird, however, I
did not discover even the rudiments of eggs.

I have also observed a male duck, having none of his own kind with him,
but associating with hens, inflamed with such desire that he would
follow a pullet even for several hours, would seize her with his bill,
and mounting at length upon the creature, worn out with fatigue, would
compel her to submit to his pleasure.

The common cock, victorious in a battle, not only satisfies his desires
upon the sultanas of the vanquished, but upon the body of his rival

The females of some animals are likewise so libidinous that they excite
their males by pecking or biting them gently about the head; they seem
as if they whispered into their ears the sweets of love; and then they
mount upon their backs and invite them by other arts to fruition: among
the number may be mentioned pigeons and sparrows.

It did not therefore appear likely that a few treads, in the beginning
of the year, should suffice to render fertile the whole of the eggs that
are to be laid in its course.

Upon one occasion, however, in the spring season, by way of helping out
Fabricius, and that I might have some certain data as to the time during
which the fecundating influence of intercourse would continue, and the
necessity of renewed communication, I had a couple of hens separated
from the cock for four days, each of which laid three eggs, all of which
were prolific. Another hen was secluded, and the egg she laid on the
tenth day afterwards was fruitful. The egg which another laid on the
twentieth day of her seclusion also produced a chick. It would therefore
seem that intercourse, once or twice repeated, suffices to impregnate
the whole bunch of yelks, the whole of the eggs that will be laid during
a certain season.

I shall here relate another observation which I made at this time. When
I returned two of the hens, which I had secluded for a time, to the
cock, one of which was big with egg, the other having but just laid, the
cock immediately ran to the latter and trod her greedily three or four
times; the former he went round and round, tripping himself with his
wing and seeming to salute her, and wish her joy of her return; but he
soon returned to the other and trod her again and again, even compelling
her to submit; the one big with egg, however, he always speedily
forsook, and never solicited her to his pleasure. I wondered with myself
by what signs he knew that intercourse would advantage one of these hens
and prove unavailing to the other. But indeed it is not easy at any time
to understand how male animals, even from a distance, know which females
are in season and desirous of their company; whether it be by sight, or
hearing, or smell, it is difficult to say. Some on merely hearing the
voice of the female, or smelling at the place where she has made water,
or even the ground over which she has passed, are straightway seized
with desire and set off in pursuit to gratify it. But I shall have more
to say on this subject in my treatise on the Loves, Lusts, and Sexual
Acts of Animals. I return to the matter we have in hand.


_Of the abdomen of the common fowl and of other birds._

From the external orifice proceeding through the vulva we come to the
uterus of the fowl, in which the egg is perfected, surrounded with the
white and covered with its shell. But before speaking of the situation
and connections of this part it seems necessary to premise a few words
on the particular anatomy of the abdomen of birds. For I have observed
that the stomach, intestines, and other viscera of the feathered kinds
were otherwise placed in the abdomen, and differently constituted, than
they are in quadrupeds.

Almost all birds are provided with a double stomach; one of which is the
crop, the other the stomach, properly so called. In the former the food
is stored and undergoes preparation, in the latter it is dissolved and
converted into chyme.[1] The familiar names of the two stomachs of birds
are the crop or craw, and the gizzard. In the crop the entire grain, &c.
that is swallowed is moistened, macerated, and softened, and then it is
sent on to the stomach that it may there be crushed and comminuted. For
this end almost all the feathered tribes swallow sand, pebbles, and
other hard substances, which they preserve in their stomachs, nothing of
the sort being found in the crop. Now the stomach in birds consists of
two extremely thick and powerful muscles (in the smaller birds they
appear both fleshy and tendinous), so placed that, like a pair of
millstones connected by means of hinges, they may grind and bruise the
food; the place of teeth, which birds want, being supplied by the stones
which they swallow. In this way is the food reduced and turned into
chyme[143]; and then by compression (just as we are wont, after having
bruised an herb or a fruit, to squeeze out the juice or pulp) the softer
or more liquid part is forced out, comes to the top, and is transferred
to the commencement of the intestinal canal; which in birds takes its
rise from the upper part of the stomach near the entrance of the
œsophagus. That this is the case in many genera of birds is obvious; for
the stones and other hard and rough substances which they have
swallowed, if long retained, become so smooth and polished that they are
unfit to comminute the food, when they are discharged. Hence birds, when
they select stones, try them with their tongue, and, unless they find
them rough, reject them. In the stomach of both the ostrich and
cassowary I found pieces of iron and silver, and stones much worn down
and almost reduced to nothing; and this is the reason why the vulgar
believe that these creatures digest iron and are nourished by it.

If you apply the body of a hawk or an eagle, or other bird of prey,
whilst fasting, to your ear, you will hear a distinct noise, occasioned
by the rubbing, one against another, of the stones contained in the
stomach. For hawks do not swallow pebbles with a view to cool their
stomachs, as falconers commonly but erroneously believe, but that the
stones may serve for the comminution of their food; precisely as other
birds, which have muscular stomachs, swallow pebbles, sand, or something
else of the same nature, to crush and grind the seeds upon which they

The stomach of birds, then, is situated within the cavity of the
abdomen, below the heart, lungs and liver: the crop, however, is without
the body in some sort, being situated at the lower part of the neck,
over the os jugale or merry-thought. In this bag, as I have said, the
food is only macerated and softened; and several birds regurgitate and
give it to their young, in some measure as quadrupeds feed their progeny
with milk from their breasts; this occurs in the whole family of the
pigeons, and also among rooks. Bees, too, when they have returned to
their hives, disgorge the honey which they have collected from the
flowers and concocted in their stomachs, and store it in their waxen
cells; and so also do hornets and wasps feed their young. The bitch has
likewise been seen to vomit the food which she had eaten some time
before, in a half-digested state, and give it to her whelps: it is not,
therefore, to be greatly wondered at, if we see the poor women, who beg
from door to door, when their milk fails, feeding their infants with
food which they have chewed and reduced to a pulp in their own mouths.

The intestines commence in birds, as has been said, from the upper part
of the stomach, and are folded up and down in the line of the
longitudinal direction of the body, not transversely as in man.
Immediately below the heart, about the waist, and where the diaphragm is
situated in quadrupeds, for birds have no [muscular] diaphragm, we find
the liver, of ample size, divided into two lobes situated one on either
side (for birds have no spleen,) and filling the hypochondria. The
stomach lies below the liver, and downwards from the stomach comes the
mass of intestines, with numerous delicate membranes, full of air,
interposed; the trachea opening in birds, as already stated, by several
gaping orifices into membranous abdominal cells. The kidneys, which are
of large size in birds, are of an oblong shape, look as if they were
made up of fleshy vesicles, without cavities, and lie along the spine on
either side, with the descending aorta and vena cava abdominalis
adjacent; they further extend into and seem to lie buried within ample
cavities of the ossa ilia. The ureters proceed from the anterior aspects
of the kidneys, and run longitudinally towards the cloaca and podex, in
which they terminate, and into which they pour the liquid excretion of
the kidneys. This, however, is not in any great quantity in birds,
because they drink little, and some of them, the eagle for example, not
at all. Nor is the urine discharged separately and by itself, as in
other animals; but, as we have said, it distils from the ureters into
the common cloaca, which is also the recipient of the fæces, and the
discharge of which it facilitates. The urine is also different in birds
from what it is in other animals; for, as the urine in the generality of
animals consists of two portions, one more serous and liquid, another
thicker, which, in healthy subjects constitutes the hypostasis or
sediment, and subsides when the urine becomes cold; so is it in birds,
but the sedimentary portion is the more abundant, and is distinguished
from the liquid by its white or silvery colour; nor is this sediment met
with only in the cloaca, (where it abounds, indeed, and surrounds the
fæces,) but in the whole course of the ureters, which are distinguished
from the coverings of the kidneys by their white colour. Nor is it only
in birds that this abundant thicker renal secretion is seen; it is
conspicuous in serpents and other ovipara, particularly in those whose
eggs are covered with a harder or firmer membrane. And here, too, is the
thicker in larger proportion than the thinner and more serous portion;
its consistency being midway between thick urine and stercoraceous
excrement: so that, in its passage through the ureters, it resembles
coagulated or inspissated milk; once discharged it soon concretes into a
friable mass.


_Of the situation and structure of the remaining parts of the fowl’s

Between the stomach and the liver, over the spine, and where, in man and
other animals the pancreas is situated; between the trunk of the porta
and the descending cava; at the origin of the renal and spermatic
arteries, and where the cœliac artery plunges into the mesentery, there,
in the fowl and other birds, do the ovary and the cluster of yelks
present themselves; having in their front the trunk of the porta, the
gullet, and the orifice of the stomach: behind them, the vena cava and
the aorta descending along the spine; above the liver, and beneath the
stomach, lie adjacent. The infundibulum, therefore, which is a most
delicate membrane, descends from the ovary longitudinally with the
spine, between it and the gizzard. And from the infundibulum (between
the gizzard, the intestines, the kidneys, and the loins,) the processus
uteri or superior portion of this organ descends with a great many
turnings and cells (like the colon and rectum in man), into the uterus
itself. Now the uterus, which is continuous with this process, is
situated below the gizzard, between the loins, the kidneys, and the
rectum, in the lower part of the abdomen, close to the cloaca; so that
the egg surrounded with its white, which the uterus contains, is
situated so low that, with the fingers, it is easy to ascertain whether
it be soft or hard, and near the laying.

The uterus in the common fowl varies both in point of size and of
structure. In the fowl that is with egg, or that has lately laid, it is
very different from what it is in the pullet, the uterus of which is
fleshy and round, like an empty purse, and its cavity so insignificant
that it would scarcely contain a bean; smooth externally, it is wrinkled
and occupied by a few longitudinal plicæ internally: at first sight you
might very well mistake it either for a large urinary bladder or for a
second smaller stomach. In the gravid state, however, and in the fowl
arrived at maturity (a fact which is indicated by the redder colour of
the comb), the uterus is of much larger dimensions and far more fleshy;
its plicæ are also larger and thicker, it in general approaches the size
which we should judge necessary to receive an egg; it extends far
upwards in the direction of the spinal column, and consists of numerous
divisions or cells, formed by replications of the extended uterus,
similar to those of the colon in quadrupeds and man. The inferior
portion of the uterus, as the largest and thickest, and most fleshy of
all, is strengthened by many plicæ of large size. Its configuration
internally is oval, as if it were the mould of the egg. The ascending or
produced portion of the uterus I designate the processus uteri: this
part Fabricius calls the “uterus secundus,” and says that it consists of
three spiral turns or flexures; Ulyssus Aldrovandus, again, names it the
“stomachum uteri.” I must admit that in this part there are usually
three turns to be observed; they are not, however, by any means so
regular but that, as in the case of the cells of the colon, nature
sometimes departs from her usual procedure here.

The uterus as it ascends higher, so does it become ever the thinner and
more delicate, containing fewer and smaller plicæ, until at length going
off into a mere membrane, and that of the most flimsy description, it
constitutes the infundibulum; which, reaching as high as the waist or
cincture of the body, embraces the entire ovary.

On this account, therefore, Fabricius describes the uterus as consisting
of three portions; viz., the commencement, the middle, and the end. “The
commencement,” says he, “degenerating into a thin and most delicate
membrane, forms an ample orifice, and bears a resemblance to an
open-mouthed tube or funnel. The next portion (which I call the
processus uteri), consisting of three transverse spiral turns, serves
for the supply of the albumen, and extends downwards to the most
inferior and capacious portion--the termination of the uterus--in which
the chalazæ, the two membranes, and the shell are formed.[144]”

The whole substance of the uterus, particularly the parts about the
plicæ, both in its body and in its process, are covered with numerous
ramifications of blood-vessels, the majority of which are arterial
rather than venous branches.

The folds which appear oblique and transverse in the interior of the
uterus are fleshy substances; they have a fine white or milky colour,
and a sluggish fluid oozes from them, so that the whole of the interior
of the uterus, as well the body as the process, is moistened with an
abundance of thin albumen, whereby the vitellus as it descends is
increased, and the albumen that is deposited around it is gradually

The uterus of the fowl is rarely found otherwise than containing an egg,
either sticking in the spiral process or arrived in the body of the
organ. If you inflate this process when it is empty it then presents
itself as an oblique and contorted tube, and rises like a turbinated
shell or cone into a point. The general arrangement of the spirals and
folds composing the uterus, is such as we have already observed it in
the vulva: there is a ready enough passage for the descending egg, but
scarce any return even for air blown in towards the superior parts.

The processus uteri with its spirals, very small in the young pullet, is
so much diminished in the hen which has ceased laying, that it shrinks
into the most delicate description of membrane, and then entirely
disappears, so that no trace of it remains, any more than of the ovary
or infundibulum: nothing but a certain glandular-looking and spongy mass
appears in the place these bodies occupied, which in a boiled fowl
tastes sweet, and bears some affinity to the pancreas and thymus of
young mammiferous animals, which, in the vernacular tongue, are called
the sweetbread.

The uterus and the processus uteri are connected with the back by means
of a membranous attachment, which Fabricius designates by the name of
“mesometrium; because the second uterus, together with this vascular and
membranous body, may very fairly be compared with the intestines and
the mesentery.” For, as the intestine is bound down by the mesentery, so
is this portion of the uterus attached to the spinal column by an oblong
membranous process; lest by being too loose, and getting twisted, the
passage of the yelks should be interfered with, instead of having a free
and open transit afforded them as at present. The mesometrium also
transmits numerous blood-vessels surcharged with blood, to each of the
folds of the uterus. In its origin, substance, structure, use, and
office, this part is therefore analogous to the mesentery. Moreover,
from the fundus of the uterus lengthwise, and extending even to the
infundibulum, there is a ligament bearing some resemblance to a
tape-worm, similar to that which we notice in the upper part of the
colon. It is as if a certain portion or stripe of the external tunic had
been condensed and shortened in such a manner that the rest of the
process is thrown into folds and cells: were you to draw a thread
through a piece of intestine taken out of the body, and to tie this
thread firmly on one side, you would cause the other side of the bowel
to pucker up into wrinkles and cells; [even so is it with the uterus of
the fowl.]

This then, in brief, is the structure of the uterus in the fowl that is
laying eggs: fleshy, large, extensible both longitudinally and
transversely, tortuous or winding in spirals and convolutions from the
cloaca upwards, in the line of the vertebral column, and continued into
the infundibulum.


_Of the extrusion of the egg, or parturition of the fowl, in general._

The yelk, although only a minute speck in the ovary, gaining by degrees
in depth of colour and increasing in size, gradually acquires the
dimensions and characters that distinguish it at last. Cast loose from
the cluster, it descends by the infundibulum, and, transmitted through
the spirals and cells of the processus uteri, it becomes surrounded with
albumen; and this, without in any place adhering to the uterus (as was
rightly observed by Fabricius in opposition to Aristotle), or growing by
means of any system of umbilical vessels; but as the eggs of fishes and
frogs, when extruded and laid in the water provide and surround
themselves with albumen, or as beans, vetches, and other seeds and
grains swell when moistened, and thence supply nourishment to the germs
that spring from them, so, from the folds of the uterus that have been
described, as from an udder, or uterine placenta, an albuminous fluid
exudes, which the vitellus, in virtue of its inherent vegetative heat
and faculty, attracts and digests into the surrounding white. There is,
indeed, an abundance of fluid having the taste of albumen, contained in
the cavity of the uterus and entangled between the folds that cover its
interior. In this way does the yelk, descending by degrees, become
surrounded with albumen, until at last, having in the extreme part of
the uterus acquired a covering of firmer membranes and a harder shell,
it is perfected and rendered fit for extrusion.


_Of the increase and nutrition of the egg._

Let us hear Fabricius on these topics. He says: “As the action of the
stomach is to prepare the chyle, and that of the testes to secrete the
seminal fluid, (because in the stomach chyle is discovered, and in the
testes semen,) so we declare the act of the uterus in birds to be the
production of eggs, because eggs are found there. But this, as it
appears, is not the only action of uteri; to it must be added the
increase of the egg, which succeeds immediately upon its production, and
which proceeds until it is perfected and attains its due size. For a
fowl does not naturally lay an egg until it is perfect and has attained
to its proper dimensions. The office of the uterus is, therefore, the
growth as well as the generation of the egg; but growth implies and
includes the idea of nutrition; and, as all generation is the act of two
principles, one the agent, another the matter, the agent in the
production of eggs is nothing else than the organs or instruments
indicated, viz., the compound uterus; and the matter nothing but the

We, studious of brevity, and shunning all controversy, as in duty
bound, as we readily admit that the office and use of the uterus is the
procreation of the egg, so do we maintain the “adequate efficient,” as
it has been called, the immediate agent to inhere in the egg itself; and
we assert farther, that the egg is both engendered and made to increase,
not by the uterus, but by a certain natural principle peculiar to
itself; and that this principle flows from the whole fowl into the
rudiments of the vitellus, and whilst it was yet but a speck, and under
the influence either of the calidum innatum or of nature, causes it to
be nourished and to grow; just as there is a certain faculty in every
particle of the body which secures its nutrition and growth.

As regards the manner in which the yelk is surrounded by the albumen,
Aristotle appears to have believed[145] that in the sharp end of the egg
(where he placed the commencement of the egg), whilst it was yet
surrounded by soft membranes, there existed an umbilical canal, by which
it was nourished; a view which Fabricius[146] challenges, denying that
there is any such canal, or that the vitellus has any kind of connexion
with the uterus. He farther lessens the doubt in regard to the albumen
of the extruded egg, observing, that “the egg increases in a two-fold
manner, inasmuch as the uterus consists of two portions, one superior,
another inferior; and the egg itself consists of two matters--the yelk
and the white. The yelk increases with a true growth, to wit, by means
of the blood, which is sent to it through the veins whilst it is yet
connected with the vitellarium. The albumen, however, increases and
grows otherwise than the yelk; viz., not by means of the veins, nor by
proper nutrition like the yelk, but, by juxtaposition, adhering to the
vitellus as it is passing through the second uterus.”

But my opinion is, that the egg increases everywhere in the same manner
as the yelk does in the cluster; viz. by an inherent concocting
principle; with this single difference, that in the ovary the
nourishment is brought to it by means of vessels, whilst in the uterus
it finds that which it imbibes already prepared for it. Juxtaposition of
parts is equally necessary in every kind of nutrition and growth, and so
also are concoction and distribution of the applied nutriment. Nor is
one of these to be less accounted true nutrition than the other,
inasmuch as in both there is accession of new aliment, apposition,
agglutination, and transmutation of particles. Nor can vetches or beans,
when they attract moisture from the earth through their skins, imbibing
it like sponges, be said with less propriety to be nourished than if
they had obtained the needful moisture through the mouths of veins; and
trees, when they absorb the dew and the rain through their bark, are as
truly nourished as when they pump them in by their roots. With reference
to the mode in which nutrition is effected, we have set down much in
another place. It is another difficulty that occupies us at this time,
viz., whether the yelk, whilst it is acquiring the white, does not make
a certain separation and distinction in it; whether, in the course of
the increase, a more earthy portion does not subside into the yelk or
middle of the egg as towards the centre, which Aristotle believed, and
another lighter portion surrounds this. For between the yelk which is
still in the cluster, and the yelk which is found in the middle of a
perfect egg, there is this principal difference, that although the
former be of a yellow colour, still, in point of consistence, it rather
resembles the white; and by boiling, it is, like the latter, thickened,
compacted, inspissated, and becomes divisible into layers; whilst the
yelk of the perfect egg is rendered friable by boiling, and is rather of
an earthy consistency, not thick and gelatinous like albumen.


_Of the covering or shell of the egg._

It will now be proper, having spoken of the production of eggs, to treat
of their parts and diversities. “An egg,” says Fabricius, “consists of a
yelk, the albumen, two chalazæ, three membranes, viz. one proper to the
vitellus, two common to the entire egg, and a shell. To these two others
are to be added, which, however, cannot be correctly reckoned among the
parts of an egg; one of these is a small cavity in the blunt end of the
egg, under the shell; the other is a very small white spot, a kind of
round cicatricula connected with the surface of the yelk. The history of
each of these parts and accidents must now be given more particularly,
and we shall begin from without and proceed inwards.

“The external covering of the egg, called by Pliny the cortex and
putamen, by Quintus Serenus the testa ovi, is a hard but thin, friable
and porous covering, of different colours in different cases--white,
light green, speckled, &c. All eggs are not furnished with a shell on
their extrusion: the eggs of serpents have none; and some fowls
occasionally, though rarely, lay eggs that are without shells. The
shell, though everywhere hard, is not of uniform hardness; it is hardest
towards the upper end.” From this Fabricius[147] opines that we are to
doubt as to the matter of which, and the season at which the shells of
eggs are produced. Aristotle[148] and Pliny[149] affirm that the shell
is not formed within the body of the fowl, but when the egg is laid; and
that as it issues it sets by coming in contact with the air, the
internal heat driving off moisture. And this, says Aristotle,[150] is so
arranged to spare the animal pain, and to render the process of
parturition more easy. An egg softened in vinegar is said to be easily
pushed into a vessel with a narrow mouth.

Fabricius was long indisposed to this opinion, “because he had found an
egg within the body of the fowl covered with a hard shell; and
housewives are in the daily practice of trying the bellies of their hens
with their fingers in order that they may know by the hardness whether
the creatures are likely to lay that day or not.” But by-and-by, when
“he had been assured by women worthy of confidence, that the shells of
eggs became hardened in their passage into the air, which dissipates a
certain moisture diffused over the egg on its exit, fixing it in the
shell not yet completely hardened;” and having afterwards “confirmed
this by his own experience,” he altered his opinion, and came to the
conclusion, “that the egg surrounded with a shell, and having a
consistency betwixt hard and soft, hardened notably at the moment of its
extrusion, in consequence, according to Aristotle’s views, of the
concretion and dissipation of the thinner part of a certain viscid and
tenacious humour, bedewed with which the egg is extruded; sticking to
the recent shell this humour is dried up and hardened, the cold of the
ambient air contributing somewhat to the effect. Of all this,” he says,
“you will readily be satisfied if you have a fowl in the house, and
dexterously catch the egg in your hand as it is dropping.”

I was myself long fettered by this statement of Aristotle, indeed until
certain experience had assured me of its erroneousness; for I found the
egg still contained in the uterus, almost always covered with a hard
shell; and I once saw an egg taken from the body of a living fowl, and
still warm, without a shell but covered with a tenacious moisture; this
egg, however, did not acquire any hardness through the concretion or
evaporation of the moisture in question, as Fabricius would have us
believe, neither was it in any way changed by the cold of the
surrounding air; but it retained the same degree of softness which it
had had in the uterus.

I have also seen an egg just laid by a fowl, surrounded by a complete
shell, and this shell covered externally with a soft and membranous
skin, which however did not become hard. I have farther seen another
hen’s egg covered with a shell everywhere except at the extremity of the
sharp end, where a certain small and soft projection remained, very
likely such as was taken by Aristotle for the remains of an umbilicus.

Fabricius, therefore, appears to me to have wandered from the truth; nor
was I ever so dexterous as to catch an egg in its exit, and discover it
in the state between soft and hard. And this I confidently assert, that
the shell is formed internally, or in the uterus, and not otherwise than
all the other parts of the egg, viz. by the peculiar plastic power. A
statement which I make all the more confidently because I have seen a
very small egg covered with a shell, contained within another larger
egg, perfect in all respects, and completely surrounded with a shell. An
egg of this kind Fabricius calls an ovum centeninum; and our housewives
ascribe it to the cock. This egg I showed to his serene Majesty King
Charles, my most gracious master, in the presence of many persons. And
the same year, in cutting up a large lemon, I found another perfect but
very small lemon included within it, having a yellow rind like the
other; and I hear that the same thing has frequently been seen in Italy.

It is a common mistake with those who pursue philosophical studies in
these times, to seek for the cause of diversity of parts in diversity
of the matter whence they arise. Thus medical men assert that the
several parts of the body are both engendered and nourished by diverse
matters, either the blood or the seminal fluid; viz. the softer parts,
such as the flesh, by the thinner matter, the harder and more earthy
parts, such as the bones, &c. by the firmer and thicker matter. But we
have elsewhere refuted this too prevalent error. Nor do they err less
who, with Democritus, compose all things of atoms; or with Empedocles,
of elements. As if _generation_ were nothing more than a separation, or
aggregation, or disposition of things. It is not indeed to be denied,
that when one thing is to be produced from another, all these are
necessary, but generation itself is different from them all. I find
Aristotle to be of this opinion; and it is my intention, by-and-by, to
teach that out of the same albumen (which all allow to be uniform, not
composed of diverse parts,) all the parts of the chick, bones, nails,
feathers, flesh, &c. are produced and nourished. Moreover, they who
philosophize in this way, assign a material cause [for generation], and
deduce the causes of natural things either from the elements concurring
spontaneously or accidentally, or from atoms variously arranged; they do
not attain to that which is first in the operations of nature and in the
generation and nutrition of animals; viz. they do not recognize that
efficient cause and divinity of nature which works at all times with
consummate art, and providence, and wisdom, and ever for a certain
purpose, and to some good end; they derogate from the honour of the
Divine Architect, who has not contrived the shell for the defence of the
egg with less of skill and of foresight than he has composed all the
other parts of the egg of the same matter, and produced it under the
influence of the same formative faculty.

Although what has already been said be the fact, namely, that the egg,
even whilst contained in the uterus, is provided with a hard shell,
still the authority of Aristotle has always such weight with me that I
never think of differing from him inconsiderately; and I therefore
believe, and my observations bear me out in so much, that the shell does
gain somewhat in solidity from the ambient air upon its extrusion; that
the sluggish and slippery fluid with which it is moistened when laid,
immediately becomes hardened on its exposure to the air. For the shell,
whilst the egg is in the uterus, is much thinner and more transparent,
and smoother on the surface; when laid, however, the shell is thicker,
less translucid, and the surface is rough--it appears as if it were
powdered over with a fine white dust which had but just adhered to it.

Let us, as we are upon this subject, expatiate a little:--

In the desert islands of the east coast of Scotland, such flights of
almost every kind of sea-fowl congregate, that were I to state what I
have heard from parties very worthy of credit, I fear I should be held
guilty of telling greater stories than they who have committed
themselves in regard to the Scottish geese produced, as they say, from
the fruits of certain trees that had fallen into the sea. These geese
the narrators themselves had never seen so produced; but I will here
relate that which I have myself witnessed.

There is a small island which the Scots call the Bass Island (and
speaking of this one will suffice for all), situated in the open ocean,
not far from the shore, of the most abrupt and precipitous character, so
that it rather resembles one huge rock or stone than an island, and
indeed it is not more than a mile in circumference. The surface of this
island in the months of May and June is almost completely covered with
nests, eggs, and young birds, so that you can scarce find free footing
anywhere; and then such is the density of the flight of the old birds
above, that like a cloud they darken the sun and the sky; and such the
screaming and din that you can scarce hear the voice of one who
addresses you. If you turn your eyes below, and from your lofty stance
and precipice regard the sea, there you perceive on all sides around an
infinite variety of different kinds of sea-fowl swimming about in
pursuit of their prey: the face of the ocean is very like that of a pool
in the spring season, when it appears swarming with frogs; or to those
sunny hills and cliffy mountains looked at from below, that are covered
with numerous flocks of sheep and goats. If you sail round the island
and look up, you see on every ledge and shelf, and recess, innumerable
flocks of birds of almost every size and order; more numerous than the
stars that appear in the unclouded moonless sky; and if you regard the
flights that incessantly come and go you may imagine that it is a mighty
swarm of bees you have before you. I should scarcely be credited did I
name the revenue which was annually derived from the feathers, the eggs,
and the old nests, which, as useful for firing, are all made objects of
traffic by the proprietor; the sum he mentioned to me exceeds
credibility. There was this particular feature which, as it refers to
our subject, I shall mention, and also as it bears me out in my report
of the multitudes of sea-fowl: the whole island appears of a brilliant
white colour to those who approach it,--all the cliffs look as if they
consisted of the whitest chalk; the true colour of the rock, however, is
dusky and black. It is a friable white crust that is spread over all,
which gives the island its whiteness and splendour, a crust, having the
same consistency, colour, and nature as an egg-shell, which plasters
everything with a hard, though friable and testaceous kind of covering.
The lower part of the rock, laved by the ebbing and flowing tide,
preserves its native colour, and clearly shows that the whiteness of the
superior parts is due to the liquid excrements of the birds, which are
voided along with the alvine fæces; which liquid excrements, white,
hard, and brittle like the shell of the egg, cover the rock, and, under
the influence of the cold of the air, incrust it. Now this is precisely
the way in which Aristotle and Pliny will have it that the shell of the
egg is formed. None of the birds are permanent occupants of the island,
but visitors for purposes of procreation only, staying there for a few
weeks, in lodgings, as it were, and until their young ones can take wing
along with them. The white crust is so hard and solid, and adheres so
intimately to the rock, that it might readily be mistaken for the
natural soil of the place.

The liquid, white, and shining excrement is conveyed from the kidneys of
birds by the ureters, into the common receptacle or cloaca; where it
covers over the alvine fæces, and with them is discharged. It
constitutes, in fact, the thicker portion of the urine of these
creatures, and corresponds with that which, in our urine, we call the
hypostase or sediment. We have already said something above on this
topic, and have entered into it still more fully elsewhere. We always
find an abundance of this white excrement in mews; where hawks besmear
walls beside their perches, they cover them with a kind of gypseous
crust, or make them look as if they were painted with white lead.

In the cloaca of a dead ostrich I found as much of this gypseous cement
as would have filled the hand. And in like manner the same substance
abounds in tortoises and other oviparous animals; discharged from the
body it soon concretes either into a friable crust, or into a powder
which greatly resembles pulverized egg-shells, in consequence of the
evaporation of its thinner part.

Among the many different kinds of birds which seek the Bass island for
the sake of laying and incubating their eggs, and which have such
variety of nests, one bird was pointed out to me which lays but one egg,
and this it places upon the point of a rock, with nothing like a nest or
bed beneath it, yet so firmly that the mother can go and return without
injury to it; but if any one move it from its place, by no art can it be
fixed or balanced again; left at liberty, it straightway rolls off and
falls into the sea. The place, as I have said, is crusted over with a
white cement, and the egg, when laid, is bedewed with a thick and viscid
moisture, which setting speedily, the egg is soldered as it were, or
agglutinated to the subjacent rock.

An instance of like rapid concretion may be seen any day at a
statuary’s, when he uses his cement of burnt alabaster or gypsum
tempered with water; by means of which the likeness of one dead, or the
cast of anything else may be speedily taken, and used as a mould.

There is also in like manner a certain earthy or solid something in
almost all liquids, as, for example, tartar in wine, mud or sand in
water, salt in lixivium, which, when the greater portion of the water
has been dissipated, concretes and subsides; and so do I conceive the
white sediment of birds to descend along with the urine from the kidneys
into the cloaca, and there to cover over and incrust the egg, much as
the pavement of a mews is plastered over by falcons, and every cliff of
the aforementioned island by the birds that frequent it; much also as
chamber utensils, and places where many persons make water, become
covered with a yellow incrustation; that substance, in fact, concreting
externally, of which calculi in the kidneys, bladder, and other parts
are formed. I did formerly believe then, as I have said, persuaded
especially by the authority of Aristotle and Pliny, that the shell of
the hen’s egg was formed of this white sediment, which abounds in all
the oviparous animals whose eggs are laid with a hard shell, the matter
concreting through contact with the air when the egg was laid. And so
many additional observations have since strengthened this conclusion,
that I can scarcely keep from believing that some part at least of the
shell is thus produced.

Nevertheless, I would say with Fabricius: “Let all reasoning be silent
when experience gainsays its conclusions.” The too familiar vice of the
present age is to obtrude as manifest truths, mere fancies, born of
conjecture and superficial reasoning, altogether unsupported by the
testimony of sense.

For I have very certainly discovered that the egg still contained in the
uterus, in these countries at least, is covered with its shell; although
Aristotle and Pliny assert the contrary, and Fabricius thinks that “it
is not to be too obstinately gainsaid.” In warmer places, perhaps, and
where the fowls are stronger, the eggs may be extruded soft, and for the
most part without shells. With us this very rarely happens. When I was
at Venice in former years, Aromatarius, a learned physician, showed me a
small leaf which had grown between the two valves of a peascod, whilst
with us there is nothing more apparent in these pods than a small point
where the germ is about to be produced. So much do a milder climate, a
brighter sky, and a softer air, conduce to increase and rapidity of


_Of the remaining parts of the egg._

We have already spoken partially of the place where, the time when, and
the manner how the remaining parts of the egg are engendered, and we
shall have something more to add when we come to speak of their several

“The albumen,” says Fabricius,[151] “is the _ovi albus liquor_ of Pliny,
the _ovi candidum_ of Celsus, the _ovi albor_ of Palladius, the _ovi
album et albumentum_ of Apicius, the λευκὸν of the Greeks, the ώοῡ
λεύκωμα of Aristotle, the ὄρνιθος γάλα, or bird’s milk of Anaxagoras.
This is the cold, sluggish, white fluid of the egg, of different
thickness at different places (thinner at the blunt and sharp ends,
thicker in other situations,) and also in variable quantity (for it is
more abundant at the blunt end, less so at the sharp end, and still less
so in the other parts of the egg), covering and surrounding the yelk on
every side.”

In the hen’s egg, however, I have observed that there are not only
differences in the albumen, but two albumens, each surrounded with its
proper membrane. One of these is thinner, more liquid, and almost of the
same consistence as that humour which, remaining among the folds of the
uterus, we have called the matter and nourishment of the albumen; the
other is thicker, more viscid, and rather whiter in its colour, and in
old and stale eggs, and those that have been sat upon for some days, it
is of a yellowish cast. As this second albumen everywhere surrounds the
yelk, so is it, in like manner, itself surrounded by the more external
fluid. That these two albumens are distinct appears from this, that if
after having removed the shell you pierce the two outermost membranes,
you will perceive the external albuminous liquid to make its escape, and
the membranes to become collapsed and to sink down in the dish; the
internal and thicker albumen, however, all the while retains its place
and globular figure, inasmuch as it is bounded by its proper membrane,
although this is of such tenuity that it entirely escapes detection by
the eye; but if you then prick it, the second albumen will forthwith
begin to flow out, and the mass will lose its globular shape; just as
the water contained in a bladder escapes when it is punctured; in like
manner the proper investing membrane of the vitellus being punctured,
the yellow fluid of which it consists escapes, and the original globular
form is destroyed.

“The vitellus,” says Fabricius,[152] “is so called from the word vita,
because the chick lives upon it; from its colour it is also spoken of as
the yellow of the egg, having been called by the Greeks generally,
χρυσὸν, by Hippocrates χλωρὸν, and by Aristotle ώχρὸν and λεκυθὸν; the
ancients, such as Suidas in Menander, called it νεοττὸν, i. e. the
chick, because they believed the chick to be engendered from this part.
It is the smoothest portion of the egg, and is contained within a most
delicate membrane, immediately escaping if this be torn, and losing all
figure; it is sustained in the middle of the egg; and in one egg is of
a yellow colour, in another of a tint between white and yellow; it is
quite round, of variable size, according to the size of the bird that
lays the egg, and, according to Aristotle, of a deeper yellow in water
birds, of a paler hue in land birds.” The same author[153] also
maintains that “the yellow and the white of an egg are of opposite
natures, not only in colour but in qualities; for the yellow is
inspissated by cold, which the white is not, but is rather rendered more
liquid; and the white, on the contrary, is thickened by heat, which the
yellow is not, unless it be burned or over-done, and it is more hardened
and dried by boiling than by roasting.” As in the macrocosm the earth is
placed in the centre, and is surrounded by the water and the air, so is
the yelk, the more earthy part of the egg, surrounded by two albuminous
layers, one thicker, another thinner. And, indeed, Aristotle[154] says
that, “if we put a number of yelks and whites together, and mix them in
a pan, and then boil them with a slow and gentle fire, that the whole of
the yelks will set into a globular mass in the middle, and appear
surrounded by the whites.” But many physicians have been of opinion that
the white was the colder portion of the egg. Of these matters, however,
more by and by.

The chalazæ, the treads or treadles (gralladura Ital.) are two in number
in each egg, one in the blunt, another in the sharp end. The larger
portion of them is contained in the white; but they are most intimately
connected with the yelk, and with its membrane. They are two long-shaped
bodies, firmer than the albumen and whiter; knotty, not without a
certain transparency like hail, whence their name; each chalaza, in
fact, is made up of several hailstones, as it seems, connected by means
of albumen. One of them is larger than the other, and this extends from
the yelk towards the blunt end of the egg; the other and smaller chalaza
stretches from the yelk towards the sharp end of the egg. The larger is
made up of two or three knots or seeming hailstones, at a trifling
distance from one another, and of successively smaller size.

The chalazæ are found in the eggs of all birds, and in wind and
unprolific as well as in perfect or prolific eggs, duly disposed in both
their extremities. Whence the supposition among housewives that the
chalazæ are the tread or spermatic fluid of the cock, and that the chick
is generated from them is discovered to be a vulgar error. But Fabricius
himself, although he denies that they consist of the semen of the cock,
still gives various reasons for maintaining that “they are the immediate
matter which the cock fecundates, and from which the chick is produced;”
a notion which he seeks to prop by this feeble statement: “because in a
boiled egg, the chalazæ are so contracted on themselves that they
present the figure of a chick already formed and hatched.” But it is not
likely that several rudiments of a single fœtus should be wanted in one
egg, neither has any one ever discovered the rudiments of the future
chick save in the blunt end of the egg. Moreover the chalazæ present no
sensible difference in eggs that are fecundated by the intercourse of
the two sexes, from those of eggs that are barren. Our distinguished
author is therefore mistaken in regard to the use of the chalazæ in the
egg, as shall farther be made to appear by and by.

In the eggs of even the smallest birds there is a slender filament, the
rudiments of the chalazæ, to be discovered; and in those of the ostrich
and cassowary I have found, in either end of the egg very thick chalazæ,
of great length, and very white colour, made up of several globules
gradually diminishing in size.

A small cavity is observed in the inside of an egg under the shell, at
the blunt end; sometimes exactly in the middle, at other times more to
one side, almost exactly corresponding to the chalaza that lies below
it. The figure of this cavity is generally circular, though in the goose
and duck it is not exactly so. It is seen as a dark spot if you hold an
egg opposite a candle in a dark place, and apply your hand edgeways over
the blunt end. In the egg just laid it is of small size,--about the size
of the pupil of the human eye; but it grows larger daily as the egg is
older, and the air is warmer; it is much increased after the first day
of incubation; as if by the exhalation of some of the more external and
liquid albumen the remainder contracted, and left a larger cavity; for
the cavity in question is produced between the shell and the membrane
which surrounds the whole of the fluids of the egg. It is met with in
all eggs; I have discovered it, even in those that are still contained
in the uterus, as soon as they had become invested with the shell. They
who are curious in such matters say that if this cavity be in the point
or end of the egg it will produce a male, if towards the side, a female.
This much is certain: if the cavity be small it indicates that the egg
is fresh-laid; if large, that it is stale. But we shall have occasion
anon to say more on this head.

There is a white and very small circle apparent in the investing
membrane of the vitellus, which looks like an inbranded cicatrice, which
Fabricius therefore calls cicatricula; but he makes little of this spot,
and looks on it rather as an accident or blemish than as any essential
part of the egg. The cicatricula in question is extremely small; not
larger than a tiny lentil, or the pupil of a small bird’s eye; white,
flat, and circular. This part is also found in every egg, and even from
its commencement in the vitellarium. Fabricius, therefore, is mistaken
when he thinks that this spot is nothing more than the trace or
cicatrice of the severed peduncle, by which the egg was in the first
instance connected with the ovary. For the peduncle, as he himself
admits, is hollow, and as it approaches the vitellus expands, so as to
surround or embrace, and inclose the yelk in a kind of pouch: it is not
connected with the yelk in the same way as the stalks of apples and
other fruits are infixed, and so as to leave any cicatrice when the yelk
is cast loose. And if you sometimes find two cicatriculæ in a large
yelk, as Fabricius states, this might, perhaps, lead to the production
of a monster and double fœtus, (as shall be afterwards shown), but would
be no indication of the preexistence of a double peduncle. He is,
however, immensely mistaken when he imagines that the cicatricula serves
no purpose; for it is, in fact, the most important part of the whole
egg, and that for whose sake all the others exist; it is that, in a
word, from which the chick takes its rise. Parisanus, too, is in error,
when he contends that this is the semen of the cock.


_Of the diversities of eggs._

“The word ovum, or egg, is taken in a twofold sense, proper and
improper. An ovum, properly so designated, I call that body to which the
definition given by Aristotle[155] applies: An egg, says he, is that
from part of which an animal is engendered, and the remainder of which
is food for the animal so produced. But I hold that body to be
improperly styled an egg which is defined by Aristotle[156] in the same
place, to be that from the whole of which an animal is engendered; such
as the eggs of ants, flies, spiders, some butterflies, and others of the
tribe of extremely small eggs; which Aristotle almost always fears to
commit himself by calling eggs, but which he rather styles vermiculi.”
What precedes is from Fabricius;[157] but we, whose purpose it is to
treat especially of the generation of the hen’s egg, have no intention
to speak of the differences of all kinds of eggs; we shall limit
ourselves to the diversities among hen’s eggs.

The more recently laid are whiter than the staler, because by age, and
especially by incubation, they become darker; the cavity in the blunt
end of a stale egg is also larger than in a recent egg; eggs just laid
are also somewhat rough to the feel from a quantity of white powder
which covers the shell, but which is soon rubbed off, when the egg
becomes smoother as well as darker. New-laid eggs, unbroken, if placed
near a fire will sweat, and are much more palatable than those that have
been kept for some time--they are, indeed, accounted a delicacy by some.
[Fruitful] eggs, after two or three days’ incubation, are still better
flavoured than stale eggs; revived by the gentle warmth of the hen, they
seem to return to the quality and entireness of the egg just laid.
Farther, I have boiled an egg to hardness, after the fourteenth day of
incubation, when the chick had already begun to get its feathers, when
it occupied the middle of the egg, and nearly the whole of the yelk
remained, in order that I might better distinguish the position of the
chick: I found it lying, as it were, within a mould of the albumen, and
the yelk possessed the same agreeable flavour and sweetness as that of
the new-laid egg, boiled to the same degree of hardness. The yelk taken
from the ovarium of a live fowl, and eaten immediately, tastes much
sweeter raw than boiled.

Eggs also differ from one another in shape; some are longer and more
pointed, others rounder and blunter. According to Aristotle,[158] the
long-shaped and pointed eggs produce females; the blunt, on the
contrary, yield males. Pliny,[159] however, maintains the opposite. “The
rounder eggs,” he says, “produce females, the others males;” and with
him Columella[160] agrees: “He who desires to have the greater number of
his brood cocks, let him select the longest and sharpest eggs for
incubation; and on the contrary, when he would have the greater number
females, let him choose the roundest eggs.” The ground of Aristotle’s
opinion was this: because the rounder eggs are the hotter, and it is the
property of heat to concentrate and determine, and that heat can do most
which is most powerful. From the stronger and more perfect principle,
therefore, proceeds the stronger and more perfect animal. Such is the
male compared with the female, especially in the case of the common
fowl. On the contrary, again, the smaller eggs are reckoned among the
imperfect ones, and the smallest of all are regarded as entirely
unproductive. It was on this account too that Aristotle, to secure the
highest quality of eggs, recommends that the hens be frequently trodden.
Barren and adventitious eggs, he asserts, are smaller and less savoury,
because they are humid and imperfect. The differences indicated are to
be understood as referring to the eggs of the same fowl; for when a
certain hen goes on laying eggs of a certain character, they will all
produce either males or females. If you understand this point otherwise,
the guess as to males or females, from the indications given, would be
extremely uncertain. Because different hens lay eggs that differ much in
respect of size and figure: some habitually lay more oblong, others,
rounder eggs, that do not differ greatly one from another; and although
I sometimes found diversities in the eggs of the same fowl, these were
still so trifling in amount that they would have escaped any other than
the practised eye. For as all the eggs of the same fowl acquire nearly
the same figure, in the same womb or mould in which the shell is
deposited, (much as the excrements are moulded into scybala in the cells
of the colon,) it necessarily falls out that they greatly resemble one
another; so that I myself, without much experience, could readily tell
which hen in a small flock had laid a given egg, and they who have given
much attention to the point, of course succeed much better. But that
which we note every day among huntsmen is far more remarkable; for the
more careful keepers who have large herds of stags or fallow deer under
their charge, will very certainly tell to which herd the horns which
they find in the woods or thickets belonged. A stupid and uneducated
shepherd, having the charge of a numerous flock of sheep, has been known
to become so familiar with the physiognomy of each, that if any one had
strayed from the flock, though he could not count them, he could still
say which one it was, give the particulars as to where it had been
bought, or whence it had come. The master of this man, for the sake of
trying him, once selected a particular lamb from among forty others in
the same pen, and desired him to carry it to the ewe which was its dam,
which he did forthwith. We have known huntsmen who, having only once
seen a particular stag, or his horns, or even his print in the mud, (as
a lion is known by his claws,) have afterwards been able to distinguish
him by the same marks from every other; some, too, from the foot-prints
of deer, seen for the first time, will draw inferences as to the size,
and grease, and power of the stag which has left them; saying whether he
were full of strength, or weary from having been hunted; and farther,
whether the prints are those of a buck or a doe. I shall say thus much
more: there are some who, in hunting, when there are some forty hounds
upon the trace of the game, and all are giving tongue together, will
nevertheless, and from a distance, tell which dog is at the head of the
pack, which at the tail, which chases on the hot scent, which is running
off at fault; whether the game is still running, or is at bay; whether
the stag have run far, or have but just been raised from his lair. And
all this amid the din of dogs, and men, and horns, and surrounded by an
unknown and gloomy wood. We should not, therefore, be greatly surprised
when we see those who have experience telling by what hen each
particular egg in a number has been laid. I wish there were some equally
ready way from the child of knowing the true father.

