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Title: Harvey's Views on the Use of the Circulation of the Blood
Author: Curtis, John G.
Language: English
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  30-32 WEST 27TH STREET


[Illustration: A portrait of William Harvey by Cornelius Jonson.
This picture forms the frontispiece of _Guilielmi Harveii Opera
Omnia_, London, 1766.]






  [Illustration: logo]

  New York


  _All rights reserved_

  COPYRIGHT, 1915,


  Set up and electrotyped. Published December, 1915.

  Norwood Press
  J. S. Cushing Co.--Berwick & Smith Co.
  Norwood, Mass., U.S.A.


The writings of William Harvey, as published by him, and the letters
published as part of his works, are all in Latin. The passages from
Harvey's works which appear in English in the present paper are in
part translations by the late Dr. Willis, with changes, sometimes
considerable, by the present writer. In large part, however, the
translations from Harvey are not even based upon Dr. Willis's work,
but have been made by the present writer directly from the original
Latin. Naturally he assumes responsibility for whatever he prints
in English to represent Harvey's words; and to attempt, in print,
a more minute discrimination between his own work as a translator
and that of Dr. Willis would be tedious and unprofitable. Whoever
may wish to make such discrimination may readily do so, however,
as, in the present paper, a reference is made by page and line in
the case of each translated passage, not only to the Latin text of
Harvey's _Opera Omnia_, published by the Royal College of Physicians
of London in 1766, but also to Willis's English translation thereof,
published by the Sydenham Society in 1847, and entitled "The Works
of William Harvey, M.D." Such references to the Sydenham Society's
edition are indispensable for another purpose, viz.: in order that
to each translated passage from Harvey in the present paper a
context in English may readily be given by the reader.

It has seemed best that the various references to Harvey's Latin
text should be made to that of the easily accessible _Opera Omnia_
rather than to that of the rarer first editions of the several
treatises. In the case of the passages quoted from the treatise _De
Motu Cordis et Sanguinis in Animalibus_ and from the treatise _De
Generatione Animalium_, the Latin of the _Opera Omnia_ has been
collated by the present writer with that of the first editions.
The first editions of the Exercises to Riolanus and of the various
letters have not been accessible to him.

Much use has here been made of Harvey's private lecture notes, first
published in 1886 by the Royal College of Physicians of London.

All the passages (except those from the Scriptures) quoted in the
present paper from writers other than Harvey have been translated
into English by the present writer directly from the original Greek
text or the original Latin text, as the case may be.



Professor Curtis, to whom I am indebted for much kindly help
extended during a warm friendship of nearly thirty years, died
September 20, 1913. One of his final requests was that his younger
colleague arrange for the publication of the present paper, upon
which its writer had been engaged for a period of several years
and which happily was practically completed. This request, coming
to me after the death of my friend, could be considered only as a
command. It has, therefore, fallen to me to make a careful study of
his text, to fill in with my own words occasional slight gaps, to
make occasional verbal changes, to certify to the correctness of
his numerous references, and to make the manuscript, written and in
places rewritten many times with his own hand, ready for the press.
This I have done with affection for his memory and with appreciation
of his scholarly attainments. Dr. Curtis's work represents a more
profound study of Harvey's ideas and comparison of them with those
of the most important of Harvey's predecessors than has heretofore
appeared. It is the work of one who from the background of the
physiological science of to-day delighted in mastering the ideas of
the fathers of modern physiology. If his work is to be summarized
in a single sentence, it may be said that he has shown Harvey to
be a disciple more of Aristotle than of Galen. Although Harvey
had the courage and the originality to break away from him whose
ideas had prevailed for fourteen centuries, and to find the truth
in regard to the movement of the blood, he found much to approve in
the master who had lived five hundred years before Galen. Harvey's
true position in the world of physiological thought has not before
been made known. Herein lies Professor Curtis's contribution to the
history of his science.


  June 1, 1915.



  PREFATORY NOTE                                         v

  EDITORIAL NOTE                                       vii

  ILLUSTRATIONS                                         xi


        THE CIRCULATION                                  1




  RESPIRATION AND THE CIRCULATION                       11


        THE HEART                                       42


        PHILOSOPHERS                                    55




  THE CAUSE OF THE HEART-BEAT                           79




  THE BLOOD THE SEAT OF THE SOUL                       103


  THE BLOOD THE INNATE HEAT                            116




        OF THE HEAVENS                                 154

  NOTES                                                159

  INDEX                                                191


  Portrait of William Harvey by Cornelius Jonson   _Frontispiece_

                                                     FACING PAGE

  The Anatomical Theater at Padua                              2

  Page 80, right, of Harvey's _Prelectiones_, with
        transcript                                            42

  The Title-page of the _Editio Princeps_ of Harvey's
        _De Motu Cordis_                                      96




It is a happy moment for a physiologist when the train which is
bearing him across the luxuriant plain of Venetia stops at the cry
of "Padova!" If he have not informed himself too thoroughly about
the sights which he will see at the Paduan University, he will enjoy
his own surprise when he is ushered into the Anatomical Theater of
Fabricius ab Aquapendente--a room in which standing-places rise
steeply, tier above tier, entirely around a small central oval pit.
Looking down into this, as he leans upon the rail, the traveler
will realize with sudden pleasure that William Harvey, when a
medical student, may often have leaned upon the self-same rail to
see Fabricius demonstrate the anatomy of man. The place looks fit
to have been a nursery of object-teachers, for it is too small
to hold a pompous _cathedra_; and the veteran to whose Latin the
young Englishman listened must have stood directly beside the dead
body. To an American, musing there alone, the closing years of the
sixteenth century, the last years of Queen Elizabeth of England,
which seem so remote to him when at home, are but as yesterday.

Recent, indeed, in the history of medicine is the year 1602, when
Harvey received his doctor's degree at Padua and returned to London;
but for all that we are right in feeling that our day is far removed
from his. The tireless progress of modern times has swept on at
the charging pace; but in Harvey's time books were still a living
force which had been written in days five and six times as far
removed from the student of Padua as he from us. Galen, the Greek
who practised medicine at imperial Rome in the second century of the
Christian era; Aristotle, who had been the tutor of Alexander the
Great five hundred years before Galen, when Rome was but a petty
state warring with her Italian neighbors;--these ancients were still
great working authorities in Harvey's day.[1]

It is against this persistent glow of the Greek thought that
Harvey stands out so vividly as the first great modern figure in
physiology. But it rather heightens than lowers his achievement that
it was by the ancient glow that he saw his way forward, admiring the
past, but not dazzled by it. In his old age he bade a young student
"goe to the fountain head and read Aristotle, Cicero, Avicenna";
and in talk with the same youth Harvey called the moderns by a name
so roughly contemptuous that it will not bear repeating.[2] Yet in
his old age, in the very act of extolling the ancients, he wrote as

     "But while we acquiesce in their discoveries, and believe, such
     is our sloth, that nothing further can be found out, the lively
     acuteness of our genius languishes and we put out the torch
     which they have handed on to us."

[Illustration: The Anatomical Theatre at Padua, where William Harvey
listened to the lectures of Fabricius ab Aquapendente.]

It was in 1628, the year of his fiftieth birthday, that Harvey
published, at Frankfort-on-the-Main, his famous Latin treatise
entitled: "An Anatomical Exercise on the Motion of the Heart and
Blood in Animals." A reader of to-day will be inclined to skim
rapidly over the Introduction to this treatise and over much in
the last three chapters; and probably he will take only a languid
interest in the two brief Latin treatises which Harvey published in
defense of the circulation, after more than twenty years of silence,
in his seventy-first year, at Cambridge in 1649; these treatises
being entitled: "Two Anatomical Exercises on the Circulation of the
Blood, to Johannes Riolanus, Junior, of Paris."

The demonstration of the circulation in the treatise of 1628 is so
irresistible that the ancient strongholds of belief crash to the
ground at that summons like the walls of Jericho, and it seems a
waste of time to scan the fragments. But for all that, the edifice
which had stood for more than thirteen centuries was a goodly
structure; and whoever shall have read Aristotle and Galen at first
hand and shall then return to Harvey, will read with interest what
the same reader treated as a mere foil for the great demonstration;
and will realize that the irresistible quality of the latter is
shared by Galen's demonstration that blood is naturally contained
in the arteries.[4] Moreover, it will be seen that if the Greek of
the second century could, like Harvey, appeal to observation and
experiment, the English physician of the Renaissance, the student
of Cambridge and Padua, was an apt pupil of the Greeks. Harvey
could, and frequently and naturally did, view things from a Greek
and ancient standpoint when proof of their nature was unattainable.
This is to be seen not only in his earlier and later exercises on
the circulation, but also in his last work, his "Exercise on the
Generation of Animals" with appended essays, published in Latin
at London in 1652, in Harvey's seventy-third year, two years
after the appearance of the exercises addressed to Riolanus. This
treatise On Generation deals also at various points with the blood
and the circulation, as do in addition Harvey's published Latin
letters. We shall find, too, the same leaning upon the ancients
as immediate precursors in thinking, if we turn back from the
publications of Harvey's old age to the very first written words
of his which we possess, private lecture notes jotted down by him
in his thirty-seventh year for use in 1616--notes happily printed
and published in 1886.[1] In these notes, written more than eleven
years before the publication of his most famous treatise, he sets
forth for the first time, though briefly, the circulation of the
blood, that physiological truth which to my mind is completely
and indisputably Harvey's own discovery. It is with Harvey as the
interpreter, not the maker, of this discovery, that I shall venture
to deal in this paper.

In his old age the great discoverer recorded his own attitude, as an
interpreter, in the following words:--

     "That freedom which I freely concede to others, I demand with
     good right for myself also; liberty, that is, in dealing with
     obscure matters, to bring forward, to represent, the truth, that
     which seems probable, until the falsity thereof shall clearly be

In 1636, eight years after he had published the treatise which now
seems so convincing, Harvey was in Nuremberg and wrote to Caspar
Hofmann, M.D., a professor of repute who lived there, offering to
demonstrate the circulation to him. In his letter Harvey quotes
impatient words of his German colleague, which show that in the face
of proof the circulation still seemed to some men of high standing
too useless to be true. Harvey says to Hofmann:--

     "You have been pleased to reproach me rhetorically and chastise
     me tacitly as one who seems to you 'to accuse and condemn nature
     of folly as well as error, and to impose the character of a
     most stupid and lazy craftsman on her, since he would permit
     the blood to relapse into rawness and to return repeatedly to
     the heart to be concocted again; and, as often, to the body at
     large to become raw again; and would permit nature to ruin the
     made and perfected blood in order that she may have something to

To this attack Harvey calmly rejoins as follows, speaking of the

     "As to its concoction and the causes of this its motion and
     circulation, especially their final cause, I have said nothing,
     indeed have put the subject by entirely and deliberately; as you
     will find set down in plain words and otherwise if you will be
     pleased to read again chapters VIII and IX."[7]

More than twelve years later still, in defending the circulation
against Riolanus, Harvey finds it necessary to say:--

     "Those who repudiate the circulation because they see neither
     the efficient nor the final cause of it, and who exclaim '_Cui
     bono?_'--(As to which I have brought forward nothing so far;
     it remains to be shown)--plainly ought to inquire as to its
     existence before inquiring why it exists; for from the facts
     which meet us in the circulation regarded as existing, its uses
     and objects are to be sought."[8]

In spite, however, of these disclaimers of formal position Harvey
had repeatedly intimated, by the way, what was crossing his mind
as to the meaning of the circulation, to set forth the proofs of
which had been his main concern. Even in the eighth chapter to which
Harvey appealed in support of his disclaimer Hofmann could have
pointed to two passages as affording from his standpoint a basis for
his attack. In the second and shorter of these two passages Harvey
says of a vein as compared with an artery:--

     "This is a way from the heart, that to the heart; that contains
     cruder blood, effete and rendered unfit for nutrition; this,
     concocted, perfect, alimentary blood."[9]

Harvey, indeed, as we shall find abundant evidence, was both an
observer and a speculator. In the latter rôle he was not far removed
from his physiological predecessors of two thousand years; as an
observer it was his great merit to lead the physiologists of his
time and to point out to those of all later centuries the path which
they must follow.



That Harvey frequently took refuge in speculation need excite no
surprise. In the seventeenth century, even with his extraordinary
contributions of observed fact to the knowledge of the circulation
of the blood, the paucity of physiological knowledge in general and
of experimental methods was so great that at every turn a thinking
man was tempted to fill in the gaps with that which was beyond his
powers of ocular demonstration. Contemplation of the circulation,
indeed, led Harvey into contemplation of widely diverse problems of
the life process. The feeding of the tissues, the significance of
respiration, the cause of the heart-beat, the relative importance of
the heart and the blood in the bodily hierarchy, the bodily heat and
its source, and the seat of the soul--to these and other topics he
gave much attention, and these we must consider. Let us begin with
the circulation and its relation to the feeding of the tissues.

In the chapter of Harvey's book which follows at once upon the brief
qualitative statement quoted at the end of our last chapter, Harvey
himself brings us face to face with the difficult quantitative
question raised by his triumphant proof of the circulation. He

     "The blood under the influence of the arterial pulse enters and
     is impelled in a continuous, equable, and incessant stream into
     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."[10]

Here we see that the rapid renewal of the blood in "every part and
member of the body" presented itself to Harvey's own mind as calling
for some other explanation than the simple feeding of the tissues.
The question of "_cui bono_" which his discovery raised is still but
incompletely answered; in Harvey's day it was almost unanswerable.
In dealing from time to time with its main features he himself, as
we shall see, could only bring forward inadequate observations and
shift his ground from one erroneous doctrine to another. In justice
to his opponents, who seem to us so unreasonable, let us remember
how prodigious this new question of "_cui bono_" must have seemed
when the circulation itself was a novelty. Let us remember also
that for nearly two thousand years the tissues had been held to
feed themselves tranquilly out of the contents of the vessels in a
way fitly expressed by the old simile of irrigation ditches in a
garden--a simile which Aristotle and Galen had borrowed in turn from

But if Harvey saw only too well that the feeding of the tissues
could not explain the circulation, he had at least seen plainly how
the doctrine of the circulation clarified the ancient but current
doctrine as to the absorption of the digested food. The portal
vein had been accepted as the route of this absorption. No doubt
both Aristotle and Galen had seen its ruddy contents; at any rate
both had concluded that the chyle was changed within the portal
vein into a crude approximation to blood.[12] That the same vessel
should carry to the liver altered chyle, and from the liver blood
to nourish the stomach and intestines, had involved a difficulty
which Galen had met with characteristic cleverness. He had cited
in support of such a reversal of flow the flow of the bile into
the gall-bladder and out by the same duct, the movement of food
and vomit into and out of the stomach by the œsophagus, and the
relation of the _os uteri_ to impregnation and parturition.[13]
Harvey says:--

     "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 need we hold the improbable belief that two
     inconveniently opposed movements take place in the whole
     capillary ramification, namely, movement of the chyle upward,
     of the blood downward. 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, because they are reciprocally
     active and passive, a mixture, their union with one another
     producing something intermediate, precisely as when wine is
     mixed with water and [in] vinegar and water [oxicratum]. But
     when a minute quantity of chyle is mingled with a large quantity
     of blood flowing by, a quantity of chyle that bears no notable
     proportion to the 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 resulting total is not a mixture, but is either
     wine or water. So in the dissected mesenteric veins we do not
     find chyme or chyle and blood, separate or mingled, but only
     blood, sensibly the same in color and consistency as in the rest
     of the veins."[14]

In a second passage of the same chapter,[15] Harvey returns to this
subject; and again, twenty-one years later, in his first exercise to
Riolanus, as follows:--

     "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 (and in the veins, as he says in the
     eighth chapter of the third book,[16] the blood incessantly
     and naturally ascends, or flows back, to the heart, as in all
     the arteries it descends or departs from the heart), all the
     difficulties which were formerly felt in connection with the
     distribution of chyle and the blood by the same channels are
     brought to an equally satisfactory solution; for all the mooted
     difficulties vanish when we cease to suppose two contrary
     motions at once in the same vessels, and admit but one and
     the same continuous motion in the mesenteric vessels from the
     intestines to the liver."[17]

From this passage we see, in passing, that Harvey at the age of
seventy made little account of Caspar Aselli's discovery of the
lacteals, published twenty-two years before in 1627,[18] the year
before the announcement of the discovery of the circulation.
Harvey's mind was focused on the blood, its motion and its meaning;
this was to him the subject of prime importance. The ancient
doctrine of the feeding of the tissues provided an insufficient
reason for the existence of what his observations and his
experiments revealed to him.



So the feeding of the tissues could not sufficiently account, to
Harvey's mind, for the swiftness of the circulation. What could?
It is easy for us to recite the multitudinous modern duties of the
blood as a bearer of cells and of chemicals from point to point and
as a protector against poisoning; above all it is easy to exclaim
"respiration";--to read the most striking part of the riddle by
knowing the answer which was wrung laboriously from Nature after
Harvey had died. It is easy for us to see that speedy death from
loss of the circulating blood is practically the same as death
from ligature of the arteries of the brain, or from drowning,
or strangulation, or a broken neck. But this was veiled from
him, and what best accounts for the volume and swiftness of the
Harveian circulation was, in Harvey's day, a stumbling block to its
acceptance; for no adequate reason was apparent why the whole mass
of the blood should traverse the lungs, or why, if the veins receive
their blood from the arteries, the venous blood should differ in
color from the arterial.

Let us remember that throughout Harvey's life air was still an
elementary body in the eyes of many and, for all, blood was a quite
mysterious, ruddy, hot, vital liquid. Only weak magnifying glasses
were available for him, and the powerful lenses of Malpighi and van
Leeuwenhoek had not yet revealed to the world either capillary or
blood-corpuscle. Moreover, the gossiping John Aubrey, the man who
had been advised about his youthful studies by Harvey, wrote of him
some years after his death, that "he did not care for Chymistrey,
and was wont to speake against them [the chemists] with an
undervalue."[19] Where would physiology be to-day, had not histology
and chemistry long stood in the forefront beside her?

In a passage of the treatise of 1628 Harvey speaks of respiration,
as follows:--

     "And now it has come to this, that it would seem better worth
     while and more straightforward for those who seek the path by
     which in man the blood passes through the vena cava into the
     left ventricle and the venous artery,[20] to be willing to
     search for the truth by dissecting animals, in order to look
     for the reason why in the larger and more perfect animals, when
     full grown, nature chooses to make the blood percolate through
     the parenchyma of the lungs rather than take wide open paths as
     in all other animals (it being understood that no other path
     and transit can be thought out):--whether it is because the
     larger and more perfect animals are hotter and when they are
     full grown their heat is more ignited, so to speak, and prone
     to be smothered, that there is this permeation and transfer
     through the lungs in order that the heat may be tempered by the
     inspired air and guarded from boiling up and smothering--or for
     some other similar reason. But to determine these matters and
     explain them completely were to enter on a speculation as to the
     purpose for which the lungs are made. About these and their use
     and motion, and the whole subject of ventilation and the need
     and use of air, and other matters of this sort, and about the
     various different organs created in animals by reason thereof,
     although I have made a vast number of observations, I shall not
     speak till I can more conveniently set them forth in a treatise
     apart, lest by wandering at this point too far from my subject,
     which is the motion and use of the heart, I should seem to deal
     with something else and leave my position, to confuse and evade
     the question."[21]

Farther on in the same treatise Harvey says:--

     "Moreover, the reason why the lungs have vessels so ample, both
     vein and artery, that the trunk of the venous artery exceeds
     in size the crural and jugular branches taken both together;
     and the reason why the lungs are so full of blood as we know
     them to be by experience and inspection (heeding Aristotle's
     warning,[22] and not deceived by the inspection of such lungs as
     we have removed from dissected animals from which all the blood
     had flowed out)--the reason is, that in the lungs and heart
     is the storehouse, the source, the treasury of the blood, the
     workshop of its perfection."[23]

So the great Englishman gropes for a moment or two by the light of
ancient Greek doctrines and puts the question of respiration by. But
this very attitude shows Harvey's thought to be in such contrast
with the thought of to-day that in order to understand him we need
to learn more fully his views of respiration; and we find with
satisfaction that in his lecture notes of more than eleven years
before he had not put this question by, for he had been called upon
to lecture upon the uses of the lungs. We must seek in his lecture
notes, therefore, for what he had thought those uses to be. These
notes, however, we shall be unable to follow unless now, first of
all, we shall give the floor for a while to the ancients; for from
their doctrines Harvey necessarily took his cue, like the other
thinkers of his time.

The momentous physiological facts that the living body of man,
beast, or bird, is warm of itself and that its cooling means its
death, must always have struck and impressed the human mind, whether
trained or untrained. More than nineteen centuries before Harvey
certain thoughts of Aristotle were recorded as follows:--

     "In animals all the parts and the entire body possess a certain
     innate natural heat; wherefore they are sensibly warm when
     living, the reverse when making an end and parting with life.
     In the animals which have blood the origin of this heat is
     necessarily in the heart, in the bloodless kinds in the analogue
     thereof; for all work up and concoct the nourishment by means of
     the natural heat, the master part most of all. Life persists,
     therefore, when the other parts are chilled; but if what
     resides in this one be so affected total destruction ensues,
     because upon this part they all depend as the source of their
     heat, the soul being as it were afire within this part; that
     is, within the heart in the animals which have blood, in the
     bloodless kinds in the analogue thereof. Necessarily, therefore,
     the existence of life is coupled with the preservation of the
     heat aforesaid, and what is called death is the destruction

This heat which is innate in all living animals was styled by
Aristotle not only "innate" but "natural," "vital,"[25] and
"physical,"[26] it being indispensable to life and to the working
of the soul. He held the continued existence of the innate heat to
depend upon conditions similar to those under which a fire is kept
alive, viz.: protection both from burning out and from extinction
due to external forces. Yet the true nature of combustion was not
settled till more than a century after Harvey's death. The fact
that air is necessary to fire must always have been a matter of
common knowledge. Therefore, the views of the relations of air to
fire maintained by Aristotle nearly twenty-one centuries before the
discovery of oxygen did not seem naïve to Harvey, whatever they
may seem to us. Aristotle held that air exerts upon fire a cooling
influence which saves it from burning out too fast; and that the
same influence is exerted upon the vital innate heat of animals
by the air which they breathe in, or the water which bathes their
gills.[27] Moreover, Aristotle says:--

     "Why those animals breathe most which have lungs containing
     blood, is plain from this: that the warmer an animal is, the
     greater need it has of cooling, while at the same time the
     breath passes easily toward the source of warmth within the
     heart. But the way in which the heart is pierced through toward
     the lung must be studied from dissections and from the history
     of animals which I have written. In general terms, then, it is
     the nature of animals to need cooling on account of the firing
     of the soul within the heart."[28]

In the treatise styled the "History of Animals," to which he refers
us, Aristotle says:--

     "There are also channels from the heart which lead into the lung
     and divide in the same way as the windpipe, and they accompany
     the channels from the windpipe throughout the entire lung. The
     channels from the heart lie uppermost; but no common channel
     exists, for it is by contact[29] that they receive the breath
     and transmit it to the heart."[30]

The collection of ancient Greek commonly called the "Works of
Hippocrates" is judged to be of the fifth and fourth centuries B.C.
There is included in this collection a brief treatise on the heart;
and in this occurs the earliest known account of the structure and
use of the semilunar valves, which together with the rest of the
cardiac valves were unknown to Aristotle. In the same Hippocratic
treatise the doctrine is adhered to of the entrance of air into the
heart for cooling purposes, both the right and the left ventricle
being specified as receiving it. The author says:--

     "The vessel which leads out of the right ventricle ... closes
     toward the heart, but closes imperfectly, in order that air may
     enter, though not very much."[31]

This piece of incorrect physiology may well have received support
from the fact that the pulmonary semilunar valve is commonly found
to be not quite competent when the dead and dissected pulmonary
artery of the bullock is distended with water--an observation which
the ancient author intimates that he has made,[32] though he does
not specify the creature dissected.

Nearly five hundred years after the death of Aristotle, the analogy
between life and flame was discussed, formally and at some length,
by Galen. He knew his Aristotle well, and agreed with him as to the
importance of respiratory cooling for protracting the indispensable
heat of animals.[33] But we find Galen dealing with the uses of
respiration in a less simple way than Aristotle. In a polemical
treatise Galen debates the question whether "the breath drawn in
in respiration" actually enters the heart, or whether it cools it
without entering it. He says:--

     "It is possible that the whole is breathed out again, as was
     believed by most physicians and philosophers, and those the
     keenest, who say that the heart, while it craves to be cooled,
     is in need not of the substance, but of the quality[34] of the
     breath, and that the use of respiration is indicated by the
     part.... I have shown in my treatise on the use of respiration
     that either an absolutely minute quantity, or none at all, of
     the substance of the air, is taken into the heart."[35]

It is clear, however, that Galen, when delivering himself of the
foregoing, was a trifle carried away by the ardor of contention; for
in the very treatise to which he refers us, as well as elsewhere,
he not only dilates upon the cooling effects of breathing,
but admits the entrance of air into the heart for a definite
physiological purpose. This purpose, however, which we shall study
later, is not cooling and is counted of secondary importance by
Galen. Nevertheless, he goes so far as to say this:--

     "That some portion of the air is drawn into the heart in its
     diastole and fills the vacuum which is produced, is sufficiently
     shown by the very magnitude of the dilation."[36]

In his treatise "On the Use of the Parts of the Human Body" Galen
takes a more judicial tone in the following brief, calm summary:--

     "The use of the respiration of animals arises from the heart,
     as has been shown. The heart itself needs in some sort the
     substance of the air; but, first and foremost, it craves to
     be cooled, because it boils with heat. The heart is cooled by
     the cool quality of inspiration; but expiration also cools, by
     pouring out that which seethes within the heart and is, in a
     way, burned up and sooty."[37]

Thus do we see the modern products of respiration foreshadowed.