The principal difference between eggs, however, is their fecundity or
barrenness--the distinction of fruitful eggs from hypenemic,
adventitious, or wind eggs. Those eggs are called hypenemic, (as if the
progeny of the wind,) that are produced without the concourse of the
male, and are unfit for setting; although Varro[161] declares that the
mares, in Lusitania, conceive by the wind. For zephyrus was held a
fertilizing wind, whence its name, as if it were ζωηφερὀς, or life
bringing. So that Virgil says:

    And Zephyrus, with warming breath resolves
    The bosom of the ground, and melting rains
    Are poured o’er all, and every field brings forth.

Hence the ancients, when with this wind blowing in the spring season,
they saw their hens begin laying, without the concurrence of the cock,
conceived that zephyrus, or the west wind, was the author of their
fecundity. There are also what are called addle, and dog-day eggs,
produced by interrupted incubation, and so called because eggs often rot
in the dog-days, being deserted by the hens in consequence of the
excessive heat; and also because at this season of the year thunder is
frequent; and Aristotle[162] asserts that eggs die if it thunders whilst
the hen is sitting.

Those eggs are regarded as prolific, which, no unfavorable circumstances
intervening, under the influence of a gentle heat, produce chicks. And
this they will do, not merely through the incubation of the mother, but
of any other bird, if it be but of sufficient size to cherish and cover
them, or by a gentle temperature obtained in any way whatever. “Eggs are
hatched with the same celerity,” says Aristotle,[163] “spontaneously in
the ground, as by incubation. Wherefore in Egypt, it is the custom to
bury them in dung, covered with earth. And there was a tale in Syracuse,
of a drunken fellow, who was accustomed to continue his potations until
a number of eggs, placed under a mat bestrewed with earth, were
hatched.” The empress Livia, is also said to have carried an egg in her
bosom until a chick was produced from it. And in Egypt, and other
countries, at the present time, chickens are reared from eggs placed in
ovens. “The egg, therefore,” as Fabricius[164] truly says, “is not only
the uterus, and place where the generation of the chick proceeds, but it
is that upon which its whole formation depends; and this the egg
accomplishes as agent, as matter, as instrument, as place, and as all
else that concurs.”

For it is certain that the chick is formed by a principle inherent in
the egg, and that nothing accrues to a perfect egg from incubation,
beyond the warmth and protection; in the same way as to the chick when
disclosed, the hen gives nothing more than her warmth and her care, by
which she defends it from the cold and from injury, and directs it to
its proper food. The grand desideratum, therefore, once the chickens are
hatched, is that the hen lead them about, seek for and supply them with
proper food, and cherish them under her wings. And this you will not
easily supply by any kind of artifice.

Capons, and hybrids between the common fowl and the pheasant, produced
in our aviaries, will incubate and hatch a set of eggs; but they never
know how to take care of the brood--to lead them about properly, and to
provide with adequate care for their nurture.

And here I would pause for a moment, (for I mean to treat of the matter
more fully by and by,) to express my admiration of the perseverance and
patience with which the females of almost every species of bird, sit
upon the nest for so many days and nights incessantly, macerating their
bodies, and almost destroying themselves from want of food; what dangers
they will face in defence of their eggs, and when compelled to quit them
for ever so short a time, through necessity, with what eagerness and
haste they return to them again, and brood over them! Ducks and geese,
when they quit the nest for a few minutes, cover and conceal it with
straw. With what true magnanimity do these ill-furnished mothers defend
their eggs! which, after all, perhaps, are mere wind or addle eggs, or
not their own, or artificial eggs of chalk or ivory;--it is still the
same, they defend all with equal courage. It is truly a remarkable love
which birds display for inert and lifeless eggs; and their solicitude is
repaid by no kind of advantage or enjoyment. Who does not wonder at the
affection, or passion rather, of the clucking hen, which can only be
extinguished by a drenching with cold water. In this state of her
feeling she neglects everything,--her wings droop, her feathers are
unpruned and ruffled, she wanders about restless and dissatisfied,
disturbing other hens on their nests, seeking eggs everywhere, which she
commences forthwith to incubate; nor will she be at peace until her
desire has been gratified, until she has a brood to lead about with her,
upon which she may expend her fervour, which she may cherish, feed, and
defend. How pleasantly are we moved to laughter when we see the poor hen
following to the water the supposititious brood of ducklings she has
hatched, wandering restlessly round the pool, attempting to wade after
them to her own imminent peril, and by her noises and various artifices
striving to entice them back to the shore!

According to Aristotle,[165] barren eggs do not produce chicks because
their fluids do not thicken under incubation, nor is the yelk or the
white altered from its original constitution. But we shall revert to
this subject in our general survey of generation.

Our housewives, that they may distinguish the eggs that are addled from
those that will produce chicks, take them from the fourteenth to the
sixteenth day of the incubation, and drop them softly into tepid water,
when the spoilt ones sink, whilst the fruitful ones swim. If the
included chick be well forward, and moves about with alacrity, the egg
not only rolls over but even dances in the water. And if you apply the
egg to your ear for several days before the hatching, you may hear the
chick within kicking, scratching, and even chirping. When the hen that
is sitting hears these noises, she turns the eggs and lays them
otherwise than they were, until the chicks, getting into a comfortable
position, become quiet; even as watchful mothers are wont to treat
their infants when they are restless and cry in their cradles.

Hens lay eggs in variable numbers: “Some hens,” says the
philosopher,[166] “except the two winter months, lay through the whole
year; some of the better breeds will lay as many as sixty eggs before
they show a disposition to sit; though these eggs are not so prolific as
those of the commoner kinds. The Adrianic hens are small, and lay every
day, but they are ill-tempered, and often kill their young ones; they
are particoloured in their plumage. Some domestic fowls will even lay
twice a day; and some, by reason of their great fecundity, die young.”

In England some of the hens lay every day; but the more prolific
commonly lay two days continuously and then miss a day: the first day
the egg is laid in the morning, next day in the afternoon, and the third
day there is a pause. Some hens have a habit of breaking their eggs and
deserting their nests; whether this be from disease or vice is not

Certain differences may also be observed in the incubation: some fowls
only sit once, others twice, or thrice, or repeatedly. Florentius says,
that in Alexandria, in Egypt, there are fowls called monosires, from
which the fighting cocks are descended, which go on sitting for two or
three periods, each successive brood being removed as it is hatched, and
brought up apart. In this way the same hen will hatch forty, sixty, and
even a greater number of chickens, at a single sitting.

Some eggs too, are larger, others smaller; a few extremely small; these,
in Italy, are commonly called centenina; and our country folks still
believe that such eggs are laid by the cock, and that were they set they
would produce basilisks. “The vulgar,” says Fabricius,[167] “think that
this small egg is the last that will be laid, and that it comes as the
hundredth in number, whence the name; that it has no yelk, though all
the other parts are present--the chalazæ, the albumen, the membranes,
and the shell. And it seems probable that it is produced when all the
other yelks have been fashioned into eggs, and no more remain in the
vitellary; on the other hand, however, a modicum of albumen remains, and
out of this, it may be inferred, is the small egg in question produced.”
To me, nevertheless, this does not appear likely; because it is certain
that the whole ovary being removed, the uterus secundus also diminishes
in size in the same proportion, and shrinks into a mere membrane, which
contains neither any fluid nor any albumen. Fabricius proceeds: “The ova
centenina are met with of two kinds: one of them being without a yelk,
and this is the true centenine egg, because it is the last which the hen
will lay at that particular season--she will now cease from laying for a
time. The other is also a small egg, but it has a yelk, and will not
prove the last which the hen will then lay, but is intermediate between
those of the usual size that have preceded, and others that will follow.
It is of small size because there has been a failure of the vegetative
function, as happens to the peach, and other fruit, of which we see many
of adequate size, but a few that are very diminutive.” This may be in
consequence of the inclemency of the weather, or the want of sun, or
from defective nutriment in point either of quantity or quality. I
should not readily allow, however, that the eggs last laid are always

Monstrous eggs are not wanting; “for the augurs,” says Aristotle,[168]
“held it portentous when eggs were laid that were all yellow; or when,
on a fowl being laid open, eggs were found under the septum transversum,
where the rudimentary eggs of the female usually appear, of the
magnitude of perfect eggs.”

To this head may be referred those eggs that produce twins, that have
two yelks. Such an egg I lately found in the uterus of a fowl, perfect
in all respects, and covered with a shell; the yelks, cicatriculæ, and
thicker albuminous portions being all double, and the chalazæ present in
two pairs: a single thinner albumen, however, surrounded all these, and
this in its turn was included within the usual double common membrane,
and single shell. For, indeed, although Aristotle says that fowls always
lay some eggs of this kind, I shall hardly be induced to believe that
this does not occur against the ordinary course of nature. And although
twin chicks are produced from such eggs as I have ascertained in
opposition to the opinion of Fabricius, who says that they produce
chicks having four legs, or four wings and two heads, which, however,
are not capable of living, but for the most part speedily die, either
by reason of want of room or of air in the shell, or because the one
proves a hinderance to the other and blights it; nor can it happen that
both should be equally prepared for exclusion--that one should not prove
an abortion.

Briefly and summarily the differences among eggs are principally of
three kinds: some are prolific, some unprolific; some will produce males
and some females; some are the produce of the two sexes of the same
species, others of allied species and will produce hybrids, such as we
see between the common hen and the pheasant, the progeny being
referrible either to the first or to the last male that had connexion
with the hen. Because, according to Aristotle,[169] “the egg, which
receives its constitution by intercourse, passes from its own into
another genus, if the hen be trodden when she carries either an
adventitious egg or one that was conceived under the influence of
another male, and this renewed intercourse take place before the yellow
is changed into the white. So that hypenemic or wind eggs are made
fruitful, and fruitful eggs receive the form of the male which has
connexion last. But if the change has taken place into the white, it
cannot happen either that the wind egg is turned into a fertile one, or
that the egg which is contained in the uterus in virtue of a previous
intercourse, shall be altered into the genus of the male which has the
second communication.” For the seminal fluid of the cock, as Scaliger
wittily remarks, is like a testament, the last will or disposition in
which is that which stands in force.

To these particulars it might perhaps be added, that some eggs are more
strong and lusty than others, more full of life, if the expression may
be used; though as there is a vital principle in the egg, so must there
inhere the corresponding virtue that flows from it. For, as in other
kinds of animals, some of the females are so replete with desire, so
full of Venus, that they conceive from any and every intercourse, even
once submitted to, and from a weakly male, and produce several young
from the same embrace; others, on the contrary, are so torpid and
sluggish, that unless they are assailed by a vigorous male, under the
influence of strong desire, and that not once, but repeatedly, and for
a certain time, they continue barren. This is also the case with eggs,
some of which, though they may have been conceived in consequence of
intercourse, still remain unprolific unless perfected by repeated and
continued connections. Whence it happens that some eggs are more
speedily changed by incubation than others, exhibiting traces of the
fœtus from the third day; others again, either become spoiled, or suffer
transformation into the fœtus more slowly, exhibiting no indications of
the future chick even up to the seventh day, as shall be made to appear
by and by, in speaking of the generation of the chick from the egg.

Thus far have we discoursed of the uterus of the fowl, and its function;
of the production of the hen’s egg, and of its differences and
peculiarities, from immediate observation; and from the instances
quoted, conclusions may be drawn with reference to other oviparous

We have now to pursue the history of the generation and formation of the
fœtus from the egg. For indeed, as I have said above, the entire
contemplation of the family of birds is comprehended in these two
propositions: how is an egg engendered of a male and female; and by what
process do males and females proceed from eggs?--the circle by which,
under favour of nature, their kinds are continued to eternity.


_Of the production of the chick from the egg of the hen._

Of the growth and generation of the hen’s egg enough has already been
said; and we have now to lay before the reader our observations on the
procreation of the chick from the egg,--a duty which is equally
difficult, and profitable, and pleasant. For in general the first
processes of nature lie hid, as it were, in the depths of night, and by
reason of their subtlety escape the keenest reason no less than the most
piercing eye.

Nor in truth is it a much less arduous business to investigate the
intimate mysteries and obscure beginnings of generation than to seek to
discover the frame of the world at large, and the manner of its
creation. The eternity of things is connected with the reciprocal
interchange of generation and decay; and as the sun, now in the east and
then in the west, completes the measure of time by his ceaseless
revolutions, so are the fleeting things of mortal existence made eternal
through incessant change, and kinds and species are perpetuated though
individuals die.

The writers who have treated of this subject have almost all taken
different paths; but having their minds preoccupied, they have hitherto
gone to work to frame conclusions in consonance with the particular
views they had adopted.

Aristotle,[170] among the ancients, and Hieron. Fabricius of
Aquapendente, among the moderns, have written with so much accuracy on
the generation and formation of the chick from the egg that little seems
left for others to do. Ulyssus Aldrovandus,[171] nevertheless, described
the formation of the chick in ovo; but he appears rather to have gone by
the guidance of Aristotle than to have relied on his own experience. For
Volcherus Coiter, living at this time in Bologna, and encouraged, as he
tells us, by Aldrovandus, his master, opened incubated eggs every day,
and illustrated many points besides those noted by Aldrovandus;[172]
these discoveries, however, could scarcely have remained unknown to
Aldrovandus. Æmilius Parisanus, a Venetian physician, having discarded
the opinions of others, has also given a new account of the formation of
the chick from the egg.

But since our observations lead us to conclude that many things of great
consequence are very different from what they have hitherto been held to
be, I shall myself give an account of what goes on in the egg from day
to day, and what parts are there transmuted, directing my attention to
the first days especially, when all is most obscure and confused, and
difficult of observation, and in reference to which writers have more
particularly drawn the sword against one another in defence of their
several discordant observations, which, in sooth, they accommodate
rather to their preconceived opinions respecting the material and
efficient cause of animal generation than to simple truth.

What Aristotle says on the subject of the reproduction of the chick in
ovo is perfectly correct. Nevertheless, as if he had not himself seen
the things he describes, but received them at second hand from another
expert observer, he does not give the periods rightly; and then he is
grievously mistaken in respect of the place in which the first rudiments
of the egg are fashioned, stating this to be the sharp end, for which he
is fairly challenged by Fabricius. Neither does he appear to have
observed the commencement of the chick in the egg; nor could he have
found the things which he says are necessary to all generation in the
place which he assigns them. He will, for instance, have it that the
white is the constituent matter (since nothing naturally can by
possibility be produced from nothing.) And he did not sufficiently
understand how the efficient cause (the seminal fluid of the cock,)
acted without contact; nor how the egg could, of its own accord, without
any inherent generative matter of the male, produce a chick.

Aldrovandus, adopting an error akin to that of Aristotle, says besides,
that the yelk rises during the first days of the incubation into the
sharp end of the egg, a proposition which no eyes but those of the blind
would assent to; he thinks also that the chalazæ are the semen of the
cock, and that the chick arises from them, though it is nourished both
by the yelk and the white. In this he is obviously in opposition to
Aristotle, who held that the chalazæ contributed nothing to the
reproductive powers of the egg.

Volcherus Coiter is, on the whole, much more correct; and his statements
are far more consonant with what the eye perceives. But his tale of the
three globules is a fable. Neither did he rightly perceive the true
commencement of the chick in ovo.

Hieronymus Fabricius contends that the chalazæ are not the sperma of the
cock; but then he will have it that “from these, fecundated by the
seminal fluid of the cock, as from the appropriate matter, the chick is
incorporated.” Fabricius observed the point of origin of the chick, the
spot or cicatricula, namely, which presents itself upon the tunica
propria of the yelk; but he regarded it as a cicatrice or scar left on
the place where the peduncle had been attached; he viewed it as a
blemish in the egg, not as any important part.

Parisanus completely refutes Fabricius’s ideas of the chalazæ; but he
himself obviously raves when he speaks of certain circles, and
principal parts of the fœtus, viz., the liver and heart. He appears to
have observed the commencement of the fœtus in ovo; but what it was he
obviously did not know, when he says, “that the white point in the
middle of the circles is the semen of the cock, from which the chick is

Thus it comes to pass that every one, in adducing reasons for the
formation of the chick in ovo, in accordance with preconceived opinions,
has wandered from the truth. Some will have it that the semen or the
blood is the matter whence the chick is engendered; others, that the
semen is the agent or efficient cause of its formation. Yet to him who
dispassionately views the question is it quite certain that there is no
prepared matter present, nor any menstruous blood to be coagulated at
the time of intercourse by the semen masculinum, as Aristotle will have
it; neither does the chick originate in the egg from the seed of the
male, nor from that of the female, nor from the two commingled.


_The first examination of the egg; or of the effect of the first day’s
incubation upon the egg._

That we may be the more clearly informed of the effect which the first
day’s incubation produces upon the egg, we must set out by ascertaining
what changes take place in an egg spontaneously, changes that
distinguish a stale egg from one that is new-laid, when what is due to
the incubation _per se_ will first be clearly apprehended.

The space or cavity in the blunt end is present, as we have said, in
every egg; but the staler the egg the larger does this hollow
continually grow; and this is more especially the case when eggs are
kept in a warm place, or when the weather is hot; the effect being due
to the exhalation of a certain portion of the thinner albumen, as has
been stated in the history of the egg. This cavity, as it increases,
extends rather in the line of the length than of the breadth of the egg,
and comes finally to be no longer orbicular.

The shell, already less transparent, becomes dingy.

The albumen grows thicker and more viscid, and acquires a straw or
yellow colour.

The tunica propria of the vitellus becomes more lax, and appears
wrinkled, for it seems that some even of this fluid is dissipated in the
course of time.

The chalazæ are found in either end of every egg, in the same situation,
and having the same consistence--whether the egg be recent or stale,
fruitful or barren, it does not signify; by their means a firm connexion
is established between the yelk and the white, and the two fluids
preserve their relative positions. The chalazæ, indeed, are two mutually
opposed supports or poles, and hinges of this microcosm; and are
constructed as if made up of numerous coats of the albumen, twisted
together at either end into a knotted rope, by which they are attached
to the vitellus. And hence it happens that the yelk is separated from
the white with difficulty, unless the chalazæ are either first divided
with a knife or torn with the fingers; this done, the white immediately
falls away from the yelk. It is by means of these hinges that the
vitellus is both retained in the centre of the egg and preserved of its
proper consistence. And they are so connected that the principal part,
the cicatricula, to wit, always regards the same region of the egg, or
its upper part, and is preserved equidistant from either end. For this
spot or cicatricula is observed to be of the same consistence,
dimensions, and colour, and in the same situation in the stale as in the
new-laid egg. But as soon as the egg, under the influence of the gentle
warmth of the incubating hen, or of warmth derived from another source,
begins to pullulate, this spot forthwith dilates, and expands like the
pupil of the eye, and from thence, as the grand centre of the egg, the
latent plastic force breaks forth and germinates. This first
commencement of the chick, however, so far as I am aware, has not yet
been observed by any one.

On the second day of the incubation, after the egg has been exposed to
warmth for twenty-four hours, under the hen, as the cavity in the blunt
end has enlarged greatly and descended, so has the internal constitution
of the egg also begun to be changed. The yelk, which had hitherto lain
in the middle of the albumen, rises towards the blunt end, and its
middle, where the cicatricula is situated, is lifted up and applied to
the membrane that bounds the empty space, so that the yelk now appears
to be connected with the cavity by means of the cicatricula; and in the
same measure as the yelk rises does the thicker portion of the albumen
sink into the sharp or lower end of the egg. Whence it appears, as
Fabricius rightly remarks, that Aristotle[173] was either in error, or
that there is a mistake in the codex, when it is said, “In this time”
(viz., between three and four days, and as many nights,) “the yelk is
brought to the summit, where the commencement of the egg is, and the egg
is exposed in this part,” i. e. under the enlarged empty space. Now
Aristotle[174] calls the principium ovi, or commencement of the egg, its
smaller end, which is last extruded. But it is certain that the yelk
ascends towards the blunt end of the egg, and that the cavity there
enlarges. And Aldrovandus is undoubtedly in error when he speaks as if
he had experience of the fact, and says that the yelk rises to the sharp
end. I will confess, nevertheless, that on the second or third day I
have occasionally observed the cicatricula expanded and the beginning of
the chick already laid, the yelk not having yet risen; this, however,
happens rarely, and I am inclined to ascribe it to some weakness in the

On the second day of the incubation, or first day of inspection, the
cicatricula in question is found to have enlarged to the dimensions of a
pea or lentil, and is divided into circles, such as might be drawn with
a pair of compasses, having an extremely minute point for their centre.
It is very probable that Aldrovandus observed this spot, for he says:
“In the midst of the yellow a certain whitish something makes its
appearance, which was not noticed by Aristotle;” and also by Coiter,
when he expresses himself thus: “On the second day there is in the
middle of the yelk a part whiter than the rest;” Parisanus, too, may
have seen it; he observes: “In the course of the second day I observe a
white body of the size and form of a middling lentil; and this is the
semen of the cock covered over with a white and most delicate tunic,
which underlies the two common membranes of the entire egg, but overlies
the tunica propria of the yelk.” I believe, however, that no one has yet
said that this cicatricula occurs in every egg, or has acknowledged it
to be the origin of the chick.

Meantime the chalazæ or treadles will be seen to decline from either end
of the egg towards its sides, this being occasioned by that alteration
which we have noticed in the relative situations of the two fluids. The
treadle from the blunt end descends somewhat; the one from the sharp end
rises in the same proportion: as in a globe whose axis is set obliquely,
one pole is as much depressed below the horizon as the other is raised
above it.

The vitellus, too, particularly in the situation of the cicatricula,
begins to grow a little more diffluent than it was, and raises its
tunica propria, (which we have found in stale eggs before incubation to
be somewhat lax and wrinkled,) into a tumour; and it now appears to have
recovered the same colour, consistency, and sweetness of taste that it
had in the egg just laid.

Such is the process in the course of the first day that leads to the
production of a new being, such the earliest trace of the future chick.
Aldrovandus adds: “the albumen suffers no change,” which is correct; but
when he asserts that “the semen of the cock can be seen in it,” he as
manifestly errs. Resting on a most insufficient reason, he thought that
the chalazæ were the semen of the cock, “because,” forsooth, “the eggs
that are without chalazæ are unfruitful.” This I can very well believe;
for these were then no proper eggs; for all eggs, wind eggs as well as
those that are prolific, have chalazæ. But he, misled perhaps by the
country women, who in Italian call the chalazæ _galladura_, fell into
the vulgar error. Nor is Hieronymus Fabricius guilty of a less grave
mistake when he exhibits the formation of the chick in a series of
engravings, and contends that it is produced from the chalazæ;
overlooking the fact that the chalazæ are present the whole of the time,
and unchanged, though they have shifted their places; and that the
commencement of the chick is to be sought for at a distance from them.


_Second inspection of the egg._

The second day gone by, the circles of the cicatricula that have been
mentioned, have become larger and more conspicuous, and may now be of
the size of the nail of the ring-finger, sometimes even of that of the
middle finger. By these rings the whole cicatricula is indistinctly
divided into two, occasionally into three regions, which are frequently
of different colours, and bear a strong resemblance to the cornea of the
eye, both as respects dimensions, a certain degree of prominence, and
the presence of a transparent and limpid fluid included within it. The
centre of the cicatricula here stands for the pupil; but it is occupied
with a certain white speck, and appears like the pupil of some small
bird’s eye obscured by a suffusion or cataract, as it is called. On this
account we have called the entire object the oculum ovi, the eye of the

Within the circles of the cicatricula, I say, there is contained a
quantity of perfectly bright and transparent fluid, even purer than any
crystalline humour; which, if it be viewed transversely and against the
light, the whole spot will rather appear to be situated in the albumen
than sunk into the membrane of the yelk, as before: it presents itself
as a portion of the albumen dissolved and clarified, and included within
a most delicate tunica propria. Hence I entitle this fluid the oculum
seu colliquamentum album; it is as if a portion of the albumen,
liquefied by the heat, shone apart, (which it does, unless disturbed by
being shaken,) and formed a more spirituous and better digested fluid,
separated from the rest of the albumen by a tunica propria, and situated
between the two masses of liquid, the yelk and the albumen. It differs
from the rest of the albumen by its clearness and transparency, as the
water of a pellucid spring differs from that of a stagnant pool. The
tunic which surrounds this fluid is so fragile and delicate that, unless
the egg be handled with great care, it is apt to give way, when the pure
spring is rendered turbid by a mixture of fluids.

I was long in doubt what I should conclude as to this clear diffluent
fluid, whether I should regard it as the innate heat, or radical
moisture; as a matter prepared for the future fœtus, or a
perfectly-concocted nourishment, such as dew is held to be among the
secondary humours. For it is certain, as shall be afterwards shown, that
the earliest rudiments of the fœtus are cast in its middle, that from
this the chick derives its first nutriment, and even when of larger size
continues to live amidst it.

This solution therefore increases rapidly in quantity, particularly in
its internal region, which, as it expands, forces out and obliterates
the external regions. This change is effected in the course of a single
day, as is shown in the second figure of Fabricius. It is very much as
it is with the eyes of those animals which have a very ample pupil, and
see better by night than by day, such as owls, cats, and others, whose
pupils expand very much in the dusk and dark, and, on the contrary,
contract excessively in a brilliant light: one of these animals being
taken quickly from a light into a shady place, the pupil is seen to
enlarge in such wise that the coloured ring, called the iris, is very
much diminished in size, and indeed almost entirely disappears.

Parisanus, falling upon these regions, is grossly mistaken when he
speaks of “a honey-coloured, a white, a gray, and another white circle;”
and says that “the fœtus is formed from the white middle point” (which,
indeed, appears in these regions), and that “this is the semen of the
cock.” That he may exalt himself on a more notable subtlety he
continues: “Before any redness is apparent in the body of the fœtus, two
minute vesicles present themselves in it; in the beginning, however,
neither of them is tinged with red;” one of these he would have us
receive as the heart, the other as the liver. But in truth there is
neither any vesicle present sooner than the redness of the blood is
disclosed; nor does the embryo ever suddenly become red in the course of
the first days of its existence; nor yet does any of these vesicles
present us with a trace of the liver. Both of them belong, in fact, to
the heart, prefiguring its ventricles and auricles, and palpitating, as
we shall afterwards show, they respond reciprocally by their systoles
and diastoles.

Aristotle[175] appears to have known this dissolved fluid, when he says:
“A membrane, too, marked with sanguineous fibres, surrounds the white
fluid at this time (the third day), arising from those orifices of the
veins.” Now the philosopher can neither be supposed by the words “white
fluid,” to refer to the albumen at large, because at this period the
membrane of the white is not yet covered with veins; it is only the
membrane of the dissolved fluid which appears with a few branches of
veins distributed over it here and there. And because he says: “this
membrane, too,” as if he understood another than those which he had
spoken of as investing the albumen and the yelk before incubation, and
designated this one as first arising after the third day, and from the
orifices of the veins.

Coiter seems also to have known of this dissolved fluid; he says: “A
certain portion of the albumen acquiring a white colour, another
becoming thicker.” The fluid in question is surrounded with its proper
membrane, and is distinct and separate from the rest of the albumen
before there is any appearance of blood. We shall have occasion, by and
by, to speak of the singular importance of this fluid to the fœtuses of
every animal. Whilst they float in it they are safe from succussion and
contusion, and other external injury of every kind; and they moreover
are nourished by it. I once showed to their serene majesties the king
and queen, an embryo, the size of a French-bean, which had been taken
from the uterus of a doe; all its membranes were entire, and from its
genital organs we could readily tell that it was a male. It was, in
truth, a most agreeable natural spectacle; the embryo perfect and
elegant, floating in this pure, transparent, and crystalline fluid,
invested with its pellucid tunica propria, as if in a glass vessel of
the greatest purity, of the size of a pigeon’s egg.


_The third inspection of the egg._

Having seen the second process or preparation of the egg, towards the
production of the embryo which presents itself in the course of the
third day, we proceed to the Third Stage, which falls to be considered
after the lapse of three days and as many nights. Aristotle[176] says:
“Traces of generation commence in the egg of the hen after three days
and three nights [of incubation];” for example, on Monday morning, if in
the morning of the preceding Friday the egg has been put under the hen.
This stage forms the subject of the third figure in Fabricius.

If the inspection of the egg be made on the fourth day, the
metamorphosis is still greater, and the change likewise more wonderful
and manifest with every hour in the course of the day. It is in this
interval that the transition is made in the egg from the life of the
plant to the life of the animal. For now the margin of the diffluent
fluid looks red, and is purpurescent with a sanguineous line, and nearly
in its centre there appears a leaping point, of the colour of blood, so
small that at one moment, when it contracts, it almost entirely escapes
the eye, and again, when it dilates, it shows like the smallest spark of
fire. Such at the outset is animal life, which the plastic force of
nature puts in motion from the most insignificant beginnings!

The above particulars you may perceive towards the close of the third
day, with very great attention, and under favour of a bright light (as
of the sun), or with the assistance of a magnifying glass. Without these
aids you would strain your eyes in vain, so slender is the purple line,
so slight is the motion of the palpitating point. But at the beginning
of the fourth day you may readily, and at its close most readily,
perceive the “palpitating bloody point, which already moves,” says
Aristotle, “like an animal, in the transparent liquid (which I call
colliquamentum); and from this point two vascular branches proceed, full
of blood, in a winding course” into the purpurescent circle and the
investing membrane of the resolved liquid; distributing in their
progress numerous fibrous offshoots, which all proceed from one
original, like the branches and twigs of a tree from the same stem.
Within the entering angle of this root, and in the middle of the
resolved liquid, is placed the red palpitating point, which keeps order
and rhythm in its pulsations, composed of [alternate] systoles and
diastoles. In the diastole, when it has imbibed a larger quantity of
blood, it becomes enlarged, and starts into view; in the systole,
however, subsiding instantaneously as if convulsed by the stroke, and
expelling the blood, it vanishes from view.

Fabricius depicts this palpitating point in his third figure; and
mistakes it--a thing which is extraordinary--for the body of the embryo;
as if he had never seen it leaping or pulsating, or had not understood,
or had entirely forgotten the passage in Aristotle. A still greater
subject of amazement, however, is his total want of solicitude about his
chalazæ all this while, although he had declared the rudiments of the
embryo to be derived from them.

Ulyssus Aldrovandus,[177] writing from Bologna nearly at the same time,
says: “There appears in the albumen, as it were, a minute palpitating
point, which The Philosopher declares to be the heart. And I have
unquestionably seen a venous trunk arising from this, from which two
other branches proceeded; these are the blood-vessels, which he says
extend to either investing membrane of the yelk and white. And I am
myself entirely of his opinion, and believe these to be veins, and
pulsatile, and to contain a purer kind of blood, adapted to the
production of the principal parts of the body, the liver, to wit, the
lungs, and others of the same description.” Both of the vessels in
question, however, are not veins, neither do they both pulsate; but one
of them is an artery, another a vein, as we shall see by and by, when we
shall farther show that these passages constitute the umbilical vessels
of the embryo.

Volcher Coiter has these words: “The sanguineous point or globule, which
was formerly found in the yelk, is now observed more in the albumen, and
pulsates distinctly.” He says, erroneously, “formerly found in the
yelk;” for the point discovered in the vitellus is white, and does not
pulsate; nor does the sanguineous point or globe appear to pulsate at
the end of the second day of incubation. But the point which we have
indicated in the middle of the circle, and as constituting its centre in
connexion with the vitellus, disappears before that point which is
characterized by Aristotle as palpitating, can be discerned; or, as I
conceive, having turned red, begins to pulsate. For both points are
situated in the centre of the resolved fluid, and near the root of the
veins which thence arise; but they are never seen simultaneously: in the
place of the white point there appears a red and palpitating point.

That portion of Coiter’s sentence, however, where he says: “the punctus
saliens is now seen in the albumen rather than in the yelk,” is
perfectly accurate. And, indeed, moved by these words, I have inquired
whether the white point in question is turned into the blood-red point,
inasmuch as both are nearly of the same size, and both make their
appearance in the same situation. And I have, indeed, occasionally found
an extremely delicate bright purple circle ending near the ruddy horizon
surrounding the resolved liquid, in the centre of which there was the
white point, but not the red and pulsating point apparent; for I have
never observed these two points at one and the same time. It were
certainly of great moment to determine: Whether or not the blood was
extant before the pulse? and whether the pulsating point arose from the
veins, or the veins from the pulsating point?

So far as my observations enable me to conclude, the blood has seemed to
go before the pulse. This conclusion is supported by the following
instance: on Wednesday evening I set three hen’s eggs, and on Saturday
evening, somewhat before the same hour, I found these eggs cold, as if
forsaken by the hen: having opened one of them, notwithstanding, I found
the rudiments of an embryo, viz., a red and sanguinolent line in the
circumference; and in the centre, instead of a pulsating point, a white
and bloodless point. By this indication I saw that the hen had left her
nest no long time before; wherefore, catching her, and shutting her up
in a box, I kept her upon the two remaining eggs, and several others,
through the ensuing night. Next morning, very early, both of the eggs
with which the experiment was begun, had revived, and in the centre
there was the pulsating point, much smaller than the white point, from
which, like a spark darting from a cloud, it made its appearance in the
diastole; it seemed to me, therefore, that the red point emanated from
the white point; that the punctum saliens was in some way engendered in
that white point; that the punctum saliens, the blood being already
extant, was either originally there produced, or there began to move. I
have, indeed, repeatedly seen the punctum saliens when all but dead,
and no longer giving any signs of motion, recover its pulsatile
movements under the influence of renewed warmth. In the order of
generation, then, I conceive that the punctum and the blood first exist,
and that pulsation only occurs subsequently.

This at all events is certain, that nothing whatever of the future fœtus
is apparent on this day, save and except certain sanguineous lines, the
punctum saliens, and those veins that all present themselves as
emanating from a single trunk, (as this itself proceeds from the punctum
saliens,) and are distributed in numerous branches over the whole of the
colliquament or dissolved fluid. These vessels afterwards constitute the
umbilical vessels, by means of which, distributed far and wide, the
fœtus as it grows obtains its nourishment from the albumen and vitellus.
You have a striking example of similar vessels and their branchings in
the leaves of trees, the whole of the veins of which arise from the
peduncle or foot-stalk, and from a single trunk are distributed to the
rest of the leaf.

The entire including membrane of the colliquament traversed by
blood-vessels, corresponds in form and dimensions with the two wings of
a moth; and this, in fact, is the membrane which Aristotle[178]
describes as “possessing sanguineous fibres, and at the same time
containing a limpid fluid, proceeding from those mouths of the veins.”

Towards the end of the fourth day, and the beginning of the fifth, the
blood-red point, increased into a small and most delicate vesicle, is
perceived to contain blood in its interior, which it propels by its
contractions, and receives anew during its diastoles.

Up to this point I have not been able to perceive any difference in the
vessels: the arteries are not distinguished from the veins, either by
their coats or their pulsations. I am therefore of opinion, that all the
vessels may be spoken of indifferently under the name of veins, or,
adopting Aristotle’s[179] term, of venous canals.

“The punctum saliens,” says Aristotle, “is already possessed of
spontaneous motion, like an animal.” Because an animal is distinguished
from that which is none, by the possession of sense and motion. When
this point begins to move for the first time, consequently, we say well
that it has assumed an animal nature; the egg, originally imbued with a
vegetative soul, now becomes endowed in addition with a motive and
sensitive force; from the vegetable it passes into the animal; and at
the same time the living principle, which fashions the chick from the
egg, and afterwards gives it the measure of intelligence it manifests,
enters into the embryo. For, from the actions or manifestations, The
Philosopher[180] concludes demonstratively, that the faculties or powers
of acting are inherent, and through these the cause and principle of
life, the soul, to wit, and the actions, inasmuch as manifestation is

I am myself farther satisfied from numerous experiments, that not only
is motion inherent in the punctum saliens, which indeed no one denies,
but sensation also. For on any the slightest touch, you may see the
point variously commoved, and, as it were, irritated; just as sensitive
bodies generally give indications of their proper sensations by their
motions; and, the injury being repeated, the punctum becomes excited and
disturbed in the rhythm and order of its pulsations. Thus do we conclude
that in the sensitive-plant, and in zoophytes, there is inherent
sensibility, because when touched they contract, as if they felt

I have seen, I repeat, very frequently, and those who have been with me
have seen this punctum, when touched with a needle, a probe, or a
finger, and even when exposed to a higher temperature, or a severer
cold, or subjected to any other molesting circumstance or thing, give
various indications of sensibility, in the variety, force, and frequency
of its pulsations. It is not to be questioned, therefore, that this
punctum lives, moves, and feels like an animal.

An egg, moreover, too long exposed to the colder air, the punctum
saliens beats more slowly and languidly; but the finger, or some other
warmth being applied, it forthwith recovers its powers. And farther,
after the punctum has gradually languished, and, replete with blood, has
even ceased from all kind of motion, or other indication of life, still,
on applying my warm finger, in no longer a time than is measured by
twenty beats of my pulse, lo! the little heart is revivified, erects
itself anew, and, returning from Hades as it were, is restored to its
former pulsations. The same thing happens through heat applied in any
other way--that of the fire, or of hot water--as has been proved by
myself and others again and again; so that it seemed as if it lay in our
power to deliver the poor heart over to death, or to recall it to life
at our will and pleasure.

What has now been stated, for the most part comes to pass on the fourth
day from the commencement of the incubation--I say, for the most
part,--because it is not invariably so, inasmuch as there is great
diversity in the maturity of eggs, and some are more speedily perfected
than others. As in trees laden with fruit, some, more forward and
precocious, falls from the branches, and some, more crude and immature,
still hangs firmly on the bough; so are some eggs less forward on the
fifth day than others in the course of the third. This, that I might
give it forth as a thing attested and certain, I have repeatedly
ascertained in numerous eggs, incubated for the same length of time, and
opened on the same day. Nor can I ascribe it to any difference of sex,
or inclemency of weather, or neglect of incubation, or to any other
cause but an inherent weakness of the egg itself, or some deficiency of
the native heat.

Hypenemic or unfruitful eggs, begin to change at this time, as the
critical day when they must show their disposition. As fertile eggs are
changed by the inherent plastic force into colliquament (which
afterwards passes into blood), so do wind-eggs now begin to change and
to putrefy. I have, nevertheless, occasionally observed the spot or
cicatricula to expand considerably even in hypenemic eggs, but never to
rise into a cumulus, nor to become circumscribed by regularly disposed
concentric circles. Sometimes I have even observed the vitellus to get
somewhat clearer, and to become liquefied; but this was unequally; there
were flocks, as if formed by sudden coagulation, swimming dispersed
through it like clouds. And although such eggs could not yet be called
putrid, nor were they offensive, still were they disposed to
putrefaction; and, if continued under the hen, they soon arrived at this
state, the rottenness commencing at the very spot where in fruitful eggs
the reproductive germ appears.

The more perfect or forward eggs then, about the end of the fourth day,
contain a double or bipartite pulsating vesicle, each portion
reciprocating the other’s motion, in such order and manner that whilst
one is contracting, the other is distended with blood and ruddy in
colour; but this last contracting anon forces out its charge of blood,
and, an instant being interposed, the former rises again and repeats its
pulse. And it is easy to perceive that the action of these vesicles is
contraction, by which the blood is moved and propelled into the vessels.

“On the fourth day,” says Aldrovandus,[181] “two puncta are perceived,
both of which are in motion; these, undoubtedly, are the heart and the
liver, viscera which Aristotle allowed to eggs incubated for three

The Philosopher,[182] however, nowhere says anything of the kind;
neither, for the most part, are the viscera mentioned conspicuous before
the tenth day. And I am indeed surprised that Aldrovandus should have
taken one of these pulsating points for the liver, as if this viscus
were ever moved in any such manner! It seems much better to believe that
with the growth of the embryo one of the pulsating points is changed
into the auricles, the other into the ventricles of the heart. For in
the adult, the ventricles are filled in the same manner by the auricles,
and by their contraction they are straightway emptied again, as we have
shown in our treatise on the Motion of the Heart and Blood.

In more forward eggs, towards the end of the fourth day, I have
occasionally found I know not what cause of obscurity intervening and
preventing me from seeing these pulsating vesicles with the same
distinctness as before; it was as if there had been a haze interposed
between them and the eye. In a clearer light, nevertheless, and with the
use of magnifying glasses, the observations of one day being further
collated with those of the next succeeding day, it was discovered that
the indistinctness was caused by the rudiments of the body,--a nebula
concocted from part of the colliquament, or an effluvium concreting
around the commencements of the veins.

Aldrovandus appears to have observed this: “On the fifth day,” says he,
“the punctum, which we have stated to be the heart, is no longer seen
to move externally, but to be covered over and concealed; still its two
meatus venosi are perceived more distinctly than before, one of them
being, further, larger than the other.” But our learned author was
mistaken here; for this familiar divinity, the heart, enters into his
mansion and shuts himself up in its inmost recesses a long time
afterwards, and when the house is almost completely built. Aldrovandus
also errs when he says, “by the vis insita of the veins, the remaining
portion of the albumen acquires a straw colour,” for this colour is
observed in the thicker albumen of every spoilt egg, and it goes on
increasing in depth from day to day as the egg grows staler, and this
without any influence of the veins, the thinner portion only being

But the embryo enlarging, as we say below, and the ramifications of the
meatus venosi extending far and wide to the albumen and vitellus,
portions of both of these fluids become liquefied, not indeed in the way
Aldrovandus will have it, from some vis insita in the vessels, but from
the heat of the blood which they contain. For into whatsoever part of
either fluid the vessels in question extend, straightway liquefaction
appears in their vicinity; and it is on this account that the yelk about
this epoch appears double: its superior portion, which is in
juxtaposition with the blunt end of the egg, has already become more
diffluent than the rest, and appears like melted yellow wax in contrast
with the other colder firmer portion; like bodies in general in a state
of fusion, it also occupies a larger space. Now this superior portion,
liquefied by the genial heat, is separated from the other liquids of the
egg, but particularly the albumen, by a tunica propria of extreme
tenuity. It therefore happens that if this most delicate, fragile, and
invisible membrane be torn, immediately there ensues an admixture and
confusion of the albumen and vitellus, by which everything is obscured.
And such an accident is a frequent cause of failure in the reproductive
power, (for the different fluids in question are possessed of opposite
natures,) according to Aristotle,[183] in the place already so
frequently referred to: “Eggs are spoiled and become addled in warm
weather especially, and with good reason; for as wine grows sour in hot
weather, the lees becoming diffused through it, (which is the cause of
its spoiling,) so do eggs perish when the yelk spoils, for the lees and
the yelk are the more earthy portion in each. Wherefore wine is
destroyed by an admixture with its dregs, and an egg by the diffusion of
its yelk.”[184] And here, too, we may not improperly refer to that
passage[185] where he says: “When it thunders, the eggs that are under
incubation are spoiled;” for it must be a likely matter that a membrane
so delicate should give way amidst a conflict of the elements. And
perhaps it is because thunder is frequent about the dog days that eggs
which are rotten have been called _cynosura_; so that Columella rightly
informs us that “the summer solstice, in the opinion of many, is not a
good season for breeding chickens.”

This at all events is certain, that eggs are very readily shaken and
injured when the fowls are disturbed during incubation, at which time
the fluids are liquefied and expanded, and their containing membranes
are distended and extremely tender.


_The fourth inspection of the egg._

“In the course of the fifth day of incubation,” says Aristotle,[186]
“the body of the chick is first distinguished, of very small dimensions
indeed, and white; but the head conspicuous and the eyes extremely
prominent, a state in which they afterwards continue long; for they only
grow smaller and shrink at a later period. In the lower portion of the
body there is no rudimentary member corresponding with what is seen in
the upper part. But of the channels which proceed from the heart, one
now tends to the investing membrane, the other to the yelk; together
they supply the office of an umbilical cord. The chick, therefore,
derives its origin from the albumen, but it is afterwards nourished by
the yelk, through the umbilicus.”

These words of Aristotle appear to subdivide the entire generation of
the chick into three stages or periods, viz.: from the first day of the
incubation to the fifth; from thence on to the tenth or fourteenth: and
from this or that to the twentieth. It seems as if he had only given an
account in his history of the circumstances he observed at these three
epochs; and it is then indeed that the greatest changes take place in
the egg; as if these three critical seasons, or these three degrees in
the process which leads from the perfect egg to the evolution of the
chicken, were especially to be distinguished. On the fourth day the
first particle of the embryo appears, viz.: the punctum saliens and the
blood; and then the new being is incorporated. On the seventh day the
chick is distinguished by its extremities, and begins to move. On the
tenth it is feathered. About the twentieth it breathes, chirps, and
endeavours to escape. The life of the egg, up to the fourth day, seems
identical with that of plants, and can only be accounted as of a
vegetative nature. From this onwards to the tenth day, however, like an
animal, it is possessed by a sensitive and motive principle, with which
it continues to increase, and is afterwards gradually perfected,
becoming covered with feathers, furnished with a beak, nails, and all
else that is necessary to its escape from the shell; emancipated from
which, it enters at length on its own independent existence.

Of the incidents that happen after the fourth day, Aristotle enumerates
three particularly, viz.: the construction of the body; the distribution
of the veins, which have already the office and nature of the umbilicus;
and the matter whence the embryo first arises, and is constituted and

In reference to the structure of the body, he speaks of its size and
colour, of the parts which are most conspicuous in it, (the head and
eyes,) and of the distinction of its extremities.

The body is indeed extremely minute, and of the form of the common
maggot that gives birth to the fly; it is of a white colour, too, like
the maggot of the flesh-fly which we see cherished and nourished in
putrid meat. He happily adds, “it is most remarkable for its head and
eyes.” For what first appears is homogeneous and indistinct, a kind of
concretion or coagulation of the colliquament, like the jelly prepared
from hartshorn; it is a mere transparent cloud, and scarcely
recognizable, save as it appears, divided, seemingly, into two parts,
one of which is globular and much larger than the other; this is the
rudiment of the head, which first becomes visible on the fifth day, very
soon after which the eyes are distinguishable, being from the first of
large size and prominent, and marked off from the rest of the head and
body by a certain circumfusion of black matter. Either of the eyes is
larger than the whole of the rest of the head, in the same way as the
head surpasses the remainder of the body in dimensions. The whiteness of
the body, and prominence of the eyes, (which, as well as the brain, are
filled internally with perfectly pellucid water, but externally are of a
dark colour), continue for some time--up to the tenth day, and even
longer; for, as we have seen, Aristotle says that “the eyes decrease at
a late period, and contract to the proper proportion.” But for my own
part, I do not think that the eyes of birds ever contract in the same
ratio which we observe between the head and eyes of a viviparous animal.
For if you strip off the integuments from the head and eyes of a fowl or
another bird, you will perceive one of the eyes to equal the entire
brain in dimensions; in the woodcock and others, one of the eyes indeed
is as large as the whole head, if you make abstraction of the bill. But
this is common to all birds that the orbit or cavity which surrounds the
eye is larger than the brain, a fact that is apparent in the cranium of
every bird. Their eyes, however, are made to look smaller, because every
part, except the pupil, is covered with skin and feathers; neither are
they possessed of such a globular form as would cause them to project;
they are of a flatter configuration, as in fishes.

“In the lower part of the body,” says the philosopher, “we perceive the
rudiments of no member corresponding with the superior members.” And the
thing is so in fact; for as the body at first appears to consist of
little but head and eyes, so inferiorly there is neither any
extremity,--wings, legs, sternum, rump,--nor any viscus apparent; the
body indeed is still without any kind of proper form; in so far as I am
able to perceive, it consists of a small mass adjacent to the vein, like
the bent keel of a boat, like a maggot or an ant, without a vestige of
ribs, wings, or feet, to which a globular and much more conspicuous mass
is appended, the rudiment of the head, to wit, divided, as it seems,
into three vesicles when regarded from either side, but in fact
consisting of four cells, two of which, of great size and a black
colour, are the rudiments of the eyes; of the remaining two one being
the brain, the other the cerebellum. All of these are full of perfectly
limpid water. In the middle of the blackness of the eye, the pupil is
perceived shining like a transparent central spark or crystal. I imagine
that three of these vesicles being particularly conspicuous, has been
the cause of indifferent observers falling into error. For as they had
learned from the schoolmen that there was a triple dominion in the
animal body, and they believed that these principal parts, the brain,
the heart, and the liver, performed the highest functions in the
economy, they easily persuaded themselves that these three vesicles were
the rudiments and commencements of these parts. Coiter, however, as
becomes an experienced anatomist, affirms more truly that whilst he had
observed the beak and eyes from the seventh day of incubation, he could
yet discover nothing of the viscera.

But let us hear the philosopher further: “Of the conduits which lead
from the heart, one tends to the investing membrane, another to the
yelk, in order to perform the office of umbilicus.” The embryo having
now taken shape, these veins do indeed perform the function of the
umbilical cord, the ramifications of one of them proceeding to be
distributed to the outer tunic which invests the albumen, those of the
other running for distribution to the vitellary membrane and its
included fluid. Whence it clearly appears that both of these fluids are
alike intended for the nourishment of the embryo. And although Aristotle
says that “the chick has its commencement in the albumen, and is
nourished through the umbilicus by the yelk,” he still does not say that
the chick is formed from the albumen. The embryo, in fact, is formed
from that clear liquid which we have spoken of under the name of the
colliquament, and the whole of what we have called the eye of the egg is
contained or included within the albumen. Neither does our author say
that the whole and sole nutriment of the embryo reaches it through the
umbilicus. My own observations lead me to interpret his words in this
way: although the embryo of the fowl begins to be formed in the albumen,
nevertheless it is not nourished solely by that, but also by the yelk,
to which one of the two umbilical conduits pertains, and from whence it
derives nourishment in a more especial manner; for the albumen,
according to Aristotle’s opinion, is the more concoct and purer liquid,
the yelk the more earthy and solid one, and, therefore, more apt to
sustain the chick when it has once attained to greater consistency and
strength; and further because, as shall be explained below, the yelk
supplies the place of milk, and is the last part that is consumed, a
residuary portion, even after the chick is born, and when it is
following its mother, being still contained in its abdomen.

What has now been stated takes place from the fourth to the tenth day. I
have yet to speak of the order and manner in which each of the
particulars indicated transpires.

In the inspection made on the fifth day, we observed around the short
vein which proceeds from the angle where the two alternately pulsating
points are situated, something whiter and thicker, like a cloud,
although still transparent, through which the vein just mentioned is
seen obscurely, and as it were through a haze. The same thing I have
occasionally seen in the more forward eggs in the course of the fourth
day. Now this is the rudiment of the body, and from hour to hour it goes
on increasing in compactness and solidity; both surrounding the
afore-named vein, and being appended to it in the guise of a kind of
globule. This globular rudiment far exceeds the coronal portion, as I
shall call it, of the vermicular body; it is triangular in figure, being
obscurely divided into three parts, like so many swelling buds of a
tree. One of these is orbicular and larger than either of the other two;
and it is darkened by most delicate filaments proceeding from the
circumference to the centre; this appears to be the commencement of the
ciliary body, and therefore proclaims that this is the part which is to
undergo transformation into the eye. In its middle the minute pupil,
shining like a bright point, as already stated, is conspicuous; and it
was from this indication especially that I ventured to conjecture that
the whole of the globular mass was the rudiment of the future head, and
this black circle one of the eyes, having the other over against it; for
the two are so situated that they can by no means be seen at once and
together, one always lying over and concealing the other.

The first rudiment of the future body, which we have stated to sprout
around the vein, acquires an oblong and somewhat bent figure, like the
keel of a boat. It is of a mucaginous consistence, like the white mould
that grows upon damp things excluded from the air. The vein to which
this mucor attaches, as I have said, is the vena cava, descending along
the spinal column, as my subsequent observations have satisfied me. And
if you carefully note the order of contraction in the pulsating
vesicles, you may see the one which contracts last impelling its blood
into the root of this vein and distending it.

Thus there are two manifest contractions and two similar dilatations in
the two vesicles which are seen moving and pulsating alternately; and
the contraction of the one which precedes causes the distension or
dilatation of the other; for the blood escapes from the cavity of the
former vesicle, when it contracts, into that of the latter, which it
fills, distends, and causes to pulsate; but this second vesicle,
contracting in its turn, throws the blood, which it had received from
the former vesicle, into the root of the vein aforesaid, and at the same
time distends it.--I go on speaking of this vessel as a vein, though
from its pulsation I hold it to be the aorta, because the veins are not
yet distinguished from the arteries by any difference in the thickness
of their respective coats.

After having contemplated these points with great care, and in many
eggs, I remained for some time in suspense as to the opinion I should
adopt; whether I should conclude that the concrete appended globular
mass proceeded from the colliquament in which it swam, becoming a
compacted and coagulated matter in the way that clouds are formed from
invisible vapour condensed in the upper regions of the air; or believe
that it took its rise from a certain effluvium exhaled from the
sanguineous conduit mentioned, originating by diapedesis or
transudation, and by deriving nourishment from thence, was enabled to
increase? For the beginnings of even the greatest things are often
extremely small, and, by reason of this minuteness, sufficiently

This much I think I have sufficiently determined at all events, viz.
that the puncta salientia and meatus venosi, and the vena cava itself,
are the parts that first exist; and that the globular mass mentioned
afterwards grows to them. I am further certain that the blood is thrown
from the punctum saliens into the vein, and that from this does the
corpuscle in question grow, and by this is it nourished. The fungus or
mucor first originates from an effluvium of the vein on which it
appears, and it is thence nourished and made to increase; in the same
way as mouldiness grows in moist places, in the dark corners of houses
which long escape cleansing; or, like camphor upon cedar wood tables,
and moss upon rocks and the bark of trees; lastly, as a kind of delicate
down grows upon certain grubs.

Upon the same occasion I also debated with myself whether or not I
should conclude, that with the coagulation of the colliquament
accomplished, the rudiments of the head and body existed simultaneously
with the punctum saliens and the blood, but in a pellucid state, and so
delicate that they almost escaped the eye, until becoming inspissated
into a fungus or mucor, they acquired a more opaque white colour, and
then came into view; the blood meantime from its greater spissitude and
purple colour being readily perceptible in the diaphanous colliquament.
But now when I look at the thing more narrowly, I am of opinion that the
blood exists before any particle of the body appears; that it is the
first-born of all the parts of the embryo; that from it both the matter
out of which the fœtus is embodied, and the nutriment by which it grows
are derived; that it is in fine, if such thing there be, the primary
generative particle. But wherefore I am led to adopt this idea shall
afterwards be shown more at length when I come to treat of the primary
genital part, of the innate heat, and the radical moisture; and, at the
same time, conclude as to what we are to think of the vital principle
(anima), from a great number of observations compared with one another.

About this period almost every hour makes a difference; every thing
grows larger, more definite and distinct; the rate of change in the egg
is rapid, and one change succeeds immediately upon the back of another.
The cavity in the egg is now much larger, and the whole of its upper
portion is empty; it is as if a fifth part of the egg had been removed.

The ramifications of the veins extend more widely, and are more
numerous, not only in the colliquament as before, but they spread on one
hand into the albumen, and on the other into the yelk, so that both of
these fluids are everywhere covered over with blood-vessels. The upper
portion of the yelk has now become much dissolved, so that it very
obviously differs from the lower portion; there are now, as it were, two
yelks, or two kinds of yelk; whilst the superior, like melted wax, is
expanded and looks pellucid, the inferior has become more dense, and
with the thicker portion of the albumen has subsided to the sharp end of
the egg. The tunica propria of the upper portion of the yelk is so thin
that it gives way on the slightest succussion, when there ensues
admixture of the fluids, and, as we have said, interruption to the
further progress of the process of generation.

And now it is that the rudiments of the embryo first become conspicuous,
as may be seen in the fifth and sixth figure of Fabricius; the egg being
put into fair water it will be easy to perceive what parts of the body
are formed, what are still wanting. The embryo now presents itself in
the form of a small worm or maggot, such as we encounter on the leaves
of trees, in spots of their bark, in fruit, flowers, and elsewhere; but
especially in the apples of the oak, in the centre of which, surrounded
with a case, a limpid fluid is contained, which, gradually inspissated
and congealed, acquires a most delicate outline, and finally assumes the
form of a maggot; for some time, however, it remains motionless; but by
and by, endowed with motion and sensation it becomes an animal, and
subsequently it breaks forth and takes its flight as a fly.

Aristotle ascribes a similar mode of production to those creatures that
are spontaneously engendered.[187] “Some are engendered of the dew,” he
says, “which falls upon the leaves.” And by and by he adds, “butterflies
are engendered from caterpillars, but these, in their turn, spring from
green leaves, particularly that species of raphanus which is called
cabbage. They are smaller than millet seeds at first, and then they grow
into little worms; next, in the course of three days into caterpillars;
after which they cease from motion, change their shape, and pass into
chrysalides, when they are inclosed in a hard shell; although, if
touched, they will still move. The shell after a long time cracks and
gives way, and the winged animal, which we call a butterfly, emerges.”

But our doctrine--and we shall prove it by and by--is, that all animal
generation is effected in the same way; that all animals, even the most
perfect, are produced from worms; a fact which Aristotle himself seems
to have noted when he says: “In all, nevertheless, even those that lay
perfect eggs, the first conception grows whilst it is yet invisible; and
this, too, is the nature of the worm.”[188] For there is this difference
between the generation of worms and of other animals, that the former
acquire dimensions before they have any definite form or are
distinguished into parts, in conformity with what the philosopher[189]
says in the following sentence: “An animal is fashioned from an entire
worm, not from any one particular part, as in the case of an egg, but
the whole increases and becomes an articulated animal,” i. e. in its
growth it separates into parts.

It is indeed matter worthy of admiration, that the rudiments of all
animals, particularly those possessed of red blood, such as the dog,
horse, deer, ox, common fowl, snake, and even man himself, should so
signally resemble a maggot in figure and consistence, that with the eye
you can perceive no difference between them.

Towards the end of the fifth day or the beginning of the sixth, the head
is divided into three vesicles: the first of these, which is also the
largest, is rounded and black; this is the eye, in the centre of which
the pupil can be distinguished like a crystalline point. Under this
there lies a smaller vesicle, concealed in part, which represents the
brain; and over this lies the third vesicle, like an added crest or
rounded summit crowning the whole, from which the cerebellum is at
length produced. In the whole of these there is nothing to be discovered
but a little perfectly limpid water.

And now the rudiment of the body, which we have called the carina,
distinctly proclaims itself to be the spinal column, to which sides soon
begin to be added, and the wings and the lower extremities present
themselves, projecting slightly from the body of the maggot. The venous
conduits are, further, now clearly referrible to the umbilical vessels.


_The fifth inspection of the egg._

On the sixth day the three cells of the head present themselves more
distinctly, and the coats of the eyes are now apparent; the legs and the
wings also bud forth, much in the way in which, towards the end of June,
we see tadpoles getting their extremities, when they quit the water, and
losing their tails assume the form of frogs.

In the chick, the rump has still no other form than is conspicuous in
animals at large, even in serpents; it is a round and slender tail. The
substance of the heart now grows upon the pulsating vesicle; and shortly
afterwards the rudiments of the liver and lungs are distinguished; the
bill, too, makes its appearance at the same time. Everything is of a
pure white colour, especially the bill. About the same epoch all the
viscera and the intestines are conspicuous. But the heart takes
precedence of all the parts; and the lungs are visible before the liver
or brain. The eyes, however, are seen first of all, by reason of their
large size and black colour.

And now, too, the embryo has a power of motion, and raises its head and
slightly twists itself, although there is still nothing of the brain to
be seen, but only a little limpid fluid inclosed in a vesicle. It is at
length a perfect maggot, only differing from a caterpillar in this, that
when worms are set free from their cells they creep about hither and
thither and seek their food, whilst the worm in the egg is stationary,
and, surrounded with its proper food, is furnished with aliment through
the umbilicus.

The viscera and intestines being now formed, and the fœtus able to
execute motions, the anterior portion of the body, without either thorax
or abdomen, is perceived to be completely open; so that the heart
itself, the liver and the intestines, are seen to hang pendulous

Towards the end of this day and the beginning of the seventh, the toes
are distinguished, and the embryo already presents the outlines of the
chick, and opens its beak, and kicks with its feet; in short, all the
parts are sketched out, but the eyes, above all, are conspicuous. The
viscera, on the contrary, are so indistinct, that Coiter affirms, that
whilst he plainly saw the eyes and beak he could discover no viscus,
even obscurely and confusedly shadowed forth.

The changes that take place from the beginning of the sixth to the end
of the seventh day, occur for the major part in some eggs more quickly,
in others a little more tardily. The coats of the eyes are now visible,
but they only include a colourless and limpid fluid in their interior.
The eyes themselves project somewhat beyond their orbits, and each of
them does not less exceed the brain in size, than the head with which
they are connected exceeds the whole of the rest of the body.

The vesicle, which like a ridge or crest expands beyond the confines of
the brain, occupies the place of the cerebellum; and, like the other
vesicles, is filled with a transparent fluid.

The brain is perceived to be obscurely bipartite, and refracts the light
less than the cerebellum, though it is of a whiter colour. And as the
heart is seen lying without the confines of the thorax, so likewise does
the cerebellum protrude beyond the limits of the head.

If the head be removed, the vessels ascending to the brain may be
observed as bloody points, with the use of a magnifying glass. And now,
too, the rudiments of the spine begin to be first perceived distinct
from the rest of the pulp, of a milky colour, but firmer consistence. So
in the same way, and like flimsy threads of a spider’s web, the ribs and
other bones make their appearance in the guise of milky lines, amidst
the pulp of the body; and the same thing appears more clearly in the
formation of the larger oviparous animals. The heart, lungs, liver, and
by way of intestines certain most delicate filaments, all present
themselves of a white colour. The parenchyma of the liver is developed
upon delicate fibrous stamens over the umbilical vein at the part where
it enters, almost in the same manner as we have said that the rudiments
of the body grow to the vein descending from the heart, or the vesicula
pulsans. For in the same way as grapes grow upon the stalk of the bunch,
buds upon twigs, and the ear upon the straw, does the liver adhere to
the umbilical vein, and arise from it, even as fungi do from trees and
excessive granulations from ulcers, or as sarcoses or morbid growths
spring around the minute branches of conterminous arteries by which they
are nourished, and occasionally attain to an excessive size.

Looking back upon this office of the arteries, or the circulation of the
blood, I have occasionally and against all expectation completely cured
enormous sarcoceles, by the simple means of dividing or tying the little
artery that supplied them, and so preventing all access of nourishment
or spirit to the part affected; by which it came to pass that the
tumour, on the verge of mortification, was afterwards easily extirpated
with the knife, or the searing iron. One man in particular (and this
case I can confirm by the testimony of many respectable persons) had an
enormous hernia carnosa, or sarcocosis of the scrotum, larger than a
human head, and hanging as low as the knee; from its upper part a fleshy
mass, of the thickness of the wrist, or such a rope as is used on
ship-board, extended into the abdomen; and the evil had attained to such
a height, that no one durst attempt the cure, either with the knife or
any other means. Nevertheless, by the procedure above indicated, I
succeeded in completely removing this huge excrescence which distended
the scrotum, and involved the testicle in its middle; this latter organ,
with its vas præparans and vas deferens, and other parts which descend
in the tunica vaginalis, being left all the while safe and uninjured.
But this cure, as well as various others, accomplished in opposition to
vulgar opinion and by unusual procedures, I shall relate at greater
length in my Medical Observations, if God grant me longer life.

I mention such cases with a view of more clearly showing that the liver
grows upon the vessels, and is only developed some time after the
appearance of the blood; that its parenchyma is derived from the
arteries whence the matter is effused, and that for a while it remains
white and bloodless, like various other parts of the body. Now in the
same manner and order precisely as the chick is developed from the egg,
is the generation of man and other animals accomplished.

Whence it appears that the doctrine which makes the liver the author and
fashioner of the blood, is altogether groundless, although both formerly
and at the present time this view obtained universal assent; this was
the reason wherefore the liver was reckoned as among the principal and
first-formed organs of the body. This viscus indeed was so highly
dignified that it was thought to be produced in the very beginning, and
simultaneously with the heart, from the seminal fluid of the mother; and
the medical fable of the three vesicles or three kids, as they were
called, was eagerly defended. Among the number of modern abettors of
such views, Parisanus has of late with confidence enough, but little
skill, been singing to the old measure. These good people do not
consider that the vesicles are in motion in the egg, that the heart is
palpitating and the blood present and perfectly concocted, before any
sign or vestige of the liver appears. The blood is much rather to be
accounted the efficient cause of the liver, than this the author of the
blood: for the liver is engendered after the blood, and from it, being
adnate to the vessels that contain it.

But neither can I agree with the Aristotelians, who maintain that the
heart is the author of the blood; for its parenchyma or proper substance
arises some little time after the blood, and is superadded to the
pulsating vesicles. I am, however, in much doubt as to whether the
pulsating vesicle or point, or the blood itself be the older; whether it
be the fluid contained, or the containing sacs. It is obvious,
nevertheless, that that which contains is formed for the sake of that
which is contained, and is, therefore, made later. And this much, upon
the faithful testimony of our eyes, is certain, that the first particle
and prime basis of the body are the veins, to which all the other parts
are posthumous and superadded. But upon this point we shall say more by
and by.

Meantime we may be permitted to smile at that factitious division of the
parts into spermatic and sanguineous; as if any part were produced
immediately from the seminal fluid, and all did not spring from the same

I return to our subject. The colliquament now extends over more than
half the egg. The heart, hanging outwards, is at some short distance
from the body. And if you look attentively you may perceive some of the
umbilical vessels pulsating.


_The sixth inspection._

Everything is still more distinct upon the seventh day, and the
rudiments of several of the particular parts are now conspicuous, viz.,
the wings, legs, genital organs, divisions for the toes, thighs, ilia,
&c. The embryo now moves and kicks, and the form of the perfect chick is
recognizable; from this time forward, indeed, nothing is superadded; the
very delicate parts only increase in size. The more the parts grow the
more is the albumen consumed, and the external membranes united come to
be of the nature of the secundines, and ever more and more closely
represent the umbilical cord. Wherefore I conceive that, from the
seventh, we may at once pass on to the tenth day, nothing of any moment
occurring in this interval which is not particularly noted by other
writers, especially by Aristotle.

It happens, nevertheless, that when a number of eggs are examined
together, some are found more precocious and forward, having everything
more distinct; others, again, are more sluggish, and these have the
parts less apparent. The season of the year, the place where the
incubation is carried on, the sedulousness with which it is performed,
and other accidents, have undoubtedly great influence on this diversity
of result. I remember on one occasion, on the seventh day to have seen
the cavity in the blunt end enlarged in a sluggish egg, the colliquament
covered with veins, the vermicular embryo in its middle, the rudiments
of the eyes, and all the rest as it is met with in the generality of
eggs on the fifth day; but the pulsatory vesicles were not yet apparent,
nor was the trunk or root of the veins from which we have said that they
originate, yet to be discovered. I therefore regarded this egg as of a
feeble nature and left behind, as possessed of an inadequate
reproductive faculty, and near to its death; all the more when I
observed its colliquament less pellucid and refractive than usual, and
the vessels not of such a bright red colour as wont. When the vital
spirit is about to escape, that part which is first influenced in
generation and earliest attracts attention is also the first that fails
and disappears.


_The inspection after the tenth day._

All that presents itself on the tenth day is so accurately described by
Aristotle that scarcely anything remains for us to add. Now his opinion,
according to my interpretation of it, is this, viz., that “on the tenth
day the entire chick is conspicuous,”[190] being pellucid and white in
every part except the eyes and the venous ramifications. “The head at
this time is larger than the whole of the rest of the body; and eyes
larger than the head are connected with it,” (adhering, and being in
some sort appended to the head,) “but having as yet no pupils,”
(perfectly formed pupils must here be understood, for it is not
difficult to make out the distinct tunics of the eye at this epoch;)
“the eyes, if removed at this time, will be found as large as beans and
black, and if they be incised, a clear humour flows out, cold, and
refracting the light powerfully, but nothing else,” i. e., in the whole
head there is nothing but the limpid water which has been mentioned.
Such is the state of matters from the seventh to the tenth day, as we
have said above. “At the same time,” he continues, “the viscera also
appear, and all that appertains to the abdomen and intestines,” viz.,
the substance of the heart, the lungs, liver, &c., all of a white
colour, mucilaginous, pulpy, without any kind of consistency. “The
veins, too, that issue from the heart are already in connexion with the
umbilicus, from which one vein extends to the membrane that includes the
vitellus, which has now become more liquid and diffluent than it was
originally; another to the membrane which surrounds everything,” (i. e.,
the tunica colliquamenti,) “and embraces the fœtus, the vitellus and the
interjacent fluid. For the embryo increasing somewhat, one portion of
the vitellus is superior, another inferior; but the albumen in the
middle is liquid, and still extends under the inferior portion of the
vitellus, as it did previously.” Thus far Aristotle.

And now the arteries are seen distinctly accompanying the veins, both
those that proceed to the albumen and those that are distributed to the
vitellus. The vitellus also at this time liquefies still more and
becomes more diffluent, not entirely, indeed, but, as already said, that
portion of it which is uppermost; neither do the branches of the veins
proceed to every part of the vitellus alike, but only to that part which
we have spoken of as resembling melted wax. The veins that are
distributed to the albumen have, in like manner, arteries accompanying
them. The larger portion of the albumen now dissolves into a clear
fluid, the colliquament, which surrounds the embryo that swims in its
middle, and comes between the two portions of the vitellus, viz., the
superior and the inferior; underneath all (in the sharp end of the egg),
the thicker and more viscid portion of the albumen is contained. The
superior portion of the yelk already appears more liquid and diffluent
than the inferior; and wherever the branches of the veins extend, there
the matter seems suddenly to swell and become more diffluent.

“On the tenth day,” continues our author, “the albumen subsides, having
now become a small tenacious, viscid, and yellowish mass”--so much of
it, that is to say, as has not passed into the state of colliquament.

For already the larger portion of the white has become dissolved, and
has even passed into the body of the embryo, viz., the whole of the
thinner albumen, and the greater portion of the thicker. The yelk, on
the contrary, rather looks larger than it did in the beginning. Whence
it clearly appears that the yelk has not as yet served for the nutrition
of the embryo, but is reserved to perform this office by and by. In so
far as we can conjecture from the course and distribution of the veins,
the embryo from the commencement is nourished by the colliquament; upon
this blood-vessels are first distributed, and then they spread over the
membrane of the thinner albumen, next over the thicker albumen, and
finally over the vitellus. The thicker albumen serves for nutriment
after the thinner; the vitellus is drawn upon last of all.

The delicate embryo, consequently, whilst it is yet in the vermicular
state, is nourished with the thinnest and best concocted aliment, the
colliquament and thinner albumen; but when it is older it has food
supplied to it more in harmony with its age and strength.

Aristotle describes the relative situation of the several parts in the
following words: “In the anterior and posterior part, the membrane of
the egg lies under the shell,--I do not mean the membrane of the shell
itself, but one under this, in which there is contained a clear
fluid”--the colliquament; “then the chick and the membrane including it,
which keeps it distinct from the fluid around it.” But here I suspect
that there is an error in the text; for as the author himself indicates
the thing, it ought rather to stand thus: “then the chick, enveloped in
a membrane, continues or swims in the clear fluid;” which membrane is
not exterior to the one that immediately lines the shell, but another
lying under this; which, when the first or external albumen is consumed,
and the remainder of the thicker albumen is depressed into the sharp end
of the egg, of two membranes forms a single tunic that now begins to
present itself like the secundine called the chorion. And Aristotle says
well, “there is a clear fluid contained in it,” by which words he does
not mean the albumen, but the colliquament derived from the albumen, and
in which the embryo swims; for the albumen that remains subsides into
the small end of the egg.


_The inspection after the fourteenth day._

From the seventh to the fourteenth day everything has grown and become
more conspicuous. The heart and all the other viscera have now become
concealed within the abdomen of the embryo, and the parts that formerly
were seen naked and projecting externally, can now only be perceived
when the thorax and abdomen are laid open. The chick too now begins to
be covered with feathers, the roots of which are first perceived as
black points. The pupils of the eyes are distinguished; the eyelids
appear, as does also the membrana nictitans in the greater canthus of
the eye, a membrane which is proper to birds, and which they use for
cleansing the eyeball. The convolutions of the brain farther make their
appearance; the cerebellum is included within the skull; and the tail
acquires the characteristic shape of the bird’s rump.

After the fourteenth day the viscera, which up to this time have been
white, gradually begin to assume a flesh or reddish colour. The heart,
having now entered the penetralia of the thorax and been covered with
the sternum, inhabits the dwelling place which itself had formed. The
cerebrum and cerebellum acquire solidity under the dome of the skull;
the stomach and intestines, however, are not yet included within the
abdomen, but, connected with the parts within, hang pendulous

Of the two vessels that proceed from the abdomen to the umbilicus, near
the anus, one is an artery, as its pulse proclaims, and arises from the
arteria magna or aorta, the other is a vein, and extends from the
vitellus by the side of the intestines to the vena portæ, situated in
the concave part of the liver. The other trunk of the umbilical vessels,
collecting its branches from the albumen, passes the convexity of the
liver, and enters the vena cava near the base of the heart.

As all these things go on becoming clearer from day to day, so the
greater portion of the albumen is also gradually consumed; this,
however, is nowise the case with the vitellus, which remains almost
entire up to this time, and indeed is seen of the same size as it was
the first day.

In the course of the following days five umbilical vessels are
conspicuous; one of these is the great vein, arising from the cava above
the liver, and distributing its branches to the albumen; two other veins
proceed from the porta, both having the same origin, and run to the two
portions of the vitellus, which we have but just described; and these
are accompanied by two arteries arising one on either side from the

The chick now occupies a larger space in the egg than all the rest of
the matter included in it, and begins to be covered with feathers; the
larger the embryo grows, the smaller is the quantity of albumen that is
present. It is also worthy of observation, that the membrane of the
colliquament which we have said unites with the external investing
membrane, and constitutes the secundine or chorion, now includes the
whole of the vitellus in one, and becoming contracted, draws the
vitellus along with the intestines towards the chick, conjoins them with
its body, and incloses them as it were in a thick sac. Everything that
was previously extremely delicate and transparent, becomes more opaque
and fleshy as the sac contracts, which at length, like a hernial tumour
of the scrotum, includes and supports both the intestines and the yelk;
contracting every day in a greater and greater degree, it comes finally
to constitute the abdomen of the chick. You will find the yelk, about
the eighteenth day, lying [in its bag] among the intestines, the belly
at large being lax; yet are the parts not so firmly fixed but that the
intestines (as in the case of a scrotal hernia), along with the
vitellus, can be pushed up into the belly, or forced out of it as it
were into a pouch. I have occasionally seen the vitellus prolapsed in
this way from the abdominal cavity of a pigeon, which had been
prematurely excluded from the shell in the summer season.

The chick at this epoch looks big-bellied and as if it were affected
with a hernia, as I have said. And now the colliquament, which was at
first in large quantity, gradually grows turbid, suffers change, and is
consumed, so that the chick comes to lie bent over the vitellus. At the
same period, before the liver assumes its sanguineous colour, and
performs the business of what is called the second concoction, the bile,
which is commonly believed to be separated as an excretion by the power
of the liver, is seen of a green colour between the lobes of that organ.
In the cavity of the stomach there is a limpid fluid contained,
obviously of the same appearance and taste as the colliquament in which
the fœtus swims; this passing on by the intestines, gradually changes
its colour, and is converted into chyle; and finally in the lower
portion of the bowels an excrementitious matter is encountered, of the
same character as that which is met with in the lower intestines of
chicks already excluded from the egg. When the chick is further advanced
you may even see this fluid concocted and coagulated; just as in those
animals that feed on milk, a coagulum is formed, which afterwards
separates into serum and firmer curd.

When the albumen is almost all removed, and only a very small quantity
of the colliquament is left, for several days before the exclusion, the
chick no longer swims, but, as I have said, bends over the vitellus; and
rolled up into a round ball, with the head for the most part placed
between the right thigh and wing, it is seen with its beak, nails,
feathers, and all other parts complete. Sometimes it sleeps, and
sometimes it wakes, and moving about it breathes and chirps. If you
apply the egg to your ear, you will hear the chick within making a
noise, kicking, and unquestionably chirping; according to Aristotle, he
now also uses his eyes. If you cautiously drop the egg into warm water,
it will swim, and the chick within, aroused by the warmth, will leap,
and, as I have already said, cause the egg to tumble about. And it is by
this means that our country folks distinguish prolific from unproductive
eggs which sink when put into water.

When the albumen is entirely gone, just before the exclusion, the
umbilical vessel, which we have described as distributed to the albumen,
is obliterated; or as Aristotle says,[191] “that umbilicus which
proceeds to the external secundines is detached from the animal and
dies; but the one which leads to the vitellus becomes connected with the
small intestine of the chick.”

The excrement that is first formed in the intestines is white and
turbid, like softened egg-shell; and some of the same matter may be
found contained in the secundines. The philosopher admits this when he
says: “At the same time, too, the chick discharges a large quantity of
excrement into the outer membrane; and there are white excrements within
the abdomen, as well as those that have been evacuated.”

Time running on, very shortly before the exclusion, light green fæces
are formed, similar to those which the chick discharges when excluded
from the egg. In the crop, too, we can discover a portion of the
colliquament which has been swallowed; and in the stomach some curd or

Up to this time the liver has not yet acquired its purple or blood-red
colour, but has a tint verging from white into yellow, such as the liver
of fishes presents. The lungs, however, are of a florid red.

The yelk is now contained in the abdomen among the intestines: and this
is the case not merely whilst the chick is in the egg, but even after
its exclusion, and when it is running about following its mother in
search of food. So that what Aristotle frequently asserts appears to be
absolutely true, viz., that the yelk is destined for the food of the
chick; and the chick does certainly use it for food, included in his
interior as it is, during the few first days after his exclusion, and
until such time as his bill gains the hardness requisite to break and
prepare his food, and his stomach the strength necessary to digest it.
And, indeed, the yelk of the egg is very analogous to milk. Aristotle
gives us his support in this opinion in the place already so frequently
referred to:[192] “The chick now lies over much of the yellow, which at
last diminishes, and, in process of time, disappears entirely, being all
taken into the body of the bird, where it is stored, so that on the
tenth day after the exclusion of the chick, if the belly be laid open,
you will still find a little of the yelk upon the intestines.” I have
myself found certain remains of the yelk even upon the thirteenth day;
and if the argument derivable from the duct of the umbilical veins which
we have described as terminating in the porta of the liver by one or
another trunk, be of any avail, the chick is already nourished almost in
the same manner as it is subsequently, the sustenance being attracted
from the yelk by the umbilical vessels, in the same way as chyle is by
and by transmitted by the mesenteric veins from the intestines. For the
vessels terminate in either case in the porta of the liver, to which the
nourishment attracted in the same way is in like manner transmitted. It
is not necessary, therefore, to have recourse to any lacteal vessels of
the mesentery, which, in the feathered tribes, are nowhere to be

Let me be permitted here to add what I have frequently found: With a
view to discovering more distinctly the relative situations of the
embryo and the fluids, I have boiled an egg hard, from the fourteenth
day of the incubation up to the day when the exclusion would have taken
place, the major part of the albumen being already consumed, and the
vitellus divided. Breaking the shell, and regarding the position of the
chick, I found both the remains of the albumen and the two portions of
the vitellus (which we have said are divided by the colliquation induced
by the gentle heat), possessing the consistency, colour, taste, and
other qualities which distinguish the yelks of unincubated eggs
similarly boiled. I have, therefore, frequently asked myself how it came
to pass that unprolific eggs set under a hen are made to putrefy and
become offensive by the same extraneous heat which produces no such
effect upon prolific eggs, both of the fluids of which remain sweet and
unchanged, although they have an embryo in the midst of them, (and this
even containing some small quantity of excrementitious matter within
it,) so that did any one eat the yelk of such an egg in the dark, he
would not distinguish it from that of a fresh egg which had never been
sat upon.


_Of the exclusion of the chick, or the birth from the egg._

The egg is, as we have said, a kind of exposed uterus, and place in
which the embryo is fashioned: for it performs the office of the uterus
and enfolds the chick until the due time of its exclusion arrives, when
the creature is born perfect. Oviparous animals consequently are not
distinguished from viviparous by the circumstance of the one bringing
forth their young alive, and the other not doing so; for the chick not
only lives and moves within the egg, but even breathes and chirps whilst
there; and, when it escapes from the shell, enjoys a more perfect
existence than the fœtus of animals in general. Oviparous and viviparous
animals rather differ in their modes of bringing forth; the uterus or
place in which the embryo is formed being within the animal in
viviparous tribes, where it is cherished and brought to maturity, whilst
in oviparous tribes the uterus, or egg, is exposed or without the
animal, which, nevertheless, by sitting on it does not cherish it less
truly than if it were still contained within the body.

For though the mother occasionally quits her eggs on various errands, it
is only for a short season; she still has such affection for them that
she speedily returns, covers them over, cherishes them beneath her
breast and carefully defends them; and this on to the twenty-first or
twenty-second day, when the chicks, in search of freer air, break the
shell and emerge into the light.

Now we must not overlook a mistake of Fabricius, and almost every one
else in regard to this exclusion or birth of the chick. Let us hear

“The chick wants air sooner than food, for it has still some store of
nourishment within it; in which case the chick, by his chirping, gives a
sign to his mother of the necessity of breaking the shell, which he
himself cannot accomplish by reason of the hardness of the shell and the
softness of his beak, to say nothing of the distance of the shell from
the beak, and of the position of the head under the wing. The chick,
nevertheless, is already so strong, and the cavity in the egg is so
ample, and the air contained within it so abundant, that the breathing
becomes free and the creature can emit the sounds that are proper to it;
these can be readily heard by a bystander, and were recognized both by
Pliny and Aristotle,[194] and perchance have something of the nature of
a petition in their tone. For the hen hearing the chirping of the chick
within, and knowing thereby the necessity of now breaking the shell in
order that the chick may enjoy the air which has become needful to it,
or if you will, you may say, that desiring to see her dear offspring,
she breaks the shell with her beak, which is not hard to do, for the
part over the hollow, long deprived of moisture, and exposed to the heat
of incubation, has become dry and brittle. The chirping of the chick is
consequently the first and principal indication of the creature desiring
to make its escape, and of its requiring air. This the hen perceives so
nicely, that if she hears the chirping to be low and internal, she
straightway turns the egg over with her feet, that she may break the
shell at the place whence the voice proceeds without detriment to the
chick. Hippocrates adds,[195] “Another indication or reason of the
chick’s desiring to escape from the shell, is that when it wants food it
moves vigorously, in search of a larger supply, by which the membrane
around it is torn, and the mother breaking the shell at the place where
she hears the chick moving most lustily, permits it to escape.”

All this is stated pleasantly and well by Fabricius; but there is
nothing of solid reason in the tale. For I have found by experience that
it is the chick himself and not the hen that breaks open the shell, and
this fact is every way in conformity with reason. For how else should
the eggs that are hatched in dunghills and ovens, as in Egypt and other
countries, be broken in due season, where there is no mother present to
attend to the voice of the supplicating chick, and to bring assistance
to the petitioner? And how again are the eggs of sea and land tortoises,
of fishes, silkworms, serpents, and even ostriches to be chipped? The
embryos in these have either no voice with which they can notify their
desire for deliverance, or the eggs are buried in the sand or slime
where no chirping or noise could be heard. The chick therefore is born
spontaneously, and makes its escape from the eggshell through its own
efforts. That this is the case appears from unquestionable arguments:
when the shell is first chipped, the opening is much smaller than
accords with the beak of the mother; but it corresponds exactly to the
size of the bill of the chick, and you may always see the shell chipped
at the same distance from the extremity of the egg, and the broken
pieces, especially those that yield to the first blows, projecting
regularly outwards in the form of a circlet. But as any one on looking
at a broken pane of glass can readily determine whether the force came
from without or from within, by the direction of the fragments that
still adhere, so in the chipped egg it is easy to perceive, by the
projection of the pieces around the entire circlet, that the breaking
force comes from within. And I myself and many others with me besides,
hearing the chick scraping against the shell with its feet, have
actually seen it perforate this part with its beak, and extend the
fracture in a circle like a coronet. I have further seen the chick
raise up the top of the shell upon its head and remove it.

We have gone at length into some of these matters, as thinking that they
were not without all speculative interest, as we shall show by and by.
The arguments of Fabricius are easily answered. For I admit that the
chick in ovo produces sounds, and these perchance may even have
something of the implorative in their nature; but it does not therefore
follow that the shell is broken by the mother. Neither is the bill of
the chick so soft, nor yet so far from the shell, that it cannot pierce
through its prison walls, particularly when we see that the shell, for
the reasons assigned, is extremely brittle. Neither does the chick
always keep its head under its wing, so as to be thereby prevented from
breaking the shell, but only when it sleeps or has died. For the
creature wakes at intervals and scrapes and kicks, and struggles,
pressing against the shell, tearing the investing membranes, and chirps,
(and that this is done whilst petitioning for assistance I willingly
concede,) all of which things may readily be heard by any one who will
use his ears. And the hen listening attentively when she hears the
chirping deep within the egg does not break the shell, but she turns the
egg with her feet and gives the chick within another and a more
commodious position. But there is no occasion to suppose that the chick
by his chirping informs his mother of the propriety of breaking the
shell, or seeks deliverance from it. For very frequently for two days
before the exclusion you may hear the chick chirping within the shell.
Neither is the mother, when she turns the egg, looking for the proper
place to break it; but as the child when uncomfortably laid in his
cradle is restless and whimpers and cries, and his fond mother turns him
this way and that, and rocks him till he is composed again, so does the
hen when she hears the chick restless and chirping within the egg, and
feels it, when hatched, moving uneasily about in the nest, immediately
raise herself and observe that she is not pressing on it with her
weight, or keeping it too warm, or the like, and then with her bill and
her feet she moves and turns the egg until the chick within is again at
its ease and quiet.


_Of twin-bearing eggs._

Twin-bearing eggs are such as produce twin chickens, and according to
Aristotle,[196] “are possessed of two yelks, which, in some are
separated by a layer of thin albumen, that they may less encroach on one
another; in others, however, there is nothing of the sort, and then the
two yelks are in contact.”

I have frequently seen twin eggs, each of the yelks in which was
surrounded by an albumen, with common and proper membranes surrounding
them. I have also met with eggs having two yelks connate, as it were,
both of which were embraced by a single and common albumen.

“Some fowls” says Aristotle,[197] “always produce twins, in which the
particulars relating to the yelk that have been stated are clearly
perceived. A certain fowl laid within two of twenty eggs, all of which,
except those that were unprolific, produced twins. Of the twins,
however, one was always larger, the other smaller, and the smaller chick
was frequently deformed in addition.”

With us twin eggs are occasionally produced, and twin chicks too,
although very rarely, are engendered. I have never myself, however, seen
both of these chicks live and thrive; one of them either died within the
egg or at the time of the exclusion. And this the words of Aristotle
prepare us to expect, when he says “one of the two is larger, the other
smaller;” this is as much as to say that one of them is stronger and of
greater age, the other weaker and less prepared for quitting the shell:
my own opinion therefore is, that the two yelks are of different origins
and maturity. It is therefore scarcely possible but that the stronger
and more advanced chick, if the egg be broken and it emerge into the
light, will cause the blight and abortion of the other. But if the
stronger bird do not chip the shell, he himself is threatened with a
present danger, viz. want of air. At the exclusion from the shell,
consequently, certain death hangs over one or other, if not over both.

Fabricius either not observing the above words of Aristotle, or
neglecting them, says: “If an egg have now and then two yelks, it
engenders a chick having four legs or wings, and two heads--a monster,
in short; never two chicks distinct from one another, and that can be
spoken of as a pair; there is but one trunk, to which are appended two
heads, &c.”

Whence we may infer that he himself had never seen nor heard from
credible persons that such eggs produce two pullets, and therefore that
he agrees with me in regarding such eggs as rare, and in holding that
they never produce two chicks both alike capable of living.

I am surprised nevertheless that, with the authority of Aristotle before
him, he should have said that “two chicks, distinct and separate, are
_never_ produced from such eggs,” but always a monster; the rather as he
thinks that the embryo is engendered from the chalazæ as from the
appropriate matter, and he could not but see that there are four chalazæ
in every twin-egg.