Galen believed that the heat of animals is safeguarded also by the
entrance of cooling air through the pores of the skin into the
arterial system, and by the exit through these pores of injurious
fumes out of the arteries.[38] In the introduction to Harvey's great
treatise of 1628[39] the English physician riddles with adverse
arguments this doctrine of Galen; to this we shall return later, as
we shall to Galen's belief that the brain draws cooling air directly
into its ventricles out of the nares through the cribriform plate of
the ethmoid bone.[40]

In passing from Aristotle to Galen we have crossed nearly five
centuries. Now let us pass at a leap across fourteen centuries
more, from Galen at imperial Rome under Septimius Severus to Harvey
at London under King James the First. Having briefly scanned the
doctrines of the Greeks, let us take up our study of respiration
in Harvey's private lecture notes of 1616. His crabbed handwriting
has been deciphered by experts, and his notes have been both
photographed and printed. If we seek therein for his thoughts about
respiration, and track them through the jungle of abbreviated
careless Latin and racy English in which they were jotted down, we
shall find them Galenic in part, but also denying a truth which
Galen had accepted. Harvey's notes are often too disconnected for
quotation, calling rather for paraphrase or summary; and to make
either is a task which one cannot approach without diffidence,
especially as this task involves translation also. Of what I have
ventured to prepare to represent parts of Harvey's note-book in the
present paper some passages are simple translations, such English
words as Harvey interspersed being transcribed. Naturally such
passages are included between quotation marks. These are not used,
however, in the case of a paraphrase or summary, even if it contains
scattered English words which are Harvey's own.

Harvey fully shared the ancient view of the supreme importance
of the heat of animals. In his note-book he, like Galen, deals
with respiration under the heads: first, of a possible absorption
of some of the substance of the air; and, second, of cooling and
ventilation. Let us first take up the second head. Harvey says:--

     "Without nourishment life cannot be, nor nourishment without
     concoction, nor concoction without heat, nor heat without
     ventilation;" for heat perishes either of wasting or of
     smothering; "so there is cooling and ventilation of the native
     heat, ventilation especially."[41]

His words contain reminders of Aristotle;[24] and he continues about
respiration in a vein as ancient as Hippocrates,[42] as follows:--

     "Nothing is so necessary, neither sense nor food. Life and
     respiration are convertible terms, for there is no life without
     breathing and no breathing without life. If the eye be cut out
     there is an end of seeing; if the legs be cut off there is
     an end of walking; if the tongue, of speech, _et cetera_; if
     respiration, there is an end of everything immediately."[43]

When Harvey jotted this down he had in mind a Galenic passage which
doubtless had become the common property of all physicians in his
day; for the removal of eye and legs figures in the first chapter of
Galen "On the Use of Respiration."[44] Harvey continues:--

     "Hence large animals are much warmer and breathe frequently,
     because they have need of greater cooling and ventilation
     inasmuch as they very greatly abound in blood and heat."[45]

In the margin opposite this passage there is written:--

     "Why and how air is needed by animals which breathe and also air
     is necessary to a candle and to fire see W. H."

We may conjecture that this note refers to Harvey's promised
treatise on respiration, which was never published.

So far Harvey has simply reiterated the ancient doctrine of cooling
and ventilation, as in the passages quoted previously from the
treatise of 1628. We shall find it very interesting to see how he
deals with the other ancient doctrine that some of the substance
of the air joins the blood in respiration. That this is true, gas
analysis and the mercurial air-pump have taught us; but in this
matter modern demonstration does but confirm, extend, and make
precise one of the oldest of physiological beliefs. Regarding this
we must now give the floor once again to the ancients, in order to
make Harvey comprehensible.

Even in the days of Empedocles and Hippocrates, in the fifth and
fourth centuries before Christ, men wrote of something derived from
the outer air being present, for the use of the organism, in the
vessels which also contain the blood.[46] To express this derivative
of the outer air the ancient Greeks employed the word "_pneuma_"
(πνεῦμα), the fundamental meaning of which seems
to have been "air in motion." Various meanings were acquired by
"_pneuma_," such as the breath of living things, the wind, or simply
the air, or what we mean by the words "gas," "vapor," "steam,"
"exhalation," "emanation." The Latin word equivalent to "_pneuma_"
is "_spiritus_," and so the English derivative of this, the word
"spirits," came into use to express various meanings of the Greek
"_pneuma_." A Hippocratic writer tells us that "the spirits cannot
stand still, but go up and down" in the blood vessels. The word
"spirits" here designates a derivative of the outer air crudely
mingled with the blood.[47] To this writer the distinction between
veins and arteries was unknown.

In the genuine works of Aristotle this Hippocratic doctrine does
not reappear, though it is fairly certain that Hippocratic treatises
which contain it were written before Aristotle's time. We have
seen that the entrance of air into the heart, to cool the same, is
an important feature of the Aristotelian physiology. Beyond the
Aristotelian heart, however, we cannot trace the air which enters
it. Yet we find "_pneuma_," "spirits," referred to by Aristotle,
not seldom obscurely or in very general terms, as doing service,
sometimes momentous service, in the physiology of generation and
in certain workings within the bodies of full-grown creatures.
In disease also spirits may play a very important part. These
Aristotelian spirits, however, when their origin can be traced
at all, are either innate or appear to be vapor produced within
the body itself by heat or by disease. They do not appear to be
recruited from the outer air which has penetrated the lungs and
heart, that air seeming to complete its function within the lungs or
within the heart itself by sustaining the native heat which is the
great instrument of the soul, and in which the very soul itself is

Physicians of Aristotle's time, however, revived and handed on
the doctrine that not only blood but a derivative of the air is
distributed to the body at large through the vessels. After the
distinction between veins and arteries had been clearly made and
the latter had received their present name, a striking modification
of this doctrine of the spirits was adopted and pressed by the
Greek physician Erasistratus, about 300 B.C., not many years after
the death of Aristotle. This modified doctrine separated the paths
taken within the vessels by the blood and the spirits derived from
the air, and declared the transmission of the necessary blood to
the body at large to be by the veins only, that of the necessary
spirits, styled "vital," to be by the arteries only. More than four
hundred and fifty years later Galen shattered this doctrine and
incorporated the vital spirits in the arteries with the blood, which
he proved by epoch-making experiments to be normally present in the
arteries, he, however, clearly recognizing differences between the
cruder blood in the veins and the spirituous blood in the arteries.
The tissues, therefore, still received vital spirits by way of the
arteries, according to Galen, but not spirits in their pure gaseous
Erasistratean state.[49] Now let Galen tell us more in his own

     "The breath from the windpipes, which had been drawn in from
     without, is worked up in the flesh of the lungs in the first
     place; in the second place in the heart and arteries, and
     especially in those of the net-like plexus; and to perfection in
     the ventricles of the brain, where the spirits become completely
     animal. But what the use may be of these animal spirits and
     why we have the temerity to call them so, when we confess that
     we are still utterly ignorant as to the substance of the anima
     [_i.e._, of the soul], this is not the moment to say."[50]

The complex physiology of this passage is so obsolete that its very
phraseology is meaningless without a commentary. In the first place,
what are the animal spirits? This expression, once a technical term
of physiology, survives only in colloquial English, and even there
merely as a label of which the origin is known to few. In this
phrase the adjective "animal" does not refer to lower creatures
as opposed to man, but is used in its obsolete original sense of
"pertaining to the soul," for which latter the Latin word is
"_anima_," the Greek word "_psyche_" (πσυχή). "Psychical
spirits" would best translate into the English of to-day either
the original Greek expression "_pneuma psychikon_" (πνεῦμα
ψυχικόν) or its Latin equivalent "_spiritus animalis_." But the
expression "animal spirits" was for too long a time an English
technical term to be superseded now. These animal spirits, that is,
spirits of the soul, were not peculiar to man, but were possessed
by lower creatures also; for neither the Latin word "_anima_" nor
the Greek word "_psyche_" implied immortality, as the English
word "soul" is now so commonly understood to do. Plato formally
recognized a mortal and an immortal part of the human psyche;[51]
and Aristotle admitted the existence in animals lower than man of
the lower grades of psyche, and conceded the lowest grade even to
plants.[52] The perfected animal spirits were of the very highest
physiological importance, as their name implies, they being for
Galen no less than "the first instrument of the soul,"[53] and thus
assuming the lofty rank given by Aristotle to the native heat. For
Galen the animal spirits were the medium of sensation and volition
and were imparted by the ventricles of the brain to the spinal cord
and nerves, the fibers of which were believed, accordingly, to
consist of tubes in which the subtile animal spirits were contained,
the bore of these tubes being too small to be visible.

We can now follow the quoted Galenic passage and trace the full
significance of that entrance of the substance of the air into
the heart which Galen repeatedly acknowledged, though sometimes
grudgingly. According to Galen whatever air was taken into the heart
had first been "concocted" in "the flesh of the lungs." Next, this
aërial substance had been worked up in the heart with the vapor of
the blood into vital spirits, and these became incorporated with the
finer blood destined for the arteries. Moreover, as each arterial
diastole was due to an active expansion of the arterial wall, at
each diastole there became blended with the contents of the arteries
still more of the substance of the air, which was sucked into the
arterial skin through the countless pores of the bodily skin,
these being too fine to permit bleeding. The vital spirits, thus
formed and modified, were blended with the blood of the arteries
and supplied to the body at large. A part of these vital spirits
mounted with the blood into the carotid arteries. In the swine and
the ruminants, notably in the calf, the branch given to the brain by
each carotid artery breaks up at the base of the skull within the
cranial cavity into numerous fine twigs, which form collectively
a net-work, styled in the passage from Galen already quoted the
"net-like plexus." This plexus is called by modern anatomists the
_rete mirabile_. It was falsely assumed by Galen to exist in man.
The plexuses of the two sides anastomose freely across the median
line, and through them passes the entire blood supply of the brain;
in the animals which possess them these plexuses seem the terminal
branches of the vertebral arteries also. The small vessels of each
net-like plexus reunite, and thus reconstitute the artery of the
brain before this artery has pierced the dura mater. Galen regarded
the net-like plexus as an organ of much importance intercalated in
the course of the artery for the still further elaboration of the
vital spirits, which, thus altered, were exhaled from the cerebral
arteries into the cerebral ventricles.[54] In these ventricles
the spirits attained their final perfection, becoming "completely
animal," by the aid of still more of the substance of the air, which
the diastole of the pulsating brain had drawn into its cavities
directly from the nares through the numerous holes in the ethmoid
bones. It is a striking fact in this connection that in some of the
domestic animals on each side of the head the cavity of the nares is
separated from the ventricular cavity of the brain by an exceedingly
thin, though complex, partition: as may be seen on dissection, if
the nares and the brain _in situ_ be opened at the same time.

Now let Galen speak again as follows:--

     "I have clearly shown that the brain is, in a way, the source of
     the animal spirits, watered and fed by inspiration and by the
     abundance supplied from the net-like plexus. The proof was not
     so clear as to the vital spirits, but we may deem it not at all
     unlikely that they exist, contained in the heart and arteries,
     they, too, fed by respiration mainly, but to some degree by the
     blood also. If there be such a thing as the natural spirits,
     these would be found contained in the liver and veins."[55]

The animal spirits were sustained, as we have seen, by three kinds
of respiration which might be called pulmonary, cutaneous and
cerebral. We may perhaps conjecture that it was largely Galen's
acceptance of the two latter, the last especially, which enabled him
sometimes to treat as doubtful the entrance into the heart of that
air from which the vital spirits were held to be derived. Of the
natural spirits he evidently made small account.[56]

A modern physiologist, musing upon all this, might see in the vital
spirits a dim foreshadowing of oxyhæmoglobin; might see in the
operation of the animal spirits a plainer foreshadowing of the nerve
impulse of to-day.

Some account, such as the foregoing, of the very complex ancient
doctrine of the spirits is indispensable for the study of Harvey;
for that doctrine, more or less modified, was still the accepted
medical doctrine of his time. After this renewed study of the
ancients let us now return again to Harvey's note-book at the place
where he takes up the question of the action of the lungs upon the
blood otherwise than by the cooling and ventilation of the innate
heat. It is necessary in his opinion that a further concoction of
the blood into spirituous arterial blood should be accomplished
by the fleshy parenchyma of the lungs in animals which require a
warmer, thinner, "sprightly kind of aliment," as his own English
styles it.[57] The probability of such a concoction is shown by
the separation of excreta which indicate it, such as sputa, at the
lung.[58] On the other hand, in such creatures as frogs and turtles
the lungs are fleshless, spongy, and vesicular, and give no sign of
blood or excreta. Hence we may infer that the pulmonary concoction
of the blood, though it probably occurs, is limited to such animals
as possess fleshy and sanguinolent lungs. Hence, again, it follows
that the concoction aforesaid is a function of secondary importance,
because it is not universal; and that the foremost function of
the lungs is their motion, the windpipes constituting their most
important part, rather than the parenchyma.[59] Two functions of the
lungs, says Harvey, are affirmed by the medical authorities: first,
the cooling and tempering of the blood; second, the preparation of
natural spirits and air to be made into vital spirits in the heart.
From all this there result the excreta of pulmonary concoction,
which are something between water and air, and the fumes which are
breathed out in expiration continually and incessantly. Harvey
observes correctly that Realdus Columbus had declared himself to
have discovered the continual motion of the lung to be the means
whereby the spirits are prepared; the blood being thinned by the
agitation, thoroughly mixed with air, beaten, and prepared.[60]
Harvey also cites Galen as saying that the parenchyma of the lung
concocts spirits out of air as the flesh of the liver concocts the
blood.[61] On turning to the Galenic passage cited by Harvey one
finds that it is out of the food that the blood is thus concocted by
the liver.

Realdus Columbus, to whom Harvey refers, was the Italian anatomist
who in 1559, fifty-seven years before the Harveian circulation was
verbally announced, gave to the world the important truth that such
blood as the right ventricle imparts to the left reaches the latter
by traversing the pores of the texture of the lungs,[62] instead
of the pores of the septum of the ventricles, as Galen had taught.
The existence of these pores of the septum Vesalius had pointedly
wondered at in 1543 and had emphatically doubted in 1555.[63] Four
years later his former assistant and temporary successor, Columbus,
flatly denied the existence of the pores. It was natural, therefore,
that in the same book in which Columbus brought forward the path
through the lungs to replace that through the septum he should
declare that the vital spirits are made out of air worked up
with the blood in the lungs and then merely perfected in the left
ventricle. This doctrine was an important advance beyond what Galen
had taught, viz.: that the spirits are but slightly prepared in the
lungs out of air and then sent to the left ventricle to undergo
their main preparation and to be worked up therein with the blood
which had filtered into it directly out of the right ventricle.

So much for the views of the medical authorities. We have found
Harvey agreeing with them that the ancient doctrine of the cooling
and ventilation of the native heat by respiration is sound. We have
found him acknowledging that in some animals some sort of concoction
also of the blood destined for the arteries may be brought about by
the pulmonary parenchyma as a function of secondary importance. But
now we shall find him rejecting the second accepted doctrine of the
physicians, viz.: that some of the substance of the air is taken
into the pulmonary vessels and enters the blood. This conjecture had
had believers for two thousand years, and was destined to be proved
true triumphantly after Harvey's death. In rejecting it he threw
away a precious clue to the meaning of his own great discovery.

     "It is more philosophical," he says, "not to share the common
     belief that the spirits are distinct and separate from the
     humors and parts because the spirits are produced in diverse
     places or contained in diverse things," but to hold that the
     spirits and the blood are one thing, like the cream and watery
     part (serum) in milk or, to borrow a simile from Aristotle's
     reasonings about the blood,[64] like heat and water in hot
     water, or like flame and a vapor which feeds it (_nidor_). As
     light is to a candle, so are the spirits to the blood.[65]

In this passage the discoverer's thought rises high, but in the next
it stoops again. The next passage is headed "Spirits not from air";
and Harvey says in effect, as I understand his difficult words:--

     If spirits are made by concoction out of air, the air is made
     either thinner or thicker in the process. If made thick, how
     does it get from the windpipes into the venous artery? If the
     spirits be thinner than air, how are they held[66] by the
     tunic of the lung, since this lets pass the pus and serum of

In the treatise of 1628 Harvey says that Laurentius

     "asserts and proves that, in empyema, serosities and pus
     absorbed from the cavity of the chest into the venous artery may
     be expelled and got rid of with the urine and fæces through the
     left ventricle of the heart and the arteries."[67]

Harvey's argument in his note-book continues thus:--

     "How, since mixture consists in the union of altered matters,
     can air be thoroughly mixed and made one with blood? What is
     that which mixes and alters? If it be heat, the air is made
     thinner thereby. If it be urged that the air is thickened by
     cold during preparation (which is impossible in the lungs), then
     Aristotle's[68] argument holds good: if spirits be from the air,
     how about fishes, which are agile and abound in spirits?"[69]

At this point we may call to mind passages in the introduction to
Harvey's treatise of 1628, published more than eleven years after
he had written the notes which we are now studying. In one of
these passages he speaks of what is now called the pulmonary vein,

     "If it be contended that fumes and air pass to and fro by this
     road, as through the bronchia of the lungs, why can we find
     neither air nor fumes on dissection, when the venous artery has
     been cut out or cut into? And how comes it that we always see
     the aforesaid venous artery to be full of thick blood and never
     of air, while we perceive that there is air remaining in the

Immediately after the foregoing passage Harvey says that should an

     "make a cut in the trachea of a living dog, forcibly fill the
     lungs with air by means of a bellows and, when they have been
     distended, apply a firm ligature, on opening the chest shortly
     after, he would find great abundance of air in the lungs, up to
     their outermost tunic, but none at all in the venous artery or
     in the left ventricle of the heart. If in the living dog the
     heart drew air out of the lungs or the lungs transmitted it,
     much more ought they to do so in this experiment. Who, indeed,
     could doubt that even in a dissection, if the lungs of a dead
     body had been inflated, air would enter at once, as aforesaid,
     did any passages exist?"[71]

Yet we have found Aristotle, more than nineteen centuries before
Harvey, recognizing that no passages are needed for the transfer of
air out of the windpipe, and saying, of the channels from the heart,
that "it is by contact that they receive the breath[72] and transmit
it to the heart."[73] Moreover, sixty-nine years before Harvey's
publication Columbus had repeatedly recommended the experiment of
opening the venous artery[20] in a living dog and noting that the
"said venous artery" is full of blood, not of air or fumes. But
Columbus held this observation rather to confirm than to disprove
his doctrine that the blood in the venous artery is imbued with
vital spirits derived in the lungs from the substance of the air.
Indeed, he goes so far as to call the contents of this vessel
"modified blood and air."[74] In this matter the earlier observer,
Columbus, shows keener insight than the later, Harvey.

Decidedly, however, the stage waits for the chemists, despite
Harvey's poor opinion of them. Despite that poor opinion, too,
Harvey himself turns to making chemical conjectures in the next
passage of his note-book, to the study of which latter we will now
return. The passage is as follows:--

     "Conclusion. Opinion of W. H.

     "In animals in which lungs are fleshy and full of blood these
     concoct the blood, seeing that spirits and blood are one
     thing, in the same way that the liver does and by reason of
     the same arguments; indeed, the lungs may rather detain fatty
     and oleaginous vapor by a cooling process, as oil or balsam or
     nutritious fat is cooled in alembic and serpentina"[75]--

"alembic" and "serpentina" answering to the "still" and "worm"
of the modern distiller. Harvey, therefore, utilizes the Galenic
analogy between concoction in the lungs and that of the blood
and the vapors thereof, rejecting not only Galen's preliminary
concoction of air into spirits in the lungs, but also Columbus's
union in the lungs of blood with spirits produced in the lungs
themselves out of air. Of the entrance of "the substance of air"
into the blood Harvey makes emphatic denial and, by so doing,
reduces the spirits either to emanations from ingredients of the
body itself (thus reminding us of Aristotle), or to a mere name with
which to label qualities of the blood, in treating of which he often
uses the word "spirits" as a current term. Naturally, therefore,
where in his lecture notes he treats of the spirits in relation
to the brain and nerves his conclusions are not clearly defined,
but seem consistent with his views as to the spirits in the blood,
though his jotted words are not very easy to understand. On this
subject he refers by name to Galen, three alternatives discussed
by whom appear to be reviewed by Harvey, viz.: that sensation and
motion result either from a progression from elsewhere of spirits
in substance along and within the nerves; or from a vibration of
spirits in substance which have their native seat within the nerves;
or, lastly, from no movement of a substance, but from a transfer
of "faculty" along the nerves by means of progressive qualitative
alteration thereof, "such as is produced in air by the brightness
of the sun."[76] Of these three alternatives, the last seems to
commend itself most to Harvey, as we should expect; the second,
next; and the first, not at all;--that is, if one may so interpret
the following brief passage of his lecture notes:--

     "I believe that in the nerves there is no progression of
     spirits, but irradiation; and that the actions from which
     sensation and motion result are brought about as light is in
     air, perhaps as the flux and reflux of the sea."[77]

Also we find Harvey long years afterward saying to Riolanus:--

     "Moreover, the spirits, animal, natural, vital, which dwell,
     contained within blind windings, in solid parts, to wit,
     in ligaments and nerves (especially if there be so many
     kinds),--these spirits are not to be regarded as so many diverse
     aëreal forms, nor as so many kinds of vapors."[78]

In Harvey's lecture notes the subject of respiration is brought to
an end with an abrupt interrogation, which seems to reveal a sudden
return of doubt as to whether too much may not have been conceded in
admitting a pulmonary concoction of any sort. We read:--

     "N.B. If the blood receive concoction in the lungs, why does it
     not traverse the lungs in the embryo?"[79]

It would seem to be Harvey's tendency to adhere to the view
which limited the use of respiration entirely to the cooling and
ventilation of the innate heat, by which according to ancient
doctrine the heart was the central hearth, embedded in the cooling
and ventilating lungs; although this ancient doctrine tallied well
in most eyes with the belief that only a portion of the blood ever
entered the heart at all.[80] In the first of the two Exercises
which Harvey, when seventy years old, in 1649, addressed to Riolanus
in defense of the circulation, the ancient respiratory cooling and
ventilation take their place again as follows:--

     "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
     through the arteries into the entire body, cherish and nourish
     and keep alive all the extremities, preventing extinction due to
     the power of external cold."[81]

In none of the writings of his old age does Harvey deal expressly
with concoction in the lungs, or more than cursorily with the
entrance of the substance of air into the blood. But he repeatedly
and emphatically reaffirms that blood and spirits are one thing;[82]
he even declares the blood in comparison with the other parts of
the body to be "possessed of powers of action beyond all the rest,
and therefore, in virtue of its preëminence, meriting the title
of spirit."[83] He castigates those who give the rein to overmuch
speculation about the spirits. We learn that some suppose that the
spirits "are engendered and are fed and increased from the thinner
part of the blood"; that others suppose "the primigenial moisture"
to engender and support them.[84] Then there are "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 agitation) and the inspired air"[85]--the Galenic

     "Such spirits," says Harvey of these last mentioned, "are rather
     to be regarded as fumes and excrementitious effluvia of the
     blood and body, like odours, than as natural artificers; ...
     whence it seems probable also that pulmonary expiration is for
     the ventilation and purifying of the blood by the breathing
     out of these; while inspiration is in order that the blood, in
     passing through between the two ventricles of the heart, may
     be tempered by the ambient cold; lest the blood, being hot and
     swollen, blown up in a sort of ferment, like milk and honey
     boiling up, should so distend the lungs that the animal would be

As we read these words, published in Harvey's old age, we recollect
the following words, written in his note-book more than thirty-three
years before, viz.: "So there is cooling and ventilation of the
native heat, ventilation especially."[87]

We may recall also that the preservation of the native heat had
sufficed to explain respiration to Harvey's ancient teacher,
Aristotle, while the tenor of Aristotle's genuine works well accords
with the following dictum which we have found in Harvey's note-book:
"Spirits not from air." Yet the more firmly this dictum was upheld,
and the more simply Aristotelian in principle did Harvey's doctrine
of respiration remain, so much the less called for must have
seemed that swift and endlessly repeated passage through the lungs
of the whole mass of the blood, which was involved in the Harveian

In the actual phenomena of respiration, however, positive obstacles
confronted the doctrine of the circulation which were harder to
surmount than cobwebs of speculation, or than the mere question
"_cui bono_" which latter the steadfast observer could simply
wave aside. Spirits or no spirits, there were opponents of the
circulation, even in Harvey's old age, who insisted that the blood
in the arteries was so different from the blood in the veins that
the same blood could not be changing perpetually from arterial to
venous, and _vice versa_. There was always that stubborn difference
of color, plainly to be seen in man and beast, but so hard to
account for in Harvey's day. Therefore, we find Harvey leaving the
realm of subtleties and taking up his old weapon of demonstration,
in order to minimize the differences between arterial and venous
blood. Twenty years after the publication of his discovery he says
to Riolanus:--

     "You may also perform another experiment at the same time.
     If you fill two cups of the same measurement with blood, one
     with that which issues by leaps from an artery, the other with
     venous blood from a vein of the same animal, you can observe
     the sensible differences between the two, both immediately and
     later, when the blood in either cup has become coagulated and
     cold. This experiment will contradict those who pretend that
     the blood in the arteries is of one kind, that in the veins of
     another, on the ground that that in the arteries is more florid
     and seethes and is blown up with copious spirits, I know not
     how, like milk or honey boiling upon the fire, swelling and
     filling a larger space. For, were the blood which is thrown
     from the left ventricle of the heart into the arteries fermented
     thus into a frothy and flatulent condition, so that a drop or
     two distended the whole cavity of the aorta, unquestionably,
     upon the subsidence of this fermentation, the volume of the
     blood would return to that of a few drops (and this is, indeed,
     the reason that some assign for the empty state of the arteries
     in the dead body); and this would be apparent in the cup which
     is full of arterial blood, for so we find it to happen in milk
     and honey when they come to cool. But if in both cups 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 each cup 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 of certain people. On investigation
     sense and reason alike assure us that the blood of the left
     ventricle is not of a different kind from that of the right....
     The blood, then, when imbued with spirits to the utmost, is not
     swollen with them, or fermented or blown up so as to crave and
     require more ample room (as can be determined with the greatest
     certainty on trial by the measurement of the cups); we should
     rather understand this blood to be possessed, after the manner
     of wine, of greater strength, and of an impetus to action and
     effectiveness, in accordance with the view of Hippocrates.