I should rather imagine that when two vitelli are included by the same
albumen in a twin-egg, and are so intimately associated that their
cicatriculæ, when they are resolved together, constitute a single eye or
colliquament, may engender a monstrous embryo with four feet, two heads,
&c., because I see nothing to hinder this; and such a production do I
conceive to have been engendered by the egg of which Fabricius speaks.

But where two yelks have existed separately, parted by their several
membranes, and furnished with chalazæ, albumens, and all else requisite
to the generation of the chick, I hold that we must conclude, with
Aristotle, that such an egg, as it has all the parts of two eggs except
the shell, so does it also possess the faculty or faculties of as many;
and unless it be a wind or barren egg, that it will for the most part
produce two embryos, and but rarely a single monstrous individual.


_Certain Deductions from the preceding History of the Egg._

Such is the history of the hen’s egg; in which we have spoken of its
production, and of its action or faculty to engender a chick, at too
great length, it may appear to those who do not see the end and object
of such painstaking, of such careful observation. Wherefore I think it
advisable here to state what fruits may follow our industry, and in the
words of the learned Lord Verulam, to “enter upon our second vintage.”
Certain theorems, therefore, will have to be gathered from the history
given; some of which will be quite certain, some questionable and
requiring further sifting, and some paradoxical and opposed to popular
persuasion. Some of these, moreover, will have reference to the male,
some to the female, several to the egg, and finally, a few to the
formation of the chick. When these have been carefully discussed
seriatim, we shall be in a condition to judge with greater certainty and
facility of the generation of all other animals.


_Of the nature of the egg._

Of the theorems that refer to the egg, some teach us what it is, some
show its mode of formation, and others tell of the parts which compose

It is certain, in the first place, that one egg produces one chick only.
Although the egg be in a certain sense an external uterus, still it most
rarely engenders several embryos, but by far the most frequently
produces no more than a single pullet. And when an egg produces two
chicks, which it does sometimes, still is this egg to be reputed not
single but double, and as possessed of the nature and parts of two eggs.

For an egg is to be viewed as a conception proceeding from the male and
the female, equally endued with the virtue of either, and constituting
an unity from which a single animal is engendered.

Nor is it the beginning only, but the fruit and conclusion likewise. It
is the beginning as regards the being to be engendered; the fruit in
respect of the two parents: at once the end proposed in their
engendering, and the origin of the chick that is to be. “But the seed
and the fruit,” according to Aristotle,[198] “differ from one another in
the relations of prior and posterior; for the fruit is that which comes
of another, the seed is that from which this other comes: were it
otherwise, both would be the same.”

The egg also seems to be a certain mean; not merely in so far as it is
beginning and end, but as it is the common work of the two sexes and is
compounded by both; containing within itself the matter and the plastic
power, it has the virtue of both, by which it produces a fœtus that
resembles the one as well as the other. It is farther a mean between the
animate and the inanimate world; for neither is it wholly endowed with
life, nor is it entirely without vitality. It is still farther the
mid-passage or transition stage between parents and offspring, between
those who are, or were, and those who are about to be; it is the hinge
and pivot upon which the whole generation of the bird revolves. The egg
is the terminus from which all fowls, male and female, have sprung, and
to which all their lives tend,--it is the result which nature has
proposed to herself in their being. And thus it comes that individuals
in procreating their like for the sake of their species, endure for
ever. The egg, I say, is a period or portion of this eternity; for it
were hard to say whether an egg exists for the sake of the chick that it
engenders, or the pullet exists for the sake of the egg which it is to
engender. Which of these was the prior, whether with reference to time
or nature,--the egg or the pullet? This question, when we come to speak
of the generation of animals in general, we shall discuss at length.

The egg, moreover,--and this is especially to be noted,--corresponds in
its proportions with the seeds of plants, and has all the same
conditions as these, so that it is to be regarded, not without reason,
as the seed or sperma of the common fowl, in the same way as the seeds
of plants are justly entitled their eggs, not only as being the _matter_
or that from which, but the _efficient_ or that by which the pullet is
engendered. In which finally no part of the future offspring exists _de
facto_, but in which all parts inhere _in potentia_.

The seed, properly so called, differs however from the _geniture_, which
by Aristotle is defined to be “that which, proceeding from the
generator, is the cause, that which first obtains the principle of
generation; in those, to wit, whom nature destined to copulate. But the
seed is that which proceeds from these two in their connection: and such
is the seed of all vegetables, and of some animals, in which the sexes
are not distinct; like that which is first produced by male and female
commingled, a kind of promiscuous conception, or animal; for this
already possesses what is required of both.”

The egg consequently is a natural body endowed with animal virtues, viz.
principles of motion and rest, of transmutation and conservation; it is,
moreover, a body which, under favorable circumstances, has the capacity
to pass into an animal form; heavy bodies indeed do not sink more
naturally, nor light ones float, when they are unimpeded, than do seeds
and eggs in virtue of their inherent capacity become changed into
vegetables and animals. So that the seed and the egg are alike the fruit
and final result of the things of which they are the beginning and
efficient cause.

For a single pullet there is a single egg; and so Aristotle[199] says:
“from one seed one body is engendered; for example, from a single grain
of wheat one plant; from a single egg one animal; for a twin-egg is, in
fact, two eggs.”

And Fabricius[200] with truth observes: “The egg is not only an exposed
uterus, and place of generation, but that also on which the whole
reproduction of the pullet depends, and which the egg achieves as agent,
as matter, as instrument, as seat, and all else, if more there be, that
is needful to generation.” He shows it to be an organ because it
consists of several parts, and this, from the statement of Galen, who
will have the very essence of an organ to be that “it consist of several
parts, all of which conspire to one and the same action though diverse
in faculty and use; for some are principal instruments in the action;
some are indispensable to it,--without them it could not take place;
some secure its better performance; and some, in fine, are extant for
the safety and preservation of everything else.” He also shows it to be
an _agent_, when from Aristotle and Galen he lays down the two actions
of the egg, viz.: “the generation of the chick, and the growth and
nutrition of the pullet.” At the conclusion he expresses himself clearly
in these words: “In the works of nature we see conjunct and one, the
artificer, the instrument, and the matter; the liver, for instance, is
both the agent and the instrument for the production of the blood; and
so every part of the body; Aristotle,[201] therefore, said well that the
moving powers were not easily distinguished from the instruments. In
artificial things, indeed, the artificer and the instrument are
distinct, as much so as the workman and his hammer, the painter and his
pencil. And the reason adduced by Galen[202] is this: that in things
made by art the artificer is without the work; in natural things, again,
the artificer is within it, conjunct with the instruments, and pervading
the whole organization.”

To this I add these perspicuous words of Aristotle.[203] “Of extant
things some are consistent with nature, others with other causes.
Animals and their parts, and plants, and simple bodies, as earth, fire,
air, and water, consist with nature, and are allowed universally to do
so; but these bodies differ entirely from those that do not consist with
nature. For whatsoever consists with nature is seen to have within
itself a principle of motion and of rest, now according to place, now
according to increment and decrement, and again according to change. A
couch or litter, a garment, and other things of the same description,
however designated, inasmuch as they are made by art, have no inherent
faculty of change; but inasmuch as they are made of [wood, or] earth, or
stone, [or of wool, silk, or linen,] or of mixtures of these, they have
such a faculty. As if nature were a certain principle and cause
wherefore that should move and be at rest in which she inheres
originally, independently, and not by accident. I say, particularly,
_not by accident_, because it might happen that one being a physician
should himself be the cause of his own good health; but he is not
familiar with medicine in the same respect as he has worked his own
cure; it happens simply that the man who here recovers his health is a
physician. It therefore occasionally happens, that these two things are
distinct and separate. But it is not otherwise with everything besides
that is of art: none of these has in itself a principle of performance
or action, though some of them have such a principle in other things and
beyond themselves, such as a house, and aught else that is made with
hands; and some have even such a principle inherent, but not _per se_
and independently: everything, for example, may by accident become a
cause to itself. Nature is therefore, as stated [that which has an
inherent principle of motion]; and those things have nature within them
which possess this principle. Now all such are substances; for nature is
always some subject, and inheres in the subject.”

These things I have spoken of at length, and even quoted the words of
the writers appealed to, that it might thence appear first, that all I
attribute to the egg is actually there, viz.: matter, organ, efficient
cause, place, and everything else requisite to the generation of the
chick; and next and more especially, that the truth in regard to the
following very difficult questions might be made clearly to appear,
viz.: Which and what principle is it whence motion and generation
proceed? By what virtue does the semen act, according to Aristotle? What
is it that renders the semen itself fruitful? (for the philosopher will
have it that nature in all natural bodies is the innate principle of
motion and of rest, and not any second accident.) Whether is that which
in the egg is cause, artificer, and principle of generation and of all
the vital and vegetative operations--conservation, nutrition,
growth--innate or superadded? and whether does it inhere primarily, of
itself, and as a kind of nature, or intervene by accident, as the
physician in curing diseases? Whether is that which transforms the egg
into a pullet inherent or acquired, or is it already conceived in the
ovary, and does it nourish, augment, and perfect the egg there?

What is it besides that preserves the egg sweet after it is laid? What
is it that renders an egg fruitful--is it to be called soul, or a
portion of the soul, or something belonging to the soul, or something
having a soul, or is it intelligence, or, finally, is it Divinity?
seeing that it acts to a definite end, and orders all with inimitable
providence and art, and yet in an incomprehensible manner, always
obtaining what is best both for simple being and for well-being, for
protection also and for ornament. And all this not only in the fruitful
egg which it fecundates, but in the hypenemic egg which it nourishes,
causes to increase, and preserves. Nay, it is not merely the vitellus in
the vitellarium or egg-bed, but the smallest speck whence the yelk is
produced, of no greater size than a millet or a mustard-seed, that it
nourishes and makes to grow, and finally envelopes with albumen, and
furnishes with chalazæ, and surrounds with membranes and a shell. For it
is probable that even the barren egg, whilst it is included within the
fowl and is connected with her, is nourished and preserved by its
internal and inherent principle, and made to increase (not otherwise
than the eggs of fishes and frogs, exposed externally, increase and are
perfected), and to be transformed from a small speck into a yelk, and
transferred from the ovary to the uterus (though it have no connexion
with the uterus), there to be endued with albumen, and at length to be
completed with its chalazæ, membranes, and shell.

But what that may be in the hypenemic egg as well as in the fruitful
one, which in a similar manner and from the same causes or principles
produces the same effects; whether it be the same soul, or the same part
of the soul, or something else inherent in both, must be worthy of
inquiry: it seems probable, however, that the same things should proceed
from similar causes.

Although the egg whilst it is being produced is contained within the
fowl, and is connected with the ovary of the mother by a pedicle, and is
nourished by blood-vessels, it is not therefore to be spoken of as a
part of the mother; nor is it to be held as living and vegetating
through her vital principle, but by a virtue peculiar to itself and an
internal principle; just as fungi, and mosses, and the misletoe, which
although they adhere to vegetables and are nourished by the same sap as
their leaves and germs, still form no part of these vegetables, nor are
they ever so esteemed. Aristotle, with a view to meeting these
difficulties, concedes a vegetative soul to the egg, even to the
hypenemic one. He says:[204] “Females, too, and all things that live are
endowed with the vegetative virtue of the soul, as has been often said;
and therefore this [hypenemic] egg is perfect as the conception of a
plant, but imperfect as that of an animal.” And he inculcates the same
doctrine elsewhere,[205] when he asks: “In what manner or sense are
hypenemic eggs said to live? For they cannot do so in the same sense as
fruitful eggs, otherwise a living thing might be engendered by their
agency. Nor do they comport themselves like wood or stone; because these
perish by a kind of corruption, as having formerly had life in a certain
manner. It is positive, therefore, that hypenemic eggs have a certain
kind of soul potentially; but what? of necessity that ultimate soul,
which is the appanage of vegetables; for this equally inheres in all
things, in animals as well as vegetables.”

But it is not the same soul that is found in hypenemic as in fruitful
eggs; otherwise would a pullet be indifferently produced from both; but
how and in what respects the soul attached to each is different from the
other, Aristotle does not sufficiently explain, when he inquires:[206]
“Wherefore are all the parts of an egg present in the hypenemic egg, and
it still incapable of producing a chick? because,” he replies, “it is
requisite that it have a sensitive soul.” As if in fruitful eggs,
besides the vegetative soul, there were a sensitive soul present. Unless
you understand the vegetative soul as inhering _actually_ in the
fruitful egg, which contains the sensitive soul within it _potentially_;
whence the animal, and the sensible parts of the animal are subsequently
produced. But neither do writers satisfactorily untie this knot, nor set
the mind of the inquirer free from the difficulties that entangle him.
For he sees that the egg is a true animal seed, according to this
sentence of the Stagyrite:[207] “In those things endowed with life, in
which the male and female sexes are not distinct, the seed is already
present as a conception. I entitle _conception_ the first mixture from
the male and female (the analogue of the vegetable seed therefore).
Wherefore from one seed there is engendered one body, as from one egg
one animal.”

It appears, consequently, that for one egg there is one soul or vital
principle.[208] But whether is this that of the mother, or that of the
father, or a mixture of the two? And here the greatest difficulties are
occasioned by those eggs that are produced by the concurrence of animals
of different species, as, for example, of the common fowl and pheasant.
In such an egg, I ask, is it the vital principle of the father or that
of the mother, which inheres? or is it a mixture of the two? But how can
vital principles be mingled, if the vital principle (as form) be act and
substance, which it is, according to Aristotle? For no one will deny,
whatever it be ultimately which in the fruitful egg is the beginning and
cause of the effects we witness, that it is a substance susceptible of
divers powers, forces, or faculties, and even conditions,--virtues,
vices, health and sickness. For some eggs are esteemed to be longer,
others shorter lived; some engender chickens endowed with the qualities
and health of body that distinguished their parents, others produce
young that are predisposed to disease. Nor is it to be said that this is
from any fault of the mother, seeing that the diseases of the father or
male parent are transferred to the progeny, although he contributes
nothing to the matter of the egg; the procreative or plastic force which
renders the egg fruitful alone proceeding from the male; none of its
parts being contributed by him. For the semen which is emitted by the
male during intercourse does by no means enter the uterus of the female,
in which the egg is perfected; nor can it, indeed, (as I first
announced, and Fabricius agrees with me,) by any manner or way get into
the inner recesses of that organ, much less ascend as high as the ovary,
near the waist or middle of the body, so that besides its peculiar
virtue it might impart a portion of matter to the numerous ova whose
rudiments are there contained. For we know, and are assured by
unquestionable experience, that several ova are fecundated by one and
the same connexion,--not those only that are met with in the uterus and
ovary, but those likewise that are in some sort not yet begun, as we
shall state by and by, and indeed, as we have already had occasion to
assert in our history.

If, therefore, an egg be rendered fruitful by its proper vital
principle, or be endowed with its own inherent fecundating force, whence
or whereby either a common fowl, or a hybrid betwixt the fowl and the
pheasant is produced, and that either male or female, like the father or
the mother, healthy or diseased; we must infallibly conclude that the
egg, even when contained in the ovary, does not live by the vital
principle of the mother, but is, like the youth who comes of age, made
independent even from its first appearance; as the acorn taken from the
oak, and the seeds of plants in general, are no longer to be considered
parts of the tree or herb that has supported them, but things made in
their own right, and which already enjoy life in virtue of a proper and
inherent vegetative power.

But if we now admit that there is a living principle in a fertile egg,
it may become matter of discussion whether it is the same living
principle which already inheres in the egg that will inhere in the
future chick, or whether it is a different one that actuates each? For
it is matter of necessity that we admit the inherence of a certain
principle which constitutes and causes the egg to grow, and which
farther engenders and makes the chick to increase. We have to inquire,
therefore, whether the animating principle of the egg and of the chick
be one and the same, or several and different? And then, were several
vital principles recognized, some appertaining to the egg, others to the
chick, we should next have to inquire: whence and at what epoch the
animating principle of the chick entered it? and what is it in the egg
which causes the cicatricula to dilate before the advent of the living
principle; which draws the eye of the vitellus upwards, as stated, and
produces the colliquament, changes the constitution of the fluids of the
egg, and preordains everything for the construction of the future chick
before there is even a vestige of it to be seen? Or whence shall we say
the aliment fit for the embryo is derived, and by which it is nourished
and made to grow, before it is yet in being? For these acts are seen to
be the work of the vegetative soul of the embryo, and have reference to
the coming pullet, ensuring its nutrition and growth. And again, when
the embryo is begun, or the chick is half formed, what is it which
constitutes that embryo or that chick one and continuous and connex with
the liquids of the egg? What nourishes and makes the chick to grow, and
preserves the fluids that are fit for its nutrition from putrefaction,
and prepares, and liquefies, and concocts them?

If the vital principle be the act of the organic body possessing life
_in potentia_, it seems incredible that this principle can inhere in the
chick before something in the shape of an organized body is extant. Nor
is it more credible that the vital principle of the egg and chick can be
identical, if the vital principle be conservative of that only to which
it belongs; but the egg and the chick are different things, and manifest
dissimilar and even opposite vital acts, in so much so that one appears
to be produced by the destruction of the other. Or should we perchance
maintain that the same principle and cause of life inheres in both, in
the pullet half fashioned, to wit, and the egg half consumed, as if it
were one and a simple act of the same body; or as if from parts
producing one natural body, one soul or vital principle also arose,
which was all in all, as is commonly said, and all in each particular
part? Just as with leaves and fruit conspicuous on the stem of a tree,
wherever a division is made we still say that the principle or first
cause of the slip and of the whole tree is the same; the leaves and the
fruit are, as it were, the form and end, the trunk of the tree the
beginning. So too in a line, wherever a division is made, this will
become the end or boundary of the part behind it, the commencement of
the part before it. And the same thing is seen to obtain in respect of
quality and motion, that is to say, in every kind of transmutation and

So much at this time upon these topics, which will by and by engage us
at greater length, when we come to speak of the nature of the living
principle of the embryos of animals in general; of its being; of its
accession in respect of the how and the when; and how it is all in all,
and all in each particular part, the same and yet different. Points
which we shall determine from numerous observations.


_The egg is not the product of the uterus, but of the vital principle._

“As we have said,” says Fabricius,[209] “that the action of the stomach
was to convert the food into chyle, and the action of the testicles to
produce semen, because in the stomach we find chyle, in the testes
semen, so do we definitely assert that the egg is the product of the
uterus of birds, because it is found in this part. The organ and seat of
the generation of eggs is, therefore, intimately known and obvious to
us. And farther, inasmuch as there are two uteri in birds, one superior
and the other inferior, and these are considerably different from one
another, and consequently perform different offices, it is in like
manner clear what particular action is to be ascribed to each. The
superior is devoted to the production of the yelk, the inferior to that
of the albumen and remaining parts, or of the perfect egg, as lies
obvious to sense; for in the superior uterus we never find aught beyond
a multitude of yelks, nor in the inferior uterus, other than entire and
perfect eggs. But these are not all the functions of the uteri as it
appears, but the following are farther to be noted and enumerated, viz.:
the increase of the egg, which succeeds immediately upon its production,
and proceeds until it is perfected and acquires its proper dimensions.
For the fowl does not naturally lay an egg until it has become complete
and has acquired its due dimensions. The actions of the uteri are
consequently the increase as well as the engenderment of the egg; but
increase supposes and includes nutrition, as is obvious. And since all
generation is the effect of the concurrence of two, viz., the agent and
the matter, the agent in the generation of an egg is nothing else than
the instruments or organs aforesaid, to wit, the double uterus; and the
matter is nothing but the blood.”

Now whilst I admit the action of the uterus to be in a manner the
generation of the egg, I by no means allow that the egg is nourished and
increased by this organ. And this, both for the reasons already alleged
by us when we treated of the vital principle of the egg, which is that
which nourishes it, and also because it appears little likely (according
to Aristotle,[210] it is impossible,) that all the internal parts of the
egg, in all their dimensions, should be fashioned and made to increase
by an external agent, such as the uterus is with reference to the egg;
for how, I beseech you, can that which is extrinsic arrange the natural
matter in things that are internal, and supply fresh matter according to
the several dimensions in the place of that which has been lost? How can
anything be affected or moved by that which does not touch it?
Wherefore, without question, the same things happen in the engenderment
of eggs which take place in the beginning of all living things
whatsoever, viz.: they are primarily constituted by external and
preexisting beings; but so soon as they are endowed with life, they
suffice for their own nourishment and increase, and this in virtue of
peculiar inherent forces, innate, implanted from the beginning.

What has already been said of the vital principle appears clearly to
proclaim that the egg is neither the work of the uterus, nor governed by
that organ; for it is manifest that the vegetative principle inheres
even in the hypenemic egg, inasmuch as we have seen that this egg is
nourished and is preserved, increases and vegetates, all of which acts
are indications of the presence of the principle mentioned. But neither
from the mother nor the uterus can this principle proceed, seeing that
the egg has no connexion or union with them, but is free and
unconnected, like a son emancipated from pupillage, rolling round within
the cavity of the uterus and perfecting itself, even as the seeds of
plants are perfected in the bosom of the earth, viz., by an internal
vegetative principle, which can be nothing else than the vegetative

And it will appear all the more certain that it is possessed of a soul
or vital principle, if we consider by what compact, what moving power,
the round and ample yelk, detached from the cluster of the ovary,
descends through the infundibulum--a most slender tube composed of a
singularly delicate membrane, and possessed of no motory fibres--and
opening a path for itself, approaches the uterus through such a number
of straits, arrived in which it continues to be nourished, and grows and
is surrounded with albumen. Now as there is no motory organ discoverable
either in the ovary which expels the vitellus, or in the infundibulum
which transmits, or in the uterus which attracts it, and as the egg is
not connected with the uterus, nor yet with the ovary by means of
vessels, nor hangs from either by an umbilical cord, as Fabricius truly
states, and demonstrates most satisfactorily, what remains for us
contemplating such great and important processes but that we exclaim
with the poet:[211]

    ’Tis innate soul sustains; and mind infused
     Through every part, that actuates the mass.

And although the rudiments of eggs, which we have said are mere specks,
and have compared to millet seeds in size, are connected with the ovary
by means of veins and arteries, in the same manner as seeds are attached
to plants, and consequently seem to be part and parcel of the fowl, and
to live and be nourished after the manner of her other parts, it is
nevertheless manifest, that seeds once separated from the plants which
have produced them, are no longer regarded as parts of these, but like
children come of age and freed from leading-strings, they are maintained
and governed by their own inherent capacities.

But of this matter we shall speak more fully, when we come to treat of
the soul or living principle of the embryo in general, and of the
excellence and divine nature of the vegetative soul from a survey of its
operations, all of which are carried on with such foresight, art, and
divine intelligence; which, indeed, surpass our powers of understanding
not less than Deity surpasses man, and are allowed, by common consent,
to be so wonderful that their ineffable lustre is in no way to be
penetrated by the dull edge of our apprehension.

What shall we say of the animalcules which are engendered in our bodies,
and which no one doubts are ruled and made to vegetate by a peculiar
vital principle (anima)? of this kind are lumbrici, ascarides, lice,
nits, syrones, acari, &c.; or what of the worms which are produced from
plants and their fruits, as from gall-nuts, the dog-rose, and various
others? “For in almost all dry things growing moist, or moist things
becoming dry, an animal may be engendered.”[212] It certainly cannot be
that the living principles of the animals which arise in gall-nuts
existed in the oak, although these animals live attached to the oak, and
derive their sustenance from its juices. In like manner it is credible
that the rudiments of eggs exist in the ovarian cluster by their proper
vital principle, not by that of the mother, although they are connected
with her body by means of arteries and veins, and are nourished by the
same food as herself. Because, as we have stated in our history, all the
vitellary specks do not increase together, like the grapes of a bunch,
or the corns of an ear of wheat, as if they were pervaded by one common
actuating force or concocting and forming cause; they come on one after
another, as if they grew by their own peculiar energy, each that is most
in advance severing itself from the rest, changing its colour and
consistence, and from a white speck becoming a yelk, in regular and
determinate sequence. And what is more particularly astonishing is that
which we witness among pigeons and certain other birds, where two yelks
only come to maturity upon the ovarian cluster together, one of which,
for the major part, produces a male, the other a female, an abundance of
other vitellary specks remaining stationary in the ovary, until the term
comes round for two more to increase and make ready for a new birth. It
is as if each successive pair received fertility from the repeated
addresses of the male; as if the two became possessed of the vital
principle together; which, once infused, they forthwith increase
spontaneously, and govern themselves, living of their own not through
their mother’s right. And, in sooth, what else can you conceive working,
disposing, selecting, and perfecting, as respects this pair of vitellary
papulæ and none others, but a peculiar vital principle? And although
they attract nourishment from the mother, they still do so no otherwise
than as plants draw food from the ground, or as the embryo obtains it
from the albumen and vitellus.

Lastly, since the papula existing in the ovary receives fecundity from
the access of the male, and this of such a kind that it passes into the
form and likeness of the concurring male, whether he were a common cock
or a pheasant, and there is as great diversity in the papulæ as there
are males of different kinds; what shall we hold as inherent in the
papulæ themselves, by whose virtue they are distinguished from one
another and from the mother? Undoubtedly it must be the vital principle
by which they are distinguished both from each other and from the

It is in a similar manner that fungi and parasitic plants live upon
trees. And besides, we in our own bodies frequently suffer from cancers,
sarcoses, melicerides, and other tumours of the same description, which
are nourished and grow as it seems by their own inherent vegetative
principle, the true or natural parts of the body meantime shrinking and
perishing. And this apparently because these tumours attract all the
nourishment to themselves, and defraud the other parts of the body of
their nutritious juices or proper genius. Whence the familiar names of
phagedæna and lupus; and Hippocrates, by the words το θεῑον, perhaps
understood those diseases which arise from poison or contagion; as if in
these there was a certain vitality and divine principle inherent, by
which they increase and through contagion generate similar diseases even
in other bodies. Aristotle[213] therefore says: “all things are full of
soul;” and elsewhere he seems to think that “even the winds have a kind
of life, and a birth and a death.”[214] But there is no doubt that the
vitellus, when it is once cast loose and freed from all connexion with
the fowl, during its passage through the infundibulum and its stay in
the cavity of the uterus, attracts a sluggish moisture to itself, which
it absorbs, and by which it is nourished; there too it surrounds itself
with albumen, furnishes itself with membranes and a shell, and finally
perfects itself. All of which things, rightly weighed, we must needs
conclude that it is possessed by a proper vital principle (anima).


_The egg is not produced without the hen._

Leaving points that are doubtful, and disquisitions bearing upon the
general question, we now approach more definite and obvious matters.

And first, it is manifest that a fruitful egg cannot be produced without
the concurrence of a cock and hen: without the hen no egg can be formed;
without the cock it cannot become fruitful. But this view is opposed to
the opinion of those who derive the origin of animals from the slime of
the ground. And truly when we see that the numerous parts concurring in
the act of generation,--the testes and vasa deferentia in the male, the
ovarium and uterus and blood-vessels supplying them in the female--are
all contrived with such signal art and forethought, and everything
requisite to reproduction in a determinate direction--situation, form,
temperature,--arranged so admirably, it seems certain, as nature does
nothing in vain, nor works in any round-about way when a shorter path
lies open to her, that an egg can be produced in no other manner than
that in which we now see it engendered, viz., by the concurring act of
the cock and hen. Neither, in like manner, in the present constitution
of things, can a cock or hen ever be produced otherwise than from an
egg. Thus the cock and the hen exist for the sake of the egg, and the
egg, in the same way, is their antecedent cause; it were therefore
reasonable to ask, with Plutarch, which of these was the prior, the egg
or the fowl? Now the fowl is prior by nature, but the egg is prior in
time; for that which is the more excellent is naturally first; but that
from which a certain thing is produced must be reputed first in respect
of time. Or we may say: this egg is older than that fowl (the fowl
having been produced from it); and, on the contrary, this fowl existed
before that egg (which she has laid). And this is the round that makes
the race of the common fowl eternal; now pullet, now egg, the series is
continued in perpetuity; from frail and perishing individuals an
immortal species is engendered. By these, and means like to these, do we
see many inferior or terrestrial things brought to emulate the
perpetuity of superior or celestial things.

And whether we say, or do not say, that the vital principle (anima)
inheres in the egg, it still plainly appears, from the circuit
indicated, that there must be some principle influencing this revolution
from the fowl to the egg and from the egg back to the fowl, which gives
them perpetuity. Now this, according to Aristotle’s views,[215] is
analogous to the element of the stars; and is that which makes parents
engender, and gives fertility to their ova; and the same principle,
Proteus like, is present under a different form, in the parents as in
the eggs. For, as the same intelligence or spirit which incessantly
actuates the mighty mass of the universe, and compels the same sun from
the rising to the setting, in his passage over the various regions of
the earth, so also is there a vis enthea, a divine principle inherent in
our common poultry, showing itself now as the plastic, now as the
nutritive, and now as the augmentative force, though it is always and at
all times present as the conservative and vegetative force, and now
assumes the form of the fowl, now that of the egg; but the same virtue
continues to inhere in either to eternity. And although some animals
arise spontaneously, or as is commonly said from putrefaction, and some
are produced from the female alone, for Pliny[216] says: “in some
genera, as in certain fishes, there are no males, every one taken being
found full of roe;” still whatever is produced from a perfect egg is so
in virtue of the indispensable concurrence of male and female.
Aristotle[217] consequently says: “the grand principles of generation
must be held to be the male and the female;” the first two principles of
the egg are therefore the male and the female; and the common point or
conception of these is the egg, which combines the virtues of both
parents. We cannot, in fact, conceive an egg without the concurrence of
a male and female fowl, any more than we can conceive fruit to be
produced without a tree. We therefore see individuals, males as well as
females, existing for the sake of preparing eggs, that the species may
be perennial, though their authors pass away. And it is indeed obvious,
that the parents are no longer youthful, or beautiful, or lusty, and
fitted to enjoy life, than whilst they possess the power of producing
and fecundating eggs, and, by the medium of these, of engendering their
like. But when they have accomplished this grand purpose of nature, they
have already attained to the height, the ακμὴ of their being,--the final
end of their existence has been accomplished; after this, effete and
useless, they begin to wither, and, as if cast off and forsaken of
nature and the Deity, they grow old, and, a-weary of their lives, they
hasten to their end. How different the males when they make themselves
up for intercourse, and swelling with desire are excited by the venereal
impulse! It is surprising to see with what passion they are inflamed;
and then how trimly they are feathered, how vainglorious they show
themselves, how proud of their strength, and how pugnacious they prove!
But, the grand business of life accomplished, how suddenly, with failing
strength and pristine fervour quenched, do they take in their swelling
sails, and, from late pugnacity, grow timid and desponding! Even during
the season of jocund masking in Venus’s domains, male animals in general
are depressed by intercourse, and become submissive and pusillanimous,
as if reminded that in imparting life to others, they were contributing
to their own destruction. The cock alone, replete with spirit and
fecundity, still shows himself alert and gay; clapping his wings, and
crowing triumphantly, he sings the nuptial song at each of his new
espousals! yet even he, after some length of time in Venus’s service,
begins to fail; like the veteran soldier, he by and by craves discharge
from active duty. And the hen, too, like the tree that is past bearing,
becomes effete, and is finally exhausted.


_Of the manner, according to Aristotle, in which a perfect and fruitful
egg is produced by the male and female fowl._

Shortly before we said that a fruitful egg is not engendered
spontaneously, that it is not produced save by a hen, and by her only
through the concurrence of the cock. This agrees with the matter of the
following sentence of Aristotle:[218] “The principles of generation have
particular reference to male and female; the male as supplying the
original of motion and reproduction; the female as furnishing the

In our view, however, an egg is a true generative seed, analogous to the
seed of a plant; the original conception arising between the two
parents, and being the mixed fruit or product of both. For as the egg is
not formed without the hen, so is it not made fruitful without the
concurrence of the cock.

We have therefore to inquire how the egg is produced by the hen and is
fertilized by the cock; for we have seen that hypenemic eggs, and these
animated too, are engendered by the hen, but that they are not prolific
without the intercourse of the cock. The male and the female
consequently, both set their mark upon a fruitful egg; but not, I
believe, in the way in which Aristotle imagines, viz.: that the male
concurs in the motion and commencement of generation only, the female
supplying nothing but the matter, because the contrary of this is
obvious in hypenemic eggs. And although it be true as he says: “That
male and female differ in respect of reason, because the faculty of each
is different, and, in respect of sense, because certain parts differ
likewise. The difference according to reason boasts this distinction,
that the male has the power of engendering in another; the female has
only the power of engendering in herself; whereby it comes that that
which is engendered is produced, this being contained in that which
engenders. But as males and females are distinguished by certain
faculties and functions, and as an instrument is indispensable to every
office, and the parts of the body are adapted as instruments of the
functions, it was necessary that certain parts should be set aside for
purposes of procreation and coition, and these differing from one
another, whereby the male differs from the female.”

It does not, however, follow from thence, that what he appears inclined
to infer is correct, where he says: “The male is the efficient agent,
and by the motion of his generative virtue (genitura), creates what is
intended from the matter contained in the female; for the female always
supplies the matter, the male the power of creation, and this it is
which constitutes one male, another female. The body and the bulk,
therefore, are necessarily supplied by the female; nothing of the kind
is required from the male; for it is not even requisite that the
instrument, nor the efficient agent itself, be present in the thing that
is produced. The body, then, proceeds from the female, the vital
principle (anima) from the male; for the essence of every body is its
vital principle (anima).” But an egg, and that animated, is engendered
by the pullet without the concurrence of the male; whence it appears
that the hen too, or the female, may be the efficient agent, and that
all creative force or vital power (anima) is not derived exclusively
from the male. This view indeed appears to be supported by the instance
quoted by Aristotle himself, for he says:[219] “Those animals not of the
same species, which copulate, (which those animals do that correspond
in their seasons of heat and times of uterogestation, and do not differ
greatly in their size,) produce their first young like themselves, but
partaking of the species of both parents; of this description is the
progeny of the fox and dog, of the partridge and common fowl, &c.; but
in the course of time from diversity results diversity, and the progeny
of these different parents at length acquires the form of the female; in
the same way as foreign seed is changed at last in conformity with the
nature of the soil, which supplies matter and body to the seed.”

From this it appears, that in the generation of the partridge with the
common fowl it is not the male alone that is efficient, but the female
also; inasmuch as it is not the male form only, but one common or
subordinate that appears in the hybrid, as like the female as it is like
the male in vital endowment (anima), and bodily form. But the vital
endowment (anima) is that which is the true form and species of an

Farther, the female seems even to have a superior claim to be considered
the efficient cause: “In the course of time,” says the philosopher, “the
progeny of different species assumes the form of the female;” as if the
semen or influence of the male were the less powerful; as if the species
impressed by him disappeared with the lapse of time, and were expelled
by a more powerful efficient cause. And the instance from the soil
confirms this still farther: “for foreign seeds are changed at length
according to the nature of the soil.” Whence it seems probable that the
female is actually of more moment in generation than the male; for, “in
the world at large it is admitted that the earth is to nature as the
female or mother, whilst climate, the sun, and other things of the same
description, are spoken of by the names of generator and father.”[220]
The earth, too, spontaneously engenders many things without seed; and
among animals, certain females, but females only, procreate of
themselves and without the concurrence of the male: hens, for example,
lay hypenemic eggs; but males, without the intervention of females,
engender nothing.

By the same arguments, indeed, by which the male is maintained to be the
principle and prime ‘efficient’ in generation, it would seem that the
female might be confirmed in the prerogative of ὲνεργεία or efficiency.
For is not that to be accounted efficient in which the reason of the
embryo and the form of the work appear; whose obvious resemblance is
perceived in the embryo, and which, as first existing, calls forth the
other? Since, therefore, the form, cause, and similitude inhere in the
female not less--and it might even be said that they inhere more--than
in the male, and as she also exists previously as prime mover, let us
conclude for certain that the female is equally efficient in the work of
generation as the male.

And although Aristotle[221] says well and truly, “that the conception or
egg receives no part of its body from the male, but only its form,
species, and vital endowment (anima), and from the female its body
solely, and its dimensions,” it is not yet made sufficiently to appear
that the female, besides the matter, does not in some measure contribute
form, species, and vital endowment (anima). This indeed is obvious in
the hen which engenders eggs without the concurrence of a male; in the
same way as trees and herbs, in which there is no distinction of sexes,
produce their seeds. For Aristotle himself admits,[222] that even the
hypenemic egg is endowed with a vital principle (anima). The female must
therefore be esteemed the efficient cause of the egg.

Admitting that the hypenemic egg is possessed of a certain vital
principle, still it is not prolific; so that it must further be
confessed that the hen of herself is not the efficient cause of a
perfect egg, but that she is made so in virtue of an authority, if I may
use the word, or power required of the cock. For the egg, unless
prolific, can with no kind of propriety be accounted perfect; it only
obtains perfection from the male, or rather from the female, as it were
upon precept from the male; as if the hen received the art and reason,
the form and laws of the future embryo from his address. And so in like
manner the female fowl, like to a fruitful tree, is made fertile by
coition; by this is she empowered not only to lay eggs, but these
perfect and prolific eggs. For although the hen have as yet no rudiments
of eggs prepared in her ovary, nevertheless, made fertile by the
intercourse of the male, she by and by not only produces them there, but
lays them, teeming with life, and apt to produce embryos. And here that
practice of the poor folks finds its application: “Having hens at home,
but no cock, they commit their females to a neighbour’s male for a day
or two; and from this short sojourn the fecundity of the whole of the
eggs that will be laid during the current season is secured.”[223] Not
only are those eggs which are still nothing more than yelk and have no
albumen, or which exist only as most minute specks in the ovary, but
eggs not yet extant, that will be conceived long afterwards, rendered
fertile by the same property.


_Of the uses of this disquisition on fecundity._

This disquisition on the inherent qualities of the egg and the cause of
its fecundity, is alike in point of difficulty and subtlety, but of the
highest importance. For it was imperative on us to inquire what there
was in the conception, what in the semen masculinum, and what in the
female fowl, which render these fertile; and what there is in the
fruitful cock which makes him differ from a bird that is barren. Is the
cause identical with that which we have called the vital principle
(anima) in the embryo, or it is a certain portion of the vegetative
principle? Because, in order to apprehend the entire cause of
generation, it is of much moment that the first cause be understood; for
science is based upon causes, especially first causes, known. Nor is
this inquiry less important in enabling us to understand the nature of
the vital principle (anima). These questions, indeed, rightly
apprehended, not only are Aristotle’s opinions of the causes of
generation refuted or corrected, but all that has been written against
him is easily understood.

We ask, therefore, whether it is the same thing or something different,
which in the rudimentary ovum, yelk, egg, cock and hen, or her uterus,
confers fruitfulness? In like manner in what respect does this something
agree or differ in each? Still farther, is it a substance whence the
fecundating virtue flows?--it appears susceptible of powers, faculties,
and accidents. Likewise, is it corporeal also? for that which engenders
mixture appears to be mixed:--the progeny has a common resemblance to
the mother and father, and exhibits a doubtful nature when animals of
dissimilar species, such as the pheasant and common fowl, engender;
that, too, appears to be corporeal which suffers from without, and to
such an extent that not only are weakly embryos procreated, but even
deformed and diseased ones, obnoxious to the vices as well as to the
virtues of their progenitors.

With respect to these several particulars we may farther be permitted to
doubt whether that which confers fecundity is engendered or accrues from
without? Whether, to wit, it is transfused from the egg to the embryo
and chick, from the hen to the egg, from the cock to the hen? For there
appears to be something that is transferred or transfused, something,
namely, which from the cock is transfused into the hen, and from her is
given to the uterus, to the ovary, to the egg; something which passing
from the seed to the plant, is rendered again by the plant to the seed,
and imparts fecundity. Because there is this common to all things which
are perpetuated by generation, that they derive their origin from seed.
But the semen, the conception, and the egg, are all of the same
essential kind, and that which confers fertility on these is one and the
same, or of like nature; and this indeed is divine, the analogue of
heaven, possessed of art, intelligence, foresight. This is plainly to be
seen from its admirable operations, artifices, and wisdom, where nothing
is vain, or inconsiderate, or accidental, but all conduces to some good

Of the general principles and science of this subject we shall treat
more at length in the proper place; we have now said as much
incidentally as seems necessary, the occasion having presented itself
along with our consideration of the hen’s egg, namely, how many things
inhere which induce fertility, and how this is induced, and whether it
is an affection, a habit, a power, or a faculty; whether it is to be
regarded as a form and substance, as a something contained generally, or
only in some particular part--since it is quite certain that a hypenemic
egg is a perfect egg in so far as each sensible particular is concerned,
and yet is barren; the uterus in like manner, and the hen and the cock
are all perfect; yet are they severally sterile, as being without that
which confers fecundity. All of these matters we shall advert to after
we have shown what and how two principles, male and female, concur in
the production of the egg and the process of generation, and in what way
both may be regarded as efficient causes and parents of the egg.


_The egg is not produced by the cock and hen in the way Aristotle would
have it._

It is certain, as we have said, that a fruitful egg is not produced
without the concurrence of the cock and hen; but this is not done in the
way that Aristotle thought, viz. by the cock as prime and sole ‘agent,’
the hen only furnishing the ‘matter.’ Neither do I agree with him when
he says:[224] “When the semen masculinum enters the female uterus, it
coagulates the purest portion of the catamenia;” and shortly afterwards:
“but when the catamenia of the female has set in the uterus, it forms,
with the semen masculinum, a coagulum like that of milk; for curd is
milk containing vital heat, which attracts like particles around it, and
combines and coagulates them; and the semen of the male (genitura) bears
the same affinity to the nature of the catamenia. For milk and the
menstrual discharge are of the same nature. When coagulation has taken
place, then an earthy humour is excreted and is drawn around, and the
earthy portion drying up, the membranes are produced both as matter of
necessity, and also for a certain purpose. And these things take place
in the same manner in all creatures, both oviparous and viviparous.”

But the business in the generation of an egg is very different from
this; for neither does the semen, or rather the ‘geniture,’ proceeding
from the male in the act of intercourse, enter the uterus in any way,
nor has the hen, after she conceives, any particle of excrementitious
matter, even of the purest kind, or any blood in her uterus which might
be fashioned or perfected by the discharge of the male. Neither are the
parts of the egg, the membranes, to wit, and the fluids, produced by
any kind of coagulation; neither is there any thing like curdled milk to
be discovered in the uterus, as must be obvious from the foregoing
exercises. It follows, therefore, and from thence, that neither does the
conception, whence the animal springs, as the herb arises from a
fruitful seed, comport itself in the manner Aristotle imagined, since
this takes place in viviparous animals in the same way as the egg is
formed in oviparous animals, as he himself avows, and as shall be
demonstrated by and by in our observations. Because it is certain that
eggs of every description--prolific and barren--are engendered and
formed by the hen singly, but that fecundity accrues from the male
alone;--the cock, I say, contributes neither form nor matter to the egg,
but that only by which it becomes fertile and fit to engender a chick.
And this faculty the cock confers by his semen (genitura), emitted in
the act of intercourse, not only on the egg that is already begun, or is
already formed, but on the uterus and ovary, and even on the body of the
fowl herself, in such wise that eggs which have yet to be produced,
eggs, none of the matter of which yet exists either in the ovary or in
any other part of the body, are thence produced possessed of fecundity.


_Nor in the manner imagined by physicians._

Conception, according to the opinion of medical men, takes place in the
following way: during intercourse the male and female dissolve in one
voluptuous sensation, and eject their seminal fluids (genituræ) into the
cavity of the uterus, where that which each contributes is mingled with
that which the other supplies, the mixture having from both equally the
faculty of action and the force of matter; and according to the
predominance of this or of that geniture does the progeny turn out male
or female. It is farther imagined that immediately after the
intercourse, the active and passive principles cooperating, something of
the conception is formed in the uterus. For contrary to the
Aristotelians, they maintain that the male is no more the efficient
cause of generation than the female, but some mixture of the two; and
that neither the menstrual blood nor its purest part is the prime matter
of the conception, but the spermatic fluid; whence the first particles
or their rudiments are spoken of as spermatic, these at an after period
being nourished and made to increase through the blood.

But it is obvious that neither is the egg engendered by the cock and hen
in this way; for the hen in the act of intercourse emits no semen from
which an egg might be formed; nor can aught like a seminal fluid of the
hen be demonstrated at any time; and indeed the animal is destitute of
the organs essential to its preparation, the testes and vasa spermatica.
And though the hen have an effective force in common with the cock (as
must be manifest from what precedes), and it is a mixture of some sort
that renders an egg fruitful, still this does not happen according to
the predominance of the genitures, or the manner of their mixture, for
it is certain, and Fabricius admits it, that the semen of the cock does
not reach the cavity of the uterus; neither is there any trace of the
egg to be discovered in the uterus immediately after intercourse, and as
its consequence, although Aristotle himself repeatedly avers that there
is, asserting that “something of the conception forthwith ensues.” But I
shall by and by demonstrate that neither does any such imaginary mixture
of seminal fluids take place in any animal, nor that immediately upon
intercourse, even of a fruitful kind, is there anything in the shape of
semen or blood, or of the rudiments of an embryo present or demonstrable
in the cavity of the uterus. Nothing is found in the egg or embryo which
leads us to suppose that the semen masculinum is either there contained
or mingled. The vulgar notion of the chalazæ being the tread of the cock
is a sheer mistake; and I am surprised, since there are two of them, one
in either end of the egg, that no one has yet been found to maintain
that this was the cock’s seed, that the hen’s. But this popular error is
at once answered by the fact that the chalazæ are present with the same
characters in every egg, whether it be fertile or barren.


_The male and the female are alike efficient in the business of

The medical writers with propriety maintain, in opposition to the
Aristotelians, that both sexes have the power of acting as efficient
causes in the business of generation; inasmuch as the being engendered
is a mixture of the two which engender: both form and likeness of body,
and species are mixed, as we see in the hybrid between the partridge and
common fowl. And it does indeed seem consonant with reason to hold that
they are the efficient causes of conception whose mixture appears in the
thing produced.

Aristotle entertaining this opinion says:[225] “In some animals it is
manifest that such as the generator is, such is the engendered; not,
however, the same and identical, not one numerically, but one
specifically, as in natural things. A man engenders a man, if there be
nothing preternatural in the way, as a horse [upon an ass] engenders a
mule, and other similar instances. For the mule is common to the horse
and the ass; it is not spoken of as an allied kind; yet may horse and
ass both be there conjoined in a hybrid state.” He says farther in the
same place: “It is enough that the generator generate, and prove the
cause that the species be found in the matter: for such and such an
entire species is still found associated with such and such flesh and
bones--here it is Gallias, there it is Socrates.”

Wherefore if such an entire form, as a mule, be a mixture of two, viz.:
a horse and an ass, the horse does not suffice to produce this form of a
mule in the ‘matter;’ but, as the entire form is mixed, so another
efficient cause is contributed by the ass and added to that supplied by
the horse. That, therefore, which produces a mule compounded of two,
must itself be an ‘adequate efficient,’ and mixed, if only ‘univocal.’
For example, this woman and that man engender this Socrates; not in so
far as they are both human beings, and of one and the same species, but
in so far as this man and that woman in these bones and muscles
constitute human forms, of both of which, if Socrates be a certain
mixture, a compound of both, that by which he is made must needs be a
mixed univocal compound of the two; i. e. a mixed efficient of a mixed
effect. And therefore it is that the male and female by themselves, and
separately, are not genetic, but become so united _in coitu_, and made
one animal as it were; whence, from the two as one, is produced and
educed that which is the true efficient proximate cause of conception.

The medical writers also, in directing their attention to the
particulars of human generation alone, come to conclusions on generation
at large; and the spermatic fluid proceeding from the parents _in coitu_
has in all probability been taken by them for true seed, analogous to
the seeds of plants. It is not without reason, therefore, that they
imagine the mixed efficient cause of the future offspring to be
constituted by a mixture of the seminal matters of each parent. And then
they go on to assert that the mixture proceeding immediately from
intercourse is deposited in the uterus and forms the rudiments of the
conception. That things are very different, however, is made manifest by
our preceding history of the egg, which is a true conception.


_Of the matter of the egg, in opposition to the Aristotelians and the
medical writers._

The position taken up by the medical writers against the Aristotelians,
viz., that the blood is not the first element in a conception, is
clearly shown from the generation of the egg to be well chosen: neither
during intercourse, nor before nor after it, is there a drop of blood
contained in the uterus of the fowl; neither are the rudiments of eggs
red, but white. Many animals also conceive in whose uteri, if they be
suddenly laid open after intercourse, no blood can be demonstrated.

But when they contend that the maternal blood is the food of the fœtus
in utero, especially of its more sanguineous parts, as they style them,
and that the fœtus from the outset is as it were a portion of the
mother, being nourished and growing through her blood, and vegetating
through her spirit; so that neither does the heart pulsate, nor the
liver compose blood, nor any part of the fœtus perform any kind of
independent office, but everything is carried on through the mother’s
means, they in their turn are as certainly mistaken, and argue from
erroneous observations. For the embryo in the egg boasts of its own
blood, formed from the fluids contained within the egg; and its heart is
seen to pulsate from the very beginning: it borrows nothing in the shape
either of blood or spirits from the hen, for the purpose of forming its
so called sanguineous parts and its feathers; as most clearly appears to
any one who looks on with an unbiassed mind. From observations
afterwards to be communicated, I believe indeed that it will be held as
sufficiently proven that even the fœtus of viviparous animals still
contained in the uterus is not nourished by the blood of the mother and
does not vegetate through her spirit; but boasts of its own peculiar
vital principle and powers, and its own blood, like the chick in ovo.

With reference to the matter which the embryo obtains from its male and
female parent, however, and the way and manner of generation as commonly
discoursed of in the schools, viz.: that conception is produced or
becomes prolific from mixture of the genitures and their mutual action
and passion, as also of the seminal fluid of the female, and the parts
which are spoken of as sanguineous and spermatic, numerous and striking
observations afterwards to be related have compelled me to adopt
opinions at variance with all such views. At this time I shall only say
that I am greatly surprised how physicians, particularly those among
them who are conversant with anatomy, should pretend to support their
opinions by means of two arguments especially, which rightly understood,
seem rather to prove the opposite; viz., from the shock and resolution
of the forces and the effusion of fluid which women at the moment of the
sexual orgasm frequently experience, they argue that all women pour out
a seminal fluid, and that this is necessary to generation.

But passing over the fact that the females of all the lower animals, and
all women, do not experience any such emission of fluid, and that
conception is nowise impossible in cases where it does not take place,
for I have known several, who without anything of the kind were
sufficiently prolific, and even some who after experiencing such an
emission and having had great enjoyment, nevertheless appeared to have
lost somewhat of their wonted fecundity; and then an infinite number of
instances might be quoted of women who, although they have great
satisfaction in intercourse, still emit nothing, and yet conceive;
passing over these facts, I say, I cannot but express surprise at those
especially, who, conceiving such an emission on the part of the female
necessary to conception, have not adverted to the fact that the fluid
emitted is discharged, cast out, and is particularly abundant about the
clitoris and orifice of the vulva; that it is seldom poured out within
the vulva, never within the uterus, and so as to be mingled with the
semen of the male; moreover, it is of a mere serous or ichorous
consistency, like urine, by no means thick and apparently unctuous, like
the spermatic matter of the male. But how shall we suppose that to be of
use internally which is discharged externally? Or shall we say that this
humour, as if bidding the uterus farewell, is taken to the verge of the
vulva, that it may be then recalled with greater favour by the uterus?

The other argument is drawn from the genital organs of women, the
testes, to wit, and vasa spermatica, præparantia et deferentia, which
are held to serve for the preparation of the spermatic fluid. I, for my
part, greatly wonder how any one can believe that from parts so
imperfect and obscure, a fluid like the semen, so elaborate, concoct and
vivifying, can ever be produced, endowed with force and spirit and
generative influence adequate to overcome that of the male; for this is
implied in the discussion concerning the predominance of the male or the
female, as to which of them is to become the agent and efficient cause,
which the matter and pathic principle. How should such a fluid get the
better of another concocted under the influence of a heat so fostering,
of vessels so elaborate, and endowed with such vital energy?--how should
such a fluid as the male semen be made to play the part of mere
matter?--But of these things more hereafter.

Meantime it is certain that the egg of the hen is not engendered from
any such discharge of fluid during sexual intercourse, although after
connexion, and brimful of satisfaction, she shakes herself for joy,
and, as if already possessed of the richest treasure, as if gifted by
supreme Jove the preserver with the blessing of fecundity, she sets to
work to prune and ornament herself. The pigeon, particularly that kind
which comes to us from Africa, expresses the satisfaction she feels from
intercourse in a remarkable manner; she leaps, spreads her tail, and
sweeps the ground with its extremity, she pecks and prunes her
feathers--all her actions are as if she felt raised to the summit of
felicity by the gift of fruitfulness.

We have said that the primary matter of the egg does not consist of
blood as Aristotle would have it, neither does it proceed from any
mixture of the male and female seminal fluids. Whence it truly
originates we have already stated in part in our history; and we shall
by and by have occasion to speak of the subject more at length when we
come to treat generally of the matter from which every conception is
originally produced.


_In how far is the fowl efficient in the generation of the egg,
according to Aristotle? And wherefore is the concurrence of the male

It has been already stated that the cock and hen are the two principles
in the generation of the egg, although of the manner in which they are
so I am of a different opinion from Aristotle and medical authorities.
From the production of the egg we have clearly shown that the female as
well as the male was efficient, and that she had within her a principle
whence motion and the faculty of forming flowed; although in the sexual
act the male neither confers the matter, nor does the female eject any
semen whence the egg is constituted. It is consequently manifest, in
some animals at least, that nature has not, on account of the
distinction into male and female, established it as a law that the one,
as agent, should confer form, the other, as passive, supply matter, as
Aristotle apprehended; nor yet that during intercourse each should
contribute a seminal fluid, by the mixture of which a conception or
ovum should be produced, as physicians commonly suppose.

Now since everything that has been delivered by the ancients on
generation is comprehended in these two opinions, it appears to have
escaped every one up to this time, first, why the hen by herself does
not generate, like vegetables, but requires a male to be associated with
her in the work; and then how the conception or ovum is procreated by
the male and the female together, or what either of them contributes to
the process, and for what end intercourse was established.

Aristotle, in opposition to the entire tenor of his hypothesis, viz.
that the male is to be regarded as the agent, the female as supplying
the matter only, when he sees that eggs are actually produced by hens
without the concurrence of the male, is compelled to admit that the
female is likewise efficient; he was farther not ignorant of the fact
that an egg even when extruded could preserve itself, nourish itself,
increase in size and produce an embryo, as happens with the eggs of
fishes; and he has besides accorded a vital principle to an egg, even to
a hypenemic one. But he endeavours to explain to what extent a female is
efficient, and how a hypenemic egg is endowed with a vital principle, in
the passage where he says[226]: “Hypenemic eggs admit of generation to a
certain point; for that they can ever go the length of producing an
animal is impossible, this being the work of the senses [the sensible
soul]. But females and all things that live, as already repeatedly
stated, possess the vegetative soul. Wherefore the hypenemic egg as a
vegetable is perfect, but as an animal it is imperfect.” By this he
seems to insinuate that the hypenemic egg is possessed of a vegetative
soul, inasmuch as this is inherent in all things that live, and an egg
is alive. In like manner he ascribes to the hen the power of creating
and of conferring the vegetative soul; because all females acquire this
virtue, so that a hypenemic egg in so far as it lives as a vegetable is
perfect, in so far as it is an animal however it is imperfect. As if a
male were not required that a conception or ovum should be produced, and
produced perfect; but that from this ovum an animal should be
engendered. Not, I say, that an egg be produced as perfect in all
respects as is the conception of a vegetable; but that it should be
imbued with the animal principle. The egg, consequently, is formed by
the hen, but it is made prolific by the cock.

Aristotle adds in the same place: “There is a distinction of sexes
through the whole class of birds. And therefore it happens that the hen
perfects her egg, not yet influenced by the intercourse of the male, in
so far as it is a plant; but as it is not a plant, there she does not
perfect it: nor does anything come of it which engenders. For neither
has it arisen simply, like the seed of a plant, nor like an animal
conception, by intercourse.” He is here speaking of the wind egg; by and
by he adds: “But those eggs that are conceived through intercourse are
already characterized in a portion of the albumen: such eggs become
fruitful through the male which first copulated, for they are then
supplied with both principles.”

By this he seems to confess that the female is also effective in the
work of generation, or is possessed of the faculty of engendering;
because in every female there inheres a vegetative soul, whose faculty
it is to engender. And, therefore, when he is speaking of the
differences between the male and female, he still acknowledges both as
generative; for he says: “We call that animal male which engenders in
another, female that which engenders in itself.” From his own showing,
therefore, both engender; and as there is a vegetative soul inherent in
both, so is there also its faculty of generation. But how they differ
has already been shown in the History of the Egg: the hen generates of
herself without the concurrence of the cock, as a plant out of itself
produces fruit; but it is a wind egg that is thus produced: it is not
made fruitful without the concurrence of the cock either preceding or
succeeding. The female generates, then, but it is only up to a certain
mark, and the concurrence of the male is requisite that this faculty of
engendering be made complete, that she may not only lay an egg, but such
an egg as will, under favorable circumstances, produce a pullet. The
male appears to be ordained by nature to supply this deficiency in the
generative powers of the female, as will be clearly shown by and by, and
that that which the female of herself cannot accomplish, viz. the
production of a fruitful egg, may be supplied and made good by the act
of the male, who imparts this virtue to the fowl or the egg.


_The perfect hen’s egg is of two colours._

Every egg, then, is not perfect; but some are to be held imperfect
because they have not yet attained their true dimensions, which they
only receive when extruded; others are imperfect because they are yet
unprolific, and only acquire a fertilizing faculty from without, such
are the eggs of fishes. Other eggs again are held imperfect by
Aristotle, because they are of one colour only, inasmuch as perfect eggs
consist of yelk and albumen, and are of two colours, as if better
concocted, more distinct in their parts, endowed with higher heat. The
eggs that are called centenine or hundredth eggs, and which
Fabricius[227] will have it are engendered of certain remainders of
albumen, are of one colour only, and by reason of their deficiency of
heat and their weakness, are regarded as imperfect. Of all eggs, there
are none more perfect than those of the hen, which are produced complete
in all their fluids and appendages, of proper size and fruitful.

Aristotle assigns the following reason wherefore some eggs are of two
colours, others of one hue only:[228] “In the hotter animals those
things from which the principles of their origin are derived, are
distinct and separate from those which furnish their nutrition; now the
one of these is white, the other is yellow.” As if the chick derived its
origin from the albumen and was nourished by the vitellus alone. In the
same place he proceeds thus: “That part which is hot contributes
properly to the form in the constitution of the extremities; but the
part that is more earthy, and is further removed, supplies material for
the trunk. Whence in eggs of two colours the animal derives its origin
from the white, for the commencement of animal existence is in the
white; but the nourishment is obtained from the yellow.” He consequently
thinks that this is the reason why these fluids are distinct, and why
eggs are produced of two colours.

Now these ideas are partly true, partly false. It is not true, for
instance, that the embryo of the common fowl is first formed from the
albumen and then nourished by the vitellus; for, from the history of the
formation of the chick in ovo, from the course of the umbilical vessels
and the distribution of their branches, which undoubtedly serve for
obtaining nourishment, it obviously appears that the constituent matter,
and the nutriment are supplied to the chick from its first formation by
the yelk, as well as the white; the fluid which we have called the
colliquament seems farther to be supplied, not less by the vitellus than
the albumen; a certain portion of both the fluids seems, in fact, to be
resolved. And then the spot, by the expansion of which the colliquament
is formed in the first instance, and which we have called the eye,
appears to be impressed upon the membrane of the vitellus.

The distinction into yellow and white, however, seems to be a thing
necessary: these matters, as they are undoubtedly of different natures,
appear also to serve different offices; they are therefore completely
separate in the perfect egg, one of them being more the other less
immediately akin to proper alimentary matter; by the one the fœtus is
nourished from the very beginning, by the other it is nourished at a
later period. For it is certain, as Fabricius asserts, and as we
afterwards maintain, that both of them are truly nutritious, the albumen
as well as the vitellus, the albumen being the first that is consumed. I
therefore agree with Aristotle against the physicians, that the albumen
is the purer portion of the egg, the better concocted, the more highly
elaborated; and, therefore, whilst the egg is getting perfected in the
uterus, is the albumen as the hotter portion poured around in the
circumference, the yelk or more earthy portion subsiding to the centre.
For the albumen appears to contain the larger quantity of animal heat,
and so to be nutriment of a more immediate kind. For like reasons it is
probable that the albumen is purer and better concocted externally than
it is internally.

When medical writers affirm that the yelk is the hotter and more
nutritious portion of the egg, this I imagine is meant as it affords
food to us, not as it is found to supply the wants of the chick in ovo.
This, indeed, is obvious from the history of the formation of the chick,
by which the thin albumen is absorbed and used up sooner than the
thick, as if it formed the more appropriate aliment, and were more
readily transmuted into the substance of the embryo, of the chick that
is to be. The yelk, therefore, appears to be a more distant or ultimate
aliment than the albumen, the whole of which has been used up before any
notable portion of the vitellus is consumed. The yelk, indeed, is still
found inclosed within the abdomen of the chick after its exclusion from
the shell, as if it were destined to serve the new being in lieu of milk
for its sustenance.

Eggs, consisting of white and yellow, are therefore more perfect, as
more distinct in constitution, and elaborated by a higher temperature.
For in the egg there must be included, not only the matter of the chick
but also its first nutriment; and what is provided for a perfect animal,
must, itself, be perfect and highly elaborated; as that is, in fact,
which consists of different parts, some of which, as already stated, are
prior and purer, and so more easy of digestion; others posterior, and
therefore more difficult of transmutation into the substance of the
chick. Now the yelk and albumen differ from one another by such kinds of
distinction. Perfect eggs are, consequently, of two colours: they
consist of albumen and yelk, as if these constituted fluids of easier or
more difficult digestion, adapted to the different ages and vigour of
the chick.


_Of the manner in which the egg is increased by the albumen._

From the history it appears that the rudiments of the eggs in the ovary
are of very small size, mere specks, smaller than millet seeds, white
and replete with watery fluid: these specks, however, by and by, become
yelks, and then surround themselves with albumen.

Aristotle seems to think that the albumen is generated in the way of
secretion from the vitellus. It may be well to add his words:[229] “The
sex,” he says, “is not the cause of the double colour, as if the white
were derived from the male, the yellow from the female; both are
furnished by the female. But one of them is hot, the other is cold. Now
these two portions are distinct in animals, fraught with much heat; in
those that are not so fraught the eggs are not thus distinct. And this
is the reason why the conceptions of these are of one colour. But the
semen of the male alone sets the conception; therefore is the conception
of the bird small and white in the first instance; but in the course of
time, and when there is a larger infusion of blood, it becomes entirely
yellow; and, last of all, when the heat declines, the white portion, as
a humour of equal temperature surrounds it on every side. For the white
portion of the egg is, by its nature, moist, and includes animal heat in
itself; and it is for this reason that it is seen in the circumference,
the yellow and earthy portion remaining in the interior.”

Fabricius,[230] however, thinks that “the albumen only adheres to the
vitellus by juxtaposition. For while the yelk is rolled through the
second uterus and gradually descends, it also gradually assumes to
itself the albumen which is there produced, and made ready, that it may
be applied to the yelk; until the yelk having passed the middle spirals
and reached the last of them, already surrounded with the albumen, it
now surrounds itself with the membranes and shell.” Fabricius will
therefore have it that the egg increases in a two-fold manner: “partly
by means of the veins, as concerns the vitellus, and partly by an
appositive increase, as regards the albumen.” And, among other reasons,
this was perchance one for the above opinion: that when an egg is boiled
hard the albumen is readily split into layers lying one over another.
But this also occurs to the yelk still connected with the ovary, when
boiled hard.

Wherefore, taught by experience, I rather incline to the opinion of
Aristotle; for the albumen is not merely perceived as added in the way
Fabricius will have it, but fashioned also, distinguished by chalazæ and
membranes, and divided into two different portions; and all this in
virtue of the inherence of the same vegetative vital principle by which
the egg is more conspicuously divided into two distinct substances--a
yelk and a white. For the same faculty that presides over the formation
of the egg in general, presides over the constitution of each of its
parts in particular. Neither is it altogether true that the yelk is
first formed and the albumen added to it afterwards; for what is seen in
the ovary is not the vitellus of the egg, but rather a compound
containing the two liquids mingled together. It has the colour of the
vitellus, indeed, but in point of consistence it is more like the
albumen; and when boiled hard it is not friable like the proper yelk,
but, like the white, is concreted, jelly-like, and seen to be composed
of thin lamellæ; and it has a kind of white papula, or spot, in the

Aristotle seems to derive this separation from the dissimilar nature of
the yelk and white; for he says,[231] as we have already stated, that if
a number of eggs be thrown into a pan and boiled, in such wise that the
heat shall not be quicker than the separation of the eggs, (citatior
quam ovorum distinctio,) the same thing will take place in the mass of
eggs which occurs in the individual egg: the whole of the yelks will set
in the middle, the whites round about them.

This I have myself frequently found to be true on making the trial, and
it is open to any one to repeat the experiment; let him only beat yelks
and whites together, put the mixture into a dutch oven, or between two
plates over the fire, and having added some butter, cause it to set
slowly into a cake, he will find the albumen covering over the yelks
situated at the bottom.


_Of what the cock and hen severally contribute to the production of the

Both cock and hen are to be reputed parents of the chick; for both are
necessary principles of an egg, and we have proved both to be alike its
efficient: the hen fashions the egg, the cock makes it fertile. Both,
consequently, are instruments of the plastic virtue by which this
species of animal is perpetuated.

But as in some species there appears to be no occasion for males,
females sufficing of themselves to continue the kind; so do we discover
no males among these, but females only, containing the fertile rudiments
of eggs in their interior; in other species, again, none but males are
discovered which procreate and preserve their kinds by emitting
something into the mud, or earth, or water. In such instances nature
appears to have been content with a single sex, which she has used as an
instrument adequate to procreation.

Another class of animals has a generative fluid fortuitously, as it
were, and without any distinction of sex; the origin of such animals is
spontaneous. But “as some things are made by art, and some depend on
accident, health for example,”[232] so also some semen of animals is not
produced by the act of an individual agent, as in the case of a man
engendered by a man; but in some sort univocally, as in those instances
where the rudiments and matter, produced by accident, are susceptible of
taking on the same motions as seminal matter, as in “animals which do
not proceed from coitus, but arise spontaneously, and have such an
origin as insects which engender worms.”[233] For as mechanics perform
some operations with their unaided hands, and others not without the
assistance of particular tools; and as the more excellent and varied and
curious works of art require a greater variety in the form and size of
the tools to bring them to perfection, inasmuch as a greater number of
motions and a larger amount of subordinate means are required to bring
more worthy labours to a successful issue--art imitating nature here as
everywhere else, so also does nature make use of a larger number and
variety of forces and instruments as necessary to the procreation of the
more perfect animals. For the sun, or Heaven, or whatever name is used
to designate that which is understood as the common generator or parent
of all animated things, engenders some of themselves, by accident,
without an instrument, as it were, and equivocally; and others through
the concurrence of a single individual, as in those instances where an
animal is produced from another animal of the same genus which supplies
both matter and form to the being engendered; so in like manner in the
generation of the most perfect animals where principles are
distinguished, and the seminal elements of animated beings are divided,
a new creation is not effected save by the concurrence of male and
female, or by two necessary instruments. Our hen’s egg is of this kind;
to its production in the perfect state the cock and the hen are
necessary. The hen engenders in herself, and therefore does she supply
place and matter, nutriment and warmth; but the cock confers fecundity;
for the male, as Aristotle says,[234] always perfects generation,
secures the presence of a sensitive vital principle, and from such an
egg an animal is engendered.

To the cock, therefore, as well as to the hen, are given the organs
requisite to the function with which he is intrusted; in the hen all the
genital parts are adapted to receive and contain, as in the cock they
are calculated to give and immit, or prepare that which transfers
fecundity to the female, he engendering, as it were, in another, not in

When we anatomize the organs appropriated to generation, therefore, we
readily distinguish what each sex contributes in the process; for a
knowledge of the instruments here leads us by a direct path to a
knowledge of their functions.


_Of the cock and the particulars most remarkable in his constitution._

The cock, as stated, is the prime efficient of the perfect or fruitful
hen’s egg, and the chief cause of generation: without the male no chick
would ever be produced from an egg, and in many ovipara not even would
any egg be produced. It is, therefore, imperative on us that we look
narrowly into his offices and uses, and inquire particularly what he
contributes to the egg and chick, both in the act of intercourse and at
other times.

It is certain that the cock in coition emits his ‘geniture,’ commonly
called semen, from his sexual parts, although he has no penis, as I
maintain; because his testes and long and ample vasa deferentia are full
of this fluid. But whether it issues in jets, with a kind of spirituous
briskness and repeatedly as in the hotter viviparous animals, or not, I
have not been able to ascertain. But as I do not find any vesiculæ
containing semen, from which, made brisk and raised into a froth by the
spirits, it might be emitted; nor any penis through whose narrower
orifice it might be forcibly ejaculated, and so strike upon the interior
of the hen; and particularly when I see the act of intercourse so
rapidly performed between them; I am disposed to believe that the parts
of the hen are merely moistened with a very small quantity of seminal
fluid, only as much as will adhere to the orifice of the pudenda, and
that the prolific fluid is not emitted by any sudden ejaculation; so
that whilst among animals repeated ejaculations take place during the
same connection, among birds, which are not delayed with any complexity
of venereal apparatus, the same object is effected by repeated
connections. Animals that are long in connection, copulate rarely; and
this is the case with the swan and ostrich among birds. The cock,
therefore, as he cannot stay long in his connections, supplies by dint
of repeated treadings the reiterated ejaculations of the single
intercourse in other animals; and as he has neither penis nor glans,
still the extremities of the vasa deferentia, inflated with spirits when
he treads, become turgid in the manner of a glans penis, and the orifice
of the uterus of the hen, compressed by them, her cloaca being exposed
for the occasion, is anointed with genital fluid, which consequently
does not require a penis for its intromission.

We have said, however, that such was the virtue of the semen of the
cock, that not only did it render the uterus, the egg in utero, and the
vitelline germ in the ovary, but the whole hen prolific, so that even
the germs of vitelli, yet to be produced, were impregnated.

Fabricius has well observed, that the quantity of spermatic fluid
contained in the testes and vasa deferentia of the cock was large; not
that the hen requires much to fecundate each of her eggs, but that the
cock may have a supply for the large number of hens he serves and for
his repeated addresses to them.

The shortness and straight course of the spermatic vessels in the cock
also assist the rapid emission of the spermatic fluid: anything that
must pass through lengthened and tortuous conduits of course escapes
more slowly and requires a greater exercise of the impelling power or
spirit to force it away.

Among male animals there is none that is more active or more haughty and
erect, or that has stronger powers of digestion than the cock, which
turns the larger portion of his food into semen; hence it is that he
requires so many wives,--ten or even a dozen. For there are some
animals, single males of which suffice for several females, as we see
among deer, cattle, &c.; and there are others, of which the females are
so prurient that they are scarcely satisfied with several males, such as
the bitch and the wolf; whence prostitutes were called _lupæ_ or wolves,
as making their persons common; and stews were entitled _lupanaria_.
Whilst some animals, of a more chaste disposition, live, as it were, in
the conjugal estate, so that the male is married to a single female
only, and both take part in providing for the wants of the family; for
since nature requires that the male supply the deficiencies of the
female in the work of generation, and as she alone in many cases does
not suffice to cherish and feed and protect the young, the male is added
to the wife that he may take part in the burthen of bringing up the
offspring. Partridges lead a wedded life, because the females alone
cannot incubate such a number of eggs as they lay, (so that they are
said, by some, to make two nests,) nor to bring up such a family as by
and by appears without assistance. The male pigeon also assists in
building the nest, takes his turn in incubating the eggs, and is active
in feeding the young. In the same way many other instances of conjugal
life among the lower animals might be quoted, and indeed we shall have
occasion to refer to several in what yet remains to be said.

Those males, among animals, which serve several females, such as the
cock, have an abundant secretion of seminal fluid, and are provided with
long and ample vasa deferentia. And at whatever time or season the
clustered rudimentary papulæ in the ovary come to maturity and require
fecundation, that they may go on to be turned into perfect eggs, the
males will then be found to have an abundance of seminal fluid, and the
testicles to enlarge and become conspicuous in the very situation to
which they transfer their fecundating influence, viz. the præcordia.
This is remarkable in fishes, birds, and the whole race of oviparous
animals; the males of which teem with fecundating seminal fluid at the
same precise seasons as the females become full of eggs.

Whatever parts of the hen, therefore, are destined by nature for
purposes of generation, viz. the ovary, the infundibulum, the processus
uteri, the uterus itself, and the pudenda; as also the situation of
these parts, their structure, dimensions, temperature, and all that
follows this; all these, I say, are either subordinate to the production
and growth of the egg, or to intercourse and the reception of fecundity
from the male; or, for the sake of parturition, to which they conduce
either as principal and convenient means, or as means necessary, and
without which what is done could not be accomplished; for nothing in
nature’s works is fashioned either carelessly or in vain. In the same
way all the parts in the cock are fashioned subordinate to the
preparation or concoction of the spermatic fluid, and its transference
to the hen.

Now those males that are so vigorously constituted as to serve several
females are larger and handsomer, and in the matter of spirit and arms
excel their females in a far greater degree than the males of those that
live attached to a single female. Neither the male partridge, nor the
crow, nor the pigeon, is distinguished from the female bird in the same
decided way as the cock from his hens, the stag from his does, &c.

The cock, therefore, as he is gayer in his plumage, better armed, more
courageous and pugnacious, so is he replete with semen, and so apt for
repeated intercourse, that unless he have a number of wives he
distresses them by his frequent assaults; he not only invites but
compels them to his pleasure, and leaping upon them at inconvenient and
improper seasons, (even when they are engaged in the business of
incubation) and wearing off the feathers from their backs, he truly does
them an injury. I have occasionally seen hens so torn and worn by the
ferocious addresses of the cock, that with their backs stript of
feathers and laid bare in places, even to the bone, they languished
miserably for a time and then died. The same thing also occurs among
pheasants, turkeys, and other species.


_Of the hen._

There are two instruments and two first causes of generation, the male
and the female--for to the hen seems to belong the formation of the egg,
as to the cock the fertilizing principle. In the act of intercourse,
then, of these two, that which renders the egg fruitful is either
transmitted from the male to the female, or by means of coition is
generated in the hen. The nature of this principle, however, is no less
difficult to ascertain than are the particulars of its communication,
whether, for instance, we suppose such communication to take place with
the whole system of the hen, or simply with her womb, or with the egg
already formed, or further, with all the eggs now commencing and
hereafter about to commence their existence in the ovary. For it is
probable, from what I have formerly mentioned, and also from the
experiment of Fabricius,[235] that but a few acts of intercourse, and
the consorting of the hen with the cock for some days, are sufficient to
fecundate her, or at least her womb, during the whole year. And so far I
can myself affirm, from my own observation, to wit, that the twentieth
egg laid by a hen, after separation from the cock, has proved prolific.
So that, in like manner as it is well known that, from the seed of male
fishes shed into the water, a large mass of ova is impregnated, and that
in dogs, pigs, and other animals, a small number of acts of intercourse
suffice for the procreation of many young ones, (some even think it well
established, that if a bitch have connexion more than three or four
times, her fruitfulness is impaired, and that more females than males
are then engendered), so may the cock, by a few treadings, render
prolific not only the egg in the womb, but also the whole ovarium, and,
as has been often said, the hen herself. Nay, what is more remarkable,
and indeed wonderful, it is said that in Persia,[236] on cutting open
the female mouse, the young ones still contained in the belly are
already pregnant; in other words, they are mothers before they are
born! as if the male rendered not only the female fruitful, but also
impregnated the young which she had conceived; in the same way as our
cock fertilizes not merely the hen, but also the eggs which are about to
be produced by her.

But this is confidently denied by those physicians who assert that
conception is produced from a mixture of the seed of each sex. And hence
Fabricius,[237] although he affirms that the seed of the cock ejected in
coition never does, nor can, enter the cavity of the womb, where the egg
is formed, or takes its increase, and though he plainly sees that the
eggs when first commencing in the ovarium are, no less than those which
exist in the womb, fecundated by the same act of coition, and that of
these no part could arise from the semen of the cock, yet has he
supposed that this semen, as if it must needs be present and permanent,
is contained during the entire year in the “bursa” of the fruitful hen,
and reserved in a “foramen cæcum.” This opinion we have already
rejected, as well because that cavity is found in the male and female
equally, as because neither there, nor anywhere else in the hen, have we
been able to discover this stagnant semen of the cock; as soon as it has
performed its office, and impressed a prolific power on the female, it
either escapes out of the body, or is dissolved, or is turned into
vapour and vanishes. And although Galen,[238] and all physicians with
him, oppose by various reasonings this dissolving of the semen, yet, if
they carefully trace the anatomical arrangement of the genital parts,
and at the same time weigh other proofs of the strongest kind, they must
confess that the semen of the male, as it is derived from the testicles
through the vasa deferentia, and as it is contained in the vesiculæ
seminales, is not prolific unless it be rendered spiritual and
effervesce into a frothy nature by the incitement of intercourse or
desire. For it is not, as Aristotle[239] bears witness, its bodily form,
or fire, or any such faculty, that renders the semen prolific, but the
spirit which is contained in it, and the nature which inheres in it,
bearing a proportion to the element of the stars. Wherefore, though we
should allow with Fabricius that the semen is retained in the “bursa,”
yet, when that prolific effervescence or spirit had been spent, it
would forthwith be useless and sterile. Hence, too, physicians may learn
that the semen of the male is the architect of the progeny, not because
the first conception is embodied out of it, but because it is spiritual
and effervescent, as if swelling with a fertilising spirit, and a
preternatural influence. For otherwise the story of Averrhöes, of the
woman who conceived in a bath, might bear an appearance of truth. But of
these things more in their proper place.

In the same manner then as the egg is formed from the hen, so is it
probable, that from the _females_ of other animals, as will hereafter be
shown, the first conceptions take both material and form; and that, too,
some little time after the semen of the male has been introduced, and
has disappeared again. For the cock does not confer any fecundity on the
hen, or her eggs, by the simple emission of his semen, but only in so
far as that fluid has a prolific quality, and is imbued with a plastic
power; that is to say, is spiritual, operative, and analogous to the
essence of the stars. The male, therefore, is no more to be considered
the first principle, from which conceptions and the embryo arise,
because he is capable of secreting and emitting semen, than is the
female, which creates an egg without his assistance. But it is on this
consideration rather that he is entitled to his prerogative, that he
introduces his semen, imbued as it is with the spirit and the virtue of
a divine agent, such as, in a moment of time, performs its functions,
and conveys fertility. For, as we see things suddenly set on fire and
blasted by a spark struck from a flint, or the lightning flashing from a
cloud, so equally does the seed of the male instantly affect the female
which it has touched with a kind of contagion, and transfer to her its
prolific quality, by which it renders fruitful in a moment, not only the
eggs, but the uterus also, and the hen herself. For an inflammable
material is not set on fire by the contact of flame more quickly, than
is the hen made pregnant by intercourse with the cock. But what it is
that is transferred from him to her, we shall afterwards find occasion
to speak of, when we treat this matter specially and at greater length.

In the meantime we must remark, that, if it be derived from the soul,
(for whatever is fruitful is probably endowed also with a soul; and we
have said before, that the egg, in Aristotle’s opinion, as well as the
seeds of plants, has a vegetative soul,) that soul, or at all events the
vegetative one, must be communicated as a graft, and transferred from
the male to the female, from the female to the egg, from the egg to the
fœtus; or else be generated in each of these successively by the
contagion of coition.

The subject, nevertheless, seems full of ambiguity; and so Aristotle,
although he allows that the semen of the male has such great virtue,
that a single emission of it suffices for fecundating very many eggs at
the same time, yet, lest this admission should seem to gainsay the
efficacy of frequent repetitions of intercourse, he further says,[240]
“In birds, not even those eggs which arise through intercourse can
greatly increase in size, unless the intercourse be continued; and the
reason of this is, that, as in women, the menstrual excretion is drawn
downwards by sexual intercourse, (for the uterus, becoming warm,
attracts moisture, and its pores are opened,) so also does it happen
with birds, in which the menstrual excrement, because it accumulates
gradually, and is retained above the cincture, and cannot escape, from
being in small quantity, only passes off when it has reached the uterus
itself. For by this is the egg increased, as is the fœtus of the
viviparous animal by that which flows through the umbilicus. For almost
all birds, after but a single act of intercourse, continue to produce
eggs, but they are small.”

Now, so far perhaps would the opinion of Aristotle be correct, that more
and larger eggs are procured by frequently-repeated intercourse;
because, as he says, there may be “a flow of more fruitful material to
the womb, when warmed by the heat of coition;” not however that frequent
coition must necessarily take place in order to render the eggs that are
laid prolific. For experience, as we have said, teaches the contrary,
and the reason which he alleges does not seem convincing; since the
rudiments of eggs are not formed in the uterus from menstrual blood,
which is found in no part of the hen, but in the ovary, where no blood
pre-exists, and originate as well without, as along with the intercourse
of the cock.

The hen, as well as all other females, supplies matter, nutrition, and
place to the conception. The matter, whence the rudiments of all eggs
are produced in the ovary and take their increase, seems to be the very
same from which all the other parts of the hen, namely, the fleshy,
nervous, and bony structures, as well as the head and the rest of the
members, are nourished and grow. Nourishment is in fact conveyed to each
single papula and yelk contained in the ovary by means of vessels, in
the same way precisely as to all the other parts of the hen. But the
place where the egg is provided with membranes, and perfected by the
addition of the chalazæ and shell, is the uterus.

But that the hen neither emits any semen during intercourse, nor sheds
any blood into the cavity of the uterus, and that the egg is not formed
in the mode in which Aristotle supposed a conception to arise, nor, as
physicians imagine, from a mixture of the seminal fluids; as also that
the semen of the cock does not penetrate into, nor is attracted towards,
the cavity of the uterus of the hen, is all made manifestly clear by
this one observation, namely, that after intercourse there is nothing
more to be found in the uterus, than there was before the act. And when
this shall have been afterwards clearly established and demonstrated to
be true of all kinds of animals, which conceive in a uterus, it will at
the same time be equally evident, that what has hitherto been handed
down to us from all antiquity on the generation of animals, is
erroneous; that the fœtus is not constituted of the semen either of the
male or female, nor of a mixture of the two, nor of the menstrual blood,
but that in all animals, as well in the prolific conception as after it,
the same series of phenomena occur as in the generation of the chick
from the egg, and as in the production of plants from the seeds of their
several kinds. For, besides that, it appears the male is not required as
being in himself agent, workman, and efficient cause; nor the female, as
if she supplied the matter; but that each, male as well as female, may
be said to be in some sort the operative and parent; and the fœtus, as a
mixture of both, is created a mixed resemblance and kind. Nor is that
true which Aristotle often affirms, and physicians take for granted,
namely, that immediately after intercourse, something either of the
fœtus or the conception may be found in the uterus, (for instance, the
heart, the “three bullæ,” or some other principal part,) at any rate
_something_--a coagulum, some mixture of the spermatic substances, or
other things of the like kind. On the contrary, it is not till long
after intercourse that the eggs and conception first commence their
existence, among the greater number of animals, and these the most
perfect ones; I mean in the cases where the females have been fruitful
and have become pregnant. And that the female is prolific, before any
conception is contained in the uterus, there are many indications, as
will be hereafter set forth in the history of viviparous animals: the
breasts enlarge, the uterus begins to swell, and by other symptoms a
change of the whole system is discerned.

But the hen, though she have for the most part the rudiments of eggs in
her before intercourse, which are afterwards by this act rendered
fruitful, and there be, therefore, something in her immediately after
coition, yet even when she, as in the case of other animals, has as yet
no eggs ready prepared in the ovary, or has at the time of the
intercourse got rid of all she had, yet does she by and by, even after
some lapse of time, as if in possession of both principles or the powers
of both sexes, generate eggs by herself after the manner of plants; and
these (I speak from experience) not barren, but prolific.

Nay, what is more, if you remove all the eggs from beneath a hen that
has been fecundated and is now sitting, (after having already laid all
her eggs, and no more remain in the ovary,) she will begin to lay again;
and the eggs thus laid will be prolific, and have both principles
inherent in them.


_Of the sense in which the hen may be called the “prime efficient:” and
of her parturition._

It has already been said, that the hen is the efficient cause of
generation, or an instrument of Nature in this work, not indeed
immediately, or of herself; but when rendered prolific by commission
from, and in virtue of the male. But as the male is considered by
Aristotle to be the first principle of generation on his own merits,
because the first impulse toward generation proceeds from him, so may
the hen in some measure be put down as the first cause of generation;
inasmuch as the male is undoubtedly inflamed to venery by the presence
of the female. “The female fish,” says Pliny,[241] “will follow the male
at the season of intercourse, and strike his belly with her nose; at the
spawning time the male will do the like to the female.” I have myself at
times seen male fishes in shoals following a female that was on the
point of spawning, in the same way as dogs pursue a bitch, that they
might sprinkle the ova just laid with their milk or seed. But this is
particularly to be remarked in the more wanton and lascivious females,
who stir up the dormant fires of Cupid, and inspire a silent love; hence
it is that the common cock, so soon as he sees one of his own hens that
has been absent for ever so short time, or any other stranger-hen,
forthwith feels the sting of desire, and treads her. Moreover,
victorious in a battle, although wounded and tired from the fight, he
straightway sets about treading the wives of his vanquished foe one
after another. And that he may further feed the flame of love thus
kindled in his breast, by various gesticulations, incitements, and
caresses, often crowing the while, calling his hens to him, approaching
and walking round them, and tripping himself with his wings, he entices
his females to intercourse as by a kind of fascination. Such are the
arts of the male; but sometimes a certain sullenness of the female, and
an apparent disinclination on her part, contribute not a little to
arouse the ardour of the male and stimulate his languishing desire, so
that he fills her more quickly and more copiously with prolific spirit.
But of allurements of this kind, and in what degree they promote
conception, we shall speak more hereafter. For, if you carefully weigh
the works of nature, you will find that nothing in them was made in
vain, but that all things were ordered with a purpose and for the sake
of some good end.

Almost all females, though they have pleasure in the act of intercourse
and impregnation, suffer pain in parturition. But the reverse is the
case with the hen, who loudly complains during intercourse and struggles
against it; but in parturition, although the egg be very large in
comparison with the body and the orifice of the uterus, and it does
nothing to further its exit, (as is customary with the young of
viviparous animals,) yet she brings forth easily and without pain, and
immediately afterwards commences her exultations; and with her loud
cackling calls the cock as it seems to share in her triumph.

But, although many rudiments of eggs are found in the hen’s ovary, of
various sizes and in different stages, so that some are larger and
nearer to maturity than others, yet all of them appear to be fecundated,
or to receive the prolific faculty from the tread of the cock at the
same time and in the same degree. And though a considerable time elapse
(namely, thirty or more days) before the common hen or hen-partridge lay
all the eggs which she has conceived, yet in a stated time after the
mother has begun to sit upon them (say twenty or two and twenty days)
all the young are hatched nearly at the same time; nor are they less
perfect than if they had commenced their origin simultaneously, from the
period of one and the same conception, as the whelps of bitches do.

And while we are here, and while I think how small are the prolific
germs of eggs, mere papulæ and exudations less than millet-seeds, and
contemplate the full proportions of the cock that springs from thence,
his fine spirit, and his handsome plumage, I cannot but express my
admiration that such strength should be reposed in the nature of things
in such insignificant elements, and that it has pleased the omnipotent
Creator out of the smallest beginnings to exhibit some of his greatest
works. From a minute and scarce perceptible papula springs the hen, or
the cock, a proud and magnificent creature. From a small seed springs a
mighty tree; from the minute gemmule or apex of the acorn, how wide does
the gnarled oak at length extend his arms, how loftily does he lift his
branches to the sky, how deeply do his roots strike down into the
ground! “It is in truth a great miracle of nature,” says Pliny,[242]
“that from so small an origin is produced a material that resists the
axe, and that supplies beams, masts, and battering-rams. Such is the
strength, such the power of nature!” But in the seeds of all plants
there is a gemmule or bud of such a kind, so small that if the top
only, a very point, be lost, all hope of propagation is immediately
destroyed; in so small a particle does all the plastic power of the
future tree seem lodged! The provident ant by gnawing off this little
particle stores safely in her subterraneous hoard the grain and other
seeds she gathers, and ingeniously guards against their growing: “The
cypress,” adds Pliny, in the same place, “bears a seed that is greatly
sought after by the ant; which makes us still further wonder, that the
birth of mighty trees should be consumed in the food of so small an
animal.” But on these points we shall say more when we show that many
animals, especially insects, arise and are propagated from elements and
seeds so small as to be invisible, (like atoms flying in the air,)
scattered and dispersed here and there by the winds; and yet these
animals are supposed to have arisen spontaneously, or from
decomposition, because their ova are nowhere to be found. These
considerations, however, may furnish arguments to that school of
philosophy which teaches that all things are produced from nothing; and
indeed there is hardly any ascertainable proportion between the rudiment
and the full growth of any animal.