     "So the blood in the arteries is the same as that in the veins;
     even though the former be acknowledged more spirituous and
     possessed of greater vital force; but the blood in the arteries
     is not converted into something more aëreal or rendered more
     vaporous; as though there were no spirits not aëreal, nor
     anything which gives an impetus except wind and flatulence."[88]

It is well, one may be inclined to mutter, as one reads this, but
how about the color? It may be nearly the same, but certainly
there is a difference. In his book "On Generation" Harvey himself
describes in more detail the changes which occur in shed blood on
standing, and says: "Of the red parts the upper are more florid,
those below are blackish." In the same description he refers
shortly after to "the florid and ruddy part which is commonly
thought to be arterial blood."[89] The words last quoted evidently
refer to the upper part of coagulating blood as commonly seen. This
in medical practice would be blood drawn from a vein, and Harvey
says nothing of arteriotomy in this passage. Indeed, he refers
in the context to venesection; and earlier in the same chapter
he wrote: "Physicians observe only human blood, and this shed by
venesection into a basin, and coagulated."[90]

The foregoing passages show at once that opinions had been clarified
very little by the suggestive change of color caused in shed blood
by contact with air. Years before, in jotting down his lecture
notes, Harvey had noted that the arterial blood is redder;[91] Galen
had known it;[92] it must always have been known. In 1649 Harvey

     "Three things are especially apt to give rise to this opinion of
     the diversity of the blood: the first is that the blood which
     is drawn in arteriotomy is more florid....[93] Whenever and
     wherever blood issues through a narrow orifice it is strained,
     as it were, and the thinner and lighter part, which usually
     swims on top and is the more penetrating, is emitted."[94]

A number of observations follow, of appearances noted in nosebleed,
in the use of leeches, in cupping, and in blood-letting from veins
and arteries. All these appearances are adduced in support of the
view that it is the straining of the blood which renders it more
florid, and they all show that the brightening of the color of shed
blood on exposure to air served only to lead Harvey off on a false
scent. Continuing he refers, as follows, to direct inspection of the
dissected lungs:--

     "The blood is found to be much more florid within the lungs and
     after it is squeezed out of them, than in the arteries."[95]

A few pages farther on he states, categorically, the false
conclusion to which he has been driven, saying:--

     "It is no less plain why the blood of the lungs is so ruddy; for
     it is thinner, because there it is filtered through."[96]

Nothing indicates better Harvey's readiness to minimize the
essential differences between venous and arterial blood than a
passage in the treatise of 1628, in which he says that, compared
with the left ventricle, the right ventricle "is of greater
capacity, that it may supply not only matter to the left ventricle,
but also nourishment to the lungs."[97] It should be remembered
that, in Harvey's day, the so-called bronchial arteries were still
unknown, through which the tissues of the lungs are supplied with
arterial blood from the aorta.[98] Not only Columbus,[99] but even
Galen,[100] had each devised an erroneous way in which to provide
the lungs with "spirituous" or "vital" blood, in addition to the
venous blood from the right ventricle; but Harvey is obviously
content to let the latter suffice for their nutrition.

What has gone before indicates how erroneous it is to speak of the
pulmonary transit, as Columbus had set it forth in 1559, nineteen
years before Harvey's birth, as though Columbus were in some sort
a sharer in the discovery of the circulation. Those who so speak
fail to note the difference between blood and _the_ blood. Although
Columbus girded at Galen and corrected him, Columbus's pulmonary
transit of a fraction of the blood by curing more than one defect of
the Galenic doctrine strengthened the erroneous Galenic physiology
of the blood-movement. Of these larger features Columbus not
only was no enemy, but remained a devoted adherent. His doctrine
certainly paved the way for Harvey's, but in no more immediate sense
than did Galen's doctrine that blood is naturally contained in the

Indeed, Harvey categorically stated that the movement of blood
through the lungs had nothing to do with his discovery. In a Latin
letter from London written in 1651 to P. M. Siegel in Hamburg,
Harvey says in his old age:--

     "Meantime, as Riolanus uses his utmost efforts to oppose the
     passage of blood into the left ventricle through the lungs, and
     brings it all hither through the septum, and so vaunts himself
     as having upset the very foundation of the Harveian circulation,
     (although I have nowhere laid that down as a foundation for
     my circulation; for the blood fetches a circuit in very many
     red-blooded animals in which no lungs are to be found), it may
     be well here to relate an experiment which I lately tried in the
     presence of several of my colleagues, and from the cogency of
     which there is no escape."[101]

The parenthesis certainly is a striking one.

No less striking is the last word published by Harvey about
respiration. We have heard him deny the entrance of air into the
blood and doubt the occurrence of any concoction in the lungs. Now
we shall hear him throw over even the cooling of the innate heat, a
respiratory doctrine to which he has seemed hitherto to hold with
conviction. In the essay "On Parturition" published in 1651 with the
treatise "On Generation," he says:--

     "In the meantime I would propose this question to the learned:
     How comes it that the fœtus continues in its mother's womb
     after the seventh month? If brought forth at that time it
     breathes at will, indeed could not survive one little hour
     without breathing; yet, as I have said, if it remain in the womb
     it keeps alive and well beyond the ninth month without the aid
     of respiration.... Whoso shall attend carefully to these things
     and consider more closely the nature of air, will, I think,
     readily grant that air is given to animals neither for cooling
     nor as nutriment; for it is a fact that after the fœtus has
     once drawn breath it may be suffocated more quickly than when
     entirely excluded from the air; as though heat were unkindled by
     air within the fœtus rather than allayed. Thus much, merely
     by the way, on the subject of respiration; perhaps I shall treat
     of it more fully in its proper place. Surely a more knotty
     subject could hardly be found, as the arguments on both sides
     are very evenly balanced."[102]

So we find Harvey in his old age induced by lifelong study to
question, if not deny, even the cooling effects of respiration,
and to end with a practical confession of ignorance. Instead,
therefore, of the circulation and its swiftness being explained by
the urgent need of "the substance of the air" experienced by certain
tissues, that movement of the whole mass of the blood through the
lungs, which was so novel a physiological fact, does not seem to
have affected his view of the problems of respiration. Nor could he
properly explain the respiratory change in the color of the blood,
which seemed to support the ancient doctrine that the blood is
of two different kinds. Since he could not invoke respiration to
elucidate the circulation and its rapidity, and since he himself
declared that such rapidity could not be needed for the simple
feeding of the tissues, what was left to be invoked? It is no wonder
that eight years[103] after the publication of his discovery Harvey
denied that he had ever seriously undertaken to explain the use of
the circulation; that at the end of thirteen years more he repeated
this denial in his old age;[104] although he had not refrained from
expressing such conjectures as must always be evoked in the mind
of a great observer by a discovery of the first importance made by
himself. Yet the phenomena of the very circulation used were so
striking as to cry aloud for elucidation; for Harvey's own clinching
statement that the heart drives into the aorta at least one thousand
drachms of blood in half an hour,[105] this _reductio ad absurdum_,
which cut the ground from under the feet of his opponents, left him
helpless in his turn to account for the need of so huge a flooding
of the arteries.

Since it was not to be swiftly altered in the lungs that the whole
mass of the blood hurried back from all parts of the chest, what



It has been stated already that the first announcement of the
circulation is to be found in Harvey's lecture notes. The following
is the text of the memorable passage in question, which I have
translated from Harvey's Latin. He says:--

     "It is proved by the structure of the heart that the blood is
     perpetually transferred through the lungs into the aorta, as
     by two clacks of a water-bellows to rayse water. It is proved
     by the ligature that there is a transit of the blood from
     the arteries to the veins; whereby it is demonstrated that a
     perpetual movement of the blood in a circle is brought about by
     the beat of the heart. Is this for the sake of nutrition, or of
     the better preservation of the blood and members by infusion of
     heat, the blood in turn being cooled by heating the members and
     heated by the heart?"[106]

The words "as by two clacks of a water-bellows to rayse water"
are Harvey's own racy English, embedded in his Latin text. The
"ligature" is the flat band which is tied about the upper arm when
bleeding from a vein is to be practised at the bend of the elbow.
The Hippocratic physicians called this band a "_taenia_,"[107] and
even in their day it was known to hasten the flow of blood from
the opened vein when applied as above stated, but yet to check the
flow if tied too tight. This clinical observation had awaited
a rational explanation for more than nineteen centuries.[108]


Page 80, right, of William Harvey's _Prelectiones Anatomiæ
Universalis_, or Lecture Notes of 1616. The passage contains the
first recorded mention of the movement of the blood in a circle.]


  WH constat per fabricam cordis sanguinem
      per pulmones in Aortam perpetuo
      transferri, as by two clacks of a
      water bellows to rayse water
      constat per ligaturam transitum sanguinis
      ab arterijs ad venas
      vnde Δ perpetuum sanguinis motum
      in circulo fieri pulsu cordis
      An? hoc gratia Nutritionis
      an magis Conservationis sanguinis
      et Membrorum per Infusionem calidam
      vicissimque sanguis Calefaciens
      membra frigifactum a Corde

  Transcript of the preceding page.]

Our most immediate interest in the foregoing passage lies in this:
that on the very same page, with the few clear simple words which
tell for the first time of Harvey's facts and proofs, he has briefly
written down conjectures as to the meaning of the circulation.
These are as strikingly put as certain jottings are obscure which
deal on a neighboring page with some possible meanings of the
heart-beat.[109] In neither group of conjectures do the functions of
the lungs play a part; but the discoverer asks himself whether it
be not to revisit the heat of the heart that the whole mass of the
blood circles back to the chest in its Harveian course! More than
thirty-two years after the date of Harvey's note-book Harvey wrote
to Riolanus:--

     "There are some who consider that as no impulsion of nutriment
     is required for the nutrition of plants, their particles
     attracting little by little whatever they need to replace what
     they have lost, so in animals there is no need of any impulsion,
     the vegetative faculty in both working alike. But there is a
     difference. In animals a perpetual flow of warmth is required to
     cherish the members, to keep them alive by the aid of vivifying
     heat, and to restore parts injured from without. It is not
     merely nutrition that needs to be provided for."[110]

In the first Exercise to Riolanus Harvey had touched also upon the
use of the circulation, interweaving this doctrine of heat with the
doctrine of respiration as he then held it, in a passage the last
part of which I have quoted already. Quoted more fully he says:--

     "And this, indeed, is the principal use and end of the
     circulation, for which the blood revolves with perpetual
     influence in its ceaseless course and is driven along its
     circuit: namely, that all the parts in dependence upon the
     blood may be kept alive by the primary innate heat and in their
     state of vital and vegetative being, and may perform all 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 center of the body and effects the expulsion of
     suffocating fumes, so in its turn does the hot blood, thrown
     through the arteries into the entire body, cherish and nourish
     and keep alive all the extremities, preventing extinction due to
     the power of external cold."[111]

"The innate fire is not in the right ventricle," a Hippocratic
author had written, who had written also that the wall of the
left ventricle is dense, to guard the strength of the heat.[112]
Aristotle, too, had placed in the heart the "origin" of the "natural
innate heat";[113] had likened the heart to "the hearth on which
shall lie the natural kindling, well protected also, as being the
acropolis of the body."[114] At a later day Galen had affirmed the
same doctrine.[115]

Let us turn now to the famous treatise of 1628, published twelve
years after the note-book had been written. In the chapter in which
Harvey says "I tremble lest I have mankind at large for my enemies"
and then publishes and names the circulation,--in this chapter,
before passing to his proofs, he published the following words
which resound in a way very different from the simplicity of the

     "So probably it may come to pass in the body through the
     movement of the blood that all the parts are nourished,
     cherished, quickened, by the hotter, perfected, vaporous,
     spirituous, and, so to speak, alimentive blood; that the blood,
     on the other hand, is cooled, coagulated, and rendered, as it
     were, effete in the parts; whence it returns to its origin,
     namely, the heart, as to its fountain, or the hearth of the
     body, to regain perfection. There by the potent and fervid
     natural heat, a treasury of life, as it were, the blood is
     liquefied anew and becomes pregnant with spirits and, so to
     speak, with balsam. Thence the blood is distributed again; and
     all this depends upon the motion and pulsation of the heart.

     "The heart, therefore, is the origin of life and the sun of the
     microcosm, even as the sun in his turn might well be called the
     heart of the world; by the vigor and pulsation of the heart
     the blood is moved, perfected, quickened, and delivered from
     corruption and thickening; and the function of nourishing,
     cherishing, quickening the entire body is performed by that
     intimate hearth, the heart, the foundation of life, the author
     of all. But of these matters more conveniently when I shall
     speculate as to the final cause of motion such as this."[116]

Upon this florid passage follow the classic six chapters which bring
forward with such power and calm the proofs of the circulation.
These are succeeded in their turn by words which echo their
sobriety, as follows:--

     "It will not be beside the question to show also from certain
     familiar reasonings, that the circulation is both convenient and
     necessary. In the first place, since death is corruption from
     deficiency of heat[117] and since all living things are warm,
     all dying things cold, the heat requires a seat and origin, a
     home and hearth, as it were, in which the tinder of nature,
     the first beginning of the innate fire, may be contained and
     preserved; a place from which, as from their origin, heat and
     life may flow out into all the parts, whence nutriment may come
     and upon which concoction and nutrition and all quickening may
     depend. That this place is the heart, that this is the origin of
     life as aforesaid, I should hope that none would doubt.

     "Hence the blood has need of motion, of motion such that it may
     return to the heart; for, if sent to the outer parts of the
     body, far from its source,[118] and left unmoved, it would
     become coagulated. Heat and spirits are seen to be generated
     and preserved in all by motion, to vanish if quiet supervene.
     Therefore, the blood, thickened or stiffened by the cold of the
     extremities and of the ambient [air] and destitute of spirits,
     as in the dead, must needs return to its source and origin in
     order to keep itself whole, to seek thence and repair again its
     heat and spirits."...[119]

     "Moreover," Harvey says, a page farther on, "since all animals
     live by nutriment concocted in their interior, it is necessary
     that the concoction and distribution thereof be perfect; and,
     further, that a place and receptacle exist where the nutriment
     may be perfected and whence it may be led off to the several
     members. Now this place is the heart, for it alone of all the
     parts contains blood for the public use in its cavities, the
     auricles and ventricles, as in cisterns and storehouse; not
     merely blood for its private use in the coronary vein and

In the next chapter we obtain glimpses of the pathological relations
of this physiology. Harvey brings forward tertian fever as a case in
point, explaining that the febrile paroxysm is produced when

     "the preternatural heat which has been kindled in the heart is
     diffused throughout the entire body by way of the arteries,
     together with the morbific matter which thus is evaporated and
     dissolved by nature."[121]

As a student of the Greek science reads the foregoing passages,
he clearly sees that the new wine of the circulating blood is
poured into the old bottles of the Aristotelian physiology; and
Harvey tells us so himself, in the last chapter of his most famous
treatise. He says:--

     "No less should we agree with Aristotle as to the sovereignty of
     the heart, in dealing with the following and similar questions:
     Does it receive motion and sensation from the brain, blood
     from the liver; or is it the origin of the veins and of the
     blood? For they who try to refute him leave out, or do not
     grasp, the main argument, which is that the heart is the first
     part to exist and has in it blood, life, sensation, motion,
     before the brain or the liver has been made or is clearly to
     be distinguished, or at least before either can perform any
     function. So the heart with its own proper organs constructed
     for motion--as it were, an internal animal--is the earlier
     formed; and, this being the first made part, it is the will of
     nature that thereafter the entire animal be made, nourished,
     preserved, perfected by the heart to be its achievement and
     abode. The heart is governor everywhere, like the chief in
     a commonwealth with whom is lodged the first and highest
     authority. In an animal all power is derived from and depends
     upon the heart as its origin and foundation."[122]

The main argument, which is that the heart is the first part to
exist, is simply the argument from the development of the embryo
in the hen's egg. The study of this development day by day had
been recommended by one of the Hippocratic writers,[123] and
Aristotle had laid stress upon the changes in the embryo during
incubation.[124] Harvey, in his turn, had studied them carefully.
The ancients could have made their observations only with the naked
eye, but Harvey had the aid of a simple lens, though of nothing
approaching in power to a microscope.[125] In the treatise of 1628
he speaks as follows of what he thus observed:--

     "If you turn to the formation of the chick in the egg, the first
     thing to exist therein, as I have said, is a mere vesicle, or
     auricle, or pulsating drop of blood. Afterward, when growth has
     gone on, the heart is completed.... In a hen's egg after four
     or five days of incubation I have shown the visible presence of
     the rudiment of the chick in the form of a little cloud; in an
     egg, that is, which had been immersed in clear tepid water after
     removal of the shell. In the middle of the aforesaid little
     cloud there was a palpitating bloody point, so fine that in
     contracting it disappeared and became invisible, but reappeared
     on its relaxation, looking like the point of a needle, and of
     a ruddy color; so that being now visible and now invisible, as
     though now existent and now non-existent, it evinced palpitation
     and the beginning of life."[126]

In the same treatise Harvey promises to publish more observations

     "on the formation of the fœtus, where numerous problems of
     the following order can find a place: Why should this point be
     made or perfected earlier, that later? As regards the dominance
     of the members: Which part is the cause of the other? There are
     very many problems connected with the heart, such as: Why should
     it be the first thing (as Aristotle says in his third book on
     the parts of animals)[127] to acquire consistency, and be seen
     possessed of life, motion, and sensation, before anything has
     been perfected in the rest of the body? And in like manner
     regarding the blood: Why is it before all, and how possessed
     of the beginnings[128] of life and of the animal, and of the
     craving to move and be impelled hither and thither, to which end
     the heart would seem to have been made?"[129]

In Harvey's celebrated treatise, despite various frank questionings
by the way, such as that just quoted about the blood, he so
frankly follows in the footsteps of "the master of them that know"
that Aristotle need not be cited at length to prove the fact. To
Aristotle are largely due Harvey's references to the heart as
the central source of indispensable vital heat; his references
to aliment perfected in the heart; his blending of psychological
doctrines with the doctrine of the movement of the blood. Therefore,
a brief account of how this became possible will be germane.

When an ancient observer looked with the naked eye at the very early
embryo of the fowl, he distinguished at first only a blood-red
point, which pulsated, or "leapt." This Aristotle judged to be the
heart, containing blood before any blood-vessel had shown itself
and before blood was visible in any other part. Very soon, however,
two vessels containing blood were seen, according to him, to extend
from the rudimentary heart toward the periphery. From these and
other considerations Aristotle inferred that both the blood and all
its containing vessels owe their first origin to the heart; and that
throughout life the liquid made elsewhere from the food enters the
heart, there to be perfected into blood by the action of the vital
innate heat, of which, as we have seen, he held the fiery central
hearth to be within the heart. Naturally, therefore, he believed the
blood not to be hot of itself, but to acquire its vivifying heat at
the heart, the pulsation of which he held to be caused directly by
the seething of the blood within. When thus perfected and charged
with heat the blood, according to him, is distributed from the heart
through the vena cava as well as the aorta. These great vessels and
their subdivisions Aristotle distinguished anatomically; but he
made no serious physiological distinction between what we call the
veins and the arteries, and, himself, applied the word "artery" to
the windpipe only. As to the cavities and contents of the heart,
even as to the number of its cavities, he had obscure, complex, and
erroneous ideas, and of the valves he knew nothing. He recognized
no essential differences between the matters distributed by way of
the vena cava and by way of the aorta, all being, alike, one thing,
blood; though the blood was hotter or cooler, thinner or thicker,
purer or cruder, in different regions or parts of the body, in
different sets of vessels, in different cavities of the heart, or at
different times in the same place.

We have seen already that, in the genuine works of Aristotle, there
is no sign that what we call the tissues of the adult require or
receive a derivative of the air, whether crudely mingled with the
blood in the earlier Hippocratic way, or separate in Erasistratean
fashion, or in the form of such "spirituous blood" as Galen
afterward accepted. We have seen that the air which Aristotle
believed to enter the heart for cooling purposes, cannot be traced
beyond it; that whatever spirits may exist in the body for him,
would seem to be either of the nature of vapor produced within the
body itself, or of a nature quite indeterminate.[130]

The living egg of the hen has had a vast deal to do with the history
of psychology as well as of physiology. It is partly owing to what
Aristotle believed to go on in the egg that we speak to-day of
good hearts and bad hearts--even of sweethearts. Aristotle knew
nothing of the nerves, and, therefore, could reasonably fail to find
conclusive evidence that the brain and spinal cord had to do with
what we call nervous functions. So he fell back upon a doctrine at
least as old as the Iliad,[131] and made a psychological center of
the heart. This being proved, for Aristotle, largely by its demeanor
in the early embryo, to be the life-long source of the nutritive
blood; and being, for him, the central hearth of the heat by means
of which the blood is perfected and warmed; he held it a matter of
necessity that in the heart should dwell the so-called "nutritive
soul"; that is, the faculty which uses as its most immediate
instrument the "innate," "natural," "vital," "psychical," heat, to
bring about nutrition, growth, and generation. He says:--

     "It is impossible that the other faculties of the soul should
     exist without the nutritive, or these without the natural fire;
     for in this has nature set that faculty aglow."[132]

Dealing with these other faculties, he sees that there must be an
organ where the results of sight, hearing, and the other senses, are
compared; and deliberately discussing and rejecting the claims made
for the brain he makes the heart this "common sense-organ of all the
sense-organs," as he styles it. He says:--

     "If in all the creatures the seat of life is in this part, it is
     clear that here also must the origin of sensation be; for we say
     that the body has life because it is an animal, but we say that
     it is animal because it has sensation."[133]

Less hollow rings the argument in the modern ear, when the ancient
thinker bases it on conclusions drawn from observation. We learn
from him that only those parts are sensitive which contain blood, as
opposed to hair and nails, or even to the blood, if taken by itself.
We learn, therefore, that as the heart of the embryo is the first
part to contain blood, it is the first part to be sensitive and
hence is the central source of sensation. Moreover, Aristotle, like
Plato,[134] knowing nothing of the nerves, judges the blood-vessels
to be sensory paths; and blood-vessels connect, not only the
sensitive flesh, but all the more special sense-organs with the
heart. Such is the outline of the reasons why Aristotle held the
heart to be the lifelong seat, not only of the "nutritive soul," but
of the "sensory soul" as well.

Pain, pleasure, and desire would naturally dwell beside sensation
in the heart, which Aristotle held to be obviously the seat of the
emotions, as proved by its palpitation when they are stirred.
Moreover, it is desire, seated in the heart, which incites to
action, to motion, movement thus resulting from sensation; and,
in general, "the movements" of every sense both begin and end at
the heart; the word here translated "movement"[135] being used, in
the technical diction of Aristotle, to include not only the "molar
motion" of modern parlance, but also subtle forms of change of
state. Further, in the early embryo the heart itself is plainly the
first part which possesses motion; it visibly taking the lead in
this, moving "as though itself an animal." The pulsating movements
of the heart are the direct effects of the seething and vaporization
within it; while, in the respiratory movements, the chest wall is
pushed out by an expansion due to the vital heat, whose cardiac
hearth the lungs inclose, and then follows inward a contraction due
to the cooling air which has been drawn into the expanding lungs.
As the bodily movements, in general, are "brought about by drawing
and slackening" and originate at the heart, it is appropriate that
the heart contains tendinous structures[136] within itself; "for
it needs the service and strength" of such.[137] It is too, in a
sense, the origin of the discontinuous tendinous and ligamentous
structures of the body. Aristotle's doctrine of the heart as the
source of motion seems especially vague. But, hardy thinker though
he was, he scarcely could be definite on this subject, even in
speculation. He knew that heat expands and cold contracts; he
recognized the force which, as he believed, confined or compressed
vapor exerts in living bodies, not only in health but in disease;
and he knew the strength imparted to bodily effort by holding the
breath. His genuine writings, however, bring forward no _modus
operandi_, except in the case of respiration and of the movements
of the heart itself. We are given no inkling as to how the tendons
are normally drawn and slackened in obedience to the will, for the
true function of muscle was unknown to Aristotle (Harvey to the
contrary notwithstanding),[138] and the blood-vessels were the
only continuous special paths between center and periphery which
Aristotle could make out. In his time, as we have seen, the nerves
had not been distinguished, even anatomically, from the bands and
cords of the ligaments and tendons.

So, for Aristotle, the nutritive, sensory, and motor faculties, the
desires and emotions, in short all the souls or parts of the soul
(to use the ancient phraseology) that are not the most exalted,
dwell in fire within the heart, suitably and honorably placed at the
central "acropolis." To the divine mind of man, on the other hand,
he does not assign a definite special dwelling-place within the body.

Harvey differed often and widely from Aristotle. Yet even in
his old age he wrote: "The authority of Aristotle has always
such weight with me that I never think of differing from him
inconsiderately."[139] Cannot one fancy, may not one conjecture,
that in the eyes of the discoverer of the circulation his great
discovery, fundamental, new, and original, as he rightly claimed it
to be, may at times have seemed to constitute a thorough correcting
and filling in of a rough sketch dashed off at the Lyceum? Let us

Aristotle had no conception of anything resembling a circulation of
the blood, nor any definite mechanical ideas as to its movement.
While the vena cava as well as the aorta received blood from his
valveless heart and yielded it to the body at large, blood ebbed
back to the heart during sleep, and the warm nutrient liquid which
the vena cava and the aorta yielded to the tissues had previously
entered the heart continuously but in an imperfect state through
both of these great vessels, to go forth again through both,
perfected into blood and heated, with no perplexing differences of
color noted between that in the great vein and that in the aorta.
The relations between the food, the blood, the heart, and the body
at large, though recognized to be complex, may well have presented
themselves to Aristotle with something of the vagueness with which
the relations between the food, the liquids, the contractile
vacuole, and the living substance of a protozoön, present themselves
to us. If the heart, retaining its Aristotelian powers, were found
to receive the blood imperfect or impaired, but to receive it by the
veins only, and to send it out, but only by the arteries, warmed and
perfected or restored to perfection at its Aristotelian source; what
have we but the systemic part of the circulation, as it may have
pictured itself sometimes to Harvey?[140]



Thus it is striking to find Harvey, as the champion against Galen of
a view essentially Aristotelian, entering the field of controversy
where ancient Greek still met ancient Greek in the modern Europe of

The discoveries of the nerves and the valves of the heart had
made great difficulties for the Aristotelian psychology and
physiology shortly after Aristotle's time. We have seen that the
semilunar valves were described, and their use noted, in a treatise
included in the Hippocratic collection;[141] and all the valves,
both arterial and auriculo-ventricular, were well recognized by
Erasistratus, whose acquaintance we have made already, and who
flourished about 300 B.C., Aristotle having died in 322 B.C.
Erasistratus, we remember, was more than four centuries earlier than
Galen and more than nineteen centuries earlier than Harvey.

That the heart throughout life is not only the source of the
perfected blood, but gives out blood to the vena cava for
distribution, had been rendered a hard saying, especially by the
recognition of the tricuspid valve.[142] Galen, however, like the
somewhat earlier Greek physician Aretæus, the Cappadocian,[143]
was not confronted by this difficulty, for they both adhered to
an ancient doctrine to be found in the Hippocratic treatise
"On Nourishment," and there sketched with mingled clearness and
vagueness in the following pithy saying:--

     "Root of the veins, the liver; root of the arteries, the heart.
     Out of these wander into all parts blood and spirits, and
     through these heat comes in."[144]

Obviously the doctrine here foreshadowed was quite irreconcilable
with the views of Aristotle.