Nor should we so much wonder what it is in the cock that preserves and
governs so perfect and beautiful an animal, and is the first cause of
that entity which we call the soul; but much more, what it is in the
egg, aye, in the germ of the egg, of so great virtue as to produce such
an animal, and raise him to the very summit of excellence. Nor are we
only to admire the greatness of the artificer that aids in the
production of so noble a work, but chiefly the “contagion” of
intercourse, an act which is so momentary! What is it, for instance,
that passes from the male into the female, from the female into the egg,
from the egg into the chick? What is this transitory thing, which is
neither to be found remaining, nor touching, nor contained, as far as
the senses inform us, and yet works with the highest intelligence and
foresight, beyond all art; and which, even after it has vanished,
renders the egg prolific, not because it now touches, but because it
formerly did so, and that not merely in the case of the perfect and
completed egg, but of the imperfect and commencing one when it was yet
but a speck; aye, and makes the hen herself fruitful before she has yet
produced any germs of eggs, and this too so suddenly, as if it were
said by the Almighty, “Let there be progeny,” and straight it is so?

Let physicians, therefore, cease to wonder at what always excites their
astonishment, namely, the manner in which epidemic, contagious, and
pestilential diseases scatter their seeds, and are propagated to a
distance through the air, or by some ‘fomes’ producing diseases like
themselves, in bodies of a different nature, and in a hidden fashion
silently multiplying themselves by a kind of generation, until they
become so fatal, and with the permission of the Deity spread destruction
far and wide among man and beast; since they will find far greater
wonders than these taking place daily in the generation of animals. For
agents in greater number and of more efficiency are required in the
construction and preservation of an animal, than for its destruction;
since the things that are difficult and slow of growth, decay with ease
and rapidity. Seneca[243] observes, with his usual elegance, “How long a
time is needed for conception to be carried out to parturition! with
what labour and tenderness is an infant reared! to what diligent and
continued nutrition must the body be subject, to arrive at adolescence!
but by what a nothing is it destroyed! It takes an age to establish
cities, an hour to destroy them. By great watching are all things
established and made to flourish, quickly and of a sudden do they fall
in pieces. That which becomes by long growth a forest, quickly, in the
smallest interval of time, and by a spark, is reduced to ashes.” Nor is
even a spark necessary, since by the solar rays transmitted through a
small piece of glass and concentrated to a focus, fire may be
immediately produced, and the largest things be set in flames. So easy
is every thing to nature’s majesty, who uses her strength sparingly, and
dispenses it with caution and foresight for the commencement of her
works by imperceptible additions, but hastens to decay with suddenness
and in full career. In the generation of things is seen the most
excellent, the eternal and almighty God, the divinity of nature, worthy
to be looked up to with reverence; but all mortal things run to
destruction of their own accord in a thousand ways.


_Of the manner in which the generation of the chick takes place from the

Hitherto we have considered the egg as the fruit and end; it still
remains for us to treat of it as the seed and beginning. “We must now
inquire,” says Fabricius[244], “how the generation of the chick results
from the egg, setting out from that principle of Aristotle and Galen,
which is, even conceded by all, to wit, that all things which are made
in this life, are manifestly made by these three: workers, instruments,
and matter.”

But since in natural phenomena, the work is not extrinsic, but is
included in the matter, or the instruments, he concludes that we must
take cognizance only of the agent and the matter.

As we are here about to shew in what manner the chick arises from the
egg, however, I think it may be of advantage for me to preface this, by
showing the number of modes in which one thing may be said to be made
from another.

For so it will appear, more clearly and distinctly, after which of these
generation takes place in the egg, and what are the right conclusions in
regard to its matter, its instruments, and efficient cause.

Aristotle[245] has laid down that there are four modes in which one
thing is made from another: “first, when we say that from day night is
made, or from a boy a man, since one is after the other; secondly, when
we say that a statue is made from brass, or a bed from wood, or any
thing else from a certain material, so that the whole consists of
something, which is inherent and made into a form; thirdly, as when from
a musical man is made an unmusical one, or from a healthy, a sick one,
or contraries in any way: fourthly, as Epicharmus exaggerates it, as of
calumnies, cursing; of cursing, fighting. But all these are to be
referred to that from whence the movement took its rise; for the calumny
is a certain portion of the whole quarrel. Since then these are the
methods in which one thing is made from another, it is clear that the
seed is in one of two of these. For that which is born arises out of it,
either as from matter, or as from the prime mover. For it is not, ‘as
this is after that,’ in the same way as after the Panathenœa navigation;
nor as ‘one contrary from another,’ for in such case, a thing would be
born out of its contrary, because it is in a state of decay, and there
must be something else as subject matter.”

By these words, Aristotle rightly infers, that the semen proceeding from
the male, is the efficient or instrumental cause of the embryo; since it
is no part of what is born, either in the first or third manner;
(namely, as one thing is after another, or as it is out of its
contrary;) nor does it arise from the subject matter.

But then, as he adds, in the same place, “that which comes out of the
male in coition, is not with truth and propriety called semen, but
rather geniture; and it is different from the seed properly so called.
For that is called the geniture which, proceeding from the generant, is
the cause which first promotes the beginning of generation. I mean in
those creatures, which nature designed to have connection; but the seed
is that which derives its origin from the intercourse of the two (i. e.
of the male and female); such is the seed of all plants; and of some
animals in which the sex is not distinct; it is the produce, as it were,
of the male and female mixed together originally, like a kind of
promiscuous conception;” and such as we have formerly in our history
declared the egg to be, which is called both fruit and seed. For the
seed and the fruit are distinct from each other, and in the relation of
antecedent and consequent; the fruit is that which is out of something
else, the seed is that out of which something else comes; otherwise both
were the same.

It remains then, to inquire, in how many of the aforesaid ways the fœtus
may arise, not indeed from the geniture of the male, but out of the true
seed, or out of the egg or conception, which is in reality the seed of


_In how many ways the chick may be said to be formed from the egg._

It is admitted, then, that the fœtus is formed from a prolific egg, as
out of the proper matter, and as it were by the requisite agency, and
that the same egg stands for both causes of the chick. For inasmuch as
it derives its origin from the hen, and is considered as a fruit, it is
the matter: but, in so far as it contains in its whole structure the
prolific and plastic faculty infused by the male, it is called the
efficient cause of the chick.

Moreover, not only as Fabricius supposed, are these, namely, the agent
and the instrument, inseparably joined in one and the same egg, but it
is also necessary, that the aliment by which the chick is nourished, be
present in the same place. Indeed, in the prolific egg, these four are
found together, to wit, the agent, the instrument, the matter, and the
aliment, as we have shown in our history.

Wherefore, we say, that the chick is formed from the prolific egg in all
the aforesaid ways, namely, as from matter, by an efficient, and by an
instrument; and moreover, as a man grows out of a boy, as the whole is
made up of its parts, and as a thing grows from its nutriment; a
contrary thing springs from a contrary.

For after incubation is begun, as soon as by the internal motive
principle a certain clear liquid which we have called the eye of the egg
is produced, we say that that liquid is made as it were out of a
contrary; in the same way as we suppose the chyle through concoction to
be formed out of its contraries, (namely, crude articles of food,) and
in the same way as we are said to be nourished by contraries; so, from
the albumen is formed and augmented that to which we have given the
names of the eye and the colliquament; and in the same manner, from that
clear fluid do the blood and pulsating vesicle, the first particles of
the chick, receive their being, nutrition, and growth. The nutriment, I
say, is by the powers of an inherent and innate heat, assimilated by
means of concoction, as it were out of a contrary. For the crude and
unconcocted are contrary to the concocted and assimilated, as the
unmusical man is to the musical, and the sick to the sound man.

And when the blood is engendered from the clear colliquament, or a clear
fluid is produced from the white or the yelk, there is generation as
regards the former, corruption as regards the latter; a transmutation,
namely, is made from the extremes of contraries, the subject-matter all
the while remaining the same. To explain: by the breaking up of the
first form of the white, the colliquament is produced; and from the
consumption of this colliquament, follows the form of the blood, in the
same way precisely as food is converted into the substance of the thing

It is thus, then, that the chick is said to be made out of the egg, as
it were by a contrary; for in the nutrition and growth of the chick in
the egg, white and yelk are equally broken up and consumed, and finally
the whole substance of the egg. It is clear, therefore, that the chick
is formed from the egg, as it were by a contrary, namely the aliment,
and as if by an abstraction, and from a non-entity. For the first
particle of the chick, viz.: the blood or punctum saliens, is
constituted out of something which is not blood, and altogether its
contrary, the same subject-matter always remaining.

The chick too is made from the egg, as a man is made from a boy. For in
the same way, as out of plants seeds arise, and out of seeds, buds,
sprouts, stems, flowers, and fruits; so also out of the egg, the seed of
the hen is produced, the dilatation of the cicatricula and the
colliquament, the blood and the heart, as the first particle of the
fœtus or fruit; and all this, in the same way as the day from the night,
the summer from the spring, a man from a boy--one follows or comes after
the other. So that, in the same way as fruits arise after flowers on the
same stem, so likewise is the colliquament formed after the egg, the
blood after this, as from the primogeneous humour, the chick after the
blood, and out of it, as the whole out of a part; in the same way, as by
Epicharmus’s exaggeration, out of calumnies comes cursing, and out of
cursing fighting. For the blood first begins its existence with the
punctum saliens, and at the same time, seems to be as well a part of the
chick, and a kind of efficient or instrument of its generation,
inseparable, as Fabricius thinks, from the agent. But how the egg may be
called the efficient and instrument of generation, has partly been
explained already, and will be illustrated more copiously by what we
shall presently say.

So much has been fully established in our history, that the punctum
pulsans and the blood, in the course of their growth, attach round
themselves the rest of the body, and all the other members of the chick,
just as the yelk in the uterus, after being evolved from the ovary,
surrounds itself with the white; and this not without concoction and
nutrition. Now the common instrument of all vegetative operations, is,
in the opinion of all men, an internal heat or calidum innatum, or a
spirit diffused through the whole, and in that spirit a soul or faculty
of a soul. The egg, therefore, beyond all doubt, has its own operative
soul, which is all in the whole, and all in each individual part, and
contains within itself a spirit or animal heat, the immediate instrument
of that soul. To one who should ask then, how the chick is made from the
egg, we answer: after all the ways recited by Aristotle, and devised by
others, in which it is possible for one thing to be made from another.


_Fabricius is mistaken with regard to the matter of the generation of
the chick in ovo._

As I proposed to myself at the outset, I continue to follow Fabricius as
pointing out the way; and we shall, therefore, consider the three things
which he says are to be particularly regarded in the generation of the
chick, viz.: the agent, the matter, and the nourishment of the embryo.
These must needs be all contained in the egg; he proposes various doubts
or questions, and quotes the opinions of the most weighty authorities in
regard to them, these opinions being frequently discordant. The first
difficulty is in reference to the matter and nourishment of the chick.
Hippocrates,[246] Anaxagoras, Alcmaeon, Menander, and the ancient
philosophers, all thought that the chick was engendered from the
vitellus, and was nourished by the albumen. Aristotle,[247] however, and
after him, Pliny,[248] maintained, on the contrary, that the chick was
incorporated from the albumen, and nourished by the vitellus. But
Fabricius himself, will have it that neither the white nor yelk forms
the matter of the chick; he strives to combat both of the preceding
opinions, and teaches that the white and the yellow alike do no more
than nourish the chick. One of his arguments, amongst a great number of
others which I think are less to be acquiesced in, appears to me to have
some force. The branches of the umbilical vessels, he says, through
which the embryo undoubtedly imbibes its nourishment, are distributed to
the albumen and the vitellus alike, and both of these fluids diminish as
the chick grows. And it is on this ground, that Fabricius in
confirmation of his opinion, says[249]: “Of the bodies constituting the
egg, and adapted to forward the generation of the chick, there are only
three, the albumen, the vitellus, and the chalazæ; now the albumen and
vitellus are the nourishment of the chick; so that the chalazæ alone
remain as matter from which it can be produced.”

Nevertheless, that the excellent Fabricius is in error here, we have
demonstrated above in our history. For after the chick is already almost
perfected, and its head and its eyes are distinctly visible, the chalazæ
can readily be found entire, far from the embryo, and pushed from the
apices towards the sides: the office of these bodies, as Fabricius
himself admits, is that of ligaments, and to preserve the vitellus in
its proper position within the albumen. Nor is that true, which
Fabricius adds in confirmation of his opinion, namely, that the chalazæ
are situated in the direction of the blunt part of the egg. For after
even a single day’s incubation, the relative positions of the fluids of
the egg are changed, the yelk being drawn upwards, and the chalazæ on
either hand removed, as we have already had occasion to say.

He is also mistaken when he speaks of the chalazæ, as proper parts of
the egg. The egg consists in fact but of white and yelk; the chalazæ as
well as the membranes, are mere appendages of the albumen and vitellus.
The chalazæ, in particular, are the extremities of certain membranes,
twisted and knotted; they are produced in the same way as a rope is
formed by the contortion of its component filaments, and exist for the
purpose of more certainly securing the several elements of the egg in
their respective places.

Fabricius, therefore, reasons ill when he says, that “the chalazæ are
found in the part of the egg where the embryo is produced, wherefore it
is engendered from them;” for even on his own showing, this could never
take place, he admitting that the chalazæ are extant in either extremity
of the egg, whilst the chick never makes its appearance save at the
blunt end; in which, moreover, at the first commencement of generation,
no chalaza can be seen. Farther, if you examine the matter in a fresh
egg, you will find the superior chalaza not immediately under the blunt
end or its cavity, but declined somewhat to the side; not to that side,
however, where the cavity is extending, but rather to the opposite side.
Still farther, from what has preceded, it is obvious that the relative
positions of the fluids of the egg are altered immediately that
incubation is begun: the eye increased by the colliquament is drawn up
towards the cavity in the blunt end of the egg, whence the white and the
chalaza are on either hand withdrawn to the side. For the macula or
cicatricula which before incubation was situated midway between the two
ends, now increased into the eye of the egg, adjoins the cavity in the
blunt end, and whilst one of the chalazæ is depressed from the blunt
end, the other is raised from the sharp end, in the same way as the
poles of a globe are situated when the axis is set obliquely; the
greater portion of the albumen, particularly that which is thicker,
subsides at the same time, into the sharp end.

Neither is it correct to say, that the chalazæ bear a resemblance in
length and configuration to the chick on its first formation, and that
the number of their nodules corresponds with the number of the principal
parts of the embryo; a statement which gives Fabricius an opportunity of
adducing an argument connected with the _matter_ of the chick, based on
the similarity of its consistency to that of the chalazæ. But the red
mass (which Fabricius regarded as the liver) is neither situated in nor
near the chalaza, but in the middle of the clear colliquament; and it is
not any rudiment of the liver but of the heart alone. Neither does his
view square with the example he quotes of the tadpole, “of which,” he
says, “there is nothing to be seen but the head and the tail, that is to
say, the head and spine, without a trace of upper or lower extremities.”
And he adds, “he who has seen a chalaza, and this kind of conception, in
so far as the body is concerned, will believe that in the former, he has
already seen the latter.” I, however, have frequently dissected the
tadpole, and have found the belly of large size, and containing
intestines and liver and heart pulsating; I have also distinguished the
head and the eyes. The part which Fabricius takes for the head, is the
rounded mass [or entire body] of the tadpole, whence the creature is
called ‘gyrinus,’ from its circular form. It has a tail with which it
swims, but is without legs. About the epoch of the summer solstice, it
loses the tail, when the extremities begin to sprout. Nothing however
occurs in the nature of a division of the embryo pullet into the head
and spine, which should induce us to regard it as produced from the
chalazæ, and in the same manner as the tadpole.

The position and fame of Fabricius, however, a man exceedingly well
skilled in anatomy, do not allow me to push this refutation farther. Nor
indeed, is there any necessity so to do, seeing that the thing is so
clearly exhibited in our history.

Our author concludes, by stating that his opinion is of great antiquity,
and was in vogue even in the times of Aristotle.

For my own part, nevertheless, I regard the view of Ulysses Aldrovandus
as the older, he maintaining, that the chalazæ are the spermatic fluid
of the cock, from which and through which alike the chick is engendered.

Neither notion, however, is founded on fact, but is the popular error of
all times: the chalazæ, treads, or treadles, as our English name
implies, are still regarded by the country folks as the semen of the

“The treadles (grandines),” says Aldrovandus; “are the spermatic fluid
of the cock, because no fertile egg is without them.” But neither is any
unprolific egg without these parts, a fact which Aldrovandus was either
ignorant of or concealed. Fabricius admits this fact; but though he has
denied that the semen of the male penetrates to the uterus or is ever
found in the egg, he nevertheless, contends, that the chalazæ alone of
all the parts of the egg are impregnated with the prolific power of the
egg, and are the repositories of the fecundating influence; and this,
with the fact staring him in the face all the while, that there is no
perceptible difference between the chalazæ of a prolific and an
unprolific egg. And when he admits, that the mere rudiments of eggs in
the ovary, as well as the vitelli that are surrounded with albumen,
become fecundated through the intercourse of the cock, I conceive that
this must have been the cause of the error committed by so distinguished
an individual. It was the current opinion, as I have said oftener than
once, both among philosophers and physicians, that the matter of the
embryo in animal generation, was the geniture, either of the male, or of
the female, or resulted from a mixture of the two, and that from this,
deposited in the uterus, like a seed in the ground, which produces a
plant, the animal was engendered. Aristotle, himself, is not very far
from the same view, when he maintains the menstrual blood of the female
to be the seed, which the semen of the male coagulates, and so composes
the conception.

The error which we have announced, having been admitted by all in former
times, as a matter of certainty, it is not to be wondered at, that
various erroneous opinions based on each man’s conjecture, should have
emanated from it. They, however, are wholly mistaken, who fancy that
anything in the shape of a ‘prepared or fit matter’ must necessarily
remain in the uterus after intercourse, from which the fœtus is
produced, or the first conception is formed, or that anything is
immediately fashioned in the uterine cavity that corresponds to the seed
of a plant deposited in the bosom of the ground. For it is quite
certain, that in the uterus of the fowl, and the same thing is true of
the uterus of every other female animal, there is nothing discoverable
after intercourse more than there was before it.

It appears, consequently, that Fabricius erred when he said:[250] “In
the same way as a viviparous animal is incorporated from a small
quantity of seminal matter, whilst the matter which is taken up as food
and nourishment is very large; so a small chalaza suffices for the
generation of a chick, and the rest of the matter contained in the egg
goes to it in the shape of nutriment.” From which it is obvious, that he
sought for some such ‘prepared matter’ in the egg, whence the chick
should be incorporated; mainly, as it seems, that he might not be found
in contradiction with Aristotle’s definition of an egg,[251] viz.: as
“that from part of which an animal is engendered; and the remainder of
which is food for the thing engendered.” This of Fabricius, therefore,
has the look of a valid argument, namely, “Since there are only three
parts in the egg,--the albumen, the vitellus, and the chalazæ; and the
two former alone supply aliment; it necessarily follows, that the
chalazæ alone are the matter from which the chick is constituted.”

Thus, our learned anatomist, blinded by a popular error, seeking in the
egg for some particular matter fitted to engender the chick distinct
from the rest of the contents of the egg, has gone astray. And so it
happens to all, who forsaking the light, which the frequent dissection
of bodies, and familiar converse with nature supplies, expect that they
are to understand from conjecture, and arguments founded on
probabilities, or the authority of writers, the things or the facts
which they ought themselves to behold with their own eyes, to perceive
with their proper senses. It is not wonderful, therefore, when we see
that we have so many errors accredited by general consent, handed down
to us from remote antiquity, that men otherwise of great ingenuity,
should be egregiously deceived, which they may very well be, when they
are satisfied with taking their knowledge from books, and keeping their
memory stored with the notions of learned men. They who philosophise in
this way, by tradition, if I may so say, know no better than the books
they keep by them.

In the egg then, as we have said, there is no distinct part or prepared
matter present, from which the fœtus is formed; but in the same way as
the apex or gemmule protrudes in a seed; so in the egg, there is a
macula or cicatricula, which endowed with plastic power, grows into the
eye of the egg and the colliquament, from which and in which the
primordial or rudimentary parts of the chick, the blood, to wit, and the
punctum saliens are engendered, nourished, and augmented, until the
perfect chick is developed. Neither is Aristotle’s definition of an egg
correct, as a body from part of which an embryo is formed, and by part
of which it is nourished, unless the philosopher is to be understood in
the following manner: The egg is a body, from part of which the chick
arises, not as from a special matter, but as a man grows out of a boy;
or an egg is a perfect conception from which the chick is said to be
partly constituted, partly nourished; or to conclude, an egg is a body,
the fluids of which serve both for the matter and the nourishment of the
parts of the fœtus. In this sense, indeed, Aristotle[252] teaches us
that the matter of the human fœtus is the menstrual blood; “which (when
poured into the uterus by the veins) nature employs to a new purpose;
viz., that of generation, and that a future being may arise, such as the
one from which it springs; for potentially it is already such as is the
body whose secretion it is, namely, the mother.”


_What is the material of the chick, and how is it formed in the egg?_

Since, then, we are of opinion, that for the acquisition of truth, we
cannot rely on the theories of others, whether these rest on mere
assertions, or even may have been confirmed by plausible arguments,
except there be added thereto a diligent course of observation; we
propose to show, by clearly-arranged remarks derived from the book of
nature, what is the material of the fœtus, and in what manner it thence
takes its origin. We have seen that one thing is made out of another
(tanquam ex materia) in two ways, and this as well in works of art, as
in those of nature, and more particularly in the generation of animals.

One of these ways, viz., when the object is made out of something
pre-existing, is exemplified by the formation of a bed out of wood, or a
statue from stone; in which case, the whole material of the future piece
of work has already been in existence, before it is finished into form,
or any part of the work is yet begun; the second method is, when the
material is both made and brought into form at the same time. Just then
as the works of art are accomplished in two manners, one, in which the
workman cuts the material already prepared, divides it, and rejects what
is superfluous, till he leaves it in the desired shape (as is the custom
of the statuary); the other, as when the potter educes a form out of
clay by the addition of parts, or increasing its mass, and giving it a
figure, at the same time that he provides the material, which he
prepares, adapts, and applies to his work; (and in this point of view,
the form may be said rather to have been _made_ than _educed_;) so
exactly is it with regard to the generation of animals.

Some, out of a material previously concocted, and that has already
attained its bulk, receive their forms and transfigurations; and all
their parts are fashioned simultaneously, each with its distinctive
characteristic, by the process called metamorphosis, and in this way a
perfect animal is at once born; on the other hand, there are some in
which one part is made before another, and then from the same material,
afterwards receive at once nutrition, bulk, and form: that is to say,
they have some parts made before, some after others, and these are at
the same time increased in size and altered in form. The structure of
these animals commences from some one part as its nucleus and origin, by
the instrumentality of which the rest of the limbs are joined on, and
this we say takes place by the method of epigenesis, namely, by degrees,
part after part; and this is, in preference to the other mode,
generation properly so called.

In the former of the ways mentioned, the generation of insects is
effected where by metamorphosis a worm is born from an egg; or out of a
putrescent material, the drying of a moist substance or the moistening
of a dry one, rudiments are created, from which, as from a caterpillar
grown to its full size, or from an aurelia, springs a butterfly or fly
already of a proper size, which never attains to any larger growth
after it is first born; this is called metamorphosis. But the more
perfect animals with red blood are made by epigenesis, or the
superaddition of parts. In the former, chance or hazard seems the
principal promoter of generation, and there, the form is due to the
potency of a preexisting material; and the first cause of generation is
‘matter,’ rather than ‘an external efficient;’ whence it happens too
that these animals are less perfect, less preservative of their own
races, and less abiding, than the red-blooded terrestrial or aquatic
animals, which owe their immortality to one constant source, viz. the
perpetuation of the same species; of this circumstance we assign the
first cause to nature and the vegetative faculty.

Some animals then are born of their own accord, concocted out of matter
spontaneously, or by chance, as Aristotle seems to assert, when he
speaks of animals whose matter is capable of receiving an impulse from
itself, viz. the same impulse given by hazard, as is attributable to the
seed, in the generation of other animals. And the same thing happens in
art, as in the generation of animals. Some things, which are the result
of art, are so likewise of chance, as good health; others always owe
their existence to art; for instance, a house. Bees, wasps, butterflies,
and whatever is generated from caterpillars by metamorphosis, are said
to have sprung from chance, and therefore to be not preservative of
their own race; the contrary is the case with the lion and the cock;
they owe their existence as it were to nature or an operative faculty of
a divine quality, and require for their propagation an identity of
species, rather than any supply of fitting material.

In the generation by metamorphosis forms are created as if by the
impression of a seal, or, as if they were adjusted in a mould; in truth
the whole material is transformed. But an animal which is created by
epigenesis attracts, prepares, elaborates, and makes use of the
material, all at the same time; the processes of formation and growth
are simultaneous. In the former the plastic force cuts up, and
distributes, and reduces into limbs the same homogeneous material; and
makes out of a homogeneous material organs which are dissimilar. But in
the latter, while it creates in succession parts which are differently
and variously distributed, it requires and makes a material which is
also various in its nature, and variously distributed, and such as is
now adapted to the formation of one part, now of another; on which
account we believe the perfect hen’s-egg to be constituted of various

Now it appears clear from my history, that the generation of the chick
from the egg is the result of epigenesis, rather than of metamorphosis,
and that all its parts are not fashioned simultaneously, but emerge in
their due succession and order; it appears, too, that its form proceeds
simultaneously with its growth, and its growth with its form; also that
the generation of some parts supervenes on others previously existing,
from which they become distinct; lastly, that its origin, growth, and
consummation are brought about by the method of nutrition; and that at
length the fœtus is thus produced. For the formative faculty of the
chick rather acquires and prepares its own material for itself than only
finds it when prepared, and the chick seems to be formed and to receive
its growth from no other than itself. And, as all things receive their
growth from the same power by which they are created, so likewise should
we believe, that by the same power by which the chick is preserved, and
caused to grow from the commencement, (whether that may have been the
soul or a faculty of the soul,) by that power, I say, is it also
created. For the same efficient and conservative faculty is found in the
egg as in the chick; and of the same material of which it constitutes
the first particle of the chick, out of the very same does it nourish,
increase, and superadd all the other parts. Lastly, in generation by
metamorphosis the whole is distributed and separated _into_ parts; but
in that by epigenesis the whole is put together _out of_ parts in a
certain order, and constituted _from_ them.

Wherefore Fabricius was in error when he looked for the material of the
chick, (as a distinct part of the egg, from which its body was formed,)
as if the chick were created by metamorphosis, or a transformation of
the material in mass; and as if all, or at least the principal parts of
the body sprang from the same material, and, to use his own words, were
incorporated simultaneously. [He is, therefore, of course opposed to the
notion] of the chick being formed by epigenesis, in which a certain
order is observed according to the dignity and the use of parts, where
at first a small foundation is, as it were, laid, which, in the course
of growth, has at one and the same time distinct structures formed and
its figure established, and acquires an additional birth of parts
afterwards, each in its own order; in the same way, for instance, as the
bud bursting from the top of the acorn, in the course of its growth, has
its parts separately taking the form of root, wood, pith, bark, boughs,
branches, leaves, flowers, and fruit, until at length out comes a
perfect tree; just so is it with the creation of the chick in the egg:
the little cicatrix, or small spot, the foundation of the future
structure, grows into the eye and is at the same time separated into the
colliquament; in the centre of which the punctum sanguineum pulsans
commences its being, together with the ramification of the veins; to
these is presently added the nebula, and the first concretion of the
future body; this also, in proportion as its bulk increases, is
gradually divided and distinguished into parts, which however do not all
emerge at the same time, but one after the other, and each in its proper
order. To conclude, then: in the generation of those animals which are
created by epigenesis, and are formed in parts, (as the chick in the
egg,) we need not seek one material for the incorporation of the fœtus,
another for its commencing nutrition and growth; for it receives such
nutrition and growth from the same material out of which it is made;
and, vice versâ, the chick in the egg is constituted out of the
materials of its nutrition and growth. And an animal which is capable of
nutrition is of the same potency as one which is augmentative, as we
shall afterwards show; and they differ only, as Aristotle says, in their
distinctness of being; in all other respects they are alike. For, in so
far as anything is convertible into a substance, it is nutritious, and
under certain conditions it is augmentative: in virtue of its repairing
a loss of substance, it is called nutriment, in virtue of its being
added, where there is no such loss of substance, it is called increment.
Now the material of the chick, in the processes of generation,
nutrition, and augmentation is equally to be considered as aliment and
increment. We say simply that anything is generated, when no part of it
has pre-existed; we speak of its being nourished and growing when it has
already existed. The part of the fœtus which is first formed is said to
be begotten or born; all substitutions or additions are called
adnascent, or aggenerate. In all there is the same transmutation or
generation from the same to the same; as concerns a part, this is
performed by the process of nutrition and augmentation, but as regards
the whole, by simple generation; in other respects the same processes
occur equally. For from the same source from which the material first
takes its existence, from that source also does it gain nutriment and
increase. Moreover, from what we shall presently say, it will be made
clear that all the parts of the body are nourished by a common
nutritious juice; for, as all plants arise from one and the same common
nutriment, (whether it be dew or a moisture from the earth,) altered and
concocted in a diversity of manners, by which they are also nourished
and grow; so likewise to identical fluids of the egg, namely, the
albumen and the yelk, do the whole chick and each of its parts owe their
birth and growth.

We will explain, also, what are the animals whose generation takes place
by metamorphosis, and of what kind is the pre-existent material of
insects which take their origin from a worm or a caterpillar; a material
from which, by transmutation alone, all their parts are simultaneously
constituted and embodied, and a perfect animal is born; likewise, to
what animals any constant order in the successive generation of their
parts attaches, as is the case with such as are at first born in an
imperfect condition, and afterwards grow to maturity and perfection; and
this happens to all those that are born from an egg. As in these the
processes of growth and formation are carried on at the same time, and a
separation and distinction of parts takes place in a regularly observed
order, so in their case is there no immediate pre-existing material
present, for the incorporation of the fœtus, (such as the mixture of the
semina of the male and female is generally thought to be, or the
menstrual blood, or some very small portion of the egg,) but as soon as
ever the material is created and prepared, so soon are growth and form
commenced; the nutriment is immediately accompanied by the presence of
that which it has to feed. And this kind of generation is the result of
epigenesis as the man proceeds from the boy; the edifice of the body, to
wit, is raised on the punctum saliens as a foundation; as a ship is made
from a keel, and as a potter makes a vessel, as the carpenter forms a
footstool out of a piece of wood, or a statuary his statue from a block
of marble. For out of the same material from which the first part of the
chick or its smallest particle springs, from the very same is the whole
chick born; whence the first little drop of blood, thence also proceeds
its whole mass by means of generation in the egg; nor is there any
difference between the elements which constitute and form the limbs or
organs of the body, and those out of which all their similar parts, to
wit, the skin, the flesh, veins, membranes, nerves, cartilages, and
bones, derive their origin. For the part which was at first soft and
fleshy, afterwards, in the course of its growth, and without any change
in the matter of nutrition, becomes a nerve, a ligament, a tendon; what
was a simple membrane becomes an investing tunic; what had been
cartilage is afterwards found to be a spinous process of bone, all
variously diversified out of the same similar material. For a similar
organic body (which the vulgar believe to consist of the elements) is
not created out of elements at first existing separately, and then put
together, united, and altered; nor is it put together out of constituent
parts; but, from a transmutation of it when in a mixed state, another
compound is created: to take an instance, from the colliquament the
blood is formed, from the blood the structure of the body arises, which
appears to be homogeneous in the beginning, and resembles the spermatic
jelly; but from this the parts are at first delineated by an obscure
division, and afterwards become separate and distinct organs.

Those parts, I say, are not made similar by any successive union of
dissimilar and heterogeneous elements, but spring out of a similar
material through the process of generation, have their different
elements assigned to them by the same process, and are made dissimilar.
Just as if the whole chick was created by a command to this effect, of
the Divine Architect: “let there be a similar colourless mass, and let
it be divided into parts and made to increase, and in the meantime,
while it is growing, let there be a separation and delineation of parts;
and let this part be harder, and denser, and more glistening, that be
softer and more coloured,” and it was so. Now it is in this very manner
that the structure of the chick in the egg goes on day by day; all its
parts are formed, nourished, and augmented out of the same material.
First, from the spine arise the sides, and the bones are
distinguishable from the flesh by minute lines of extreme whiteness; in
the head three bullæ are perceived, full of crystalline fluid, which
correspond to the brain, the cerebellum, and one eye, easily observable
by a black speck; the substance which at first appears a milky coagulum,
afterwards gradually becomes cartilaginous, has spinous processes
attached to it, and ends in being completely osseous; what was at first
of a mucous nature and colourless, is converted at length into red flesh
and parenchyma; what was at one time limpid and perfectly pure water,
presently assumes the form of brain, cerebellum, and eyes. For there is
a greater and more divine mystery in the generation of animals, than the
simple collecting together, alteration, and composition of a whole out
of parts would seem to imply; inasmuch as here the whole has a separate
constitution and existence before its parts, the mixture before the
elements. But of this more at another time, when we come to specify the
causes of these things.


_Of the efficient cause of the generation of the chick and fœtus._

We have thus far spoken of the matter from which the chick in ovo is
generated. We have still with Fabricius to say a few words on the
efficient cause of the chick. As this subject is surrounded with
difficulties, however; as writers nowhere else dispute more virulently
or more wordily, and Aristotle himself in explaining the matter is
singularly intricate and perplexed, and as various questions that can by
no means be lightly treated do in fact present themselves for
consideration, I conceive that I shall be undertaking a task worthy of
the toil if, as I have done in the disquisition on the “matter,” I set
out here by stating in how many ways anything can be said to be
“efficient” or “effective.” We shall thus obtain a clearer idea of what
it is which we are to inquire after under the name of “efficient,” and
further, what estimate we are to form of the ideas of writers upon this
subject; it will at the same time appear from our observations what is
truly and properly to be called “an efficient.”

Aristotle[253] defines an efficient cause to be that “whence is derived
the first principle of change or quiescence; as a counsel, a father; and
simply as doing that which is done; the transmute of the thing
transmuted.” In the generation of animals accordingly many and various
kinds of cause inducing motion are brought forward; sometimes an
accident or quality is assigned; and so animal heat and the formative
faculty are called efficient causes. Sometimes it is an external
substance, previously existing, in which inheres the plastic force or
formative faculty that is designated in the same way; as the cock or his
seminal fluid, by the influence of which the chick is procreated from
the egg. Occasionally it is some internal substance, self-existent, such
as spirit, or innate heat. And again, it is some other substance, such
as form, or nature, or soul, or some portion of the vegetative soul,
that is regarded as the efficient, such a principle as we have already
declared to inhere in the egg.

Besides, since one thing whence motion proceeds is nearer and another
more remote, it sometimes happens that the media between the prime
efficient and the thing last effected, and instruments are regarded as
efficient causes; subordinate conclusions, likewise, or the principles
of subsequents, are reckoned among the number of efficient causes; in
this way some parts are themselves spoken of as genital parts, such as
the heart, whence Aristotle affirms that all the rest of the body is
produced; a statement which we have found borne out by our history. The
heart, I repeat, or at all events its rudimentary parts, namely, the
vesicle and pulsating point, construct the rest of the body as their
future dwelling-place; when erected it enters and conceals itself within
its habitation, which it vivifies and governs, and applying the ribs and
sternum as a defence, it walls itself about. And there it abides, the
household divinity, first seat of the soul, prime receptacle of the
innate heat, perennial centre of animal action; source and origin of all
the faculties; only solace in adversity!

Moreover, since the “efficient” is so styled with reference to the
effect, as some parts produced by epigenesis are posterior in order to
other parts, and are different from antecedent parts,--as effects
differ, so does it seem probable that efficients also vary: from things
that produce different operations, different motions likewise proceed.
Thus physicians in their physiologies assign certain organs as the
agents of chylification, others of sanguification, others of generation,
&c.; and anatomists speak of the ossific, carnific, and neurific
faculties, which they conceive produce bones, flesh, and nerves.

But in the generation of the chick, of several actions differing not a
little from one another, it is certain that the efficient causes must
also differ; those that present themselves to us as accidental
efficients of generation must nevertheless be necessary, seeing, that
unless they are associated or intervene, nothing is effected; those, to
wit, are rightly held “efficients” which, whilst they remove external
hinderances, either cherish the conception, or stimulate and turn mere
potentiality into positive action. Under this head we should arrange
incubation, the proper temperature of the air and the place, the spring
season, the approach of the sun in the circle of the zodiac; in like
manner the preparing causes which lead the vitellus to rise, make the
macula to dilate, and the fluids in the egg to liquefy, are all properly
held “efficients.”

Further, to the number of efficient causes are to be reckoned the
generative and architectonic faculties, styled parts by Fabricius, viz.,
the immutative, the concoctive, the formative, the augmentative, as also
the effective causes of certain accidentals, viz., that which
constitutes the pullet male or female, like the father or the mother,
taking after the form of the first or last male having connection with
the mother; that too whence the offspring is an animal; whether perfect
or defective; robust and healthy, or diseased; longer or shorter lived;
keeping up the characters of the race or degenerating from them; a
monster, an hybrid, &c.

Lastly, when we were discussing the efficient causes of the fœtus, we
were not inattentive to its admirable structure, to the functions and
uses of all its parts and members; neither did we overlook the
foresight, the art, the intelligence, the divine inspiration with which
all things were ordained and skilfully continued for the ends of life.
It is not enough that we inquire what is the “efficient,” the
architect, the adviser, but that we likewise venerate and adore the
omnipotent Creator and preserver of a work, which has been well entitled
a microcosm. We also ask whence this divine something comes, when it
arrives, and where it resides in the egg; this something which is
analogous to the essence of the stars, and is near akin to art and
intelligence, and the vicar of the Almighty Creator?

From what precedes it will be apparent how difficult it were to
enumerate all the efficient causes of the chick; it is indispensable,
indeed, in the complete investigation of this subject to refer to a
general disquisition; we could not from the single generation of the
chick in ovo, and without clearer light derived from investigations
extended to other animals, venture on conclusions that should be
applicable to the whole animal creation. And this all the more, since
Aristotle himself has enumerated such a variety of efficient principles
of animals; for he at one time adduces the ‘male’[254] as the principal
efficient cause, as that, to wit, in which the reason of the engendered
chick resides, according to the axiom;[255] “all things are made by the
same ‘univocal:’” at another time he takes ‘the male semen;’[256] or,
‘the nature of the male emitting semen:’[257] sometimes it is ‘that
which inheres in the semen,’[258] ‘which causes seeds to be prolific,
spirit, to wit, and nature in that spirit corresponding in its qualities
to the essence of the stars:’ elsewhere he says it is ‘heat;’[259]
‘moderate heat;’[260] ‘a certain and proportionate degree of heat;’[261]
‘the heat in the blood;’[262] ‘the heat of the ambient air;’ ‘the
winds;’[263] ‘the sun;’ ‘the heavens;’ ‘Jupiter;’ ‘the soul;’ and,
somewhere, nature is spoken of by him as ‘the principle of motion and

Aristotle[264] concludes the discussion on the efficient cause by
declaring it “extremely doubtful” whether it be “anything extrinsic; or
something inherent in the geniture or semen; and whether it be any part
of the soul, or the soul itself, or something having a soul?”

To escape from such a labyrinth of “efficient causes,” it were necessary
to be furnished with Ariadne’s thread, composed from observations on
almost every animal that lives; on this account the subject is deferred
till we come to our more general disquisition. Meantime we shall recount
the particulars which either manifestly appear in the special history of
the chick from the egg, or which differ from the ideas usually
entertained, or that seem to demand further inquiry.


_Of the manner in which the efficient cause of the chick acts, according
to Aristotle._

It is universally allowed, that the male is the primary efficient cause
in generation, on the ground that in him the species or form resides;
and it is further affirmed, that the emission of his ‘geniture’ during
coition, is the cause both of the existence and the fertility of the
egg. But none of the philosophers nor physicians, ancient or modern,
have sufficiently explained in what manner the seed of the cock produced
a chick from the egg; nor have they solved the question proposed by
Aristotle. Nor, indeed, is Aristotle himself much more explanatory, when
he says, “that the male contributes not in respect of quantity, but of
quality, and is the origin of action; but that it is the female which
brings the material.” And a little after, “It is not every male that
emits seed, and in those which do so, this is no part of the fœtus; just
as in the case of a carpenter, nothing is translated from him to the
substance of the wood which he uses, nor does any part of the artist’s
skill reside in the work when completed; but a form and appearance are
given by his operation to the matter; and the soul, which originates the
idea of forms, and the skill to imitate them, moves the hands, or other
limb, whatever it may be, by a motion of a certain quality; or from
diversity proceeds difference; or from similarity proceeds resemblance.
But the hands and instruments move the material. So the nature of a
male, which emits semen, uses that semen as an instrument, and an act
having motion; as in works of art the instruments are moved, for in
them, in some sort, the motion of the art exists.”

By these words he seems to imply, that generation is owing to the motion
of a certain quality. Just as in art, though the first cause (the “ratio
operis”) be in the mind of the artist, yet afterwards, the work is
effected by the movement of the hands or other instruments; and although
the first cause be removed (as in automatons,) yet is it in some sort
said to move what it now does not touch, but once has touched, so long
as motion continues in the instrument.

Also in the next book, he says: “When the semen of the male has arrived
as far as the uterus of the female, it arranges and coagulates the
purest part of the excrement (meaning the menstrual blood existing in
the uterus); and, by a motion of this kind, changes the material, which
has been prepared in the uterus, till it forms part of the chick; and
this, hereafter, although the semen after the performance of this motion
disappears, exists as part of the fœtus, and becomes animate (as the
heart,) and regulates its own powers and growth, as a son emancipated
from his father, and having his own establishment. And so it is
necessary that there be some commencing principle, from which afterwards
the order of the limbs may be delineated, and a proper disposition made
of those things that concern the absolution of the animal; a principle,
which may be the source of growth and motion to all the other parts; the
origin of all, both similar and dissimilar parts, and the source of
their ultimate aliment. For that which is already an animal grows, but
the ultimate aliment of an animal is the blood, or something
corresponding to the blood, whose vessels and receptacles are the veins;
wherefore, the heart is the origin of the veins. But veins, like roots,
spread to the uterus, and through these the fœtus derives its
nourishment. The heart too, being the beginning of all nature and the
containing end, ought to be made first; as if it were a genital part by
its own nature, which, as the original of all the other parts, and of
the whole animal, and of sense, must needs be the first; and by its
heat, (since all the parts are in the material _potentially_,) when once
the beginning of the motion has taken place, all that follows is
excited, just as in spontaneous miracles; and the parts are commenced,
not by change of place, but by alteration in softness, hardness,
temperature, and the other differences observed in similar parts, these
being now actually made, which had before existed only potentially.”

This is, in nearly so many words, the opinion of Aristotle, which
supposes that the fœtus is formed from the seed by motion, although it
is not at present in communication with the fœtus, but simply has been
so at a former time: his reasonings are, indeed, ingenious, and
carefully put together, and from what we see in the order of the
generation of parts, not improbable. For the heart, with the channel of
the veins, is first noticed as an animate principle, in which motion and
sense reside; or, as it were, an emancipated son, and a genital part,
whence the order of the members is delineated, whence all things
pertaining to the completion of the animal are disposed, and which has
all the attributes bestowed upon it by Aristotle.

But it seems impossible, that the heart should be formed in the egg by
the seed of the male, when that seed neither exists in the egg, nor
touches it, nor ever has touched it; because the seed does not enter the
uterus where the egg is, (as is allowed by Fabricius,) nor is in any way
attracted by it; nay, even the maternal blood is not in the egg, nor any
other prepared matter, out of which the seed of the male may form this
genital part, the author of all the others. For it is not immediately
after coition, while the seed still remains within the body, and is in
communication, that any part of the chick exists in the egg, but after
many days, when incubation has taken place. Moreover, in fishes, when
the geniture of the male does nothing but touch the eggs externally, and
does not enter into them, it is not likely that it performs any more
ample functions when the agency is external, than does the seed of the
cock in the already formed eggs of the hen. Besides, since immediately
after coition no trace of the egg as yet exists, but it is afterwards
generated by the hen herself (I am speaking of the prolific egg); when
now the seed of the cock is departed and vanished, there is no
probability that the fœtus is formed in that egg by the aforesaid seed,
through means of one or any number of successive motions.