In studying the works of Harvey and of his contemporaries and
predecessors it must be borne in mind that, from ancient times past
the time of Harvey to more modern days, the word "heart" was very
commonly used by physicians and men of science to mean simply the
ventricular mass, without the auricles, which were reckoned in with
the great vessels. In slaughterhouses the word is still used in this
ancient sense. Harvey's practice was fluctuating; for the word is
used by him sometimes to mean the ventricular mass only, sometimes,
as in the science of to-day, to mean the ventricular mass and the
auricles taken together.

According to the more detailed views of Galen and his school the
blood was perfected and had its central source not in the heart,
but in the liver, to which the portal vein brought a cruder liquid
derived from the products of digestion. In the liver the veins
also originated, while the arteries originated at the heart. The
blood left its source in the liver, by way of the roots of the
venous system, that is, by the hepatic veins of modern anatomy.
From these it entered the great venous trunk, the vena cava, a
vessel which comprised the inferior cava, the right auricle, and
the superior cava of our present nomenclature. Upon leaving the
liver the blood at once divided into two sharply diverging streams,
one flowing directly downward through the vena cava, the belly, and
the lower extremities; the other stream flowing directly upward
through the vena cava to the chest, the upper extremities, and the
head. Therefore, that part of the vena cava which we call the right
auricle simply formed a part of the upward pathway of the blood, at
a place where some of the blood left this upward pathway and flowed
through a side opening into the right ventricle. This ventricle,
therefore, received only a fraction of that portion of the blood
which ascended from the liver. The rest of the ascending blood
mounted in the vena cava past the right opening which led into the
ventricle and, having traversed thus what we call the right auricle,
entered and traversed what we call the superior vena cava, to be
distributed to the veins and tissues of the arms and head. Of the
fraction of the blood that entered the right ventricle a part went
to the lungs simply for their nutrition, by the "arterial vein"--the
pulmonary artery of modern parlance--and a part percolated in
a refined condition through pores of the septum from the right
ventricle to the left, to be worked up there with the vital spirits
and thus become the basis of the spirituous blood of the arteries.
From the left ventricle this spirituous blood went to the body
at large by way of the arteries. There is no evidence that Galen
believed any blood to pass from the right to the left ventricle
otherwise than through the pores of the septum. As he says, however,
that the branches of the "venous artery" (our pulmonary vein)
"transmit thin and pure and vaporous blood in abundance" to the
lungs for their nutrition,[145] we may infer that he held this
supply to be derived from the left ventricle like that of the rest
of the body. This was possible, according to Galen's system, because
he held to the irrational opinion that what is now called the mitral
valve closed less perfectly than the other valves, inasmuch as it
possessed only two segments instead of three.

This supposed imperfection of the mitral valve played an important
part in Galen's system, for it was possible thereby for the lung to
receive, not only some spirituous blood from the left ventricle of
the heart, but also, and especially, the injurious fumes which Galen
held to arise from combustion in the left ventricle, to escape into
the venous artery past the imperfect mitral valve, and to be exhaled
in expiration. When this valvular door was open, therefore, the left
ventricle drew from the lungs into itself crude spirits, these to
be returned in some part perhaps to the lungs as spirituous blood
in company with the deleterious fumes, when the valvular door was
only ajar. This imperfection of the valve of two segments, however,
was but a constant and fortunate exaggeration of a condition shared
to a slight degree by all the valves; for Galen held these, in the
act of closing, to allow slight regurgitation of spirits, vapor, or
even of blood; and to do so exceptionally even when closed, if the
movement of the heart were of unusual force. He commonly, however,
assumed the tricuspid, pulmonary, and aortic valves to be competent,
especially if he could gain a polemical point by doing so.[146]

More than thirteen centuries later Columbus, as we have learned,
announced that blood from the right ventricle entered the left
ventricle, not by pores of the septum, but exclusively by pores of
the lungs, in passing through which latter it became spirituous
blood, needing but little elaboration in the ventricle before
entering the arteries for distribution to the body. Columbus denied
and derided the passage of fumes from the left ventricle to the
lungs, while he accepted the ancient doctrine of the cooling effect
of respiration. His view of the meaning of the pulmonary transit is
therefore a striking approximation to the truth--a closer one than
that of Harvey, who questioned everything except the fumes given off
in expiration, which fumes, of course, Harvey did not send along the
Galenic path. As Columbus declared the spirituous blood to be made
up in the lungs, and these, therefore, to need no supply thereof
from the left ventricle; and as he also denied the passage of fumes
through the venous artery; the flow through the latter became
simplified, spirituous blood alone passing through it, and in the
true direction from the lungs to the heart. Accordingly the mitral
valve also was cured of its Galenic imperfection; to the latter
Columbus does not even refer, but he simply describes all the four
valves as competent.

Columbus, therefore, set forth the true course, and in no small
degree the true nature and meaning, of the movement whereby blood
passes from the right auriculo-ventricular ring to the aorta, and
in so doing he expelled important errors from the Galenic system.
But, strange to say, by thus purging it he greatly strengthened
it, as was mentioned earlier in this paper, for he harmonized
the fundamental doctrine of the Galenic system with the true
mechanism and working of the cardiac valves, and with a rational
theory of respiration.[147] This fundamental Galenic doctrine was
the direct distribution of blood to the tissues through the veins
from the liver as a center; no more than a fraction of the blood
ever passing the tricuspid valve to reach the lungs or to enter the
arteries as spirituous blood. Of this doctrine Columbus was not
only an adherent, but a warm partisan against the Aristotelians;
and, like Galen more than thirteen centuries before, Columbus
points with emphasis to the tricuspid valve as evidence of the
falsity of the Aristotelian doctrine that crude blood enters the
heart to be perfected and returned thence to the vena cava for
distribution.[148] The Galenic view that the liver is the origin of
the veins and the source of the blood, by which word, unqualified,
was meant the venous blood, was known even down to Harvey's day
as the view of "the physicians," as opposed to that of "the
philosophers," who contended in ingenious ways for the view of the
great philosopher Aristotle that the heart is the origin of the
veins and the source of the blood. Harvey in this contest repeatedly
ranges himself in his writings with the Aristotelians and against
the Galenists;[149] we shall see him bring the circulation into play
to give very effective aid to the former against Galen himself.

Bearing in mind the Galenic meaning of the word "blood," and
remembering that, in spite of the weak points in Galen's own armor,
he possessed in the tricuspid valve a formidable weapon against
the followers of Aristotle, listen to the following passage from
Harvey's treatise of 1628. He says:--

     "Whether or no the heart imparts anything more to the blood
     than transposition, locomotion, and distribution, whether it
     imparts heat also, or spirits, or perfection, must be looked
     into later and gathered from other observations. For the present
     be it enough to have shown sufficiently that during the beat of
     the heart the blood is transfused and withdrawn from the veins
     into the arteries through the ventricles of the heart, and is
     distributed to the body at large.

     "This, to be sure, is conceded by all after a fashion, it being
     gathered from the structure of the heart and the arrangement,
     position, and use of the valves. But they seem to waver blindly
     as though in a dark place, and they put together varied,
     incoherent, and more or less contradictory doctrines and,
     indeed, set forth much upon conjecture, as has been shown

     "There seems to me to have been one single principal cause
     of hesitation and error in this matter, viz.: the connection
     between the heart and the lung in man. The disappearance of
     the arterial vein in the lungs having been noted, and likewise
     that of the venous artery, great obscurity prevailed as to
     whence or how the right ventricle distributed the blood to the
     body, or the left ventricle drew blood from the vena cava. This
     is attested by the words of Galen when he inveighs against
     Erasistratus regarding the origin and use of the veins and the
     coction of the blood. 'You will answer,' Galen says, 'that the
     way of it is this: that the blood is prepared beforehand in the
     liver and is transferred thence to the heart to receive the rest
     of its proper character in complete perfection. Surely this does
     not seem devoid of reason; for no great and perfect work can
     be accomplished suddenly at one attempt and receive its entire
     polish from a single instrument. If then this be so, show us
     another vessel which leads the completely perfected blood forth
     from the heart, and distributes it to the whole body as the
     artery does the spirits.'[150] Behold Galen disapproving and
     putting aside a reasonable opinion because, besides not seeing
     the path of transit,[151] he cannot find a vessel to distribute
     the blood from the heart to the whole body!

     "But had there been anyone on the spot to take the part of
     Erasistratus or of that opinion which is now our own and is
     confessed by Galen himself to be reasonable in other respects;
     and had the person aforesaid pointed his finger at the great
     artery [aorta] as the distributer of the blood from the heart
     to the body at large,--I wonder what answer that divine man
     would have made, full of genius and of learning as he was! Had
     he said that the artery distributed spirits and not blood, he
     certainly would sufficiently have refuted Erasistratus, who
     believed that only spirits were contained in the arteries; but
     in so doing Galen would have contradicted himself and would
     shamefully have denied what he sharply contends to be true in a
     special book[152] which he wrote against that same Erasistratus.
     For he proves by many powerful arguments, and demonstrates by
     experiments, that blood, and not spirits, is naturally contained
     in the arteries.

     "But since the divine man concedes, as he often does in that
     same place, 'that all the arteries of the body arise from the
     great artery, and this from the heart; and that for a certainty
     blood is naturally contained and borne onward in all of them,'
     he maintaining 'that the three sigmoid valves placed at the
     orifice of the aorta forbid the return of blood into the heart,
     and that nature would never have set these valves in apposition
     to the most preëminent of the viscera were the valves not to do
     it some most important service;'--since, I say, the father of
     physicians concedes all this and in these very words, as he does
     in the book aforesaid, I do not see how he can deny that the
     great artery is the vessel adapted to distribute the blood, now
     arrived at complete perfection, from the heart to the body at

Thus does the great English discoverer bring the pulmonary transit
and the circulation of the blood to the rescue of the Aristotelian
heart, despite Galen and the tricuspid valve! Between Harvey and
the school that refused to the heart more than a fraction of the
blood, there could be no peace. It is the Galenists whose system
he attacked and shattered so thoroughly; and those who long and
bitterly opposed the acceptance of the Harveian circulation were of
the Galenic school. In a private letter written twenty-three years
after the publication of his discovery, Harvey excuses the French
physician Riolanus for having slighted the circulation not long
before, saying, among other things:--

     "It was proper that the dean of the College of Paris should keep
     the medicine of Galen in repair; and should admit no novelties
     into his school without the utmost winnowing."[154]



We have found the discoverer of the circulation an admirer and
defender of Aristotle; but we shall leave him far less Aristotelian
than we found him. Before he died, he had transferred to the blood
itself that physiological primacy which Aristotle had given to the
heart; Harvey having come to regard the blood even as the very seat
of the soul, harking back to a Greek doctrine older than Aristotle
and expressly discountenanced by him.[155] This final view of Harvey
was not simply an outcome of his old age, though he develops and
formally declares and insists upon the doctrine of the primacy
of the blood in the writings which he published when beyond the
age of seventy, more than twenty years after the publication of
his treatise of 1628. We have seen that in this his most famous
work he adheres impressively to the Aristotelian doctrine of the
primacy of the heart; though even this work contains utterances
of Harvey which do not well accord with that doctrine. More than
eleven years earlier, when making notes for his lectures of 1616,
he asked himself in striking terms, whether the circulation do not
exist in order that the blood may be heated by the heart.[156]
Yet there are passages in those very same notes which show that,
beside vaguer conjectures,[157] the doctrine of the primacy of the
blood was present clearly to Harvey's mind even so early as in
his thirty-seventh year. In his lecture notes four passages are
especially significant as to this doctrine. Of these the first is as

     "Yf I could shew what I hav seene, y^t weare att an end between
     physicians et philosophers."

After these words in English Harvey falls into his usual Latin,
which may be translated thus:--

     "For the blood is rather the author of the viscera than they of
     it, because the blood is present before the viscera, nor yet
     coming from the mother,[158] for in the egg there is a drop. The
     soul[159] is in the blood."[160]

In a second passage of his note-book Harvey says, speaking of the

     "It is most exceeding full of contained blood, as no other
     viscus is. Wherefore Aristotle [holds] against the physicians
     that the origin of the blood is not in the liver but in the
     heart, because in the liver there is no blood outside the veins.
     Rather is the blood the origin of both, as I have seen."[161]

In a third passage Harvey says of the heart that its

     "temperature is exceeding hot, inasmuch as it is exceeding full
     of blood."[162]

In a fourth passage of the lecture notes which bears upon the
primacy of the blood we may read:--

     "1. [The heart] is the most principal part of all, not because
     of itself,[163] for its flesh is more fibrous and harder and
     colder than the liver, but because of the abundance of blood and
     spirits in the ventricles.

     "1. Whence the fount of the entire heat.

       *       *       *       *       *

     "Whence the auricles pulsate, after removal of the heart,
     because of the multitudinous blood.[164]

     "2. Nor is [the heart] the principal part because of its origin:
     for I believe that the ventricles (which in the fœtus are
     both united as in fishes) are made out of a drop of blood which
     is in the egg; and that the heart, together with the rest [of
     the parts] all sprout[165] simultaneously, as [occurs] in an
     ear of corn, from an imperceptible size. Is there only a drop
     of blood in the auricles whence bestowing heat upon all parts,
     receiving from none, it is the citadel and domicile of the heat,
     the household shrine[166] of that edifice, fowntayn conduit

More than eleven years after the making of his lecture notes Harvey,
at the age of fifty, published his treatise of 1628; and later,
after keeping silence for more than twenty years, he published
together the two Exercises addressed to Riolanus. During these
twenty years and more the blood must have been rising and the heart
declining, in Harvey's esteem, as ruling powers in the body; for at
the end of that time more than thirty-two years after the jotting
down of the statements and varied conjectures of his lecture notes,
he formally throws over Aristotle's primacy of the heart, in a
passage near the close of the second Exercise to Riolanus. Of this
passage the following is a part. Referring to certain opinions,
mainly Aristotelian, regarding the heart and blood, Harvey says:--

     "To speak openly, I do not believe that those things are so in
     the sense commonly received; and my opinion is inclined in the
     direction aforesaid by much which is visible in the generation
     of the parts, but which is not convenient to set down here.
     Soon, perhaps, I shall make public things even more wonderful
     and destined to cast even greater light upon natural philosophy.

     "For the present I will only say and set forth without
     demonstration--by good leave of the learned and with due respect
     to the ancients--that the heart, as the beginning, author,
     source, and origin of everything in the body and the first
     cause of life, should be held to include the veins and all
     the arteries and also the contained blood; just as the brain,
     including all its nerves and sensory organs and spinal marrow,
     is the one adequate organ of sensation, as the phrase is. If by
     the word 'heart,' however, only the body of the heart be meant
     with its ventricles and auricles, I do not believe that it is
     the manufacturer of the blood; nor that the blood possesses
     vigor, faculty, reason,[168] motion, or heat, as the gift of the

In the second year after that of the Exercises to Riolanus Harvey's
final publication, his treatise On Generation with appended essays,
was given to the world, not long before his seventy-third birthday.
During how many years this work had been in preparation we do not
know; but it is avowedly based upon the views of Aristotle, whom
Harvey styles his "_dux_"--his leader--as regards the subject
of this treatise.[170] In it, to be sure, the ancient master is
often weighed in the balance and found wanting by Harvey, who even
questions whether Aristotle had seen for himself what he "narrates
as to the generation of the chick," or "had accepted it from some
expert."[171] Nevertheless, it is with the doctrines of Aristotle
that Harvey incessantly compares the results of observation. Here
the veteran records anew his denial of the Aristotelian primacy of
the heart, and records as well his final emphatic assertion of the
primacy of the blood. In regard to these matters it is interesting
to note the various grades of expression which appear to mirror in
this single work the various phases of Harvey's thought.

In the following florid passage doubt of the primacy of the heart
seems hardly even hinted at. Harvey says:--

     "Certain of the parts themselves are said to be generative, such
     as the heart, from which Aristotle declares that the rest of the
     parts derive their origin; as is also clear from the history
     which I have given. The heart, I say--or at least its first
     beginning, to wit, the vesicle and leaping point--constructs the
     rest of the body to be its future abode; enters this when once
     built up, and hides in it, vivifies and governs it; fortifies it
     with ribs and sternum super-imposed as a bulwark; and is a kind
     of household shrine, as it were, the first seat of the soul, the
     first receptacle and perennial soul-endowed[172] hearth of the
     innate heat, the source and origin of all the faculties, and
     their sole relief in calamity."[173]

Divergence from Aristotle in the matter of the heart is plainly
marked, however, in the following passage of the same treatise,
where Harvey says:--

     "We find the blood formed before anything else in the egg and
     in the product of conception;[174] and almost at the same time
     the receptacles of the blood, the veins and the pulsating
     vesicle, become plainly visible. Wherefore, if the leaping point
     together with the veins and blood, which are all conspicuous
     as one single organ at the first beginning of the embryo, be
     accepted as the heart (the parenchyma of which is superadded
     to the vesicle later in the formation of the embryo), it is
     manifest that, accepted in this sense, that is, as an organ
     composed of parenchyma, ventricles, auricles, and blood, the
     heart in animals is in very truth, as Aristotle would have it,
     the principal and first generated part of the body; of which
     part, however, the first and foremost part is the blood, both by
     nature and in the order of generation."[175]

In the following third passage of the same treatise no reconciling
interpretations of the master's words are to be found; flat
disagreement with Aristotle is declared; and the "Sun of the
Microcosm"[176] declines nearly to its simple modern status of a
living pump! Harvey says:--

     "Nor can I agree with Aristotle himself, who maintained that
     the heart is the primary generative part and that it is endowed
     with soul; for, truly, I believe the blood alone to be entitled
     to these distinctions, since the blood it is which first appears
     in generation; and that such is the case not only in the egg but
     also in every fœtus and very early animal embryo, shall at
     once be made plain.[177]

     "At the beginning, I say, there appear the red leaping point,
     the pulsating vesicle, and filaments, derived thence, which
     contain blood in their interior. And, so far as can be discerned
     by accurate inspection, the blood is made before the leaping
     point is formed, and the blood is endowed with vital heat before
     it is set in motion by pulsation; and, further, as pulsation
     is begun in and by the blood, so at last it ends in the blood
     at the final instant of death. Indeed, by numerous experiments
     done upon the egg and otherwise I have made sure that it is
     the blood in which the power of returning to life persists, so
     long as the vital heat has not wholly vanished. And since the
     pulsating vesicle and the sanguineous filaments derived from it
     are seen before anything else, it stands to reason in my belief
     that the blood is prior to its receptacles--the contained, that
     is, to its container--since the latter is made for the use of
     the former. Therefore, it is probable that the filaments and
     the veins and then the vesicle and at length the heart, having
     organs destined to receive and retain the blood, are made for
     the sole purpose of transmitting and distributing it, and that
     the blood is the principal part of the body....

     "Therefore, relying with certainty upon what I have observed
     in the egg and in the dissection of living animals, I maintain
     against Aristotle that the blood is the primary generative
     part; and that the heart is its organ, destined to send it on
     a circuit. Surely the function of the heart is the propulsion
     of the blood, as is admirably clear in all animals that have
     blood; and in the generation of the chick the same duty falls
     to the pulsating vesicle, which in the very early embryos of
     animals[178] no less than in the egg I have often exhibited to
     view as something more minute than a spark, beating and when in
     action contracting itself and at the same time pressing out the
     blood contained in it, and in its relaxation receiving the same

Whether in studying the foregoing passages we read Harvey's earlier
jottings in his private note-book or the deliberate statements
published in his old age, it is evident that to his mind the
question of the primacy of the blood versus the primacy of the
heart depends for answer upon the further question whether in the
development of the embryo the blood be made before the heart, or
the heart before the blood. In no other part than one of these two
can the primacy inhere, for him; and whichever of these two has the
priority must be, to Harvey's mind, the origin of the other and of
the remaining parts and must continue to be the "principal part" of
the body throughout life. The matter of the primacy thus resolves
itself into one of well-devised and accurate observation; and the
discoverer is once more upon the ground where his undying laurels
grew. He, therefore, deals no longer "without demonstration," as
in the second Exercise to Riolanus, but makes report of actual
observations and so gives ocular evidence in support of his views,
remembering, it may be, that he had said to Riolanus: "Soon,
perhaps, I shall make public things even more wonderful and destined
to cast even greater light on natural philosophy."[180] Harvey's
contemporary Milton said to Parliament: "Truth is compar'd in
Scripture to a streaming fountain; if her waters flow not in a
perpetuall progression, they sick'n into a muddy pool of conformity
and tradition."[181] These words seem timely as we note the great
discoverer, magnifying glass in hand, searching in incubated eggs
for an answer to the question, now wholly obsolete, whether the
primacy of the heart should not give way to the primacy of the blood.

     "Surely," says Harvey, "this investigation is one of great
     moment, to wit: whether or no the blood be present before the
     pulse; and is the point[182] derived from the veins or the
     veins from the point? So far as I have been able to observe,
     the blood appears to exist before the pulse; and I will show
     cause for this opinion as follows: On a Wednesday evening I put
     three eggs under a hen; and having come back on the Saturday, a
     little before the same hour, I found these eggs cold as though
     deserted by the hen. I opened one of them, nevertheless, and
     came upon the beginning of a chick, namely, a red sanguineous
     line at the circumference,[183] but at the centre instead of
     the leaping point a point which was white and bloodless. By
     this sign I perceived that the hen had left off sitting not
     long before. So I caught her, shut her up in a box, and kept
     her there the entire night; that is, after I had put under her
     the two remaining eggs together with other fresh ones. What was
     the result? Next day in the very early morning both eggs had
     revived; and at the centre the beating point itself was visible,
     much smaller than the white point; out of which, that is, out of
     the white one, it made its appearance in diastole only, like a
     spark leaping forth from a cloud: so that the red point seemed
     to me to flash out of the white point; the leaping point being
     generated in the latter, in one way or another; and the blood
     to be already in existence, when the leaping point is brought
     into existence or at least into motion. Indeed, I have very
     often found that even when the leaping point lies still and
     devoid of all motion as though quite dead, it recovers motion
     and pulsation again if warmed afresh. From the foregoing I
     judge that in the order of generation the point and the blood
     come into existence first; but that pulsation does not come on
     till afterward. Certainly this is settled, viz.: that of the
     future embryo nothing at all appears on this day[184] except the
     sanguineous lines and the leaping point and also those veins
     which grow all from one trunk (as this grows from the leaping
     point) and are dispersed throughout the entire colliquative[185]
     region in very many ramified filaments....

     "Toward the end of the fourth day and the beginning of the fifth
     the sanguineous point is already increased in size and is seen
     to be turned into a small and very delicate vesicle containing
     blood within itself; which blood it drives out at every
     contraction, and receives afresh when its diastole takes place.

     "Up to this stage I have found it impossible to discriminate
     between the vessels; for the arteries are not to be
     distinguished from the veins either by their coats or by
     the pulse; and so I think it best to style all the vessels,
     indiscriminately, veins or, with Aristotle,[186] venous

     "On the sixth day ... the parenchyma of the heart grows on to
     the pulsating vesicle; and shortly afterward the rudiments of
     the liver and of the lungs are discernible."[188]

It is clear that Harvey's hens did not very often take such
well-timed steps against Aristotle; for in another passage of his
treatise on generation, in summing up its events and their order,
he frankly states the difficulties which render uncertain the
question of priority between the blood and the heart. He speaks of
"the first generated and generative part; that is to say, the blood
together with its receptacles or, if you prefer, the heart with its
veins."[189] A few lines further on he says:--

     "In the generation of this first part (which is accomplished
     in the egg on the fourth day) although I have not been able to
     observe any order, because all portions of the part aforesaid
     (namely, the blood, the veins and the pulsating vesicle) appear
     at the same time; nevertheless, my belief would be, as I have
     said, that the blood is present before the pulse; and that,
     therefore, in obedience to a law of nature the blood is prior to
     its receptacles, that is, to the veins."[190]

In Harvey's first publication, of 1628, we have read:--

     "If you turn to the formation of the chick in the egg, the first
     thing to exist therein, as I have said, is a mere vesicle, or
     auricle, or pulsating drop of blood. Afterward, when growth has
     gone on, the heart is completed."[191]

In his last publication, of 1651, we have read:--

     "So far as can be discerned by accurate inspection, the blood
     is made before the leaping point is formed, and the blood
     is endowed with vital heat before it is set in motion by
     pulsation; and further, as pulsation is begun in and by the
     blood, so at last it ends in the blood at the final instant of

Harvey's own words in the foregoing two passages effectively sum up
both the nature of his doctrine that the blood is the first part of
the body to live, and the nature of his evidence. But the words of
the second passage foreshadow a closely related doctrine, advanced
and held by him on the evidence of observation, viz.: that the
blood, being the first part to live, is also the last part of the
body to die. That the first part to live is always the last to die,
is a doctrine set forth by Aristotle. This, Harvey seems to accept
without question and to apply upon proper evidence to the blood; as
he accepts and warmly upholds the ancient master's doctrine that
there is a primacy of the body. The results of observation have
forced Harvey to transfer this primacy from the heart to the blood,
but it is the Aristotelian primacy still. Presently he shall show us
that the blood is not only the first part to live, but the last to
die. Before he does so, however, let Aristotle speak for himself,
saying briefly:--

     "The point[193] of origin [of the rest of the body] is the
     first thing generated. The point of origin in the animals which
     possess blood is the heart; in the rest, the analogue thereof,
     as I have often said. Moreover, the fact that the heart is the
     first thing generated is evident, not only to the senses, but
     from its death.[194] For therein life ceases the last; and in
     all cases the last generated is the first to make an end, the
     first generated, the last to make an end; nature, as it were,
     doubling back and returning upon her point of origin whence
     she came.[195] For generation is the change from not being to
     being; destruction is the reverse change, from being to not

Aristotle does not tell us why "in all cases ... the first
generated" is "the last to make an end," and _vice versa_. Let
it suffice that Harvey accepts this sweeping doctrine. Now let
him complete his evidence in favor of the primacy of the blood by
showing that the blood is not only the first part to live and to
live tenaciously, but the last part to die.

In a passage of the treatise On the Motion of the Heart and Blood,
we have already read Harvey's promise to publish observations

     "on the formation of the fœtus, where numerous problems of
     the following order can find a place: Why should this part be
     made or perfected earlier, that later? As regards the dominance
     of the members: Which part is the cause of the other? There are
     very many problems connected with the heart, such as: Why should
     it be the first thing (as Aristotle says in his third book On
     the Parts of Animals)[127] to acquire consistency, and be seen
     possessed of life, motion, and sensation, before anything has
     been perfected in the rest of the body? And in like manner
     regarding the blood: Why is it before all, and how possessed
     of the beginnings[128] of life and of the animal, and of the
     craving to move and be impelled hither and thither, to which end
     the heart would seem to have been made?"[129]

That Harvey should have printed this passage in 1628, in the same
work with his repeated eulogies of the Aristotelian heart, shows
that the idea of the possible primacy of the blood must have been
in his mind early. It was, indeed, so from the jotting down of
his private notes of 1616, to the publication of the Exercises to
Riolanus in 1649 and the treatise On Generation in 1651. The same
mental attitude is revealed, perhaps more strongly, in the following
passage of an earlier chapter of Harvey's treatise of 1628. Here
we come upon the thought that it may be the blood, and neither
ventricle nor auricle, which is the last to die. Harvey says:--

     "Besides this, however, I have occasionally observed, after
     the heart and even its right auricle[197] had ceased their
     pulsations as though in the act of dying, that an obscure
     motion and flow and a sort of palpitation manifestly remained
     in the blood itself contained in the right auricle, so long,
     that is, as the blood appeared to be imbued with heat and
     spirits. Something of the sort is very plainly to be seen at
     the beginning of the generation of an animal, in the hen's egg
     within the first seven days of incubation. There is present,
     first and before all else, a drop of blood which palpitates (as
     Aristotle also noted); from which, when growth has taken place
     and the chick has been formed to some extent, the auricles of
     the heart are made; and in these, which pulsate perpetually,
     life inheres....

     "Whoever, therefore, shall choose to investigate more closely
     will say that the heart is not the first to live and the last to
     die, but that the auricles, and the part which answers thereto
     in serpents, fishes, and such animals, are alive sooner than the
     heart itself and also die later than the heart. Whether even
     earlier the blood itself, or the spirit, have not an obscure
     palpitation of its own, which it has seemed to me to retain
     after death, may well be questioned; and whether we should not
     speak of life as beginning with palpitation."[198]

It is plain that fibrillar contractions of cardiac muscle misled
Harvey into thinking and writing of "an obscure motion and flow,"
of "an obscure palpitation," of the blood itself within the dying
auricle. It is plain that when he wrote his most famous treatise he
was loath, even under Aristotle's leadership, to reach out so far
beyond the evidence of the senses as to attribute the palpitation
of the visible drop of blood in the very early embryo to anything
but the hot blood itself. Later, in his treatise On Generation,
he published a passage which in some ways runs parallel with the
foregoing. In the earlier passage the results of observation are
brought forward as food for thought; in the later one, as proofs of
a theory, fully, clearly, and emphatically stated by a thinker who
is near the end of life and is imparting his final judgment. This
later passage is as follows:--

     "In whatsoever part of the body heat and motion have their
     beginning, in that same part life also first arises and therein
     is extinguished last; nor may it be doubted that there, too,
     life has its innermost home, that there the soul itself has
     fixed its seat.

     "The life then inheres in the blood (as we read also in Holy
     Writ[199]), because therein the life and the soul are manifest
     first and fail last. For, as I have said, in the dissection of
     living animals I have found repeatedly that, though the animal
     be dying and breathe no longer, nevertheless, the heart pulsates
     for some time and keeps the life in it. Moreover, when the heart
     is quieted you may see movement surviving in the auricles, and
     latest in the right auricle; and at length all pulsation ceasing
     there, you may find in the blood itself a kind of undulation and
     obscure agitation or palpitation, the last indication of life.
     And anyone can perceive that the blood retains in itself to the
     last the heat which is the author of pulsation and life; if this
     heat is once wholly extinguished and the blood now is blood
     no more, but cruor, so there is left no hope of a return to
     life again. Nevertheless, after all pulsation has disappeared,
     both in the egg, as I have said, and in dying animals, if you
     will make a gentle warm application, in the former case to the
     leaping point, in the latter to the right auricle of the heart,
     you shall see movement, pulsation, and life, renewed immediately
     by the blood; provided it have not utterly lost all its innate
     heat and vital spirits."[200]

How readily heat from without can revive the cool leaping point, is
strikingly set forth by Harvey in another chapter of this treatise
On Generation. He says:--

     "Moreover, if an egg be exposed too long to a colder atmosphere,
     its leaping point pulsates less often and stirs more languidly;
     but if a warm finger be applied to it, or any other bland source
     of warmth, straightway it recovers strength and vigor. Indeed,
     when such a point has become gradually weak and though full of
     blood ceases to move at all and gives no sign of life, seeming
     utterly to have succumbed to death, if my lukewarm finger be
     placed over it for the space of twenty pulsations of my artery,
     behold! the little heart revives once more, becomes erect, and
     renews its pristine dance as though come back from Hades. This
     I myself and others, too, have brought about again and again by
     means of gentle warmth of any kind, such as that of a fire or of
     tepid water; thus at our pleasure being able to give over the
     poor little soul to death, or call it back to the light."[201]

As in the embryo the leaping point may be revived by external
warmth, so may the heart in the full-grown bird. In his treatise of
1628 Harvey says:--

     "In the pigeon, at any rate, at an actual experiment, after the
     heart had wholly ceased to move and even the auricles had left
     off moving, I placed my finger, wetted with saliva and warm,
     upon the heart and kept it there for a while; as the result of
     which fomentation the heart, as though restored to strength and
     life again, and its auricles with it, were seen to move and
     contract and relax themselves and, as it were, to be recalled
     from death."[202]

In his treatise On Generation, Harvey confirms the doctrine of the
primacy of the blood by citing observations made upon sluggish or
hibernating animals and also certain morbid phenomena in man, as

     "This, too, clearly follows from many observations; especially
     the cases of certain animals which possess blood yet live a long
     time without a pulse; and of some which lie hidden the whole
     winter and, nevertheless, continue alive, although meanwhile all
     movement of the heart has ceased and their lungs enjoy a rest
     from breathing, like people who lie half dead and pulseless in
     syncope or faintness or hysterical affections."[203]

So Harvey convinced himself, by observation, that the first part of
the developing embryo to appear is the blood of the "sanguineous
lines"; after this the blood which seems to palpitate of itself at
the leaping point, which later develops into a pulsating vesicle
wherein blood is contained within a contractile wall; to this being
superadded still later the contractile parenchyma of the heart.
Also, by observation, he convinced himself that in a dying animal
the blood within the right auricle may palpitate of itself after the
palpitations due to contractions of the auricular wall have ceased.
Thus was Harvey led to believe that the blood and not the heart is
the first part to live and the last to die, the principal part of
the body, the generator of the heart and of all the rest. In spite
of his appeal to observation, his impressive primacy of the blood is
now as completely forgotten in its turn as is Aristotle's impressive
primacy of the heart, which Harvey felt called upon to supersede.
Naturally in this matter the great discoverer used true methods of
investigation; and doubtless his imperfect conclusions were due in
large part to the weakness of his magnifying glasses and to the
deficient technique of his day. Harvey said of himself, speaking
generally, that he trusted much to the plain use of his senses.[204]
That he did so, was well for him and for all mankind; yet because of
this very trust he did not always escape the pitfalls dug by what we
now call "naked-eye" appearances.



The primacy of the blood was no isolated fact for Harvey, but one
linked with the very existence of the circulation. This primacy
depended largely upon the blood being the primal abode of the innate
heat. Palpitation produced by the innate heat in the blood itself,
he held to be the first sign of life in the embryo and the last sign
of life in the dying creature; and a swelling produced by the innate
heat, he held to take place throughout life, localized in the blood
just outside of the entrance to the heart. This local swelling of
the blood was, to him, the exciting cause of the heart-beat and,
therefore, of the circulation. We have heard him deny that the
blood possesses motion "as the gift of the heart."[205] We can now
grasp the probable meaning of this denial. He would not have been
illogical had he said also that the heart possesses motion as the
gift of the blood. This view of the cause of the heart-beat was
first set forth by Harvey in 1649 in the Exercises to Riolanus,
and in immediate connection with declarations in favor of the
primacy of the blood, which also was first formally advocated in
those Exercises. As we know, the question of this primacy had given
Harvey food for thought long before. But his view of the cause of
the heart-beat is not to be found in his lecture notes, nor in the
treatise of 1628, and may well have been a later outgrowth from the
larger doctrine of the primacy of the blood.

Let us now turn to the Exercises and to Harvey's own account of the
cause of the heart-beat. The first passage to be quoted begins with
a few sentences which have been introduced previously, but which
form a necessary cue for the statement we are to study. Harvey says
to Riolanus:--

     "For the present I will only say and set forth without
     demonstration--by good leave of the learned and with due respect
     to the ancients--that the heart, as the beginning, author,
     source, and origin of everything in the body and the first
     cause of life, should be held to include the veins and all
     the arteries and also the contained blood; just as the brain,
     including all its nerves and sensory organs and spinal marrow,
     is the one adequate organ of sensation, as the phrase is. If by
     the word 'heart,' however, only the body of the heart be meant
     with its ventricles and auricles, I do not believe that it is
     the manufacturer of the blood; nor that the blood possesses
     vigor, faculty, reason,[168] motion, or heat, as the gift of the
     heart. Moreover, I judge the cause of diastole and expansion not
     to be the same as that of systole and contraction, either in the
     arteries, or in the auricles or the ventricles of the heart;
     but that part of the pulse which is called diastole has another
     cause, different from the systole, and always and everywhere
     must precede every systole; I judge the first cause of expansion
     to be the innate heat and expansion to occur first in the
     blood itself, gradually thinned and swelling up like matters
     in fermentation, and to be extinguished last in the same; and
     I accept Aristotle's parallel with pottage or milk with this
     proviso, that the rising or falling of the blood is not brought
     about by vapors, or exhalations, or spirits, excited into some
     vaporous or aërial form, and is caused, not by an external
     agent, but by an internal principle, and is regulated by nature.

     "Nor is the heart (like a hot kettle), as some imagine, the
     origin of the heat and of the blood in the same sense as a hot
     coal or a fire-place. The blood rather imparts heat to the
     heart, as to all other parts, than receives heat from it, for
     the blood is, of all things within the body, the hottest; and
     so the heart is provided with coronary arteries and veins for
     the same purpose as that of the arteries and veins of other
     parts, viz.: to secure an influx of heat which shall foster and
     preserve. Hence it is to use convertible terms to say that all
     the hotter parts contain more blood and that the richer they
     are in blood, the hotter they are. It is in this sense that the
     heart, so remarkable for its cavities, should be reckoned a
     workshop, source, perpetual fire-place; it is like a hot kettle
     by virtue, not of its body, but of its contained blood, in the
     same sense in which the liver, the spleen, the lungs, and other
     parts are reckoned hot; because they contain many veins or
     vessels containing blood. In this way also I maintain that the
     native heat, or innate warmth, being the common instrument of
     all the functions, is likewise the prime efficient cause of the
     pulse. This I do not now assert positively, but only propose as
     a thesis. Whatever may be brought forward to the contrary by
     learned and upright men without scurrilous language, clamor, or
     contumely, I shall be glad to know, and whoever shall do that
     will earn my gratitude."[206]

Harvey has thus transferred to the blood the primacy of the body,
making the blood in place of the Aristotelian heart the primal abode
of the innate heat, "the common instrument of all the functions."
Nevertheless, the blood of the Harveian circulation cannot perform
the duties of the primacy without the aid of Aristotle.

If we turn from the Exercises to the treatise On Generation,
published about two years later, we find the author saying:--

     "The primacy of the blood is evident from this also, that
     the pulse has its origin in the blood. For since a pulsation
     consists of two parts, to wit: an expansion and a contraction,
     or a diastole and systole, and since the prior of these
     movements is the expansion, it is plain that this action is due
     to the blood, but that the contraction is set a-going in the
     egg by the pulsating vesicle, as by the heart in the chick, by
     means of its own fibres as though by an instrument devised for
     that purpose. It is certain also that the aforesaid vesicle
     and, at a later time, the cardiac auricle from which pulsation
     starts, is excited by the blood, which expands to the motion
     which constricts. The diastole, I say, is produced by the blood
     which swells up as if with interior spirits; and so Aristotle's
     opinion as to the heart's pulsation--namely, that it is produced
     after the manner of ebullition--is in some measure true. For the
     same thing which we see every day in milk heated over the fire
     and in the fermentation of our beer, comes into play also in the
     pulsation of the heart, in which the blood swells as from some
     fermentation, is expanded, and subsides; and what is brought
     about in the cases aforesaid by accident and by an external
     agent, to wit, by adventitious heat from somewhere, is effected
     in the blood by the internal heat or innate spirits, and is
     also regulated by the soul in conformity to nature, and is kept
     up for the health of living things. Pulsation, therefore, is
     accomplished by a double agency: that is to say, the expansion
     or dilatation is accomplished by the blood, but the contraction
     or systole is accomplished in the egg by the membrane of the
     vesicle, in the fœtus after birth by the auricles and
     ventricles of the heart; and these alternate and mutually
     associated efforts once begun, the blood is impelled through the
     whole body, and thus the life of animals is perpetuated."[207]

Nearly two thousand years before Harvey's time Aristotle had said:--

     "The volume of leaven[208] changes from small to great,
     by its more solid part becoming liquefied and its liquid,
     vaporized.[209] This is brought about in animals by the nature
     of the psychical heat, but in the case of leaven by the heat of
     the blended juices."[210]

Moreover, Aristotle, as Harvey says, had likened to
"ebullition"[211] what Aristotle himself described as "the pulsation
which occurs at the heart, at which the heart is always to be seen
incessantly at work." "For," says Aristotle, "ebullition takes place
when liquid is vaporized[212] by heat; for it rises up owing to its
bulk becoming greater."[213] He continues:--

     "In the heart the swelling up from heat of the liquid which
     is always arriving from the food produces pulsation, for the
     swelling rises against the outer tunic[214] of the heart; and
     this process is always and incessantly going on, for the liquid
     is always and incessantly flowing in, out of which the nature
     of the blood arises; for the blood is first worked up in the
     heart. The thing is plain in generation from the beginning; for
     before the vessels have been marked out the heart is to be seen
     containing blood. Hence, too, it pulsates more in the young than
     in the old; for the vapor[215] arises more abundantly in the

     "All the vessels also pulsate and do so simultaneously one with
     another, because they are dependent upon the heart.[216] This
     is always moving, so that they, too, are always moving, and
     simultaneously one with another, when[217] the heart moves.
     Leaping [of the heart],[218] then, is the reaction which takes
     place against the condensation produced by cold, and pulsation
     is the vaporization[219] of heated liquid."[220]

In another treatise Aristotle says: "In all animals the blood
pulsates in the vessels everywhere at the same time."[221] It
is interesting, in a negative way, that his sweeping and faulty
references to the pulsation of the vessels put into words no
physiological idea except the vague one of "dependence" on the heart.

One may be tempted to see in the seething of the heart's blood the
source of some of those spirits within the body elsewhere than in
and about the heart, of which one gets brief ill-defined glimpses
here and there in the genuine works of Aristotle. But no words of
his can be adduced to confirm such a conjecture.

Evidently, however, the seething of the nascent blood suffices, in
Aristotle's eyes, to explain both the phases of the heart-beat;
for both the rising and the falling of the wall of the hot central
laboratory of the blood are movements as passive apparently as
those of the lid of a boiling pot. One may be excused for wondering
at the crudity of such a conception; nor is one's wonder lessened by
recalling that elsewhere in Aristotle's works he places at the heart
the central origin of the bodily movements. But when it is recalled,
as well, that Aristotle was totally ignorant of the function of
muscle and, therefore, even of the mode of working of the limbs, his
doctrine of the heart-beat may seem less amazing.

There are indications that the function of muscle, though unknown to
Aristotle, was known not long after his time,[222] and in Galen's
time that function was entirely familiar, he styling the muscles
"the organs of voluntary movement," and calling their contraction
their "systole," a term which has survived only in connection with
the heart and arteries.[223] For Harvey, born more than thirteen
centuries after Galen's death, the function of muscle was a portion
of ancient knowledge; and in his treatise On the Motion of the
Heart and Blood, he expressly states that the heart, including
the auricles, is muscular both in structure and in function. The
opinions of Harvey's day rendered these statements by no means
superfluous.[224] Naturally, therefore, in accepting the aid of the
Aristotelian seething of the blood in connection with the heart-beat
Harvey utilized only the force of expansion thus generated, and
obtained from muscle the force of contraction which he required.
Indeed, the conception of the auricles and ventricles as muscular
force-pumps was fundamental to his doctrine of the circulation.
Moreover, we have found Harvey careful to limit and mitigate the
expansion of the blood, he saying to Riolanus:--

     "I accept Aristotle's parallel with pottage or milk with this
     proviso, that the rising or falling of the blood is not brought
     about by vapors, or exhalations, or spirits, excited into some
     vaporous or aërial form, and is caused, not by an external
     agent, but by an internal principle, and is regulated by

Long before, indeed, he had jotted down a terse statement among
his lecture notes which is fatal to any extreme development of the
Aristotelian idea. In dealing with the action of the heart he had

     "To what end? Aristotle: To none, but a passive process, as in
     boiling pottage. But when wounded it gives out not wind, but

Harvey, therefore, could do no less than criticize adversely his
famous contemporary, the philosopher Descartes, for accepting in
its entirety Aristotle's doctrine of the heart-beat. Referring to
Descartes he says:--

     "Nor in the matter of the pulse am I satisfied with the
     efficient cause thereof which he, following Aristotle, has
     laid down as the same at the systole as at the diastole, to
     wit: an effervescence of the blood like that produced in
     boiling. For the movements aforesaid are sudden strokes and
     swift beats; while in fermentation or ebullition nothing rises
     up and collapses thus, as it were in the twinkling of an eye,
     but there is a slow swelling with a sufficient subsidence. By
     means of dissection, moreover, one can discern for oneself that
     the ventricles of the heart are expanded as well as filled by
     the constriction of the auricles and are increased in size
     proportionately, according as they are filled more or less;
     and that the expansion of the heart is a movement of a certain
     violence, produced by impulsion, not by attraction[227] of some

In a letter written four years after the publication of the
Exercises to Riolanus and two years after that of the treatise On
Generation, Harvey sets forth anew, with admirable clearness and
brevity, his doctrine as to the nature and cause of the systole
of the ventricles. In this he stands upon purely modern ground as
an observer, and his words are free from all Aristotelian tinge.
Referring to another physiologist he says:--

     "I could wish, however, that he had observed this one thing,
     namely, that the motion which the heart enjoys is of a threefold
     kind, to wit: a systole, in which the heart contracts itself
     and drives out the blood contained in it; and then a certain
     relaxation, of a character contrary to the foregoing motion,
     a relaxation in which the fibres of the heart which make for
     motion are slackened. The two motions aforesaid are inherent
     in the very substance of the heart, just as in all other
     muscles. Finally, there takes place a diastole, in which the
     heart is expanded by blood impelled into its ventricles out of
     the auricles; and the heart is incited to its own contraction
     by this filling and expansion of the ventricles; and the
     motion aforesaid always precedes the systole, which follows at

Harvey materially clarifies his doctrine of the nature and cause of
the heart-beat in the following admirable summary. In the second
Exercise to Riolanus he says:--

     "Since I see that many are embarrassed and doubt the
     circulation, and that some attack it, because they have not
     understood me thoroughly; for their sake I will recapitulate
     briefly what I meant to say in my little book on the motion of
     the heart and blood. The blood contained in the veins, where
     its deeps are, as it were, where it is most abundant, that is,
     in the vena cava close to the base of the heart and to the
     right auricle, gradually grows warm and thin by reason of its
     own internal heat, and swells and rises up like matters in
     fermentation; whereby the auricle is dilated, contracts itself
     by reason of its own pulsific faculty, and propels the blood
     promptly and frequently into the right ventricle of the heart.
     This, when filled, frees itself of blood at its succeeding
     systole by the impulsion thereof and, as the tricuspid valve is
     a bar to the egress of the blood, drives it where an open door
     is offered, into the arterial vein, and thereby brings about
     the expansion of the latter. The blood within the arterial
     vessels cannot now go back in opposition to the sigmoid valve,
     while at the same time the lungs are widened and enlarged and
     then narrowed by inspiration and expiration--and with the lungs
     their vessels also--and offer to the blood aforesaid a path and
     transit into the venous artery. The left auricle accomplishes
     its movement, its rhythm, its order [of events], its function,
     at the same time and in the same way as the right auricle,
     and in like manner sends on into the left ventricle out of
     the vessels aforesaid the same blood which the right auricle
     had sent on into the right ventricle. As a result the left
     ventricle, at the same time and in the same way as the right,
     impels the blood into the cavity of the aorta and consequently
     into all the branches of the artery, the return of the blood
     whence it had come being prevented in the same way as before by
     the barrier of an opposing valve. The arteries are filled by
     this sudden impulsion and, as they cannot unload themselves as
     suddenly, are expanded, receive an impulse, and undergo their

Harvey seems to have attributed more importance to the auricular
systoles than do the physiologists of to-day, he making the
ventricles depend very greatly for their charge of blood upon the
systole of the auricles. This view appears in three passages already
quoted; and is tersely put by Harvey when he says elsewhere that
the heart "is dilated by the auricle, contracts of itself";[231]
that "the auricles are prime movers of the blood."[232] The unduly
high value set by him upon the auricular systole agrees well
with the polemical vigor with which Harvey exalted impulsion and
rejected suction,[233] in his general physiology as well as in
the physiology of the heart. In the heart especially the force of
suction had played for centuries a part which Harvey rejected more
completely than the physiologists of to-day feel warranted in doing.
Again he shall speak for himself, saying tersely:--

     "Hence it is made plain how the blood enters the ventricles;
     not by reason of being drawn in, or of the heart expanding, but
     because sent in by the pulse of the auricles."[234]

"The expansion of the heart," he has told us already, "is a movement
of a certain violence, produced by impulsion, not by attraction of
some sort." He says that he maintains these views

     "against the commonly received opinion; because neither the
     heart nor anything else can so expand itself that it can draw
     anything into itself in its diastole, unless as a sponge does
     which has first been forcibly compressed and is returning to its
     natural state."[235]

But, one may ask oneself, how does that modified seething in the
vena cava which produces the diastole of the right auricle produce
the diastole, the simultaneous diastole, of the left auricle? In his
lecture notes Harvey had stated, as Columbus had before him, that
the venous artery does not pulsate--at least, he means, not in the
same sense as the auricle, or ventricle, or artery.[236] Obviously
regarding the left auricle there could be available, for Harvey, no
explanation parallel to that of to-day, viz.: the swift conduction
of a stimulus from point to point of the texture of a wall which is
common to both auricles. He is careful to state that corresponding
auricular events occur simultaneously and in the same way in the
two auricles; and incidentally but frankly he confesses ignorance of
the reasons why, in the following passage:--

     "From those who declare the causes and reasons of all things
     in such a smattering way, I would be glad to learn how it is
     that both eyes move together hither and thither and in every
     direction when they look; how it is that this eye does not turn
     by itself in that direction, that eye in this; likewise, both
     auricles of the heart; and so forth."[237]

The circulation of the blood, then, according to the final view
of its discoverer, is maintained by a self-regulating mechanism
worked by causes operating within the blood itself, the "principal
part" of the body. The systolic muscular contractions of the walls
of the ventricles are caused by direct mechanical stimulation (in
modern language) due to diastolic distension by blood of the relaxed
muscular walls of these chambers. The blood which distends the
ventricles is driven forcibly into them by the auricular systole,
the muscular walls of the auricles having been stimulated to
contract by diastolic distention due likewise to blood.

So much of Harvey's doctrine of the heart-beat, although not that
of to-day, is very effective as physiology, and has advanced with
modern swiftness far beyond that of his predecessors. It seems
strange, therefore, even to one familiar with the movement of the
Renaissance, to be swept back nearly two thousand years under
Harvey's guidance to reach the underlying cause of the phenomena.
According to him the distention which stimulates the right auricle
to contract is produced by an expansion of the blood of the great
veins, due to the innate heat. The Harveian heart-beat is caused
and initiated by an Aristotelian swelling up of the hot blood. Both
this expansion and the fiery central hearth at which it is produced
have been expelled by Harvey from within the fully developed heart;
and the primal abode of the innate heat has been transferred to the
blood, with which that heat has been intimately incorporated by him.
Just without the heart, moreover, Harvey has established anew the
Aristotelian seething; making this the result of what we to-day may
style a localized automatism of the conjoined heat and blood. He
has localized this automatism of the hot blood "in the vena cava,
close to the base of the heart and to the right auricle," _i.e._,
close to that region at and between the mouths of the two venæ cavæ
of our present terminology, where the physiology of to-day places,
not within the blood but in the texture of the walls which contain
it, the seat of what is prepotent in determining the rhythm of the
mammalian heart-beat.

Observation shows that from seemingly pulseless peripheral veins
the blood continuously enters the venæ cavæ, which pulsate visibly
in the region of Harvey's swelling of the blood. Yet in his lecture
notes, in dealing with the significance of the thick resistent walls
of the arterial vein and the aorta, he wrote: "Neither the vena cava
nor the venous artery is of such construction, because they do not
pulsate but, rather, are attracted."[238] On a neighboring page he
had written:--

     "At the same time [that] the pulse of the artery is perceived by
     touch, the vena cava is attracted, as it were."[239]

We will not now search for what he meant by saying that "the vena
cava is attracted, as it were." Clearly, however, in denying that it
pulsates, he meant not to deny that its wall moves rhythmically, but
to deny only that this movement is of the nature of what he styles
pulsation in the case of the auricles or the ventricles, or the
arteries, or the arterial vein.

We know not what influence the rhythmic movements of the wall of
the vena cava may have had upon Harvey's transfer to its cavity of
the Aristotelian seething of the blood. To this was referable the
palpitation seen by him in the blood itself as the first sign of
life in the embryo and the last sign of life in the dying animal;
and in this same familiar seething he found ready to his hand a
life-long cause for the visible sharp expansion of the auricle in
its diastole, for which expansion he could find no such obvious
muscular cause as for the corresponding expansion of the ventricle
or the arteries. The seething of the blood, however, was carefully
kept by him below the point of vaporization and adapted to maintain
the circulation by keeping the muscular cardiac pump at work.