Nor indeed does the difference between prolific and unprolific or wind
eggs consist herein, that the former contained the seed of the male, as
Aldrovandus supposed; nor has it been noticed that anything has been
formed and coagulated in the egg by the seed of the male, nor has any
sensible transmutation been discovered (for indeed, there is no sensible
difference between the fertile and the wind egg); and yet a prolific
egg, conceived long after coition, has in itself the faculties of both
sexes; viz., the capability of being both formed itself, and of forming
a chick; as if, according to the idea of Aristotle, it had derived its
origin from the coition of the two, and their mutual endeavours towards
the same end; and compelled by the force of this argument, as mentioned
above, when speaking of the generation of the ovum, he has endowed the
egg with a vital principle (anima.) If such really exist, then, without
doubt it would be the origin and efficient of all the natural phenomena
which take place in the egg. For if we consider the structure of the
chick, displaying, as it does, so much art, so divine an intelligence
and foresight; when we see the eyes adapted for vision, the bill for
taking food, the feet for walking, the wings for flying, and similarly
the rest of its parts, each to its own end, we must conclude, whatever
the power be which creates such an animal out of an egg, that it is
either the soul, or part of the soul, or something having a soul, or
something existing previous to, and more excellent than the soul,
operating with intelligence and foresight.

From the generation of the chick, it is also manifest that, whatever may
have been its principle of life or first vegetative cause, this cause
itself first existed in the heart. Now, if this be the soul of the
chicken, it is equally clear, that that soul must have existed in the
punctum saliens and the blood; since we there discover motion and sense;
for the heart moves and leaps like an animal. But if a soul exists in
the punctum saliens, forming, nourishing, and augmenting the rest of the
body, in the manner which we have pointed out in our history, then it,
without doubt, flows from the heart, as from a fountain-head, into the
whole body. Likewise, if the existence of the vital principle (anima) in
the egg, or, as Aristotle supposes, if the vegetative part of the soul
be the cause of its fertility, it must follow that the punctum saliens,
or animate genital part, proceeds from the vital principle (anima) of
the egg, (for nothing is its own author,) and that the said vital
principle (anima) passes from the egg into the punctum saliens,
presently into the heart, and thence into the chick.

Moreover, if the egg have a prolific virtue, and a vegetative soul, by
which the chick is constructed, and if it owe them, as is allowed on all
hands, to the semen of the cock; it is clear that this semen is also
endowed with an active principle (anima.) For such is Aristotle’s
opinion, when he expresses himself as follows: “As to whether the semen
has a vital principle (anima) or not, the same reasoning must be adduced
which we have employed in the consideration of other parts. For no
active principle (anima) can exist, except in that thing whose vital
principle it is; nor can there be any part which is not partaker of the
vital principle, except it be equivocally, as the eye of a dead man. We
must, therefore, allow, both that the semen has an active principle
(anima) and is potential.”

Now from these premises, it follows that the male is the primary
efficient in which the ratio and forma reside, which produces a seed or
rather a prolific geniture, and imparts it, imbued as it is with an
anima vegetativa (with which also the rest of its parts are endowed) to
the female. The introduction of this geniture begets such a movement in
the material of the hen, that the production of an animate egg is the
result, and from thence too the first particle of the chick is animated,
and afterwards the whole chick. And so, according to Aristotle, either
the same soul passes, by means of some metempsychosis, from the cock
into his geniture, from the geniture into the material of the female,
thence into the egg, and from the egg into the chick; or else, it is
raised up in each of the subsequent things by its respective antecedent;
namely, in the seed of the male by the male himself, in the egg by the
seed, last in the chick by the egg, as light is derived from light.

The efficient, therefore, which we look for in the egg, to explain the
birth of the chick, is the vital principle (anima); and therefore, the
vital principle of the egg; for, according to Aristotle, a soul does not
exist except in that thing whose soul it is.

But it is manifest, that the seed of the male is not the efficient of
the chick; neither as an instrument capable of forming the chick by its
motion, as Aristotle would have it, nor as an animate substance
transferring its vitality (anima) to the chick. For in the egg there is
no semen, neither does any touch it, nor has ever done so; (“and it is
impossible that that which does not touch should move, or that anything
should be affected by that which does not move it,”) and therefore the
vitality of the semen ought not to be said to exist in it; and although
the vital principle may be the efficient in the egg, yet it would not
appear to result more from the cock or his semen, than from the hen.

Nor, indeed, is it transferred by any metempsychosis or translation from
the cock and his semen into the egg, and thence into the chick. For how
can this translation be carried on into the eggs that are yet to exist,
and to be conceived after intercourse? unless either some animate semen
be in the mean time working in some part of the hen; or the vital
principle only have been translated without the seed, in order to be
infused into any egg which might thereafter be produced; but neither of
these alternatives is true. For in no part of the hen is the semen to be
found; nor is it possible that the hen after coition should be possessed
of a double vital principle, to wit, her own, and that of the future
eggs and chicks; since “the living principle or soul is said to be
nowhere but in that thing whose soul it is,” much less can one or more
vital principles lie hidden in the hen, to be afterwards subservient to
the future eggs and chicks in their order, as they are produced.

We have adduced these passages out of Aristotle in order to set forth
his opinion of the manner in which the seed of the cock produces the
chick from the egg; and thereby throw at least some light on this
difficult question. But whereas the said passages do not explain the
mode in which this is accomplished, nor even solve the doubts proposed
by himself, it appears that we are still sticking in the same mud, and
caught in the same perplexities (concerning the efficient cause of the
fœtus in the generation of animals;) indeed, so far from Aristotle’s
arguments rendering this question more clear, they appear on the
contrary to involve it in more and greater doubts.

Wherefore it is no wonder that the most excellent philosopher was in
perplexity on this head, and that he has admitted so great a variety of
efficient causes, and at one time has been compelled to resort to
automatons, coagulation, art, instruments, and motions, for
illustrations; at another time to an ‘anima’ in the egg, and in the seed
of the male. Moreover, when he seems positively and definitively to
determine what it is in each seed, whether of plants or animals, which
render the same fertile, he repudiates heat and fire as improper agents;
nor does he admit any faculty of a similar quality; nor can he find
anything in the seed which should be fit for that office; but he is
driven to acknowledge something incorporeal, and coming from foreign
sources, which he supposes (like art, or the mind) to form the fœtus
with intelligence and foresight, and to institute and ordain all its
parts for its welfare. He takes refuge, I say, in a thing which is
obscure and not recognizable by us; namely, in a spirit contained in the
seed, and in a frothy body, and in the nature in that spirit,
corresponding in proportion to the elements of the stars. But what that
is, he has nowhere informed us.


_The opinion of Fabricius on the efficient cause of the chick is

As I have chosen Aristotle, the most eminent among the ancient
philosophers, and Fabricius of Aquapendente, one of the foremost
anatomists of modern times, as my especial guides and sources of
information on the subject of animal generation, when I find that I can
make nothing of Aristotle upon a particular topic, I straightway turn to
Fabricius; and now I desire to know what he thought of the efficient
cause of generation.

I find that he endeavours to satisfy three doubts or difficulties
involved in this subject: First, What is the ‘efficient’ of the chick?
This he answers, by saying, the semen of the male. Secondly, How does
this appear in the egg, and in what way does the semen of the cock
fecundate the egg? Thirdly and lastly, In what order are the parts of
the chick engendered?

As to the first query, it appears from our observations, that the cock
and his seminal fluid are verily the ‘efficient,’ but not the
‘adequate’ cause of generation; that the hen comes in here as something.
In this place, therefore, we are principally to inquire how the semen of
the cock fecundates the egg otherwise unprolific, and secures the
engenderment of a chick from it?

But let us hear Fabricius:[265] “Those things differ,” he observes,
“that are produced from eggs, from those that originate from semen, in
this, that oviparous animals have the matter from which the embryo is
incorporated distinct and separate from the agent; whilst viviparous
animals have the efficient cause and the matter associate and
concorporate. For the ‘agent’ in the oviparous animal is the semen of
the male, in the fowl the semen of the cock, which neither is nor can be
in the egg; the ‘matter,’ again, is the chalazæ from which the fœtus is
incorporated. These two differ widely from one another; for the chalazæ
are added after the vitellus is formed, whilst it is passing through the
second uterus, and are an accession to the internal egg; the semen
galli, on the contrary, is stored near the fundament, is separated from
the chalazæ by a great interval, and nevertheless by its irradiating
faculty, fecundates both the whole egg and the uterus. Now in the
viviparous animal, the semen is both ‘matter’ and ‘agent,’ the two
consisting and being conjoined in the same body.”

Our author appears to have introduced this distinction between oviparous
and viviparous animals, that he might spare, or at all events, that he
might not directly shock or upset the notions of medical writers on the
generation of man, they teaching that the seminal fluids of either sex,
projected together in intercourse, are mingled; that as one or other
preponderates, this becomes the ‘efficient,’ that stands in lieu of the
‘matter;’ and that the two together, tending to the same end, amalgamate
into the ‘conception’ of the viviparous animal.

But when he finds that neither in the egg nor uterus of the fowl is
there any semen or blood, and avows his belief that nothing is emitted
by the male in intercourse, that can by possibility reach the uterus of
the female, nor in the egg discovers a trace of aught supplied by the
male, he is compelled to doubt how the semen, which is nowhere to be
detected, which is neither mixed with the ‘geniture’ of the female, nor
yet is added to it, nor touches it, can fecundate the egg, or constitute
the chick. And this all the more urgently, when he has stated that a few
connections in the beginning of the season suffice to secure the
fecundity of all the eggs that will be laid in its course. For how
should it seem otherwise than impossible that from the semen galli
communicated in the spring, but now long vanished, lost or consumed, the
eggs that continue to be laid through the summer and autumn, should
still be rendered fruitful and fit to produce pullets?

It is that he may meet such a difficulty half way, that he coins the
difference which has been noticed. By way of bolstering up his views, he
farther adduces three additional considerations:--First, since the semen
galli is neither extant in the egg, nor was ever present in the uterus,
nor is added as ‘material cause’ as in viviparous animals, he has chosen
to make it resident for a whole year in the body of the hen. And then
that he may have a fit receptacle or storehouse for the fecundating
fluid, he finds a blind sac near the inlet to the uterus, in which he
says the cock deposits his semen, wherein, as in a treasury, it is
stored, and from which all the eggs are fecundated. Lastly, although the
semen in that bursa comes into contact neither with the uterus, nor the
egg, nor the ovary, whereby it might fecundate the egg, or secure the
generation of a chick, he says, nevertheless, that from thence, a
certain spiritual substance or irradiation penetrates to the egg,
fecundates its chalazæ, and from these produces a chick. By this
affirmation, however, he appears to support the opinion of Aristotle,
namely, that the female supplies the ‘matter’ in generation, the male
the ‘efficient force;’ and to oppose the postulate of medical writers
about the mixture of seminal fluids, for the sake of which,
nevertheless, as I have said, he seems to have laid down his distinction
between oviparous and viviparous animals. To give an air of greater
likelihood to this notion of his, he goes on to enumerate the changes
which the semen, not yet emitted, but laid up in the testes and vesiculæ
seminales of animals, occasions.

But besides the fact that all this does not bear upon the question, for
the principal element under discussion is, not how the semen galli
renders the egg prolific, but rather, how does the semen galli fashion
and construct the chick from the egg? Almost everything he adduces in
support of his view appears either false or open to suspicion, as is
obvious, from the facts stated in our history; for neither is the blind
cavity situated at the root of the uropygium or coccyx of the fowl,
which he entitles “bursa,” destined as a receptacle for the semen of the
cock, nor can any semen be discovered there, as we have said; but the
cavity is encountered in the male as well as in the female fowl.

Our authority nowhere explains what he understands by a “spiritual
substance,” and an “irradiation;” nor what he means by “a substance
through whose virtue the egg is vivified:” he does not say whether it is
any “corporeal” or “formal” substance, which by “irradiation” proceeds
from the semen laid up in the bursa, and, (what is especially required,)
constructs a pullet from the egg.

In my opinion, Fabricius does no more here than say: “It produces the
chick because it irradiates the egg; and forms because it vivifies;” he
attempts to explain or illustrate the exceedingly obscure subject of the
formation of a living being by means still more obscure. For the same
doubt remains untouched, how, to wit, the semen of the cock without
contact, an “external efficient” at best, separate in point of place,
and existing in the bursa, can form the internal parts of the fœtus in
ovo,--the heart, liver, lungs, intestines, &c., out of the chalazæ by
“irradiation.” Unless, indeed, our author will have it that all takes
place at the dictum as it were of a creator seated on his throne, and
speaking the words: Let such things be! namely, bones for support,
muscles for motion, special organs for sense, members for action,
viscera for concoction and the like, and all ordered for an end and
purpose with foresight, and understanding and art. But Fabricius nowhere
demonstrates that the semen has any such virtue, nowhere explains the
manner in which without so much as contact the semen can effect such
things; particularly when we see that the egg incubated by a bird of
another kind than that which laid it, or cherished in any other way, or
in dung, or in an oven, far from the bursa of the parent hen, is still
quickened and made to produce an embryo.

The same difficulty still remains, I say: how or in what way is the
semen of the cock the “efficient” of the chick? It is in no wise removed
by invoking the irradiation of a spiritual substance. For did we even
admit that the semen was stored in the bursa, and that it incorporated
the embryo from the chalazæ by metamorphosis and irradiation, we should
not be the less deeply immersed in the difficulty of accounting for the
formation of all the internal parts of the chick. But these notions have
already been sufficiently refuted by us.

Wherefore, in investigating the efficient cause of the chick, we must
look for it as inhering in the egg, not as concealed in the bursa; and
it must be such, that although the egg have long been laid, be miles
removed from the hen that produced it, and be set under another hen than
its parent, even under a bird of a different kind, such as a turkey or
guinea-fowl, or merely among hot sand or dung, or in an oven constructed
for the purpose, as is done in Egypt, it will still cause the egg to
produce a creature of the same species as its parents, like them, both
male and female, and if the parents were of different kinds, of a hybrid
species, and having a mixed resemblance.

The knot therefore remains untied, neither Aristotle nor Fabricius
having succeeded even in loosening it, namely: how the semen of the male
or of the cock forms a pullet from an egg, or is to be termed the
“efficient” of the chick, especially when it is neither present in, nor
in contact with, nor added to the egg. And although almost all assert
that the male and his semen are the efficient cause of the chick, still
it must be admitted, that no one has yet sufficiently explained how it
is so, particularly in our common hen’s egg.


_The inquiry into the efficient cause of the chick is one of great

The discussion of the efficient cause of the chick is, as we have said,
sufficiently difficult, and all the more in consequence of the various
titles by which it has been designated. Aristotle, indeed, recites
several efficient causes of animals, and numerous controversies have
arisen on the subject among writers, (these having been particularly hot
between medical authors and Aristotelians,) who have come into the arena
with various explanations, both of the nature of the efficient cause and
of the mode of its operation.

And indeed the Omnipotent Creator is nowhere more conspicuous in his
works, nowhere is his divinity more loudly proclaimed, than in the
structure of animals. And though all know and admit that the offspring
derives its origin from male and female, that an egg is engendered by a
cock and a hen, and that a pullet proceeds from an egg, still we are not
informed either by the medical schools or the sagacious Aristotle, as to
the manner in which the cock or his semen fashions the chick from the
egg. For from what we have had occasion to say of the generation of
oviparous and other animals, it is sufficiently obvious that neither is
the opinion of the medical authorities admissible, who derive generation
from the admixture of the seminal fluids of the two sexes, nor that of
Aristotle, who holds the semen masculinum for the efficient, and the
menstrual blood for the material cause of procreation. For neither in
the act of intercourse nor shortly after it, is aught transferred to the
cavity of the uterus, from which as matter any part of the fœtus is
immediately constituted. Neither does the “geniture” proceeding from the
male in the act of union (whether it be animated or an inanimate
instrument) enter the uterus; neither is it attracted into this organ;
neither is it stored up within the fowl; but it is either dissipated or
escapes. Neither is there anything contained in the uterus immediately
after intercourse, which, proceeding from the male, or from the female,
or from both, can be regarded as the matter or rudiment of the future
fœtus. Neither is the semen galli stored and retained in the bursa
Fabricii of the hen or elsewhere, that from thence, as by the
irradiation of some spiritual substance, or by contact, the egg may be
fashioned or the chick constituted from the egg. Neither has the hen any
other semen save papulæ, yelks, and eggs. These observations of ours,
therefore, render the subject of generation one of greater difficulty
than ever, inasmuch as all the presumptions upon which the two old
opinions repose are totally overthrown. The fact is especial, as we
shall afterwards demonstrate, that all animals are alike engendered from
eggs; and in the act of intercourse, whether of man or the lower
quadrupeds, there is no seminal fluid, proceeding from the male or the
female, thrown into the uterus or attracted by this organ; there is
nothing to be discovered within its cavity, either before intercourse,
during the act, or immediately after it, which can be regarded as the
matter of the future fœtus, or as its efficient cause, or as its

Daniel Sennert, a man of learning and a close observer of nature, having
first passed the reasonings of a host of others under review, approaches
the subject himself; and concludes that the vital principle inheres in
the semen and is almost identical with that which resides in the future
offspring. So that Sennert does not hesitate to aver that the rational
soul of man is present in his seminal fluid, and by a parity of
reasoning that the egg possesses the animating principle of the pullet;
that the vital principle is transported to the uterus of the female with
the semen of the male, and that from the seminal fluids of either
conjoined, not mixed (for mixture, he says, is applied to things of
different species), and endowed with soul or the vital principle a
perfect animal emerges. And therefore, he says, the semen of either
parent is required, whether to the constitution of the ovum or of the
embryo. And having said so much, he seems to think that he has overcome
all difficulties, and has delivered a certain and perspicuous truth.

But in order that we should concede a soul or vital principle (anima)
to the egg, and that combined from the souls of the parents, these being
occasionally of different species, the horse and the ass, the common
fowl and the pheasant, for example, this vital principle not being a
mixture but only an union; and allow the pullet to be produced in the
manner of the seeds of plants, by the same efficient principle by which
the perfect animal is afterwards preserved through the rest of its life,
so that it would be absurd to say that the fœtus grew by one vital
principle without the uterus or ovum, and by another within the uterus
or ovum--did we grant all this, I say (although it is invalid and
undeserving faith), our history of generation from the egg,
nevertheless, upsets the foundations of the doctrine, and shows it to be
entirely false; namely, that the egg is produced from the semen of the
cock and hen, or that any seminal fluid from either one or other is
carried to the uterus, or that the embryo or any particle of it is
fashioned from any seminal fluid transported to the uterus, or that the
semen galli, as efficient cause and plastic agent, is anywhere stored up
or reserved within the body of the hen to serve when attracted into the
uterus, as the matter and nourishment whence the fœtus which it has
produced should continue to grow. The conditions are wanting which he
himself admits, after Aristotle, to be necessary, viz., that the embryo
be constituted by that which is actual and preexists, and the chick by
that which is present and exists in the place where the chick is first
formed and increases; further, that it be produced by that which is
accomplished immediately and conjunctly, and is the same by which the
chick is preserved and grows through the whole of its life. For the
semen galli (and whether it is viewed as animate or inanimate is of no
moment) is nowise present and conjunct either in the egg or in the
uterus; neither in the matter from which the chick is fashioned, nor yet
in the chick itself already begun, and as contributing either to its
formation or perfection.

He dreams, too, when he seeks illustrations of his opinions on an
animated semen from such instances as the seeds of plants and acorns;
because he does not perceive the difference alleged by Aristotle[266]
between the “geniture” admitted in intercourse and the first conception
engendered by both parents; neither does he observe on the egg produced
originally in the cluster of the vitellarium, and without any geniture,
whether proceeding from the male or the female, translated to the
uterus. Neither does he understand that the uterus is, even after
intercourse, completely empty of matter of every kind, whether
transmitted by the parents, or produced by the intercourse, or
transmuted in any way whatever. Neither had he read, or at all events he
does not refer to the experiment of Fabricius, namely, that a hen is
rendered so prolific by a few treads of the cock, that she will continue
to lay fruitful eggs for the rest of the year, although in the interval
she receives no new accessions of semen for the fecundation of each egg
as it is laid, neither does she retain any of the seminal fluid which
she received so long ago.

So much is certain, and disputed by no one, that animals, all those at
least that proceed from the intercourse of male and female, are the
offspring of this intercourse, and that they are procreated as it seems
by a kind of contagion, much in the same way as medical men observe
contagious diseases, such as leprosy, lues venera, plague, phthisis, to
creep through the ranks of mortal men, and by mere extrinsic contact to
excite diseases similar to themselves in other bodies; nay, contact is
not necessary; a mere halitus or miasm suffices, and that at a distance
and by an inanimate medium, and with nothing sensibly altered: that is
to say, where the contagion first touches, there it generates an
“univocal” like itself, neither touching nor existing in fact, neither
being present nor conjunct, but solely because it formerly touched. Such
virtue and efficacy is found in contagions. And the same thing perchance
occurs in the generation of animals. For the eggs of fishes, which come
spontaneously to their full size extrinsically, and without any addition
of male seminal fluid, and are therefore indubitably possessed of
vitality without it, merely sprinkled and touched with the milt of the
male, produce young fishes. The semen of the male, I say, is not
intromitted in such wise as to perform the part of “agent” in each
particular egg, or to fashion the body, or to introduce vitality
(anima); the ova are only fecundated by a kind of contagion. Whence
Aristotle calls the milt of the male fish, or the genital fluid diffused
in water, at one time “the genital and fœtific fluid,” at another, “the
vital virus.” For he says[267]: “The male fish sprinkles the ova with
his genital semen, and from the ova that are touched by this vital virus
young fishes are engendered.”

Let it then be admitted as matter of certainty that the embryo is
produced by contagion. But a great difficulty immediately arises, when
we ask: how, in what way is this contagion the author of so great a
work? By what condition do parents through it engender offspring like
themselves, or how does the semen masculinum produce an “univocal” like
the male whence it flowed? When it disappears after the contact, and is
naught in act ulteriorly, either by virtue of contact or presence, but
is corrupt and has become a nonentity, how, I ask, does a nonentity act?
How does a thing which is not in contact fashion another thing like
itself? How does a thing which is dead itself impart life to something
else, and that only because at a former period it was in contact?

For the reasoning of Aristotle[268] appears to be false, or at all
events defective, where he contends “That generation cannot take place
without an active and a passive principle; and that those things can
neither act nor prove passive which do not touch; but that those things
come into mutual contact which, whilst they are of different sizes, and
are in different places, have their extremes together.”

But when it clearly appears that contagion from noncontingents, and
things not having their extremities together, produce ill effects on
animals, wherefore should not the same law avail in respect of their
life and generation? There is an “efficient” in the egg which, by its
plastic virtue (for the male has only touched though he no longer
touches, nor are there any extremes together), produces and fashions the
fœtus in its kind and likeness. And through so many media or instruments
is this power, the agent of fecundity, transmitted or required that
neither by any movement of instruments as in works of art, nor by the
instance of the automaton quoted by Aristotle, nor of our clocks, nor of
the kingdom in which the mandate of the sovereign is everywhere of
avail, nor yet by the introduction of a vital principle or soul into
the semen or “geniture,” can the aforementioned doctrine be defended.

And hence have arisen all the controversies and problems concerning the
attraction of the magnet and of amber; on sympathy and antipathy; on
poisons and the contagion of pestilential diseases; on alexipharmics and
medicines which prove curative or injurious through some hidden or
rather unknown property, all of which seem to come into play
independently of contact. And above all on what it is in generation
which, in virtue of a momentary contact--nay, not even of contact, save
through several media--forms the parts of the chick from the egg by
epigenesis in a certain order, and produces an “univocal” and like
itself, and that entirely because it was in contact at a former period.
How, I ask again, does that which is not present, and which only enjoyed
extrinsic contact, come to constitute and order all the members of the
chick in the egg exposed without the body of the parent, and often at a
long interval after it is laid? how does it confer life or soul, and a
species compounded of those of the concurring generants? Inasmuch as
nothing, it seems, can reproduce itself in another’s likeness.


_Of the efficient cause of animals, and its conditions._

That we may proceed in our subject, therefore, and penetrate so far into
the knowledge of the efficient cause of animal generation as seems
needful in this place, we must begin by observing what instruments or
media are devoted to it. And here we come at once to the distinction
into male and female; seminal fluid and ovum, and its primordium. For
some males, as well as some females, are barren, or but little prolific;
and the seed of the male is at one time more, at another time less
prolific; because the semen masculinum stored up in the vesiculæ
seminales is esteemed unfruitful, unless it is raised into froth by the
spirits and ejected with force. And even then perchance it is not
endowed with equal fecundating force at all times. Neither are all the
germs of yelks in the ovary, nor all the eggs in the uterus made fertile
at the same instant.

Now I call that fruitful which, unless impeded by some extrinsic cause,
attains by its inherent force to its destined end, and brings about the
consequence for the sake of which it is ordained. Thus the cock is
called fruitful which has his hens more frequently and surely pregnant,
the eggs they lay being at the same time perfect and proper for

The hen in like manner is esteemed fruitful which has the faculty of
producing eggs, or of receiving and long retaining the virtue of
prolific conception from the cock. The cluster of germs and the ovary
itself are regarded as prolific when the germs are numerous and of good

The egg in the same way is fruitful which differs from a subventaneous
or hypenemic egg, and which, cherished by incubation, or in any other
way, does not fail to produce a chick.

Such an efficient cause consequently is required for the chick, as shall
impart the virtue of fecundity to it, and secure it the power of acting
as an efficient cause in its turn. Because that, or its analogue at
least, by means of which they become prolific, is present in all
animals. And the inquiry is the same in each case, when we ask what it
is in the egg which renders it prolific, and distinguishes it from a
wind egg; what in the vitellary germ and ovary; what in the female;
what, finally, in the semen and the cock himself? What, moreover, it is
in the blood and punctum saliens, or first formed particle of the chick,
whence all the other parts arise with their appropriate structures and
arrangements; what in the embryo or chick itself whereby it becomes more
or less robust and agile, attains to maturity with greater or less
rapidity, and lives with various degrees of health, for a longer or
shorter period?

Nor is the inquiry very different which goes to ascertain what sex the
male and the female, or the cock and the hen, confer upon the prolific
egg; and what proceeds from each that contributes to the perfection or
resemblance of the chick, viz., whether the egg, the conception, the
matter, and the nutriment proceed from the mother, and the plastic
virtue from the father; or rather a certain contagion immitted during
intercourse, or produced and received from him, which in the body of the
hen, or in the eggs, either permanently excites the matter of the eggs,
or attracts nourishment from the female, and concocts and distributes it
first for the growth of the eggs, and then for the production of the
chicks; finally, whether from the male proceeds all that has reference
to form and life and fecundity, from the female, again, all that is of
matter, constitution, place, and nourishment? For among animals where
the sexes are distinct, matters are so arranged, that since the female
alone is inadequate to engender an embryo and to nourish and protect the
young, a male is associated with her by nature, as the superior and more
worthy progenitor, as the consort of her labour, and the means of
supplying her deficiencies; in the case of the hen, of correcting by his
contagion the inferiority of the hypenemic eggs which she produces, and
so rendering them prolific. For as the pullet, engendered of an egg, is
indebted to that egg for his body, vitality, and principal or generative
part, so and in like manner does the egg receive all that is in it from
the female, the female in her turn being dependent on the male for her
fecundity which is conferred in coition.

And here we have an opportunity of inquiring, whether the male be the
first and principal cause of the generation of the offspring; or whether
the male along with the female are the mediate and instrumental causes
of nature itself, or of the first and supreme generator? And such an
inquiry is both becoming and necessary, for perfect science of every
kind depends on a knowledge of causes. To the full understanding of
generation, therefore, it is incumbent on us to mount from the final to
the first and supreme efficient cause, and to hold each and every cause
in especial regard.

We shall have occasion to define that which is the first and supreme
efficient cause of the chick in ovo by and by, when we treat of that
which constitutes the efficient cause [of generation] among animals in
general. Here, meantime, we shall see what its nature may be.

The first condition, then, of the primary efficient cause of generation,
properly so called, is, as we have said, that it be the prime and
principal fertilizer, whence all mediate causes receive the fecundity
imparted. For example, the chick is derived from the punctum saliens in
the egg, not only as regards the body, but also, and this especially, as
respects the life (anima): the punctum saliens, or heart, is derived
from the egg, the egg from the hen, and the hen has her fecundity from
the cock.

Another condition of the prime efficient is discovered from the work
achieved, viz., the chick, because that is the prime efficient in which
the reason of the effect is principally displayed. But since every
generative efficient engenders another like itself, and the offspring is
of a mixed nature, the prime efficient must also be a certain mixed

Now, I maintain that the offspring is of a mixed nature, inasmuch as a
mixture of both parents appears plainly in it, in the form and
lineaments, and each particular part of its body, in its colour,
mother-marks, disposition to diseases, and other accidents. In mental
constitution, also, and its manifestations, such as manners, docility,
voice, and gait, a similar temperament is discoverable. For as we say of
a certain mixture, that it is composed of elements, because their
qualities or virtues, such as heat, cold, dryness, and moisture, are
there discovered associated in a certain similar compound body, so, in
like manner, the work of the father and mother is to be discerned both
in the body and mental character of the offspring, and in all else that
follows or accompanies temperament. In the mule, for instance, the body
and disposition, the temper and voice, of both parents (of the horse and
the ass, _e. g._) are mingled; and so, also, in the hybrid between the
pheasant and the fowl, in that between the wolf and the dog, &c.,
corresponding traits are conspicuous.

When, therefore, the chick shows his resemblance to both parents, and is
a mixed effect, the primary genital cause (which it resembles) must
needs be mixed. Wherefore that which fashions the chick in the egg is of
a mixed nature, a certain something mixed or compounded, and the work of
both parents. And if any kind of contagion, engendered under the
influence of sexual intercourse, in which the male and female mingle and
form but one body, either originates or remains in the body of the
female, that, too, must be of a mixed nature or power, whence,
subsequently, a fertile egg will be produced, endowed with plastic
powers, the consequence of a mixed nature, or of a mixed efficient
instrument, from which a chick, also of a mixed nature, will be

I have used the word _contagion_ above, because Aristotle’s view is
contradicted by all experience, viz., that a certain part of the embryo
is immediately made by intercourse. Neither is it true, as some of the
moderns assert, that the vital principle (anima) of the future chick is
present in the egg; for that cannot be the vital principle of the chick
which inheres in no part of its body. Neither can the living principle
be said either to be left or to be originated by intercourse; otherwise
in every pregnant woman there would be two vital principles (animæ)
present. Wherefore, until it shall have been determined what the
efficient cause of the egg is, what it is of mixed nature that must
remain immediately upon intercourse, we may be permitted to speak of it
under the title of a Contagion.

But where this contagion lies hid in the female after intercourse, and
how it is communicated and given to the egg, demands quite a special
inquiry, and we shall have occasion to treat of the matter when we come
to discuss the conception of females in general. It will suffice,
meantime, if we say that the same law applies to the prime efficient--in
which inheres the reason of the future offspring--as to the offspring;
as this is of a mixed nature, the nature of its cause must also be
mixed; and it must either proceed equally from both parents, or from
something else which is employed by both concurrently as instruments,
animated, co-operating, mixed, and in the sexual act coalescing unto
one. And this is the third condition of the prime efficient, that it
either imparts motion to all the intermediate instruments in succession,
or uses them in some other way, but comes not itself into play. Whence
the origin of the doubt that has arisen, whether, in the generation of
the chick, the cock were the true prime efficient, or whether there were
not another prior, superior to him? For, indeed, all things seem to
derive their origin from a celestial influence, and to follow the
movements of the sun and moon. But we shall be able to speak more
positively of this matter after we have shown what we understand by the
“instrument,” or “instrumental efficient cause,” and how it is

Instrumental efficients, then, are of different kinds: some, according
to Aristotle, are factive, others active; some have no capacity any way
unless conjoined with another prior efficient, as the hand, foot,
genital organs, &c. with the rest of the body; others have an influence
even when separate and distinct, as the seminal fluid and the ovum. Some
instruments, again, have neither motion nor action beyond those that are
imparted to them by the prime efficient; and others have peculiar
inherent principles of action, to which nature indeed allows no motion
in the business of generation, though she still uses their faculties,
and prescribes them laws or limits in their operations, not otherwise
than the cook makes use of fire in cooking, and the physician of herbs
and drugs in curing diseases.

Sennert, that he may uphold the opinion he had espoused of the vital
principle (anima) being present in the semen, and the formative faculty
of the chick being extant in the egg, asserts that not only is the egg,
but the semen of the cock, endowed with the living principle of the
future chick. Moreover, he distinctly denies that there is any separate
instrumental efficient; and says, that that only ought to be entitled
“instrument” which is conjoined with the prime efficient; and that only
“instrumental efficient,” which has no motion or action save that which
is imparted to it by the prime efficient, or which is continuously and
successively received, and in virtue of which it acts. And on this
ground he rejects the example of projectiles, which have received force
from the projecting agent, and, separated from it, act nevertheless; as
if swords and spears were properly to be called warlike weapons, but
arrows and bullets to be refused this title. He also rejects the
argument derived from the republic, denying thereby that magistrates,
counsellors, or ministers, are instruments of government; although
Aristotle regards a counsel as an efficient, and in express terms calls
a minister an instrument.[269] Sennert likewise denies the example of
automata; and says and gainsays much besides, with a view to confirming
himself in his position, that the semen and the egg are possessed of a
living principle (anima), and are not mediate or instrumental, but
principal agents. Sennert, nevertheless, as it were compelled by the
force of truth, lays down such conditions for a principal agent, as
fully and effectually contradict all that he had said before. He tells
us, for instance, that “whatever produces a work or an effect more noble
than itself, or an effect unlike itself, is not a principal efficient,
but an instrumental cause;” granting which, who would not infer that the
semen and the egg were instruments? seeing that the pullet is an effect
more noble than the egg, and every way unlike either this or the
spermatic fluid. Wherefore, when the learned Sennert denies the semen
and the egg to be instruments or organs, because they are distinct from
the prime agents, he takes his position upon a false basis; because, as
the prime generator procreates offspring by various means or media, the
medium being here conjunct, as the hand of the workman is with his body,
there separate and distinct, as is the arrow let loose from the bow, it
is still to be regarded as an instrument.

From the conditions now enumerated of an instrumental cause, it seems to
follow that the prime efficient in the generation of the chick is the
cock, or, at all events, the cock and hen, because the resulting pullet
resembles these; nor can it be held more noble than they, which are its
prime efficients or parents. I shall, therefore, add another condition
of the prime efficient, whence it may, perhaps, appear that the male is
not the prime, but only the instrumental, cause of the chick; viz., that
the prime efficient in the formation of the chick makes use of artifice,
and foresight, and wisdom, and goodness, and intelligence, which far
surpass the powers of our rational soul to comprehend, inasmuch as all
things are disposed and perfected in harmony with the purpose of the
future work, and that there be action to a determinate end; so that
every, even the smallest, part of the chick is fashioned for the sake of
a special use and end, and with respect not merely to the rearing of the
fabric, but also to its well-being, and elegance and preservation. But
the male or his semen is not such either in the act of kind or after it,
that art, intelligence, and foresight can be ascribed to him or it.

The proper inference from these premises appears to be that the male, as
well as his seminal fluid, is the efficient instrument; and the female
not less than the egg she lays the same. Wherefore, we have to seek
refuge in a prior, superior, and more excellent cause, to which, with
all propriety, are ascribed foresight, intelligence, goodness, and
skill, and which is by so much more excellent than its effect or work,
as the architect is more worthy than the pile he rears, as the king is
more exalted than his minister, as the workman is better than his hands
or tools.

The male and female, therefore, will come to be regarded as merely the
efficient instruments, subservient in all respects to the Supreme
Creator, or father of all things. In this sense, consequently, it is
well said that the sun and moon engender man; because, with the advent
and secession of the sun, come spring and autumn, seasons which mostly
correspond with the generation and decay of animated beings. So that the
great leader in philosophy says:[270] “The first motion [of the sphere?]
is not the cause of generation and destruction; it is the motion of the
ecliptic that is so, this being both continuous and having two
movements; for, if future generation and corruption are to be eternal,
it is necessary that something likewise move eternally, that
interchanges do not fail, that of the two actions one only do not occur.
The cause of the perpetuity [of animal species?] is, therefore, the law
of the universe; and the obliquity [of the ecliptic?] is the cause of
the approach and accession, [of the sun?] and of his being now nearer,
now more remote: when he quits us, and removes to a distance, it is then
that decay and corruption intervene; and, in like manner, when he
approaches, it is then that he engenders; and if, as he frequently
approaches, he engenders; so, because he frequently recedes, does he
cause corruption; for the causes of contraries are contrary.”

All things, therefore, grow and flourish in spring, (on the approach of
the sun, that is to say, he being the common parent and producer, or at
all events the immediate and universal instrument of the Creator in the
work of reproduction); and this is true not of plants only but of
animals also; nor less of those that come spontaneously, than of those
that are propagated by the consentient act of male and female. It is as
if, with the advent of this glorious luminary, Venus the bountiful
descended from heaven, waited on by Cupid and a cohort of graces, and
prompted all living things by the bland incitement of love to secure
the perpetuity of their kinds. Or (and it is thus that we have it in the
mythology) it is as if the genital organs of Saturn, cast into the sea
at this season, raised a foam, whence sprung Aphrodite. For, in the
generation of animals, as the poet says, “superat tener omnibus
humor,”--a gentle moisture all pervades,--and the genitals froth and are
replete with semen.

The cock and the hen are especially fertile in the spring; as if the
sun, or heaven, or nature, or the soul of the world, or the omnipotent
God--for all these names signify the same thing--were a cause in
generation superior and more divine than they; and thus it is that the
sun and man, i.e. the sun through man as the instrument, engender man.
In the same way the preserver of all things, and the male among birds,
give birth to the egg, from whence the chick, the perfect bird, is made
eternal in its kind by the approach and recession of the god of day,
who, by the divine will and pleasure, or by fate, serves for the
generation of all that lives.

Let us conclude, therefore, that the male, although a prior and more
excellent efficient than the female, is still no more than an
instrumental efficient, and that he, not less than the female, must
refer his fecundity or faculty of engendering as received from the
approaching sun; and, consequently, that the skill and foresight, which
are apparent in his work, are not to be held as proceeding from him but
from God; inasmuch as the male in the act of kind neither uses counsel
nor understanding; neither does man engender the rational part of his
soul, but only the vegetative faculty; which is not regarded as any
principal or more divine faculty of the soul, but one only of a lower

Since, then, there is not less of skill and prescience manifested in the
structure of the chick than in the creation of man and the universe at
large, it is imperative even in the generation of man to admit an
efficient cause, superior to, and more excellent than man himself:
otherwise the vegetative faculty, or that part of the soul or living
principle which fashions and preserves a man, would have to be accounted
far more excellent and divine, and held to bear a closer resemblance to
God than the rational portion of the soul, whose excellence,
nevertheless, we extol over all the faculties of all animals, and esteem
as that which has right and empire in them, and to which all created
things are made subservient. Or we should else have to own that in the
works of nature there was neither prudence, nor art, nor understanding;
but that these appeared to us, who are wont to judge of the divine
things of nature after our own poor arts and faculties, or to contrast
them with examples due to ourselves; as if the active principles of
nature produced their effects in the same way as we are used to produce
our artificial works, by counsel, to wit, or discipline acquired through
the mind or understanding.

But nature, the principle of motion and rest in all things in which it
inheres, and the vegetative soul, the prime efficient cause of all
generation, move by no acquired faculty which might be designated by the
title of skill or foresight, as in our undertakings; but operate in
conformity with determinate laws like fate or special commandments--in
the same way and manner as light things rise and heavy things descend.
The vegetative faculty of parents, to wit, engenders in the same way,
and the semen finally arrives at the form of the fœtus, as the spider
weaves her web, as birds build nests, incubate their eggs, and cherish
their young, or as bees and ants construct dwellings, and lay up stores
for their future wants; all of which is done naturally and from a
connate genius or disposition; by no means from forecast, instruction,
or reason. That which in us is the principle or cause of artificial
operations, and is called art, intellect, or foresight, in the natural
operations of the lower animals is nature, which is ἀυτοδίδακτος,
self-taught, instilled by no one; what in them is innate or connate, is
with us acquired. On this account it is, that they who refer all to art
and artifice are to be held indifferent judges of nature or natural
things; and, indeed, it is wiser to act in the opposite way, and
selecting standards in nature to judge of things made by art according
to them. For all the arts are but imitations of nature in one way or
another; as our reason or understanding is a derivative from the Divine
intelligence, manifested in his works; and when perfected by habit, like
another adventitious and acquired soul, gaining some semblance of the
Supreme and Divine agent, it produces somewhat similar effects.

Wherefore, according to my opinion, he takes the right and pious view of
the matter, who derives all generation from the same eternal and
omnipotent Deity, on whose nod the universe itself depends. Nor do I
think that we are greatly to dispute about the name by which this first
agent is to be called or worshipped; whether it be God, Nature, or the
Soul of the universe,--whatever the name employed,--all still intend by
it that which is the beginning and the end of all things; which exists
from eternity and is almighty; which is author or creator, and, by means
of changing generations, the preserver and perpetuator of the fleeting
things of mortal life; which is omnipresent, not less in the single and
several operations of natural things, than in the infinite universe;
which, by his deity or providence, his art and mind divine, engenders
all things, whether they arise spontaneously without any adequate
efficient, or are the work of male and female associated together, or of
a single sex, or of other intermediate instruments, here more numerous,
there fewer, whether they be univocal, or are equivocally or
accidentally produced: all natural bodies are both the work and the
instruments of that Supreme Good, some of them being mere natural
bodies, such as heat, spirit, air, the temperature of the air, matters
in putrefaction, &c., or they are at once natural and animated bodies;
for he also makes use of the motions, or forces, or vital principles of
animals in some certain way, to the perfection of the universe and the
procreation of the several kinds of animated beings.

From what has now been said, we are apprized to a certain extent of the
share which the male has in the business of generation. The cock confers
that upon the egg, which, from unprolific, makes it prolific, this being
identical with that which the fruit of vegetables receives from the
fervour of the summer sun, which secures to them maturity, and to their
seeds fertility; and not different from that which fertilizes things
spontaneously engendered, and brings caterpillars from worms, aurelias
from caterpillars, from aurelias moths, butterflies, bees, &c.

In this way is the sun, by his approach, both the beginning of motion
and transmutation in the coming fruit, and the end, also, inasmuch as he
is the author of the fertility of its included seed: and, as early
spring is the prime efficient of leaves and flowers and fruits, so is
summer, in its strength, the cause of final perfection in the ripeness
and fecundity of the seed. With a view to strengthen this position, I
shall add this one from among a large number of observations. Some
persons in these countries cultivate orange trees with singular care and
economy, and the fruit of these trees, which, in the course of the first
year, will grow to the size of the point of the thumb, comes to maturity
the following summer. This fruit is perfect in all respects, save and
except that it is without pips or seeds.

Pondering upon this with myself, I thought that I had here an example of
the barren egg, which is produced by the hen without the concurrence of
the cock, and which comprises everything that is visible in a fruitful
egg, but is still destitute of germinant seed; as if it were the same
thing that was imparted by the cock, in virtue of which a wind-egg
becomes a fruitful egg, which in warmer countries is dispensed by the
sun, and causes the fruit of the orange tree to be produced replete with
prolific seed. It is as if the summer in England sufficed for the
production of the fruit only, as the hen for the production of the egg,
but like the female fowl was impotent as a pro-genetrix; whilst in other
countries enjoying the sun’s light in larger proportion, the summer
acquired the characters of the male, and perfected the work of

Thus far have we treated this subject by the way, that, from the
instance of the egg, we might learn what conditions were required in the
prime efficient in the generation of animals;--for it is certain, that
in the egg there is an agent,--as there is also in every conception and
germ,--which is not merely infused by the mother, but is first
communicated in coitu by the father, by means of his spermatic fluid;
and which is itself primarily endowed with such virtue by heaven and the
sun, or the Supreme Creator. It is equally manifest, that this agent,
existing in every egg and seed, is so imbued with the qualities of the
parents, that it builds up the offspring in their likeness, not in its
own; and this mingled also as proceeding from both united in copulation.
Now, as all this proceeds with the most consummate foresight and
intelligence, the presence of the Deity therein is clearly proclaimed.