Connected with Harvey's doctrine of the cause of the heart-beat
there is a point which a student of his thought may find knotty,
despite the aid of a well-developed historical sense. Harvey made
the systolic contraction of auricle or ventricle dependent on the
mechanical stimulus of its next preceding diastolic distension.
It is not quite easy to see how he found this process compatible
with the orderly recurrence of all the systolic contractions in the
beating of a nearly empty heart. It is well known that the heart may
beat for a while when cut out of the body, when, therefore, the
heart is nearly drained of blood. In the treatise of 1628 Harvey
himself speaks of studying the ventricular systole of "the heart of
an eel, taken out and laid upon the table or the hand"; and says
that the phenomena seen in this are seen likewise "in the hearts
of little fishes, and in those colder animals in which the heart
is conical or elongated."[240] In his lecture notes he says, we
remember, that "the auricles pulsate after removal of the heart,
because of the multitudinous blood."[241] But this jotting, written
only as a brief reminder for himself, is obscure to others. By the
word "heart" Harvey means sometimes the ventricular mass without the
auricles and sometimes the ventricular mass and the auricles taken
together. Hence it is uncertain whether the above reference be to
auricles left attached to the body or removed with the ventricular
mass. In neither case is it easy to imagine effective distention
produced by the seething even of "the multitudinous blood." However,
in the same lecture notes a few pages farther on Harvey says:
"Nevertheless, the heart pulsates, cut away from the auricles;"[242]
and in the treatise of 1628 he says:--

     "The heart of the eel and of some fishes, and of animals even,
     when taken out, pulsates without auricles; indeed, if you cut
     it in pieces you shall see its divided parts contracting and
     relaxing separately; so that in these creatures the body of the
     heart pulsates and palpitates after the auricles have ceased to
     move. Is this, however, peculiar to the animals which are more
     tenacious of life, whose radical moisture is more glutinous, or
     rich, and sticky,[243] and not so readily dissolved? For in eels
     the thing is apparent even in their flesh, which retains the
     power of motion after they have been skinned, drawn, and cut in

At this point we may recall the following words of our author:--

     "I affirm also that in this way the native heat or innate
     warmth, being the common instrument of all the functions, is
     likewise the prime efficient cause of the pulse."[245]

Should we hazard the improbable guess that Harvey meant his cause
of the heart-beat to be effective only in warm-blooded animals, we
must remind ourselves that it certainly was well known to him as to
all the other physicians of his day that the heart of the mammal
beats after excision. If few had made experiments, all had studied
Galen; and Galen cites the beating of the heart after excision as
evidence that its beat does not depend upon the nervous system, the
context making it obvious that he refers to the heart-beat of the
mammal. Moreover, he makes it evident that the striking phenomenon
in question must have been seen by the ancients at the altar, as
an incident of sacrificial rites.[246] This fact makes it easy
to understand how it happened that earlier still, at least two
centuries before Galen's time, the layman Cicero, one of Harvey's
favorite authors, should have made a stoic say:--

     "It has often been observed that, when the heart of some animal
     has been torn out, it palpitates with a mobility which imitates
     the swiftness of fire."[247]

Moreover, thirty-five years before Harvey was born, even the beating
of the excised human heart had been seen by Vesalius, and referred
to in his celebrated treatise on anatomy, as an incident of one of
the barbarous executions of the sixteenth century.[248]

By no means in accord with the cause of the heart-beat first
advocated by Harvey in 1649, is an experiment which he himself had
brought forward in support of the circulation in 1628. In the famous
treatise of that year he tells us that if the vena cava of a living
snake be compressed at a point some distance away from the heart,
the vein between that point and the heart is nearly emptied by the
heart-beat, and the heart itself becomes paler and shrinks from lack
of blood "and at length beats more languidly."[249] These words show
that in this experiment the orderly heart-beats must have continued
after the blood remaining in the vena cava had become too scanty to
excite them by its expansion in accordance with his doctrine. It
is, therefore, an interesting question how Harvey could reconcile
the beating of the empty heart with his belief as to the "prime
efficient cause" of its beat.



It may seem surprising that the discoverer of the venous return
felt the need of a _deus ex machina_ to distend the right auricle.
On reflection, however, ought it to surprise us that, although we
find the muscular power of the heart sufficient to complete the
Harveian circulation, Harvey himself did not, but eked it out with
Aristotelian forces? Vigorous as Harvey was, he could not make
smooth the road which he himself had broken. For instance, he could
not study, like ourselves, the return of the blood to the heart
in the opened chest of an animal anæsthetized and curarized. The
knowledge gained by his own tireless investigations did not suffice
to teach him what we now know, viz.: that the unaided force of the
systole of the left ventricle is sufficient to distend the right
auricle with blood and to charge with blood the right ventricle as

The essence of Harvey's great discovery is his reversal of the
immemorial direction of the venous flow, which he also proved to
be abundant and rapid. But the laws which rule this flow were not,
and could not be, patent to him as to us, owing to the imperfect
physiological knowledge of his day. Hence at times his statements
as to the movement of the blood are conceived in what, to borrow
an architectural phrase, may be called a "transition style." As a
sequel to his doctrine of the cause of the heart-beat let us pass
in review some of these statements; but, first, let us briefly note
a few facts which may help us to realize the imperfect state of the
science of physics in Harvey's day.

Harvey was fourteen years younger than Galileo, who struck crippling
blows at the Aristotelian physics, yet could not explain the common
pump;[250] and Harvey's discovery of the circulation was made
public thirteen years before the momentous work on the movement
of liquids done by Torricelli, who was thirty years younger than
Harvey.[250] Moreover, it was only a year before the publication of
the Exercises to Riolanus in Harvey's old age that Blaise Pascal
supplied the final proof that the mercurial column below the vacuum
of Torricelli's barometer is really sustained by the pressure of the
atmosphere.[250] It was not till one hundred years after the
publication of Harvey's discovery that the Reverend Stephen
Hales published the first comparative manometric measurements of
the blood-pressure in the arteries and the veins of the same living
animal, and stated in his preface that "the animal fluids move by
Hydraulick and Hydrostatical Laws."[251]

Now let us turn to some delineations of the movement of the blood
made by Harvey himself. I have found no evidence that he knew the
venous flow to be promoted by the aspiration of the chest; but he
knew well the effect of the muscular movements of the body upon that
flow. Of course he had a perfect grasp of the fundamental truth that
the main cause of the venous return is the forcible emptying of the
ventricles into the arteries. He says to Riolanus:--

     "Among these things should be noted the force and violence and
     rapid vehemence which we perceive by touch and sight in the
     heart and greater arteries; and the systole and diastole of
     the pulse in the larger and warmer animals I do not affirm to
     be the same in all the vessels which contain blood, nor in all
     blood-containing animals; but to be such and so ample in all
     that as a result thereof a streaming and an accelerated course
     of the blood through the small arteries, the porosities of
     the parts, and the branches of all the veins are necessarily
     brought about; and as a result thereof a circulation....[252]
     In the case of the arteries, over and above the shock, pulse,
     or vibration of the blood (which is not equally perceptible in
     all), a continual flow and movement thence take place until the
     blood returns to the point whence it started first, namely, the
     right auricle."[253]

[Illustration: The Title-page of William Harvey's _Exercitatio
Anatomica de Motu Cordis et Sanguinis in Animalibus_, Frankfort,

With the calm quantitative account which a reader of Hales'
"Statical Essays" will find given by that clergyman of his
epoch-making physical experiments upon the blood-pressure, it is
interesting to compare the following vivid qualitative recital of
inferences made from surgical observations by his great predecessor.
Harvey says:--

     "Moreover, whoever shall have seen and thought upon the amount
     of difficulty and exertion with which the blood is stanched by
     compression, ligatures, or various appliances, when it leaps
     impetuously out of a petty artery, even the smallest, which
     has been cut or torn in two; and shall have seen or thought
     upon the amount of force with which the blood, as though thrown
     out from a syringe, flings off and drives before it the whole
     of the appliances, or traverses them--that man will hardly
     believe it probable, I think, that any of the blood can pass
     backward against so great an impulse and influx of the entering
     blood, unless from a point whence it is driven back with equal

Harvey rightly discountenanced the ancient idea of direct
anastomoses between the mouths of veins and the mouths of
arteries, as opposed to fine and multiplied communications. In
some situations, however, he admitted that ampler communications
exist comparable to such anastomoses; and it throws light upon
his state of mind as to the movement of the blood that, despite
his recognition of the very forcible exit of the blood from the
arteries, he suggested in his old age that in the cases aforesaid
regurgitation from vein to artery is guarded against by a valvular
arrangement, the terminal part of the artery traversing the wall of
the vein obliquely, as the ureter traverses the wall of the bladder
and as the biliary duct traverses the wall of the duodenum.[255]
We should not forget that in his day the capillary vessels, the
existence of the corpuscles, and the chemistry of the blood were
still unknown; so that the passage into the veins of the mysterious
hot vital liquid through the "porosities" of the parts might
naturally present itself to his mind in a way very strange to us. He
tells us this:--

     "The blood does not take its course through the looser texture
     of flesh and parenchyma in the same way as through the more
     compact consistency of tendinous parts. Indeed, the thinner and
     purer and more spirituous part passes through more quickly; the
     thicker, more earthy, ill-composed[256] part tarries longer and
     is rejected."[257]

After more than twenty years of the comment and criticism, called
forth by his treatise of 1628, he said to Riolanus:--

     "As to whether the moving blood be attracted, or impelled, or
     move itself by virtue of its own intrinsic nature, enough has
     been said in my little book on the motion of the heart and

Yet about two years after the Exercises to Riolanus, Harvey, in
writing a private letter, judged it necessary to accentuate, as
follows, his denial that forces of attraction really play the part
in physiology which the ancients had conceded to them. Speaking of
the impulsion of the blood through the arteries, he says:--

     "Indeed, the passage of the blood into the veins is brought
     about by that impulsion and not by any dilatation of the veins
     whereby, like bellows, they draw in the blood."[259]

But, despite the foregoing utterances and other such, his statements
are sometimes vague and sometimes quite unexpected, regarding the
nature of the movement of the blood in the veins. Indeed, in 1628 he
speaks quite as a disciple of Aristotle. He says regarding the flow
in the arteries:--

     "For this distribution and movement of the blood there is need
     of impetus and violence and of an impeller such as the heart.
     Partly because the blood readily concentrates and gathers
     together of itself--toward its seat of origin, as it were,[260]
     or as a part to the whole, or as a drop of the water sprinkled
     upon a table to the mass thereof--as the blood habitually
     and very speedily does from slight causes, from cold, fear,
     horror, and other causes of this sort; partly, also, because
     the blood is pressed out of the capillary veins into the small
     branches and thence into the greater by the movements of the
     limbs and the compression of the muscles; the blood is more
     disposed and prone to move from the circumference on the center
     than the other way, even supposing no valves to be present as
     a hindrance. In order, therefore, to relinquish its seat of
     origin, and enter constricted and colder places, and move in
     opposition to its bent,[261] the blood has need not only of
     violence but of an impeller, such as is the heart alone, and
     after the fashion described already."[262]

This picture of the blood hesitating to leave its warm cardiac
birthplace for the chill regions of the periphery, but very ready to
return, has a tone far from hydraulic, but may so much the better
prepare us for the view, made public by Harvey in his old age, that
the blood is the primal seat of the soul itself. Except in the light
of the foregoing passage the following words would be quite obscure.
He says that the auricles

     "are filled as being the storehouse and reservoir[263] of the
     blood, the blood turning of itself and compressed toward the
     center by the movement of the veins."[264]

With due allowance for the use of modes of expression no longer
familiar we find Harvey in 1649 handling the venous flow with
no very modern touch, in the following passage--a passage which
also reminds us that not till twelve years later, four years
after Harvey's death, did Malpighi announce his discovery of the
capillary blood-vessels in the lung of the frog.[265] Harvey says to

     "The arteries are never depleted except into the veins or the
     porosities of the parts, but are continually stuffed full by the
     pulse of the heart; but in the vena cava and the circulatory
     vessels, into which the blood glides at a quick pace and hastens
     toward the heart, there would be the greatest scarcity of blood,
     did not all the parts incessantly pour out again the blood
     poured into them. Add, also, that the impetus of the blood which
     is urged and driven at every pulsation into all parts of the
     second and third regions, forces the blood contained therein
     from the porosities into the little veins and from the branches
     into the larger vessels; this being effected also by the motion
     and compression of the surrounding parts; for contents are
     squeezed out of whatever contains them, when it is compressed
     and narrowed. So by the movements of the muscles and limbs the
     venous branches which creep on between are pressed upon and
     narrowed, and push on the blood from the lesser toward the

A similar touch of vagueness is perceptible when the venous flow is
dealt with by Harvey in that very same résumé of the circulation
which seats the underlying cause of the pulse in the hot blood
of the vena cava close to the auricle. In that résumé he says to

     "I assert, further, that the blood in the veins courses always
     and everywhere from the lesser into the greater and hastens from
     all parts toward the heart; whence I gather that the amount,
     continuously sent into the arteries, which the arteries have
     received is transferred through the veins, and at length returns
     and flows back whence it first was impelled; and that in this
     wise the blood is moved in a circle in flux and reflux by the
     heart, by an impulsion the impetus of which forces the blood
     through all the arterial filaments; and that afterward in a
     continuous flow from all parts it goes back through the veins,
     one after another, by which it is absorbed, drained away, and

As to the flow in the lungs Harvey says in the treatise of 1628:--

     "It being the will of nature that the blood itself be strained
     through the lungs, she was obliged to superadd the right
     ventricle, in order that by the beat thereof the blood might be
     driven through the lungs themselves, out of the vena cava into
     the cavity of the left ventricle."[268]

We have already found Harvey saying to Riolanus, in regard to
the pulmonary transit, that the blood within the branches of the
arterial vein

     "cannot now go back in opposition to the sigmoid valve, while
     at the same time the lungs are widened and enlarged and then
     narrowed, by inspiration and expiration, and with the lungs
     their vessels also, and offer to the blood aforesaid a path and
     transit into the venous artery."[269]

More than thirty-two years earlier Harvey had written in his
note-book the following words:--

     "N.B. The lungs by their movement in subsiding propel blood from
     the arterial vein into the venous artery and thence into the
     left auricle."[270]

When we review and ponder the foregoing delineations of the
character of the movement of the blood, we may cease to wonder
that Harvey did not recognize the simple hydraulic cause of the
distention of the right auricle and felt obliged to seek a more
recondite explanation thereof, finding this in an Aristotelian
expansion of the hot blood.



No doctrine of Harvey sounds stranger to a biologist of to-day than
his doctrine that the blood is the seat of the soul; nor does any
other belief of the great discoverer reveal him more clearly to be a
link between the old and the new; not simply an innovator who fixed
a gulf between them. We have heard him explicitly deny in his old
age the Aristotelian doctrine that the heart "is endowed with soul."
We have seen that thirty-five years earlier he had jotted down in
his note-book these words: "The soul is in the blood."[271] Let us
study him now as he lays stress, not merely on the primacy of the
blood, but on its psychological endowments.

Thirteen years before the date of Harvey's note-book Shakspere's
play of "Hamlet" had appeared in print; in which the prince speaks
thus of following his father's ghost:--

          "Why, what should be the fear?
    I do not set my life at a pin's fee;
    And, for my soul, what can it do to that,
    Being a thing immortal as itself?"[272]

It has been foreshadowed that for Harvey, the graduate of
Cambridge and of Padua, the physician of the Renaissance, the word
"_anima_"--"soul"--did not simply mean the immortal part of man,
as for Hamlet, but was equivalent to the "_psyche_" of ancient
philosophy. In order, therefore, readily to follow Harvey's thought
at this juncture, we must first, like him, go to the fountain head;
for only sayings of Aristotle can give us a sufficient clue to what
he, and after him Harvey, meant by "soul."

Aristotle says in his treatise On Soul:--

     "Some natural bodies have life and some have not. By life we
     mean the being nourished, and growing, and decaying, of oneself."

In the same treatise he says further:--

     "The soul is that by which primarily we are alive, and
     display sensation and intellect; ... but it is not matter and

Again he says:--

     "Were the eye an animal, vision would be the soul thereof; for
     reason indicates that vision is the essence of the eye.[273] The
     eye in its turn is the material [basis] of vision; which latter
     failing, the eye is not an eye except in name, like an eye of
     stone or in a drawing."

The doctrines of the foregoing three passages are developed and made
more explicit in the following, still from the treatise On Soul:--

     "It is the presence of life, we say, which makes the difference
     between that which has soul and that which has not. To amplify
     regarding life: we call anything alive which possesses even a
     single one of the following: intellect, sensation, motion and
     rest in space, and also the motion[274] involved in nutrition,
     and both decay and growth. Therefore, even all the plants are
     held to be alive."

A few lines further on Aristotle says, speaking of the power or
faculty[275] of taking nourishment:--

     "This can exist without the others, but not the other faculties
     without this, in mortal beings. The aforesaid is clear in the
     case of plants; for they possess no other faculty of the soul.
     To this faculty then life owes its origin in living things; but
     the being an animal owes its origin primarily to sensation;
     for beings that neither move nor change their place but yet
     possess sensation, we call animals and not merely living things.
     The primary sense, which exists in all, is touch; and just as
     the nutritive faculty can exist without touch or sensation of
     any kind, so can touch exist without the other senses. The
     "nutritive" is our term for such part of the soul as is shared
     even by plants, all animals, however, evidently possessing the
     sense of touch. The cause of the presence of each of the two
     aforesaid shall be told later. Now let us only go so far as to
     say that the soul is the source of the [faculties] aforesaid,
     and is defined by means of them, to wit: the nutritive, the
     sensory, the intellectual, the motor.[276] As to whether each of
     these is a soul or is a part of the soul; and if a part, whether
     in the sense that it is only separable by reasoning,[277] or
     locally as well--as to some of these points, it is not hard to
     see our way, but some present difficulties."[278]

If we turn to Aristotle's treatise On Generation we find him dealing
with the relations of the body to the nutritive soul, in virtue
whereof the body is alive; with its relations to the sensory soul,
in virtue whereof it is an animal body; and, finally, in man with
its relations to the intellectual soul. Of these three kinds of
soul or parts of the soul, he concludes, the mind "is alone divine;
for in the working thereof no bodily working is involved."[279]
Only soul of this divine quality does he admit to be separable from

The master has spoken. Now let the great pupil speak. In the last
Exercise but one of his treatise On Generation, Harvey says,
referring to the blood:--

     "It assuredly contains the soul first and foremost, not only
     the nutritive, but the sensory soul as well, and the motor. The
     blood penetrates in all directions and is present everywhere;
     if it be taken away, the soul itself is made away with
     also and at once; so that the blood would seem to be wholly
     indistinguishable from the soul or, at least, should be reckoned
     the substance of which the soul is the activity. The soul I aver
     to be such that neither is it body at all, nor yet entirely
     without body, but comes in part from without, in part is born
     on the premises,[281] and in a manner is part of the body;
     in a manner, however, is the origin and cause of everything
     within the body of an animal, certainly of nutrition, sense,
     and motion, and hence, in like manner, of life and death; for
     whatsoever is nourished, that same is living, and _vice versa_.
     So, likewise, whatsoever is nourished abundantly, increases; but
     whatsoever too sparingly, dwindles; and whatsoever is nourished
     perfectly, keeps its health; whatsoever otherwise, lapses into
     disease. Therefore, as is the soul, so also is the blood to be
     reckoned the cause and author of youth and old age, of sleep
     and of waking, and even of respiration also--especially in view
     of this, that in the things of nature the first instrument
     contains within itself an internal moving cause. Therefore, it
     comes to the same whether one say that the soul and the blood,
     or the blood together with the soul, or, if preferred, the soul
     together with the blood, bring everything within an animal to

Only two years before these words were published the aged Harvey had
said the following:--

     "Nor does the blood possess vigor, faculty, reason, motion, or
     heat, as the gift of the heart."[283]

A comparison of the foregoing passages from Harvey with the
preceding passages from Aristotle makes it clear that, for Harvey,
although the soul dwells no longer in its Aristotelian seat, it is
no other than the Aristotelian soul which pervades the "principal
part" of the body, the living blood of the Harveian circulation.

What proofs does Harvey offer that the soul is in the blood? He has
offered already one weighty piece of evidence noted by many from
of old in the chase, in butchery, in sacrifice, in battle--the
evidence from fatal hæmorrhage. This had been set forth nineteen
centuries before him by one of his Hippocratic predecessors, who had
referred to the reasoning

     "used by those who say that the blood is the man; for, seeing
     men slaughtered and the blood running out of the body, they
     conclude that the blood is the soul of man."[284]

Presently Harvey himself shall tell us that in placing the soul in
the blood he is consciously reaffirming one of the most ancient of
beliefs; but he is far from basing his adhesion to it merely on such
immemorial evidence, known to all, as the result of loss of blood,
for he also adduces once more his own observations of the early
embryo of the fowl, to prove not only the primacy of the blood but
the presence of the soul therein. His testimony follows, and in
reading it one must bear carefully in mind that in Harvey's time
no clear scientific distinction had yet been worked out between
movements which imply sensation, and movements, whether reflex or
not, which do not depend upon consciousness. In his treatise On
Generation Harvey says:--

     "For my own part I am sure from numerous experiments that not
     only motion is inherent in the leaping point,--which no one
     denies--but sensation also. For you will see this point thrown
     into varied commotion and, as it were, irritated, at any touch
     whatever, even the slightest, just as sensitive bodies in
     general usually give evidence of sensation by movements proper
     to themselves. Moreover, if the injury be repeated often, the
     leaping point becomes excited and the rhythm and order of its
     pulsations disturbed. In like manner do we infer the presence
     of sensation in the so-called sensitive plant and in zoöphytes,
     from the fact that when they are touched they draw themselves
     together as though taking it ill.... So there is no doubt that
     the leaping point lives, moves, and feels like an animal."[285]

In a later part of the same treatise he says:--

     "It is manifest that all motion and sensation do not proceed
     from the brain, since we plainly perceive the presence of motion
     and sensation before the brain has come into existence; what
     I have related proves that clearly sensation and motion dawn
     forthwith in the first droplet of blood in the egg, before a
     vestige of the body has been formed. Moreover, in that first
     state of the structure or constitution of the body which I have
     called the mucilaginous, before any members are discernible and
     when the brain is nothing but limpid water, if the body be only
     lightly pricked it moves, contracts, and twists itself obscurely
     like a worm or caterpillar; so that it gives clear evidence of

In another Exercise of the same treatise he says:--

     "It is evident also from the generation of the chick, that
     whatever the source of its life or the vegetative first cause of
     it may be, this had a prior existence in the heart. Wherefore,
     if the said first cause be itself the soul of the chick, it
     stands proved likewise that this had a prior existence in the
     leaping point and the blood; seeing that we observe therein
     motion and sensation; for it moves and leaps like an animal. If,
     then, there exist in the leaping point the soul, which (as I
     have taught in my account) constructs for itself the rest of the
     body, nourishes and increases it, certainly from the heart as
     from a fount the soul flows out[287] into the entire body.

     "So, likewise, if the egg be prolific because there is a soul
     in it, or (as Aristotle would have it) the vegetative part of
     the soul, it is clearly proved that the leaping point, in other
     words the generative part endowed with soul, springs from the
     soul of the egg, for nothing is the author of itself, and that
     the soul is transferred from the egg to the leaping point, next
     to the heart, and then to the chick."[288]

In still another chapter of his treatise On Generation Harvey

     "Nor does the blood deserve to be called the original[289] part
     and the principal part, merely because in it and by it motion
     and pulsation are originated, but also because in the blood the
     psychical heat first comes into existence, the vital spirits
     are generated, and the soul itself inheres. For wherever the
     immediate and principal instrument of the vegetative faculty is
     first found, there probably the soul also is first present and
     takes its origin thence; since the soul is inseparable from the
     spirits and the innate heat....[290]

     "The life then inheres in the blood (as we read also in Holy
     Writ),[291] because therein the life and the soul are manifest
     first and fail last....[292]

     "It stands clearly proved that the blood is a generative part,
     the source of life, the first to live and the last to die, the
     primary seat of the soul; that in the blood, as in its source,
     the heat first and chiefly abounds and flourishes; and that by
     and from the blood all the other parts of the whole body are
     fostered and obtain their life by means of the influx of heat.
     Indeed, the heat which accompanies the blood floods, fosters,
     and preserves the entire body, as I have demonstrated already in
     my book on the motion of the blood."[293]

Harvey's proof that the blood is "the first to live and the last to
die," we have scanned already in an earlier chapter of this paper.
In the next chapter of his treatise On Generation he says:--

     "No heat is to be found, either innate or inflowing, other than
     the blood, to be the soul's immediate instrument."[294]

On the next page, after briefly making certain suppositions, he says

     "Why should we not affirm with equal reason that there is soul
     in the blood; and also, since the blood is the first thing
     generated, nourished, and moved, that out of the blood the soul
     is first evoked and kindled? Certainly it is the blood in which
     vegetative and sensitive workings first come to light; in which
     heat, the primary and immediate instrument of the soul, is
     innate; it is the blood which is the common bond of body and
     soul, and in which as a vehicle soul flows into all parts of the
     whole body."[295]

But no matter how far on high the blood may have been exalted by
Harvey the physician and psychologist, it is still subject to the
lancet of Harvey the clinician, the heir of Hippocrates; for in his
treatise On Generation, in the same Exercise with the foregoing
passage, occurs the following:--

     "While I assert that the seat of the soul is in the blood,
     first and foremost, I would not have the false conclusion drawn
     from this that all blood-letting is dangerous or hurtful; nor
     have it believed, as the multitude believes, that just to the
     degree that the blood is taken away does the life pass away at
     the same time, because holy scripture has placed the life in
     the blood. For it is known from everyday experience that the
     taking of blood is a wholesome aid against very many diseases
     and is chief among the universal remedies; seeing that depravity
     of the blood, or excess thereof, is at the bottom of a very
     great host of diseases; and that the timely evacuation of
     blood often brings exemption from most dangerous diseases and
     even from death itself. For just to the degree that the blood
     is taken away as our art prescribes, is an addition made to
     life and health. This very thing has been taught us by Nature,
     whom physicians set themselves to imitate; for Nature often
     makes away with the gravest affections by means of a large
     and critical evacuation by the nares, by menstruation, or by

Not only does Harvey affirm that "the soul is in the blood" and, as
we have seen, appeal to observation and experiment in support of
this doctrine; but he refers to those who had believed it before
him, and maintains it against Aristotle's express denial. We
have heard him testify as an observer; now let us hear him deal
historically and polemically with the doctrine in question. Quite
simply, in the final work of his old age, does the veteran tell of
the wide acclaim which at last has greeted his discovery of the
circulation--the most modern and revolutionary achievement of his
time. The contrast is startling when, in the same breath, with equal
simplicity he proceeds formally to identify his own latest view of
the significance of the circulating blood with a doctrine which had
been ancient in ancient times; a doctrine not only found in the Old
Testament, but held by Greek thinkers who were historic figures
even in the eyes of Aristotle. In his treatise On Generation Harvey

     "I see that the admirable circulation of the blood which I
     discovered long ago has proved satisfactory to nearly all, and
     that so far no one has made any objection to it which greatly
     calls for answer. Therefore, if I shall add the causes and
     uses of the circulation and reveal other secrets of the blood,
     showing how much it conduces to mortal happiness and to the
     welfare of soul as well as body, that the blood be kept pure
     and sweet by a right regimen, I truly believe that I shall do a
     work as useful and grateful to philosophers and physicians as
     it will be new; and that the following view will seem to nobody
     so improbable and absurd as it formerly seemed to Aristotle,
     viz.: that the blood, a domestic deity as it were, is the very
     soul within the body, as Critias and others thought of old;
     they 'believing that capacity for sensation is the most special
     attribute of the soul, and exists because of the nature of the
     blood.' By others again that which derives from its own nature
     the power of causing motion was held to be the soul; as Thales,
     Diogenes, Heraclitus, Alcmæon, and others believed.[297] It is
     made plain, however, by very numerous signs that both sensation
     and motion inhere in the blood in spite of Aristotle's[298]

We have noted with Harvey the doctrine of Leviticus, which still
rules the procedure of the Jewish butcher; and as we look backward
to Athens across the centuries, we find Plato putting this question
into the mouth of Socrates: "Whether it be the blood with which
we think, or air, or fire, or none of these."[300] In Hellas
this doctrine had been well known before Plato, Socrates, or the
Hippocratic writers, one of whom we have found referring to it.
The Sicilian Greek Empedocles, a philosopher and physician born at
Acragas about 495 B.C., is said to have held, long before Aristotle,
that the heart is the part formed first in the embryo;[301] and
in a line of verse which has come down to us Empedocles said: "In
the blood about man's heart is his understanding."[302] Empedocles
is reported to have held to this because in the blood "are most
perfectly blended the elements of the parts,"[303] that is, earth,
water, air, and fire.

The accomplished and wicked Athenian Critias, to whom Harvey refers,
was that chief of the Thirty Tyrants who was slain in 403 B.C., four
years before Socrates drank the hemlock and nineteen years before
the birth of Aristotle. With the opinion of "Critias and others"
Harvey, as we have seen, identifies his own view that the soul is in
the blood. They held capacity for sensation to be the mark of soul
and to be due to the nature of the blood; and Harvey's statement
of these views is a literal quotation from the second chapter of
the first book of Aristotle's treatise On Soul, which Harvey cites.
This chapter is also the source of his summary and not quite exact
reference to those other ancients who, as he avers, held spontaneous
motor power to be the mark of soul--a power which Harvey unites in
the blood with capacity for sensation.[304]

In the aforesaid chapter of Aristotle's work On Soul this
philosopher had curtly reckoned among the "cruder" thinkers those
of his predecessors who, "like Critias," had held the soul to be
blood. Harvey notes the master's condemnation, but, as we have seen,
stoutly ranges himself with the condemned ancients and affirms that
sensation is inherent in the blood despite the master's denial.
It is strange to note how the London physician seems less modern,
for the moment, than the ancient philosopher of Athens. Aristotle,
like a man of to-day, treats the blood simply as the immediate
food of the tissues, noting expressly that it has "no feeling when
touched in any animal, just as the excrement in the belly has no
feeling."[305] Harvey deals as follows with this obvious truth in
dealing with the question whether the blood can properly be reckoned
a part of the body in the technical sense. He says:--

     "At this time I will only say this: Even if we concede that
     the blood does not feel, nevertheless, it does not follow that
     it is not a part of a sensitive body and the principal part at

We do not know that Aristotle ever saw or noted in the dying auricle
the "undulation" by which Harvey was so much impressed; but we
have seen that, like Harvey, Aristotle treated of the development
of the early embryo within the hen's egg and that, like Harvey,
he laid special stress upon the red "leaping point." Aristotle
concluded that the heart is the first generated living part, that
it makes and will make throughout life the blood which it contains
and distributes. In the heart he fixed the focus of the innate heat
and, knowing nothing of the nervous system, he fixed in the heart
the seat of the soul also. Harvey came to the conclusion that the
blood is the first generated living part; that it has made the heart
which contains it and which keeps it circulating and which it will
nourish throughout life, as it will the other parts. In the blood
itself he placed the innate heat and, though he knew the nervous
system, he placed in the circulating blood the seat of the soul,
which animates every part.

     "We conclude," he says, "that the blood lives and is nourished
     of itself and in no wise depends upon any other bodily part
     either prior to or more excellent than itself."[307]

Thus the rigorously proved and demonstrated circulation of the
blood was linked by its discoverer with the speculations of remote

As we have seen, the use of the circulation became to Harvey a
life-long subject of speculation, because this discovery had raised
questions which no man could answer before the finding of oxygen.
How obscure a problem Harvey found the functions of the blood to be,
is nowhere better indicated than where he says in his old age:--

     "So with better right one might maintain that the blood is
     equally the material of the body and its preserver, but not
     merely its food. For it is well known that in animals that
     perish of hunger, and also in men who waste away and die, there
     is abundance of blood to be found in the vessels, even after

Is it the least part of Harvey's glory that his mind had cloven its
way through long-lived beliefs to a truth which he could demonstrate
but could not explain, and which seemed to other eminent men to be
no truth, because too senseless to be true?[309] When he finally
broke with the ancient master, Harvey could not be content with
sheer ignorance; and the same observations and experiments which
led him out of Aristotelian error misled him into error quite as
grave. As to the venerable doctrine regarding the seat of the soul,
which he at last embraced upon grounds now seen to be too slender,
was not this doctrine one with which the Harveian circulation
could harmonize well and which in turn could greatly glorify the
circulation? Let us pause, think, and read further.



The latter part of Harvey's treatise On Generation is devoted to
that of the mammal; but the treatise does not end with the end of
this subject, for from his account of generation the author turns
abruptly to append two Exercises on other topics. The first of these
two is entitled "On the Innate Heat," and the second, which is very
brief, is entitled "On the Primitive Moisture."

The Exercise On the Innate Heat is Harvey's express and polemical
contribution to this subject, which had been much discussed both
during and before his time;[310] a subject with which the famous
discoverer deals roundly by maintaining that the innate heat is
neither more nor less than the circulating blood. So the last words
as to the significance of the circulating blood which he wrote for
publication are contained in this Exercise. It begins as follows:--

     "Since mention is often made of the innate heat, I propose now,
     by way of dessert, briefly to discuss the same and the primitive
     moisture also; and this the more willingly that I see there are
     many who take the greatest delight in those names and yet, in
     my judgment, comprehend but little of the things themselves.
     Truly, there is no need to seek for any spirits distinct from
     the blood, or to bring in heat from elsewhere, or call gods
     upon the stage and load philosophy with fanciful opinions;
     for what we so commonly would fetch from the stars is born at
     home. In truth, the blood alone is the innate warmth, or the
     first-born psychical heat;[311] as is proved excellently well
     by our observations of the generation of animals, especially of
     the chick in the egg; so that it were superfluous to multiply
     entities. Indeed, there is nothing to be met with in the animal
     body prior to the blood, or more excellent; nor are the spirits
     which they distinguish from the blood to be found anywhere
     separate from it; for the very blood itself, if without spirits
     or heat, does not deserve the name of blood, but of cruor....

     "Scaliger, Fernelius, and others lay less weight on the
     extraordinary endowments of the blood and imagine other
     spirits to exist, aërial or ethereal or composed of substance
     both ethereal and elemental, constituting an innate heat more
     excellent and more divine, as it were; and these spirits
     they believe to be the soul's most immediate instrument, the
     fittest for every use. They rely especially upon this argument,
     viz.: that the blood, being composed of elements, can exert
     no activity beyond the powers of the elements or of bodies
     consisting of a mixture thereof. Therefore, they imagine a
     spirit, another innate heat, of celestial origin and nature,
     to wit: a body most simple, most subtile, most fine, most
     mobile, most swift, most clear, ethereal, and sharing in the
     quintessence. Nowhere, however, has any such gift of spirit been
     demonstrated by them, nor that the same acts beyond the powers
     of the elements, or accomplishes greater works than could the
     blood alone. As for us who use our senses to guide us in the
     scrutiny of things, nowhere have we been able to find anything
     of the kind. Furthermore, there exist no cavities destined
     for the generation or preservation of these spirits, or even
     assigned thereto by the persons aforesaid."[312]

A little farther on we read:--

     "I deem it, however, most wonderful that spirits which draw
     their origin from heaven and are adorned with such surpassing
     endowments should be nourished by our common and elemental air;
     especially seeing that their advocates hold that none of the
     elements can act beyond its own powers....[313] What need then
     is there, say I, of that foreign guest, ethereal heat, since
     all can be accomplished by the blood, even as by it; while
     from the blood the spirits cannot withdraw a hair's breadth
     without perishing? Most assuredly nowhere do they wander or
     penetrate as separate bodies without the blood. For whether it
     be said that they are generated, nourished, and increased from
     the thinner part of the blood, as some believe, or from the
     primitive moisture, as others hold; yet it is confessed that
     they are never found outside the blood but forever cleave to
     the same as to their sustenance, as flame does to oil or to
     a wick. Wherefore their tenuity, subtility, mobility, and so
     forth, confer no greater advantage than does the blood which
     they continually accompany. It follows that the blood suffices
     and is fit to be the immediate instrument of the soul, since the
     blood is present everywhere and most swiftly permeates hither
     and thither."[314]

The two opponents named by Harvey were not his contemporaries, but
worthies of the Renaissance who had written about one hundred years
before the publication of his treatise On Generation and had died
before he was born. The Italian physician Julius Cæsar Scaliger
had written learned commentaries on Aristotle, as well as other
works; and the Frenchman Jean Fernel, physician to King Henri II of
France, had taught anatomy at Paris and had been a medical writer
of importance. Each of these two authors was nearly sixty years
of age in 1543, in which memorable year were first published the
revolutionary writings of the aged astronomer Copernicus and of
the young anatomist Vesalius, in the second year after the death
of the hardy innovator Paracelsus. Such were the men against whose
doctrines Harvey was impelled in his old age to launch his vigorous
criticism, in order to clear the way for his own doctrine of the
preëminence of the blood. What can we workers of to-day make of
their opinions, which were living for Harvey but now are so deeply
buried? Test-tube and balance, telescope, spectroscope, microscope,
manometer, and the rest, have served their purpose so well since
Harvey's time that even he, one of the foremost worthies of science,
must seem merely to beat the air with words in his last message to
us, unless we can recover his standpoint. Happily he himself shall
attempt to clarify the meaning of his polemic by setting before us
certain words of Aristotle, embodying far-reaching speculations as
to body and soul in relation to the universe. Yet we shall find
these not easy to understand.

Let Harvey continue his criticism of his predecessors. He says:--

     "But while they believe that there are found in animals spirits
     and ultimate or primitive nourishment, or something else, which
     acts beyond the powers of the elements more than does the blood,
     they do not seem to have a sufficient grasp of what it may be to
     'act beyond the powers of the elements'; nor have they rightly
     interpreted the words of Aristotle where he says:[315] 'The
     virtue or potency of every soul[316] seems to be associated with
     a body[317] other than the so-called elements and more divine.'"

And a little farther on:[318]--

     "'For there exists in the semen of all [animals] that which
     makes their semen generative, the so-called heat. Yet this is
     not fire, nor any such power, but the spirits[319] included
     in the semen and in foaminess, and in the spirits the nature
     which is analogous to the element of the stars.[320] Wherefore
     fire generates no animal, nor does anything [animal] appear in
     process of formation in that, whether moist or dry, which is
     undergoing the action of fire;[321] whereas the heat of the sun
     and that of animals--not only that [which acts] through the
     semen,[322] but also, should there occur some excretion of a
     different nature[323]--even this, too, possesses a life-giving
     principle. It is patent, then, from such [facts] as these that
     the heat in animals is not fire and does not take its origin
     from fire.'[324]

     "I, too, would say the same, for my part, of the innate heat
     and the blood, to wit: that it is not fire and does not take
     its origin from fire, but is associated with another body and
     that more divine, and, therefore, does not act by reason of
     any elemental faculty; but, just as there exists in the semen
     something which makes it generative and exceeds the powers of
     the elements in building an animal--to wit, spirits, and in the
     spirits a nature analogous[325] to the element of the stars--so
     likewise in the blood there exist spirits or some power which
     acts beyond the powers of the elements, a power very conspicuous
     in the nourishing and preserving of the several parts of an
     animal; and in the spirits and blood exist a nature, yea, a
     soul, analogous to the element of the stars. It is manifest,
     therefore, that the heat in the blood of animals during life is
     not fire and does not take its origin from fire; and this is
     taught excellently well by our own observations....[326]

     "Therefore, those who assert that nothing composed of the
     elements can work beyond the powers of these, unless it be
     associated at the same time with another body and that more
     divine, and maintain, therefore, that the spirits aforesaid
     consist in part of the elements, in part of some ethereal and
     celestial substance--truly, such persons seem to me to have
     drawn their conclusions ill. For you shall find scarcely any
     elemental body which, when in action, will not exceed its own
     proper powers."[327]

On reaching the end of the last quoted words of Harvey's polemic,
a physician or biologist of to-day may easily be conscious of
disappointment, even of a mild despair; for the once celebrated
passage from Aristotle, about the interpretation of which Harvey
gives battle, seems at first the source of all the obscurities of
the controversy, rather than of the promised light which shall clear
them away. Yet that light must come by way of that rugged passage.
The gist of the first part of the Aristotelian passage may be set
forth as follows: In the semen soul is potential, being associated
therein with a "body" or "nature" which possesses a "life-giving
principle" and is in the spirits, _i.e._, in the hot vapor, within
the foam-bubbles of the semen. This body or nature is called heat,
yet it is not that one of the four elemental bodies which is known
as fire, nor yet a derivative of this, but is "a body other than
the so-called elements and more divine," a "nature analogous to
the element of the stars." What is this "element of the stars"?
It is clear that only from the answer to this question can the
light which we are seeking begin to shine. To find this celestial
element we must immediately take a rapid glance at the Aristotelian
universe--that grand conception which the master mainly accepted
from his predecessors and contemporaries, but owed, in part, to
the work of his own mind. Let us swiftly scan what he styled the

At the center thereof is the earth, spherical and motionless. The
core of the universe consists not only of this central globe with
everything in or upon it, but also of the atmosphere or, more
correctly, of all which extends between the surface of the globe
and the nearest of the distant revolving hollow spheres of heaven,
in some of which spheres are set the heavenly bodies. Below the
heavenly spheres this core of the universe is made up of the four
elements, earth, water, air, and fire; and all things composed of
these are subject to opposed and limited and compounded motions, to
generation, alteration, and corruption. The inclosing heaven, on the
other hand, is unchangeable and eternal, has never been created,
and will never be destroyed. Its many component hollow spheres are
contiguous and concentric, and concentric also with our globe.
In a single sphere, the outermost, called the "first heaven,"
all the fixed stars are set. In separate spheres, nearer to the
earth, are set the seven bodies which the astronomy of Aristotle's
day styled "planets." To these (here designated by their present
names) that ancient astronomy assigned the following order from the
earth outward toward the fixed stars: the moon, the sun, Venus,
Mercury, Mars, Jupiter, and Saturn. Each of the celestial spheres
revolves with simple circular motion in one direction forever. The
"first heaven," the sphere of the fixed stars, needs but the one
simple motion which is its own, and it carries with it in its daily
revolution all the inner spheres. These are more numerous than the
seven planets; for though each planet is set in but a single sphere,
each planet's complex course results from the combined simple
motions of more spheres than one. In spite of these more or less
intimate relations, the spheres of heaven are separate existences,
self-moved, like animals; and, like animals, possess activity, life,
and soul. But the motion and life of the heavenly existences are
continuous and eternal, and hence these existences--the spheres,
and the planets and fixed stars set therein--are all divine; much
more divine than man, though man possesses a far larger share of the
divine than other animals.[328]

Just as the troubled regions which lie below the sphere of the moon
are contrasted with the serene heaven which incloses and limits
them, so the changing forms of matter which compose our globe and
its nearer surroundings are contrasted with the simple unalterable
substance of the heavenly spheres. "Of necessity," says Aristotle,
"there exists a simple body whose very nature it is to be borne
on in circular motion."[329] Elsewhere he says that the men of old
"would seem to have assumed that the body which moves forever is
likewise divine by nature."[330] This is "an embodied substance
different from the compounds here, more divine and prior to them
all";[331] a body "of a nature the more precious the farther it is
withdrawn from what is here."[332] After reasoning about this body
Aristotle says:--

     "If what has been laid down be accepted, it is plain from the
     foregoing why the first of bodies is eternal, and shows neither
     growth nor decay nor old age nor alteration, and is affected by
     nothing. The conception seems to testify to the phenomena and
     the phenomena to the conception.... Therefore, as the first body
     is something different from earth and fire and air and water,
     [the ancients] gave the name of ether to the region most on
     high, naming it from its moving always during all eternity."[333]

The place in nature of "the first element," so grandly conceived,
is fixed more definitely by Aristotle when he says "that the whole
universe in the region of the courses on high is filled with that

Now, therefore, we have attained the object of our rapid quest;
at last we have reached "the element of the stars"; for Aristotle
tells us that not only heaven, but all the heavenly bodies as well,
consist of the ether, saying:--

     "It is most reasonable and consequent, in view of things already
     said, for us to make each of the stars out of that body in which
     it has its course, since we have declared the existence of
     something of which the nature is to be borne in a circle."[335]

At a later day the ethereal element of the stars was distinguished
from the four inferior elements not by its Aristotelian name of
first element but by that of fifth element, or fifth existence, or
fifth "essence." Hence arose and was applied to the fifth element
the name "quintessence"; a word which in its turn acquired various

Ten years after Harvey's death Milton published his description of
the creation of heaven; a description couched, however, in terms of
the uncreated heaven of Aristotle. Milton wrote:--

    "And this ethereal quintessence of heaven
    Flew upward, spirited with various forms,
    That roll'd orbicular, and turned to stars
    Numberless, as thou seest, and how they move;
    Each had his place appointed, each his course;
    The rest in circuit walls this universe."[336]

We may now return from this excursion through the "Cosmos," to bring
its light to bear upon those high-sounding words of Aristotle which,
according to Harvey, formed the basis of speculations about the
innate heat, the spirits, and the blood, which were handed down by
"Scaliger, Fernelius, and others," and affected the views of Harvey
himself. Aristotle had written:--

     "The virtue or potency of every soul[316] seems to be associated
     with a body[317] other than the so-called elements, and more

And a little farther on:--

     "For there exists in the semen of all [animals] that which makes
     their semen generative, the so-called heat. Yet this is not
     fire, nor any such power, but the spirits[319] included in the
     semen and in foaminess, and in the spirits the nature which is
     analogous to the element of the stars."[337]

That generative heat which is not elemental fire, but a "body" or
"nature" diviner than the lower elements, can be the analogue of
nothing else than the celestial ether.

What led Aristotle to so lofty a flight of speculation? He does not
tell. One may guess, however, that it may well have been this: that
he had found himself obliged not only to deny the identity of the
generative heat of the semen with elemental fire, but also to deny
the identity with elemental fire even of the glowing sun, as well
as of the other planets and the fixed stars; and to maintain that
all the heavenly bodies consist of ether. These denials we have
read already; they shall presently be commented on. Taking them for
granted: now, since the life-giving sun is not elemental fire but
ether, would not the life-giving seminal heat, which also is not
elemental fire, naturally be the analogue of the ether? "Man and
the sun generate man," said Aristotle, in a famous passage.[338]
He needed no knowledge of chlorophyll to teach him this. The ether
is the element of the sun, moon, stars, and spheres; of it consist
the bodies associated with the souls of the living, unalterable,
immortal, divine existences of the eternal heaven. To associate
a body analogous to this ether with the dormant soul of a living
existence--a living existence alterable and mortal as an individual,
but one of an immortal race--in the medium which shall maintain
that racial immortality by begetting a new individual out of the
lower elements--this is a stroke characteristic of the man who
declared that "the race of men, and of animals, and of plants,
exists forever";[339] the man who assigned to every bloodless animal
an analogue of the blood and an analogue of the heart,[340] to the
octopus, an analogue of the brain;[341] the man in whose eyes
the heavenly bodies were divine living existences running eternal
courses and so, we may presume, were analogous in some degree to the
living existences of the earth.[342]

Harvey in one of the earlier Exercises of his treatise On Generation
had already followed the ancient master's footsteps in this matter.
Discoursing of the endless succession of generations the pupil says
that this

     "makes the race of fowls eternal; since now the chick and now
     the egg, in an ever-continued series, produce an immortal
     species out of individuals which fail and perish. We discern,
     too, that in similar fashion many lower things rival the
     perpetuity of higher things. And whether or no we say that
     there is a soul in the egg, it clearly appears from the cycle
     aforesaid that there underlies this revolution from hen to egg
     and from egg again to hen, a principle which bestows eternity
     upon them. That same, according to Aristotle,[343] is analogous
     to the element of the stars; and it makes parents generate,
     makes their semen or eggs prolific, and, like Proteus, is ever

Let us return now to Harvey's polemic. In it he does not give
chapter and verse by which we can properly verify more than a few of
his statements of the views of "Scaliger, Fernelius, and others";
but the words of Aristotle which Harvey quotes go far to justify
his intimation that the views which he states and combats, as the
champion of the circulating blood, are largely derived from those
Aristotelian words--whether by misinterpretation, as he roundly but
indefinitely declares, or with deliberate modification of doctrine,
need not now concern us.

At the very outset of Harvey's discourse about the innate heat, the
first doctrine that he reprobates is a striking one, viz.: that the
innate heat is one and the same thing with spirits distinguishable
from the blood, though not separable from it. Of these spirits he
stoutly denies the existence, on the true scientific ground of
lack of all evidence from observation in their favor. Our earlier
studies of ancient doctrines of respiration have brought before
us, as supposed to exist in the blood, spirits variously styled
"elemental," "aërial," "nourished by our common and elemental air,"
"nourished and increased from the thinner part of the blood." We
have even read Galen's words of spirits which are "the soul's most
immediate instrument," viz.: the "animal spirits" in the brain and
nerves. Indeed, during the eighteen centuries between the death
of Aristotle and the boyhood of Fernelius and Scaliger, the word
"_pneuma_"--"spirits" or "spirit"--did most varied duties in the
service of physicians, philosophers, alchemists, and theologians;
and this same word is of great importance in the scriptures.[345] It
is noticeable that, although Harvey rejects the doctrine of spirits
in the blood, even he himself talks of the blood being itself
spirits.[346] This fact, however, should not militate against him
or lead to confusion. The word "spirits" being a very comprehensive
technical term of his day, he does not refuse to employ it as a
label for qualities of the blood after he has denied the very
existence of what is properly denoted by the word "spirits." He
simply behaves as we behave when we talk of the "sympathetic"
nerves, though the theory is exploded which the adjective expresses;
or when we speak of "animal cell," well knowing that no proper wall
necessarily surrounds the living substance.

Despite the protean forms of the spirits it is not till we have
reached Harvey's Exercise On the Innate Heat that we have fallen
in with spirits in the blood which, for some of his predecessors,
"constitute an innate heat more excellent and more divine, as it
were"; nor with "a spirit, another innate heat, of celestial origin
and nature." For this treatment of spirits within the blood and
of innate heat, as convertible terms, the way may well have been
paved by the words in which Aristotle intimates that the generative
heat of the semen resides in the spirits therein, _i.e._, in hot
vapor produced within the body of the male and included within the
films of foam-bubbles in the semen. Referring to "the so-called
heat" the words of Aristotle are: "Yet this is not fire nor any
such power, but the spirits included in the semen and in foaminess,
and in the spirits the nature which is analogous to the element of
the stars."[347] The transition can hardly have been too difficult
from the view of Aristotle that in the spirits of the semen is heat
which is not elemental fire, to the view combated by Harvey that the
spirits of the blood are heat which is not elemental fire.