But we shall have to speak at greater length upon this subject, when we
strive to show what it is that remains with the female immediately after
intercourse, and where it is stored; at the same time that we
explain--since there is nothing visible in the cavity of the uterus
after intercourse--what that prolific contagion or prime conception is;
whether it is corporeal and laid up within the female, or is
incorporeal; whether the conception of the uterus be of the same nature
or not with the conceptions of the brain, and fecundity be acquired in
the same way as knowledge--a conclusion, in favour of which there is no
lack of arguments; or, as motion and the animal operations, which we
call appetites, derive their origin from the conceptions of the brain,
may not the natural motions and the operations of the vegetative
principle, and particularly generation, depend on the conception of the
uterus? And then we have to inquire how this prolific contagion is of a
mixed nature, and is imparted by the male to the female, and by her is
transferred to the ovum? Finally, how the contagious principle of all
diseases and preternatural affections spreads insensibly, and is


_Of the order of generation; and, first, of the primary genital

It will be our business, by and by, when we come to treat of the matter
in especial, to show what happens to the female from a fruitful embrace;
what it is that remains with her after this, and which we have still
spoken of under the name of contagion, by which, as by a kind of
infection, she conceives, and an embryo subsequently begins to grow of
its own accord. Meantime, we shall discourse of those things that
manifestly appear in connexion with the organs of generation which seem
most worthy of particular comment.

And first, since it appears certain that the chick is produced by
epigenesis, or addition of the parts that successively arise, we shall
inquire what part is formed first, before any of the rest appear, and
what may be observed of this and its particular mode of generation.

What Aristotle[271] says of the generation of the more perfect animals,
is confirmed and made manifest by all that passes in the egg, viz.: that
all the parts are not formed at once and together, but in succession,
one after another; and that there first exists a particular genital
particle, in virtue of which, as from a beginning, all the other parts
proceed. As in the seeds of plants, in beans and acorns, to quote
particular instances, we see the gemmula or apex, protruding, the
commencement of the entire prospective herb or tree. “And this particle
is like a child emancipated, placed independently, a principle existing
of itself, from whence the series of members is subsequently thrown out,
and to which belongs all that is to conduce to the perfection of the
future animal.”[272] Since, therefore, “No part engenders itself, but,
after it is engendered, concurs in its own growth, it is indispensable
that the part first arise which contains within itself the principle of
increase; for whether it be a plant or an animal, still has it within
itself the power of vegetation or nutrition;”[273] and at the same time
distinguishes and fashions each particular part in its several order;
and hence, in this same primogenate particle, there is a primary vital
principle inherent, which is the author and original of sense and
motion, and every manifestation of life.

That, therefore, is the principal particle whence vital spirit and
native heat accrue to all other parts, in which the calidum innatum sive
implantatum of physicians first shows itself, and the household deity or
perennial fire is maintained; whence life proceeds to the body in
general, and to each of its parts in particular; whence nourishment,
growth, aid, and solace flow; lastly, where life first begins in the
being that is born, and last fails in that which dies.

All this is certainly true as regards the first engendered part, and
appears manifestly in the formation of the chick from the egg. I am
therefore of opinion that we are to reject the views of certain
physicians, indifferent philosophers, who will have it that three
principal and primogenate parts arise together, viz.: the brain, the
heart, and the liver; neither can I agree with Aristotle himself, who
maintains that the heart is the first engendered and animated part; for
I think that the privilege of priority belongs to the blood alone; the
blood being that which is first seen of the newly engendered being, not
only in the chick in ovo, but in the embryo of every animal whatsoever,
as shall plainly be made to appear at a later stage of our inquiry.

There appears at first, I say, a red-coloured pulsating point or
vesicle, with lines or canals extending from it, containing blood in
their interior, and, in so far as we are enabled to perceive from the
most careful examination, the blood is produced before the punctum
saliens is formed, and is farther endowed with vital heat before it is
put in motion by a pulse; so that as pulsation commences in it and from
it, so, in the last struggle of mortal agony, does motion also end
there. I have indeed ascertained by numerous experiments instituted upon
the egg, as well as upon other subjects, that the blood is the element
of the body in which, so long as the vital heat has not entirely
departed, the power of returning to life is continued.

And since the pulsating vesicle and the sanguineous tubes extending
thence are visible before anything else, I hold it as consonant with
reason to believe that the blood is prior to its receptacles, the thing
contained, to wit, to its container, inasmuch as this is made
subservient to that. The vascular ramifications and the veins,
therefore, after these the pulsating vesicle, and, finally, the heart,
as being every one of them organs destined to receive and contain the
blood, are, in all likelihood, constructed for the express purpose of
impelling and distributing it, and the blood is, consequently, the
principal portion of the body.

This conclusion is favoured by numerous observations; particularly by
the fact that some animals, and these red-blooded, too, live for long
periods without any pulse; some even lie concealed through the whole
winter, and yet escape alive, though their heart had ceased from motion
of every kind, and their lungs no longer played; they had lain in fact
like those who lie half dead in a state of asphyxia from syncope,
leipothymia, or the hysterical passion.

Emboldened by what I have observed both in studying the egg, and whilst
engaged in the dissection of living animals, I maintain, against
Aristotle, that the blood is the prime part that is engendered, and the
heart the mere organ destined for its circulation. The function of the
heart is the propulsion of the blood, as clearly appears in all animals
furnished with red blood; and the office of the pulsating vesicle in the
generation of the chick ab ovo, as well as in the embryos of mammiferous
animals, is not different, a fact which I have repeatedly demonstrated
to others, showing the vesicula pulsans as a feeble glancing spark,
contracting in its action, now forcing out the blood which was contained
in it, and again relaxing and receiving a fresh supply.

The supremacy of the blood farther appears from this, that the pulse is
derived from it; for, as there are two parts in a pulsation, viz.:
distension or relaxation, and contraction, or diastole and systole, and,
as distension is the prior of these two motions, it is manifest that
this motion proceeds from the blood; the contraction, again, from the
vesicula pulsans of the embryo in ovo, from the heart in the pullet, in
virtue of its own fibres, as an instrument destined for this particular
end. Certain it is, that the vesicle in question, as also the auricle of
the heart at a later period, whence the pulsation begins, is excited to
the motion of contraction by the distending blood. The diastole, I say,
takes place from the blood swelling, as it were, in consequence of
containing an inherent spirit, so that the opinion of Aristotle in
regard to the pulsation of the heart,--namely, that it takes place by a
kind of ebullition,--is not without some mixture of truth; for what we
witness every day in milk heated over the fire, and in beer that is
brisk with fermentation, comes into play in the pulse of the heart; in
which the blood, swelling with a sort of fermentation, is alternately
distended and repressed; the same thing that takes place in the liquids
mentioned through an external agent, namely adventitious heat, is
effected in the blood by an intimate heat, or an innate spirit; and
this, too, is regulated in conformity with nature by the vital principle
(anima), and is continued to the benefit of animated beings.

The pulse, then, is produced by a double agent: first, the blood
undergoes distension or dilatation, and secondly, the vesicular membrane
of the embryo in the egg, the auricles and ventricles in the extruded
chick, effect the constriction. By these alternating motions associated,
is the blood impelled through the whole body, and the life of animals is
thereby continued.

Nor is the blood to be styled the primigenial and principal portion of
the body, because the pulse has its commencement in and through it; but
also because animal heat originates in it, and the vital spirit is
associated with it, and it constitutes the vital principle itself, (ipsa
anima); for wheresoever the immediate and principal instrument of the
vegetative faculty is first discovered, there also does it seem likely
will the living principle be found to reside, and thence take its rise;
seeing that the life is inseparable from spirit and innate heat.

For “however distinct are the artist and the instrument in things made
by art,” as Fabricius[274] well reminds us, “in the works of nature they
are still conjoined and one. Thus the stomach is the author and the
organ of chylopoesis.” In like manner are the vital principle and its
instrument immediately conjoined; and so, in whatever part of the body
heat and motion have their origin, in this also must life take its rise,
in this be last extinguished; and no one, I presume, will doubt that
there are the lares and penates of life enshrined, that there the vital
principle (anima) itself has its seat.

The life, therefore, resides in the blood, (as we are also informed in
our sacred writings,)[275] because in it life and the soul first show
themselves, and last become extinct. For I have frequently found, from
the dissection of living animals, as I have said, that the heart of an
animal that was dying, that was dead, and had ceased to breathe, still
continued to pulsate for a time, and retained its vitality. The
ventricles failing and coming to a stand, the motion still goes on in
the auricles, and finally in the right auricle alone; and even when all
motion has ceased, there the blood may still be seen affected with a
kind of undulation and obscure palpitation or tremor, the last evidence
of life. Every one, indeed, may perceive that the blood--this author of
pulsation and life,--longest retains its heat; for when this is gone,
and it is no longer blood, but gore, so is there, then, no hope of a
return to life. But, truly, as has been stated, both in the chick in ovo
and in the moribund animal, if you but apply some gentle stimulus either
to the punctum saliens or to the right auricle of the heart after the
failure of all pulsation, forthwith you will see motion, pulsation, and
life restored to the blood--provided always, be it understood, that the
innate heat and vital spirit have not been wholly lost.

From this it clearly appears that the blood is the generative part, the
fountain of life, the first to live, the last to die, and the primary
seat of the soul; the element in which, as in a fountain head, the heat
first and most abounds and flourishes; from whose influxive heat all the
other parts of the body are cherished, and obtain their life; for the
heat, the companion of the blood, flows through and cherishes and
preserves the whole body, as I formerly demonstrated in my work on the
motion of the blood.

And since blood is found in every particle of the body, so that you can
nowhere prick with a needle, nor make the slightest scratch, but blood
will instantly appear, it seems as if, without this fluid, the parts
could neither have heat nor life. So that the blood, being in ever so
trifling a degree concentrated and fixed,--Hippocrates called the state
ἀπύληψις τῶν φλεβῶν--stasis of the veins,--as in lipothymia, alarm,
exposure to severe cold, and on the accession of a febrile paroxysm, the
whole body is observed to become cold and torpid, and, overspread with
pallor and livor, to languish. But the blood, recalled by stimulants, by
exercise, by certain emotions of the mind, such as joy or anger,
suddenly all is hot, and flushed, and vigorous, and beautiful again.

Therefore it is that the red and sanguine parts, such as the flesh, are
alone spoken of as hot, and the white and bloodless parts, on the
contrary, such as the tendons and ligaments, are designated as cold. And
as red-blooded animals excel exsanguine creatures, so also, in our
estimate of the parts, are those which are more liberally furnished with
native heat and blood, held more excellent than all the others. The
liver, spleen, kidneys, lungs, and heart itself,--parts which are
especially entitled viscera,--if you will but squeeze out all the blood
they contain, become pale and fall within the category of cold parts.
The heart itself, I say, receives influxive heat and life along with the
blood that reaches it, through the coronary arteries; and only so long
as the blood has access to it. Neither can the liver perform its office
without the influence of the blood and heat it receives through the
cœliac artery; for there is no influx of heat without an afflux of blood
by the arteries, and this is the reason wherefore, when parts are first
produced, and before they have taken upon them the performance of their
respective duties, they all look bloodless and pale, in consequence of
which they were formerly regarded as spermatic by physicians and
anatomists, and in generation it was usual to say that several days were
passed in the milk. The liver, lungs, and substance of the heart itself,
when they first appear, are extremely white; and, indeed, the cone of
the heart and the walls of the ventricles are still seen to be white,
when the auricles, replete with crimson blood, are red, and the coronary
vein is purple with its stream. In like manner, the parenchyma of the
liver is white, when its veins and their branches are red with blood;
nor does it perform any duty until it is penetrated with blood.

The blood, in a word, so flows around and penetrates the whole body, and
imparts heat and life conjoined to all its parts, that the vital
principle, having its first and chief seat there, may truly be held as
resident in the blood; in this way, in common parlance, it comes to be
all in all, and all in each particular part.

But so little is it true, as Aristotle and the medical writers assert,
that the liver and the heart are the authors and compounders of the
blood, that the contrary even appears most obviously from the formation
of the chick in ovo, viz.: that the blood is much rather the fashioner
of the heart and liver; a fact, which physicians themselves appear
unintentionally to confirm, when they speak of the parenchyma of the
liver as a kind of effusion of blood, as if it were nothing more than so
much blood coagulated there. But the blood must exist before it can
either be shed or coagulated; and experience palpably demonstrates that
the thing is so, seeing that the blood is already present before there
is a vestige either of the body or of any viscus; and that in
circumstances where none of the mother’s blood can by possibility reach
the embryo, an event which is vulgarly held to occur among viviparous

The liver of fishes is always perceived of a white colour, though their
veins are of a deep purple or black; and our fowls, the fatter they
become, the smaller and paler grows the liver. Cachectic maidens, and
those who labour under chlorosis, are not only pale and blanched in
their bodies generally, but in their livers as well, a manifest
indication of a want of blood in their system. The liver, therefore,
receives both its heat and colour from the blood; the blood is in no
wise derived from the liver.

From what has now been said, then, it appears that the blood is the
first engendered part, whence the living principle in the first instance
gleams forth, and from which the first animated particle of the embryo
is formed; that it is the source and origin of all other parts, both
similar and dissimilar, which thence obtain their vital heat and become
subservient to it in its duties. But the heart is contrived for the sole
purpose of ministering between the veins and the arteries--of receiving
blood from the veins, and, by its ceaseless contractions, of propelling
it to all parts of the body through the arteries.

This fact is made particularly striking, when we find that neither is
there a heart found in every animal, neither does it necessarily and in
every instance pulsate at all times where it is encountered; the blood,
however, or a fluid which stands in lieu of it, is never wanting.


_Of the blood as prime element in the body._

It is unquestionable, then, and obvious to sense, that the blood is the
first formed, and therefore the genital part of the embryo, and that it
has all the attributes which have been ascribed to it in the preceding
exercise. It is both the author and preserver of the body; it is the
principal element moreover, and that in which the vital principle
(anima) has its dwelling-place. Because, as already said, before there
is any particle of the body obvious to sight, the blood is already
extant, has already increased in quantity, “and palpitates within the
veins,” as Aristotle expresses it,[276] “being moved hither and thither,
and being the only humour that is distributed to every part of the
animal body. The blood, moreover, is that alone which lives and is
possessed of heat whilst life continues.”

And further, from its various motions in acceleration or retardation,
in turbulence and strength, or debility, it is manifest that the blood
perceives things that tend to injure by irritating, or to benefit by
cherishing it. We therefore conclude that the blood lives of itself, and
supplies its own nourishment; and that it depends in nowise upon any
other part of the body, which is either prior to itself or of greater
excellence and worth. On the contrary, the whole body, as posthumous to
it, as added and appended as it were to it, depends on the blood, though
this is not the place to prove the fact; I shall only say, with
Aristotle,[277] that “The nature of the blood is the undoubted cause
wherefore many things happen among animals, both as regards their
tempers and their capacities.” To the blood, therefore, we may refer as
the cause not only of life in general,--inasmuch as there is no other
inherent or influxive heat that may be the immediate instrument of the
living principle except the blood,--but also of longer or shorter life,
of sleep and watching, of genius or aptitude, strength, &c. “For through
its tenuity and purity,” says Aristotle in the same place, “animals are
made wiser and have more noble senses; and in like manner they are more
timid and courageous, or passionate and furious, as their blood is more
dilute, or replete with dense fibres.”

Nor is the blood the author of life only, but, according to its
diversities, the cause of health and disease likewise: so that poisons,
which come from without, such as poisoned wounds, unless they infect the
blood, occasion no mischief. Life and death, therefore, flow for us from
the same spring. “If the blood becomes too diffluent,” says
Aristotle,[278] “we fall sick; for it sometimes resolves itself into
such a sanguinolent serum, that the body is covered with a bloody sweat;
and if there be too great a loss of blood, life is gone.” And, indeed,
not only do the parts of the body at all times become torpid when blood
is lost, but if the loss be excessive, the animal necessarily dies. I do
not think it requisite to quote any particular experiment in
confirmation of these views: the whole subject would require to be
treated specially.

The admirable circulation of the blood originally discovered by me, I
have lived to see admitted by almost all; nor has aught as yet been
urged against it by any one which has seemed greatly to require an
answer. Wherefore I imagine that I shall perform a task not less new and
useful than agreeable to philosophers and medical men, if I here briefly
discourse of the causes and uses of the circulation, and expose other
obscure matters respecting the blood; if I show, for instance, how much
it concerns our welfare that by a wholesome and regulated diet we keep
our blood pure and sweet. When I have accomplished this it will no
longer, I trust, seem so improbable and absurd to any one as it did to
Aristotle[279] in former times, that the blood should be viewed as the
familiar divinity, as the soul itself of the body, which was the opinion
of Critias and others, who maintained that the prime faculty of the
living principle (anima) was to feel, and that this faculty inhered in
the body in virtue of the nature of the blood. Thales, Diogenes,
Heraclitus, Alcmæon, and others, held the blood to be the soul, because,
by its nature, it had a faculty of motion.

Now that both sense and motion are in the blood is obvious from many
indications, although Aristotle[280] denies the fact. And, indeed, when
we see him, yielding to the force of truth, brought to admit that there
is a vital principle even in the hypenemic egg; and in the spermatic
fluid and blood a “certain divine something corresponding with the
element of the stars,” and that it is vicarious of the Almighty Creator;
and if the moderns be correct in their views when they say that the
seminal fluid of animals emitted in coitu is alive, wherefore should we
not, with like reason, affirm that there is a vital principle in the
blood, and that when this is first ingested and nourished and moved, the
vital spark is first struck and enkindled? Unquestionably the blood is
that in which the vegetative and sensitive operations first proclaim
themselves; that in which heat, the primary and immediate instrument of
life, is innate; that which is the common bond between soul and body,
and the vehicle by which life is conveyed into every particle of the
organized being.

Besides, if it be matter of such difficulty to understand the spermatic
fluid as we have found it, to fathom how through it the formation of the
body is made to begin and proceed with such foresight, art, and divine
intelligence, wherefore should we not, with equal propriety, admit an
exalted nature in the blood, and think at least as highly of it as we
have been led to do of the semen?--the rather, as this fluid is itself
produced from the blood, as appears from the history of the egg; and the
whole organized body not only derives its origin, as from a genital
part, but even appears to owe its preservation to the blood.

We have, indeed, already said so much incidentally above, intending to
speak on the subject more particularly at another time. Nor do I think
that we are here to dispute whether it is strictly correct to speak of
the blood as a _part_; some deny the propriety of such language, moved
especially by the consideration that it is not sensible, and that it
flows into all parts of the body to supply them with nourishment. For
myself, however, I have discovered not a few things connected with the
manner of generation which differ essentially from those motions which
philosophers and medical writers generally either admit or reject. At
this time I say no more on this point; but though I admit the blood to
be without sensation, it does not follow that it should not form a
portion, and even a very principal portion, of a body which is endowed
with sensibility. For neither does the brain nor the spinal marrow, nor
the crystalline or the vitreous humour of the eye, feel anything,
though, by the common consent of all, philosophers and physicians alike,
these are parts of the body. Aristotle placed the blood among the partes
similares; Hippocrates, as the animal body according to him is made up
of containing, contained, and impelling parts, of course reckoned the
blood among the number of parts contained.

But we shall have more to say on this topic when we treat of that
wherein a part consists, and how many kinds of parts there are.
Meantime, I cannot be silent on the remarkable fact, that the heart
itself, this most distinguished member in the body, appears to be

A young nobleman, eldest son of the Viscount Montgomery, when a child,
had a severe fall, attended with fracture of the ribs of the left side.
The consequence of this was a suppurating abscess, which went on
discharging abundantly for a long time, from an immense gap in his side;
this I had from himself and other credible persons who were witnesses.
Between the 18th and 19th years of his age, this young nobleman, having
travelled through France and Italy, came to London, having at this time
a very large open cavity in his side, through which the lungs, as it was
believed, could both be seen and touched. When this circumstance was
told as something miraculous to his Serene Majesty King Charles, he
straightway sent me to wait on the young man, that I might ascertain the
true state of the case. And what did I find? A young man, well grown, of
good complexion, and apparently possessed of an excellent constitution,
so that I thought the whole story must be a fable. Having saluted him
according to custom, however, and informed him of the king’s expressed
desire that I should wait upon him, he immediately showed me everything,
and laid open his left side for my inspection, by removing a plate which
he wore there by way of defence against accidental blows and other
external injuries. I found a large open space in the chest, into which I
could readily introduce three of my fingers and my thumb; which done, I
straightway perceived a certain protuberant fleshy part, affected with
an alternating extrusive and intrusive movement; this part I touched
gently. Amazed with the novelty of such a state, I examined everything
again and again, and when I had satisfied myself, I saw that it was a
case of old and extensive ulcer, beyond the reach of art, but brought by
a miracle to a kind of cure, the interior being invested with a
membrane, and the edges protected with a tough skin. But the fleshy
part, (which I at first sight took for a mass of granulations, and
others had always regarded as a portion of the lung,) from its pulsating
motions and the rhythm they observed with the pulse,--when the fingers
of one of my hands were applied to it, those of the other to the artery
at the wrist--as well as from their discordance with the respiratory
movements, I saw was no portion of the lung that I was handling, but the
apex of the heart! covered over with a layer of fungous flesh by way of
external defence, as commonly happens in old foul ulcers. The servant of
this young man was in the habit daily of cleansing the cavity from its
accumulated sordes by means of injections of tepid water; after which
the plate was applied, and, with this in its place, the young man felt
adequate to any exercise or expedition, and, in short, he led a pleasant
life in perfect safety.

Instead of a verbal answer, therefore, I carried the young man himself
to the king, that his majesty might with his own eyes behold this
wonderful case: that, in a man alive and well, he might, without
detriment to the individual, observe the movement of the heart, and,
with his proper hand even touch the ventricles as they contracted. And
his most excellent majesty, as well as myself, acknowledged that the
heart was without the sense of touch; for the youth never knew when we
touched his heart, except by the sight or the sensation he had through
the external integument.

We also particularly observed the movements of the heart, viz.: that in
the diastole it was retracted and withdrawn; whilst in the systole it
emerged and protruded; and the systole of the heart took place at the
moment the diastole or pulse in the wrist was perceived; to conclude,
the heart struck the walls of the chest, and became prominent at the
time it bounded upwards and underwent contraction on itself.

Neither is this the place for taking up that other controversy; to wit,
whether the blood alone serves for the nutrition of the body? Aristotle
in several places contends that the blood is the ultimate aliment of the
body, and in this view he is supported by the whole body of physicians.
But many things of difficult interpretation, and that hang but
indifferently together, follow from this opinion of theirs. For when the
medical writers speak of the blood in their physiological disquisitions,
and teach that the above is its sole use and end, viz.: to supply
nourishment to the body, they proceed to compose it of four humours, or
juices, adducing arguments for such a view from the combinations of the
four primary qualities; and then they assert that the mass of the blood
is made up of the two kinds of bile, the yellow and the black, of
pituita, and the blood properly so called. And thus they arrive at their
four humours, of which the pituita is held to be cold and moist; the
black bile cold and dry; the yellow bile hot and dry; and the blood hot
and moist. Further, of each of these several kinds, they maintain that
some are nutritious, and compose the whole of the body; others, again,
they say are excrementitious. Still further, they suppose that the blood
proper is composed of the nutritious or heterogeneous portions; but the
constitution of the mass is such, that the pituita is a cruder matter,
which the more powerful native heat can convert into perfect blood.
They deny, however, that the bile can by any means be thus transformed
into blood; although the blood, they say, is readily changed into bile,
an event which they conceive takes place in melancholic diseases,
through an excess of the concocting heat.

Now, if all this were true, and there be no retrogressive movement, viz.
from black bile to bile, from bile to blood, they would be brought to
the dilemma of having to admit that all the juices were present for the
production of black bile, and that this was a principal and most highly
concocted nutriment. It would further be imperative on them to recognize
a kind of twofold blood, viz. one consisting of the entire mass of fluid
contained in the veins, and composed of the four humours aforesaid; and
another consisting of the purer, more fluid and spirituous portion, the
fluid, which in the stricter sense they call blood, which some of them
contend is contained in the arteries apart from the rest, and which they
then depute upon sundry special offices. On their own showing,
therefore, the pure blood is no aliment for the body, but a certain
mixed fluid, or rather black bile, to which the rest of the humours

Aristotle,[281] too, although he thought that the blood existed as a
means of nourishing the body, still believed that it was composed as it
were of several portions, viz. of a thicker and black portion which
subsides to the bottom of the basin when the blood coagulates, and this
portion he held to be of an inferior nature;[282] “for the blood,” he
says, “if it be entire, is of a red colour and sweet taste; but if
vitiated either by nature or disease, it is blacker.” He also will have
it fibrous in part or partly composed of fibres, which being removed, he
continues,[283] the blood neither sets nor becomes any thicker. He
farther admitted a sanies in the blood: “Sanies is unconcocted blood, or
blood not yet completely concocted, or which is as yet dilute like
serum.” And this part, he says, is of a colder nature. The fibrous he
believed to be the earthy portion of the blood.

According to the view of the Stagirite, therefore, the blood of
different animals differs in several ways; in one it is more serous and
thinner, a kind of ichor or sanies, as in insects, and the colder and
less perfect animals; in another it is thicker, more fibrous, and
earthy, as in the wild boar, bull, ass, &c. In some where the
constitution is distempered, the blood is of a blacker hue; in others it
is bright, pure, and florid, as in birds, and the human subject

Whence, it appears, that in the opinion of the physicians, as well as of
Aristotle, the blood consists of several parts, in some sort of the same
description, according to the views of each. Medical men, indeed, only
pay attention to human blood, taken in phlebotomy and contained in cups
and coagulated. But Aristotle took a view of the blood of animals
generally, or of the fluid which is analogous to it. And I, omitting all
points of controversy, and passing by any discussion of the
inconveniences that wait upon the opinions of writers in general, shall
here touch lightly upon the points that all are agreed in, that can be
apprehended by the senses, and that pertain more especially to our
subject; intending, however, to treat of everything at length elsewhere.

Although the blood be, as I have said, a portion of the body,--the
primogenial and principal part, indeed,--still, if it be considered in
its mass, and as it presents itself in the veins, there is nothing to
hinder us from believing that it contains and concocts nourishment
within itself, which it applies to all the other parts of the body. With
the matter so considered, we can understand how it should both nourish
and be nourished, and how it should be both the matter and the efficient
cause of the body, and have the natural constitution which Aristotle
held necessary in a primogenial part, viz. that it should be partly of
similar, partly of dissimilar constitution; for he says, “As it was
requisite for the sake of sensation that there should be similar members
in animal bodies, and as the faculty of perceiving, the faculty of
moving, and the faculty of nourishing, are all contained in the same
member (viz. the primogenate particle), it follows necessarily that this
member, which originally contains inherent principles of the above kind,
be extant both simply, that it may be capable of sensation of every
description, and dissimilarly, that it may move and act. Wherefore, in
the tribes that have blood, the heart is held to be such a member; in
the bloodless tribes, however, it is proportional to their state.”

Now, if Aristotle understands by the heart that which first appears in
the embryo of the chick in ovo, the blood, to wit, with its containing
parts--the pulsating vesicles and veins, as one and the same organ, I
conceive that he has expressed himself most accurately; for the blood,
as it is seen in the egg and the vesicles, is partly similar and partly
dissimilar. But if he understands the matter otherwise, what is seen in
the egg sufficiently refutes him, inasmuch as the substance of the
heart, considered independently of the blood--the ventricular cone--is
engendered long afterwards, and continues white without any infusion of
blood, until the heart has been fashioned into that form of organ by
which the blood is distributed through the whole body. Nor indeed does
the heart even then present itself with the structure of a similar and
simple part, such as might become a primogenial part, but is seen to be
fibrous, fleshy, or muscular, and indeed is obviously what Hippocrates
styled it,--a muscle or instrument of motion. But the blood, as it is
first perceived, and as it pulsates, included within its vesicle, has as
manifestly the constitution which Aristotle held necessary in a
principal part. For the blood, whilst it is naturally in the body, has
everywhere apparently the same constitution; when extravasated, however,
and deprived of its native heat, immediately, like any dissimilar
compound, it separates into several parts.

Were the blood destined by nature, however, for the nourishment of the
body only, it would have a more _similar_ constitution, like the chyle
or the albumen of the egg; or at all events it would be truly one and a
single body composed of the parts or juices indicated, like the other
humours, such as bile of either kind, and pituita or phlegm, which
retain the same form and character without the body, which they showed
within their appropriate receptacles;--they undergo no such sudden
change as the blood.

Wherefore, the qualities which Aristotle ascribed to a principal part
are found associated in the blood; which as a natural body, existing
heterogeneously or _dissimilarly_, is composed of these juices or parts;
but as it lives and is a very principal animal part, consisting of these
juices mingled together, it is an animated _similar_ part, composed of
a body and a vital principle. When this living principle of the blood
escapes, however, in consequence of the extinction of the native heat,
the primary substance is forthwith corrupted and resolved into the parts
of which it was formerly composed; first into cruor, afterwards with red
and white parts, those of the red parts that are uppermost being more
florid, those that are lowest being black. Of these parts, moreover,
some are fibrous and tough, (and these are the uniting medium of the
rest,) others ichorous and serous, in which the mass of coagulum is wont
to swim. Into such a serum does the blood almost wholly resolve itself
at last. But these parts have no existence severally in living blood; it
is in that only which has become corrupted and is resolved by death that
they are encountered.

Besides the constituents of the blood now indicated, there is yet
another which is seen in the blood of the hotter and stronger animals,
such as horses, oxen, and men also of ardent constitution. This is seen
in blood drawn from the body as it coagulates, in the upper part of the
red mass, and bears a perfect resemblance to hartshorn-jelly, or
mucilage, or thick white of egg. The vulgar believe this matter to be
the pituita; Aristotle designated it the crude and unconcocted portion
of the blood.

I have observed that this part of the blood differs both from the others
and from the mere serous portion in which the coagulated clot is wont to
swim in the basin, and also from the urine which percolates through the
kidneys from the blood. Neither is it to be regarded as any more crude
or colder portion of the blood, but rather, as I conceive, as a more
spiritual part; a conclusion to which I am moved by two motives: first,
because it swims above the bright and florid portion--commonly thought
to be the arterial blood--as if it were hotter and more highly charged
with spirits, and takes possession of the highest place in the
disintegration of the blood.

Secondly, in venesection, blood of this kind, which is mostly met with
among men of warm temperament, strong and muscular, escapes in a longer
stream and with greater force, as if pushed from a syringe, in the same
way as we say that the spermatic fluid which is ejected vigorously and
to a distance is both more fruitful and full of spirits.

That this mucaginous matter differs greatly from the ichorous or watery
part of the blood, which, as if colder than the rest, subsides to the
bottom of the basin, appears on two distinct grounds: for the watery and
sanious portion is too crude and unconcocted ever to pass into purer and
more perfect blood; and the thicker and more fibrous mucus swimming
above the clot of the blood itself appears more concoct and better
elaborated than this; and so in the resolution or separation of the
blood it comes that the mucus occupies the upper place, the sanies the
lower; the clot and red parts, however,--both those of a brighter and
those of a darker colour,--occupy the middle space.

For it is certain that not only this part, but the whole blood, and
indeed the flesh itself--as may be seen in criminals hung in chains--may
be reduced to an ichorous sanies; that is to say, become resolved into
the matters of which they were composed, like salt into the lixivium
from which it had been obtained. In like manner, the blood taken away in
any cachexy abounds in serum, and this to such an extent that
occasionally scarce any clot is seen--the whole mass of blood forms one
sanies. This is observed in leucophlegmatia, and is natural in bloodless

Further, if you take away some blood shortly after a meal, before the
second digestion has been completed and the serum has had time to
descend by the kidneys, or at the commencement of an attack of
intermittent fever, you will find it sanious, inconcoct, and abounding
in serum. On the contrary, if you open a vein after fasting, or a
copious discharge of urine or sweat, you will find the blood thick, as
if without serum, and almost wholly condensed into clot.

And in the same way as in coagulating blood you find a little of the
afore-mentioned supernatant mucus, so if you expose the sanies in
question, separated from the clot, to a gentle heat over the fire, you
will find it to be speedily changed into the mucus; an obvious
indication that the water or sanies which separates from the blood in
the basin, is perchance a certain element in the urine, but not the
urine itself, although in colour and consistence it seems so in fact.
The urine is not coagulated or condensed into a fibrous mucus, but
rather into a lixivium; the watery or sanious portion of the urine,
however, when lightly boiled, does occasionally run into a mucus that
swims through the fluid; in the same way, as the mucus in question
rendered recrudescent by corruption, liquefies and returns to the state
of sanies.

So far at this time have I thought fit to produce these my own
observations on this constituent of the blood, intending to speak more
fully of it as well as of the other constituents cognizable by the
senses, and admitted by Aristotle and the medical writers.

That I may not seem to wander too widely from my purpose, I would here
have it understood that with Aristotle I receive the blood as a part of
the living animal body, and not as it is commonly regarded in the light
of mere gore. The Stagirite says:[284] “The blood is warm, in the sense
in which we should understand warm water, did we designate that fluid by
a simple name, not viewing it as heated. For heat belongs to its nature;
just as whiteness is in the nature of a white man. But when the blood
becomes hot through any affection or passion, it is not then hot of
itself. The same thing must be said in regard to the qualities of
dryness and moistness. Wherefore, in the nature of such things they are
partly hot and partly moist; but separated, they congeal and become
cold; and such is the blood.”

The blood consequently, as it is a living element of the body, is of a
doubtful nature, and falls to be considered under two points of view.
Materially and _per se_ it is called nourishment; but formally and in so
far as it is endowed with heat and spirits, the immediate instruments of
the vital principle, and even with vitality (anima), it is to be
regarded as the familiar divinity and preserver of the body, as the
generative first engendered and very principal part. And as the prolific
egg contains within it the matter, instrument, and framer of the future
pullet, and all physicians admit a mixture of the seminal fluids of the
two sexes in the uterus during or immediately after intercourse as
constituting the mixed cause, both material and efficient, of the fœtus;
so might one with more propriety maintain that the blood was both the
matter and preserver of the body, though not the sole aliment; because
it is observed that in animals which die of hunger, and in men who
perish of marasmus, a considerable quantity of blood is still found
after death in the veins. And farther, in youthful subjects still
growing, and in aged individuals declining and falling away, the
relative quantity of blood continues the same, and is in the ratio of
the flesh that is present, as if the blood were a part of the body, but
not destined solely for its nourishment; for if it were so, no one would
die of hunger so long as he had any blood left in his veins, just as the
lamp is not extinguished whilst there is a drop of inflammable oil left
in the cruise.

Now when I maintain that the living principle resides primarily and
principally in the blood, I would not have it inferred from thence that
I hold all bloodletting in discredit, as dangerous and injurious; or
that I believe with the vulgar that in the same measure as blood is
lost, is life abridged, because the sacred writings tell us that the
life is in the blood; for daily experience satisfies us that
bloodletting has a most salutary effect in many diseases, and is indeed
the foremost among all the general remedial means: vitiated states and
plethora of the blood, are causes of a whole host of diseases; and the
timely evacuation of a certain quantity of the fluid frequently delivers
patients from very dangerous diseases, and even from imminent death. In
the same measure as blood is detracted, therefore, under certain
circumstances, it may be said that life and health are added.

This indeed nature teaches, and physicians at all events propose to
themselves to imitate nature; for copious critical discharges of blood
from the nostrils, from hemorrhoids, and in the shape of the menstrual
flux, often deliver us from very serious diseases. Young persons,
therefore, who live fully and lead indolent lives, unless between their
eighteenth and twentieth year they have a spontaneous hemorrhage from
the nose or lower parts of the body, or have a vein opened, by which
they are relieved of the load of blood that oppresses them, are apt to
be seized with fever or smallpox, or they suffer from headache and other
morbid symptoms of various degrees of severity and danger. Veterinary
surgeons are in the habit of beginning the treatment of almost all the
diseases of cattle with bloodletting.


_Of the inferences deducible from the course of the umbilical vessels in
the egg._

We find the blood formed in the egg and embryo before any other part;
and almost at the same moment appear its receptacles, the veins and the
vesicula pulsans. Wherefore, if we regard the punctum saliens as the
heart, and this along with the blood and the veins as constituting one
and the same organ, conspicuous in the very commencement of the embryo,
although we should admit that the proper substance of the heart was
deposited subsequently, still we should be ready to admit with Aristotle
that the heart (an organ made up of ventricles, auricles, vessels, and
blood) was in truth the principal and primogenate part of the body, its
own prime and essential element having been the blood, both in the order
of nature and of genetic production.

The parts that in generation succeed the blood are the veins, for the
blood is necessarily inclosed and contained in vessels; so that, as
Aristotle observes, we find two meatus venales even from the very first,
which canals, as we have shown in our history, afterwards constitute the
umbilical vessels. It seems necessary, therefore, to say something here
of the situation and course of these vessels.

In the first place, then, it is to be observed that all the arteries and
veins have their origin from the heart, and are as it were appendices or
parts added to the central organ. If therefore you carefully examine the
embryo of the human subject, or one of the lower animals, and having
divided the vena cava between the right auricle and the diaphragm, look
into it upwards or towards the heart, you will perceive three foramina,
the largest and most posterior of which tending to the spine is the vena
cava; the anterior and lesser proceeds to the root and trunk of the
umbilical vessels; the third and least of all enters the liver and is
the origin and trunk of all the ramifications distributed to the
convexity of that organ. Whence it clearly appears that the veins do by
no means all proceed from the liver as their origin and commencement,
but from the heart--unless indeed any one would be hardy enough to
contend that a vessel proceeded from its branches, not the branches from
the trunk of the vessel.

Moreover, as the vessels in question are distributed equally to the
albumen and vitellus of the egg, not otherwise than as the roots of
trees are connected with the ground, it is obvious that both of these
substances must serve for the nutriment of the embryo, and that they are
taken up and carried to it by these vessels. But this view is opposed to
that of Aristotle, who everywhere maintains that the chick is formed
from the albumen, and receives nourishment through the umbilicus alone.
The albumen indeed is first consumed, and the yelk serves subsequently
for food, supplying the place of the milk, which viviparous animals
receive after their birth from their mothers. The food which nature
provides for the young of viviparous tribes in the dug of the mother,
she supplies in the yelk of the egg to the young of oviparous animals.
Whence it happens, that when the albumen is almost wholly consumed, the
vitellus still remains nearly entire in the egg, the chick being already
perfect and complete; more than this, the yelk is still found in the
abdomen of the chick long after its exclusion. Aristotle discovered some
on the eighteenth day after the hatching; and I have myself seen a small
quantity connected with the intestine at the end of six weeks from that

Nevertheless, from the yelk (which certainly does not decrease in the
same ratio as the albumen whilst the chick is forming) that is taken
into the abdomen of the chick, and from the distribution of vessels
through its substance, the whole of these collecting into a single trunk
which enters the porta of the liver, and doubtless earning that portion
of yelk they have absorbed for more perfect elaboration in that
viscus--these and other arguments of the like kind force me to say that
I cannot do otherwise than admit with Aristotle that the yelk supplies
food to the chick, and is analogous to milk.

The whole of the yelk, indeed, does not remain after the fœtus of the
fowl is fully formed; for a certain portion of it has been liquefied on
the very first appearance of the embryo, and receives branches of
vessels no less than the albumen, by which, already prepared, it is
carried as nourishment for the chick; still it is certain that the
greater portion of the yelk remains after the disappearance of the
albumen; that it is laid up in the abdomen of the chick when excluded,
and, attracted or absorbed by the branches of the vena portæ, that it is
finally carried to the liver.

It is manifest, therefore, that the chick when hatched, is nourished by
the yelk in the first period of its independent existence. And as within
the egg the embryo was nourished partly by the albumen, partly by the
vitellus, but principally by the albumen, which is both present in
larger quantity, and is more speedily consumed, so when the chick is
hatched, and when all the nourishment that is taken must pass through
the liver to undergo ulterior preparation, is it nourished partly by the
vitellus and partly by chyle absorbed from the intestines, but
principally by chyle, which the host of subdivisions of the mesenteric
vessels seize upon, whilst there is but a single vessel from the porta
distributed to the vitellus, and by and by but little of it remains.
Nature, therefore, acts as does the nurse, who gradually habituates her
infant to the food which is to take the place of her failing supply of
milk. The pullet is thus gradually brought from food of more easy to
food of more difficult digestion,--from yelk to chyle.

Wherefore there is every reason for what we perceive in connexion with
the course of the veins in the egg. When the embryo first begins to be
formed, they are distributed to the colliquament only, where the blood
finds suitable nutriment and matter for the formation of the body; but
by and by they extend into the thinner albumen, whence the chick, whilst
it is yet in the state of gelatine or mucor, and resembles a maggot in
form, derives its increase; the branches next extend into the thicker
albumen, and then into the vitellus, that they may also contribute to
the support of the fœtus, which, having at length arrived at maturity
and been extruded, still preserves a portion of the yelk (or milk)
within its abdomen, whereby it is maintained in part, in part by food
selected and prepared for it by the mother, until it is able to look out
for and to digest its own aliment. Thus does nature most wisely provide
food through the whole round of generation, suited to the various
strength of the digestive faculty in the future being. In the first
period of the fœtal chick’s existence a more delicate food is prepared
for it; more advanced, firmer and firmer food is supplied; and this is
the reason, I apprehend, wherefore, the perfect egg consists not only of
two portions of different colours, but is even provided with two kinds
of albumen.

Now all this that we discover from actual experience of the matter
accords with the opinion of Aristotle, where he says:[285] “The part
which is hot is best adapted to give form to the limbs; that which is
more earthy rather conduces to the constitution of the body and is more
remote. Wherefore in eggs of two colours, the animal begins to be
engendered from the white (for the beginning of animal life is in the
hot), and derives its nourishment from the yellow. In the warmer
animals, consequently, these parts are kept distinct from one another,
viz. that from which the beginning is derived, and that whence the
nourishment is obtained, and the one is white, the other yellow.”

From what has now been said it appears that the chick--and we shall show
that it is not otherwise in all other animals--arises and is constituted
as it were by a principle or soul inherent in the egg, and that in the
same way the proper aliment is sought for and is supplied within the
egg; whereby it comes that the chick is not dependent on its mother in
the same way as plants are dependent on the ground; and it is not more
correct to say that the chick is nourished by the blood of its mother,
or that its heart beats, and that it lives through the spirits of its
parent, than it would be to assert that it moved and felt through the
organs, or grew and attained to adult age through the vital principle of
its parent. It is manifest, on the contrary, and is allowed by all that
the fœtal chick is nourished through its umbilical vessels; and that the
vascular ramifications dispersed over the albumen and yelk imbibe
nourishment from them and convey it to the fœtus. It is also admitted
that the chick, when excluded from the shell, is supplied with
nourishment, partly from yelk, partly from chyle, and that in either
case the aliment passes by the same route, viz. by the vena portæ into
the liver, the branches of this vessel effecting the transit.

It is therefore obvious, as I now say by the way, that the chyle by
which all animals are nourished is brought by the mesenteric veins from
the intestines; nor is there occasion to look for any new passage--by
the lacteal vessels, to wit--or any route in adult animals other than
that which we discover in the egg and chick. But we shall recur more
fully in another place to the inconveniences of such an opinion as that
referred to.

Lastly, from the structure of the umbilical vessels of the chick in ovo,
some of which as stated in the history are veins, others arteries, it is
legitimate to conclude that there is here a circular motion of the
blood, such as we have already demonstrated in the animal body, in our
book on the Motion of the Blood, and this for the sake of the nutrition
and growth of the embryo, and because the umbilical veins are
distributed to either fluid of the egg, that they may thence bring
nutriment to the chick, and the arteries accompany the veins, that by
their affluxive heat the alimentary matter may be duly concocted,
liquefied, and made fit to answer the ends of nutrition.

And hence it happens that wherever veins--and here I would have it
understood that both arteries and veins are intended--make their way
into the albumen or vitellus, there these fluids look liquefied and
different from the rest. For as soon as the branches of the veins shoot
forth, the upper portion of the albumen in which they are implanted
passing into colliquament, becomes transparent, whilst the lower
portion, continuing thick and compact, is pushed into the inferior angle
of the egg. In like manner a separation of the vitellus, as it seems
into two portions, makes its appearance, the one being superior, and the
other inferior, and these do not differ less from one another in
character than melted differs from solid wax; now this division
corresponds to the two parts which severally receive or do not receive

Hence are we farther made more certain as to the commencement of animal
generation and the prime inherent principle of the egg. For it is
assuredly known that the cicatricula or spot on the yelk is the chief
point in the egg, that to which all the rest are subordinate, and to
which, if to any one thing more than another, is to be referred the
cause, whatever it be, of fecundity in the egg:--certain it is that the
generation of the embryo is begun within its precincts. Wherefore, as we
have said, the first effect of incubation is to cause dilatation of the
cicatricula, and the formation of the colliquament, in which the blood
first flushes and veins are distributed, and where the effects of the
native heat and the influence of the plastic power first show
themselves. And then, the more widely the ramifications of these veins
extend, in the same proportion do indications of the presence of the
vital power and vegetative force appear. For every effect is a clear
evidence of its efficient cause.

In a word I say,--from the cicatricula (in which the first trace of the
native heat appears) proceeds the entire process of generation; from the
heart the whole chick, and from the umbilical vessels