Aristotle's striking biological doctrine that the generative seminal
heat is a "nature which is analogous to the element of the stars"
appears to be an obvious source of those seeming fantasies, written
down eighteen centuries later, at which Harvey girds when he says:
"For what we so commonly would fetch from the stars is born at
home." If we use our judgment simply, upon Harvey's statement of
their opinions, the men whom he castigates, having strayed from the
ancient master's footsteps by making the spirits one and the same
with the innate heat instead of the vehicle thereof, next stray
still more blindly by identifying this heat, _alias_ these spirits,
not with an analogue of the ether, but with a portion of the ether
itself. Therefore is it that we read in the words of Harvey's
polemic, of "that foreign guest, ethereal heat"; of those spirits
"aërial or ethereal, or composed of substance both ethereal and
elemental"; of spirits "which draw their origin from heaven" and
elicit Harvey's ironical wonder that they "should be nourished by
our common and elemental air." Therefore, too, is he able to tell us
of that amazing spirit, _alias_ innate heat, which is "a body" and
qualified by many imposing adjectives and finally styled "ethereal
and sharing in the quintessence." The doctrine of Aristotle that
in the semen there are spirits which are the vehicle of generative
heat which is analogous to the element of the stars, is a baseless
doctrine, but it is a subtle and far-reaching speculation. The
doctrine stated and attacked by Harvey that in the blood there are
spirits which are the innate heat, which consists as a whole or in
part of the element of the stars, is not only a baseless doctrine,
as Harvey vigorously shows, but certainly is lame as speculation
despite its glittering appeal to the imagination. To make spirits
and innate heat convertible terms may pass as but one among many
phases of speculation. But to bring down actual ether from heaven to
earth, although attempted by eminent thinkers[348] centuries before
Scaliger and Fernelius, is to bring chaos into that conception
of the universe which requires the "first element" to revolve
forever on high, above that lower world which lies beneath the
sphere of the moon. To Aristotle such chaos surely would have been
abhorrent; indeed, it runs counter to his expressed description
of the ether.[349] Moreover, Aristotle's application of the term
"analogue" to the generative heat is equivalent to a denial that the
generative heat is actually ether; for analogues do frequent service
in his doctrines and he explicitly states the analogue of a thing
to be something different from the thing itself.[350] What that
mysterious analogue of the ether may be with which the generative
heat is identified we are not explicitly told, as we are not told
what the analogue of the heat may be in bloodless animals. We are
left to judge for ourselves after deeper investigation of nature or
deeper study of the Aristotelian writings. Had Aristotle been ready
to define and describe the body which is more divine than the four
lower elements, but is not the first element on high, he probably
would not have chosen an analogue as the fittest vehicle for his

According to Harvey the horse of battle of his criticized
predecessors was the argument stated by him as follows: "That
nothing composed of the elements can work beyond the powers of
these, unless it be associated at the same time with another body
and that more divine; and ... therefore, that the spirits aforesaid
consist in part of the elements, in part of some ethereal and
celestial substance."[351] The "spirits aforesaid" are held to be
one and the same with the innate heat and reside in the blood.
Aristotle had written, we remember: "The virtue or potency of every
soul seems to be associated with a body other than the so-called
elements and more divine,"[352] viz.: the generative seminal heat,
which is not fire but an analogue of the ether. It would seem fairly
probable that largely from this doctrine of Aristotle was developed
the doctrine about the "powers of the elements" which Harvey
sets forth in his polemic. Nothing can be more emphatic than his
disagreement with the advocates of this doctrine. "Such persons,"
he says, "seem to me to have drawn their conclusions ill. For you
shall find scarcely any elemental body which, when in action, will
not exceed its own proper powers."[353] On the same page with this
sweeping statement we find it supported by the following very simple
line of thought:--

     "All natural bodies present themselves in a double relation, to
     wit: according as they are reckoned with apart and comprehended
     within the circuit of their own proper nature, or according as
     they are the instruments of some nobler and superior authority.
     For, as to their own proper powers, there is no doubt that all
     things which are subject to generation and corruption derive
     their origin from the elements, and work according to the
     standard thereof. In so far, however, as all things so subject
     are instruments of a more excellent agent and are regulated
     thereby, their works do not proceed from their own proper nature
     but from the rule of that other; and, consequently, they seem to
     be associated with another and more divine body and to exceed
     the powers of the elements."[354]

In the very next Exercise, however, that On the Primitive Moisture,
the last Exercise of Harvey's treatise On Generation, we come
suddenly upon a reason why "the powers of the elements" must have
seemed to him something to be treated rather as a convenient
form of words than as a serious doctrine, despite his respectful
argument just quoted. Speaking of the "primitive moisture," the
great observer says that he sees in the hen's egg that out of
that "crystalline colliquament," that "simplest body" alone,
all the parts of the embryo are made and increased;[355] and
proceeds bluntly to question the reality of the elements, "namely,
the fire, air, water, and earth of Empedocles and Aristotle; or
the salt, sulphur, and mercury of the chemists; or the atoms of
Democritus."[356] Harvey says:--

     "Therefore, the so-called elements do not exist prior to
     whatever is generated or arises; but rather are subsequent
     thereto, being remains rather than origins. Not even Aristotle
     himself, nor any one else, has ever demonstrated that elements
     exist separately in nature, or give rise to bodies which consist
     of parts similar one to another."[357]

Almost immediately after this tug at the foundations of the
Aristotelian universe, Harvey brings his treatise On Generation to
an end.

The admirable feature of Harvey's brief last-published discussion
of the circulating blood is this, that the aged veteran ever
strikes vigorous blows for observation, for the use of the senses,
in the search for truth. But we have seen already that by his arm,
as by another's, the blows are delivered both for better and for
worse. Rightly does he drive out of court the spirits "ethereal
and elemental" which no man can demonstrate. Wrongly does he
discredit the real complexity of that humor, to the eye so simple
and crystal-clear, out of which he believes all the diverse parts of
the living bird to be developed. In Harvey's present polemic we find
no new appeal to nature; he vindicates the justice of his former
appeals and maintains with vigor the doctrines already familiar to
us, that the blood is the principal part of the body, is itself the
innate heat, and is the seat of the soul. This relation of blood
and soul he reaffirms very impressively in this, his final public
utterance; a most important passage of which, about the presence
of the soul in the blood, has been embodied in the chapter on that
subject of the present paper.[358]

But evidently the main purpose of his polemical Exercise on the
Innate Heat is to cast out of the blood the futile spirits which
obscure the real relation of that heat to the circulating blood; and
so to defend the thesis best set forth in the following words of his

     "In truth, the blood alone is the innate warmth, or the first
     born psychical heat; as is proved excellently well by our
     observations of the generation of animals, especially of the
     chick in the egg; so that it were superfluous to multiply
     entities....[359] What need, then, is there, say I, of that
     foreign guest, ethereal heat, since all can be accomplished by
     the blood, even as by it?"[360]

Harvey has expelled from the blood the mythical spirits which had
stood in the way of the direct identification of the blood with
the innate heat. But how does he interpret the famous words of
Aristotle which he quotes, and declares not to have been "rightly
interpreted" by the champions of ethereal spirits? When we seek an
answer to this question, we do not find the veteran discoverer at
his best. The ancient philosopher surely would have been as much
surprised at Harvey's interpretation of his words as at any use of
them made by Scaliger or Fernelius. We have seen that Harvey follows
up his quotation from Aristotle by promptly applying its language,
literally or by paraphrase, to the innate heat and the blood.[361]
Emphatic are the words which immediately follow the words of
Aristotle. Harvey says:--

     "I, too, would say the same, for my part, of the innate heat and
     the blood, to wit: that it is not fire and does not take its
     origin from fire, but is associated with another body and that
     more divine."

This denial he soon repeats, adding the words: "and this is taught
excellently well by our observations."

According to Aristotle the soul in the semen is associated with a
body diviner than the four lower elements, viz.: the generative
heat, an analogue of the element of the stars, which analogue
resides in spirits, _i.e._, in hot vapor within bubbles of seminal
foam. In the case of the blood, according to Harvey, it is the heat
itself, the innate heat _alias_ the blood, which is associated with
"another body and that more divine," and Harvey, having denied the
reality of the spirits, uses the word "spirits" as equivalent to
"some power" in the blood, which power is "very conspicuous in the
nourishing and preserving of the several parts of an animal." In
the spirits, so understood, and the blood, dwells the soul; and it
is the soul itself which Harvey states to be "a nature analogous
[_respondens_ not _proportione respondens_] to the element of the
stars." Even as the word "spirits" has become, in effect, a label
for powers of the blood, so the analogue of the ether becomes, in
effect, a pious epithet applied to the soul; and only to the soul
itself can Harvey have referred as "another body and that more
divine." In the next page to the passage now under discussion he

     "The blood, therefore, is spirits, because of its extraordinary
     virtues and powers. It is also celestial, inasmuch as in the
     spirits aforesaid is lodged a nature, the soul, to wit, which
     is analogous to the element of the stars; something, that is,
     analogous to heaven, the instrument of heaven, vicarious of
     heaven....[362] The heat of the blood is psychical, inasmuch as
     it is governed in its operations by the soul;[363] it is also
     celestial, because subservient to heaven; and divine, because
     the instrument of God, the best and greatest....[364] The lower
     world, according to Aristotle, is so connected with the courses
     on high that all its motives and changes seem to take thence
     their origin and to be governed thence.[365] Truly, in that
     world which the Greeks called the 'Cosmos' from the beauty of
     its order,[366] lower and corruptible things are subject to
     other higher and incorruptible things; but all are beneath the
     highest, the omnipotent and eternal Creator, and obey Him."[367]

It is obvious that, although Harvey in dealing with the blood
does not forego the use of the phrases used by the ancient master
in dealing with the semen, nevertheless, the entities recognized
by Harvey are not only fewer than those of Aristotle, but are
differently disposed within the draperies of Aristotelian language.
Harvey's entities are simply the innate heat _alias_ the blood, and
the soul which dwells therein; but he sincerely takes himself to
be an interpreter of Aristotle's words, as appears a second time
from an echo of those words which we meet in an earlier Exercise of
Harvey's treatise On Generation. Here, pleading that it is true that
the soul is in the blood, Harvey refers to Aristotle by name and
immediately says:--

     "Indeed, if he is constrained by the truth to acknowledge that
     there is a soul in an egg, even in a wind-egg;[368] and that
     in the semen and the blood also there is found something which
     is divine and analogous to the element of the stars and is
     vicarious of the omnipotent Creator; and if certain of the
     modems truly say," etc., etc.[369]

These zealous words show Harvey drawn into statements by no
means warranted by the text of Aristotle. We have seen that the
Aristotelian heaven was uncreated;[370] and, whatever Harvey in his
day may have thought, no "omnipotent Creator" is revealed by more
modern study of the Aristotelian philosophy. Whatever inferences
Harvey may have drawn from Aristotle's words, Aristotle does not
"acknowledge"[371] that the analogue of the ether exists in the
blood. Moreover, when in Harvey's Exercise On the Innate Heat that
analogue of the element of the stars which Aristotle associated with
the soul is identified by Harvey with the soul itself, the change is
almost as great as if one should declare that protoplasm is life,
instead of styling it with Huxley "the physical basis of life." In
a third Exercise of the treatise On Generation, the earliest of the
three, Harvey had dealt in a better and more characteristic way with
the analogue of the ether; though here, too, his exposition gives
no accurate idea of Aristotle's doctrine. In discussing Aristotle's
opinion as to how the semen of the cock causes the formation of the
embryo Harvey says of Aristotle:--

     "Indeed, where he appears to settle and determine with certainty
     what that may be in whatsoever seed, whether of plants or of
     animals, which renders the same fruitful, he rejects heat and
     fire as unfit for the work, but does not give recognition to any
     similar faculty, nor yet discover in the seed aught suitable
     for that duty; but is forced to admit something incorporeal,
     and coming from without, which shall act with understanding and
     foresight (like art or mind) to form the fœtus, and therein
     shall establish and order all things to a purpose and for the
     better. He betakes himself, I say, to something obscure and to
     us unknown, 'spirits included in the semen and in foaminess, and
     in the spirits the nature which is analogous to the element of
     the stars.' But what that may be he has nowhere taught us."[372]

We have found that Aristotle describes "the element of the stars"
as a "body,"[373] and that in the passage about the semen which
Harvey quotes Aristotle expressly applies the same term, "body," to
the analogue of the element of the stars.[374] Yet to this analogue
Harvey seems to refer as "something incorporeal" in his last-quoted
words, which tend to confound it with soul. Harvey agrees with
Aristotle, however, in calling fire a "body";[375] and where in his
Exercise On the Innate Heat he extols at some length[376] fire, air
and water in motion as flame, wind and flood, he also sets forth how
they each claim the title of spirits "by virtue of their movement
and perpetual flux,"[377] and says:--

     "These three, therefore, in so far as they acquire a certain
     life, appear to act beyond the powers of the elements and to
     have a share[378] of another and diviner body; wherefore they
     were reckoned among the deities by the heathen. For that of
     which the outcome is some extraordinary work, exceeding the bare
     faculties of the elements, that same they held to proceed from
     some diviner agent; as though it were one and the same to act
     beyond the powers of the elements and to have a share of another
     and diviner body--diviner, because it does not derive its origin
     from the elements."[379]

Nowhere but in the third chapter of the second book of Aristotle's
treatise On Generation does he refer to the analogue of the ether;
and the complete text of this chapter--rugged, here and there,
especially in Gaza's Latin translation--may help us perhaps to
account for some of Harvey's efforts at exposition.[380] But when
these and his reports of his predecessor's doctrines are compared
with the words of Aristotle, Harvey and those other biologists of
the Renaissance seem like sturdy children reaching forward in the
dust, each still clasping a finger of the strong old father who
strides among them.



So Harvey denies the doctrine falsely based upon Aristotle's words,
the doctrine of the ethereal nature of the innate heat; but he
affirms and adopts as his own the Aristotelian distinction between
the heat which is sterile and the heat which gives life. This
weighty affirmation obliges us who study Harvey to examine this
impressive distinction further.[381]

Aristotle says, we remember: "The heat in animals is not fire and
does not take its origin from fire." We remember also that Harvey
says: "I, too, would say the same, for my part, of the innate heat
and the blood, to wit: that it is not fire and does not take its
origin from fire." This doctrine is based by both Aristotle and
Harvey upon observation; and Aristotle's argument is contained in
the passage which Harvey quotes, a passage obscure in the Latin
and rugged in the Greek. Briefly, Aristotle's argument is this:
Observation shows that fire is sterile, but that the heat of the sun
is generative and the heat of animals likewise; therefore, the heat
of animals is not fire. Harvey declares that this same conclusion
"is taught excellently well" by his observations also--by which he
does not expressly say. That Aristotle, in drawing the distinction
aforesaid between the heat of fire and the heat of the sun, was
playing at hide and seek with a great truth of biology, would soon
be apparent to whosoever should take a flourishing green plant from
a window warmed by sunshine and try to make the same plant flourish
in a dark room warmed by a hidden fire.

At this point let us scan further the words of Aristotle which
Harvey has quoted.[337] Aristotle says:[318]--

     "For there exists in the semen of all [animals] that which
     makes their semen generative, the so-called heat. Yet this is
     not fire, nor any such power, but the spirits[319] included
     in the semen and in foaminess, and in the spirits the nature
     which is analogous to the element of the stars.[320] Wherefore
     fire generates no animal, nor does anything [animal] appear in
     process of formation in that, whether moist or dry, which is
     undergoing the action of fire;[321] whereas the heat of the sun
     and that of animals--not only that [which acts] through the
     semen,[322] but also, should there occur some excretion of a
     different nature[323]--even this, too, possesses a life-giving
     principle. It is patent, then, from such [facts] as these that
     the heat in animals is not fire and does not take its origin
     from fire."[324]

In this passage a forcible presentment is made of the sterilizing
power of fire, and elsewhere we are told by Aristotle that "only in
earth and in water are there animals; there are none in air and in
fire."[382] That by the word "fire" we are to understand elemental
heat of greater or less intensity is sufficiently shown perhaps by
the context. But no doubt will linger if we glance at two lines from
another treatise in which, referring expressly to the four elements,
Aristotle speaks of earth, water, air, and "what as a matter of
custom we call 'fire' but it is not fire; for fire is an excess, a
boiling, as it were, of heat."[383]

Harvey, looking askance as he did at the four ancient elements and
even bluntly questioning the elementary constitution of matter,
felt himself free to reduce the analogue of the ether to a pious
epithet, and yet to accept with emphasis the Aristotelian doctrine
that the heat of animals "is not fire." At the end of his Exercise
On the Primitive Moisture he says: "Nor, lastly, do we find that
anything is naturally generated out of fire, as out of something
capable of mixture, and the thing is perhaps impossible." Here,
however, he is not dealing merely with the generation of living
beings, but with a subject deeper yet, the possibility of fire
acting as an element at all.[384]

The drift of those sentences which Harvey quotes is lighted up,
better perhaps than by any modern commentary, by a passage of
Cicero's treatise On the Nature of the Gods, a treatise mentioned by
Harvey in his lecture notes,[385] as we have seen. In the orator's
lucid Latin we may read what purports to be a quotation from the
Greek philosopher Cleanthes, who was a child when Aristotle died in
322 B.C., and who became the second head of the Stoic school, the
powerful younger rival of the school of Aristotle. Let us listen to
the Roman stoic of 45 or 44 B.C., who is set up by Cicero to quote
and expound Cleanthes as follows:--

     "Cleanthes says: 'Since the sun is fiery and is nourished by
     the humors of Ocean (seeing that no fire can last without some
     kind of food), therefore, the sun must needs be similar either
     to the fire which we use and apply in our daily life, or to that
     fire which is contained in the bodies of animate beings. But
     this fire of ours, which is requisite for the uses of life, is
     the destroyer and consumer of all things, and wheresoever it has
     made its way disturbs and dissipates everything; whereas that
     fire of the body is vital and salutary and by it everything is
     preserved, nourished, increased, sustained, and endowed with
     sense.' Cleanthes denies, therefore, that it is doubtful to
     which of these two fires the sun is similar, seeing that the
     sun likewise makes all things flourish and ripen, each after
     its kind. Wherefore, since the sun's fire is similar to those
     fires which exist in the bodies of animate beings, the sun,
     too, must be an animate being and, indeed, the rest of the
     stars that arise in the celestial ardor which is named ether or

Unlike Aristotle, Cicero's stoic admits that the sun and even the
heavenly ether are fire. But we see him to be no less impressed
than Aristotle by the difference between the killing heat of flame
and the life-giving heat of heaven and of living things. It is
interesting to find this difference expressly given as a reason for
believing the heavenly bodies to be alive; and one wonders whether
this difference may not have had some share in convincing Aristotle
that the ether is an element distinct from fire and the other three
elements, and more exalted than they. It must be said, however, that
Aristotle's habitual use of language about "the heat contained in
animals" prepares us ill for the momentous distinction drawn by him
between this and elemental heat.

We have found him speaking of "the soul being, as it were, afire"
within the heart;[387] and he says also that "the concoction through
which nutrition takes place in animals does not go on either in the
absence of soul or in the absence of heat, seeing that everything
is done by fire."[388] Moreover, there is in his treatise On Soul
a passage deserving immediate quotation, no less as a picture of
the nascent stage of biological thought, than as showing a phase of
Aristotelian doctrine contrasting with the doctrine of the analogue
of the ether. He says:--

     "By some the nature of fire is held to be quite simply the cause
     of nutrition and growth; for fire alone among bodies or elements
     is seen being nourished and growing; wherefore one might assume
     it to be that which does the work both in plants and in animals.
     It is, in a way, the contributing cause[389] but not the cause
     in the simple sense, the soul rather being that; for the growth
     of fire is limitless, so long as there are combustibles, but in
     the case of all natural organisms[390] there is a limit to size
     and growth, and a rationale[391] thereof; these things depending
     upon the soul, not upon fire, and upon reason rather than upon

Nevertheless, in spite of seeming inconsistencies, we find Aristotle
declaring that the heat of fire sterilizes, but the heat of the
sun and of animals gives life. Moreover, when he tells us in the
passage quoted by Harvey[393] that not only the heat of the sun and
of semen, but also the heat of other animal excretions possesses
a "life-giving principle," the words appear to suggest not merely
generation without sex, but the spontaneous generation either of
parasites within the animal body, or of living things in matters
cast off from it. We seem to be confronted with the far-reaching
thought that there is in the world a life-giving principle by which,
when associated with soul, matter is quickened in ways of which
sexual generation is only one; and that this principle is generative
heat, streaming from the sun or transmitted by the male in coition,
and, thereafter, innate in the resulting creature and shared by the
humors thereof. The fact must always have been recognized that in
some way the existence of living things on earth depends upon the
sun. On the other hand, no modern methods fortified Aristotle's
intelligence against spontaneous generation, which he accepted as a
matter of course and called "automatic generation," even asserting
that eels and some other fishes originate in this way.[394] Further
statements of his own shall show us now that the sun in its orbit
dominates the changes upon and above the earth and is the giver of
life, whether imparted by sexual intercourse or otherwise. Then
Harvey shall repeat the lesson and thus help us to understand his
declaration regarding the innate heat and the blood, to wit: that it
"is not fire and does not take its origin from fire."

Aristotle refers to a region beneath the celestial spheres, which
region he calls "the first in proximity to the earth," or "the
region common to water and air." He says of the events therein:--

     "Of these the efficient[395] cause and ruler and first origin is
     the circle of the sun's course, which, it is evident, produces
     separation and combination by its approach or withdrawal and is
     the cause of generation and corruption."[396]

These last words are used in a large sense to mean the formation and
disintegration of whatever is composed of the four elements.

But the annual circuit of the sun does more than bring to pass
the rhythmic changes of the seasons with their effects upon man's
environment. To the sun's circuit man owes his life. Aristotle has
said to us already: "Man and the sun generate man," in words which
have no biological context.[338] He does better when he enumerates
among the "causes" of a man these three: his father, the sun,
and "the oblique circle," _i.e._, the ecliptic. These he styles
"efficient[397] causes" of man,[398] as we have heard him style "the
circle of the sun's course" the "efficient cause" of the mighty
changes in inanimate things. We learn in what sense a father is the
"efficient cause" of his offspring when Aristotle says: "The female
always provides the matter, while the male provides that which
fashions it";[399] and when we are told that this matter provided
by the female "is quickened by the principle derived from the male,
which thus perfects the animal";[400] "the animal" meaning the
product of conception. "The body," says Aristotle further, "is from
the female, but the soul from the male."[401] For although he says
elsewhere that "Genesis is the first obtaining in heat of a share
of nutritive soul, and life is the tarrying thereof";[402] although
he concedes a share of this lowest kind of soul to wind-eggs, to
plants, and to the humblest things which live; nevertheless, he
holds that, where the sexes are divided, the indispensable "sensory
soul" which distinguishes the animal from the plant is derived from
the male parent only.[403] So the seminal fluid and the solar rays
are coupled together as "efficient causes" of man; and thus the
moving sun is made responsible, by what chain of causation we are
not told expressly, for the results of sexual generation.

From this we may turn now to other forms of generation in the light
of the following prodigious analogy. Aristotle says:--

     "We call 'male' an animal which engenders within another, and
     'female' one which engenders within itself; and, therefore, in
     the case of the universe the earth's nature is held to be female
     and maternal, while heaven and the sun and other such are called
     engenderers and fathers."[404]

Next, after these sweeping generalities, let us peruse Aristotle's
account of spontaneous generation. He says:--

     "Animals and plants arise in earth and in moisture, because in
     earth there is water and in water there is air,[319] and in
     all air there is psychical heat; so that in a certain sense
     all things are full of soul. Therefore, when once inclusion of
     this[405] has taken place, an individual is quickly formed.[406]
     Inclusion takes place and a kind of foam-bubble arises, produced
     by the heating of moisture which has body[407] of its own."[408]

The last expression in this passage evidently means moisture
which is charged with earthy matter in solution; for Aristotle
says in the same treatise that seawater "has much more body" than
drinking-water.[409] Still speaking of spontaneous generation he
says a little further on:--

     "Whoever would inquire aright should ask: What product in such
     cases answers to that material principle which in the female is
     a certain animal excretion,[410] potentially similar to what it
     came from? That excretion is quickened by the principle derived
     from the male, which thus perfects the animal. In the present
     case what should be likened to that excretion, and whence and
     what is the quickening principle which answers to the principle
     from the male? Now we must assume that, even in animals which
     procreate, the heat within the animal[411] separates and
     concocts, and thus makes out of the nourishment which enters the
     animal the excretion which is the beginning of the embryo. Such
     is the case with plants likewise; although in these and in some
     animals there is no need of the principle imparted by the male,
     for this they have within and mingled with themselves; whereas
     in most animals the excretion aforesaid stands in need of that
     principle. The nourishment of some is water and earth, that of
     others is derived from water and earth; so that what the heat
     in animals[412] prepares out of their nourishment, the heat of
     the season in the circumambient air combines by concoction out
     of the sea and the earth, and puts together.[413] But so much
     of the psychical principle as is included or separated within
     the air[319] constructs and quickens[414] the embryo. In like
     manner are put together such plants as arise by spontaneous

The doctrine that in sexual generation the semen furnishes soul and
generative heat but none of the matter[416] of which the embryo
consists, renders logical the view, which Aristotle would seem to
hold, that it is soul from the air and generative heat from the sun
which in spontaneous generation represent the derivatives from the
male.[417] The presence about us of "the psychical principle," thus
diffused, may well seem startling to a modern biologist; but we may
remind ourselves that in ancient times many believed the soul to
be conveyed by the air into even the higher animals; even into man
himself, even man's "understanding" reaching him thus.[418] Indeed,
not only the words "_pneuma_" and "_spiritus_," as we have learned,
but also the Greek and Latin words for "soul," viz.: "_psyche_" and
"_anima_," meant originally simply "breath." Let us recall the words
of scripture, which seem so vivid to one who watches the change in
a new-born child as the first breath is taken: "And the Lord God
formed man of the dust of the ground, and breathed into his nostrils
the breath of life; and man became a living soul."[419]

That the soul enters with the breath is, however, expressly denied
by Aristotle. Conceding a share of soul to every living thing he
points out quite simply that there are animals which do not breathe
at all, to say nothing of plants.[420] Clearly, the doctrine which
he rejects would be hard to reconcile with his theory of sexual
generation, according to which theory the sensory soul, and in man
even the divine intellectual soul, is potential in the semen and
imparted thereby to the product of conception.[421] Indeed, there is
a chapter of Aristotle's treatise On Soul in which he even seems
to argue against the presence of soul in the air, in a polemic
directed against those who believe the soul to be "composed of the
elements."[422] In this polemic he is the subtle philosopher; but in
his statements about generation he seems more the biologist; for in
these his thought, if not more ripe, appears to be less concerned
with disputation than with phenomena and the interpretation thereof.

The generation of living things is but generation still, whether
it be sexual or spontaneous; and the modern student of general
physiology may trace further parallels of thought in Aristotle's
account of spontaneous generation and in those words of his about
the semen which Harvey quotes and we have studied. That living
rudiment, spontaneously generated, which consists of a foam-bubble
whose film of earth and water was formed by the heat of the sun
and includes air charged with generative heat associated with
soul--surely that reminds one of the foamy semen, and of "the
spirits included in the semen and in foaminess," and of that within
the spirits "which makes semen generative, the so-called heat,"
the "nature which is analogous to the element of the stars," which
nature is derived from the male parent and is associated with the
soul potential in the semen. In the Greek text of Aristotle one
and the same word, "_pneuma_" is used to express both the air
in the foam-bubbles of spontaneous generation, and the vapor in
the foam-bubbles of the semen. In translation "_pneuma_" must be
rendered "spirits" in the case of the semen, and the verbal identity
is lost which, by reason of the very vagueness of the Greek word,
helps to mark the parallelism of thought. It is with _pneuma_,
spirits, that the testicles and breasts are swollen at the advent
of puberty,[423] according to Aristotle; and with the presence of
_pneuma_ he connects the pleasure of the sexual act.[424] We have
found him laying stress upon the fact that "the nature of semen
is foamy"--that its "generative medium ἡ γονή is foam":
and he tells of the spontaneous generation of certain shellfish
in a place where there is "foamy mud."[425] When he obscurely
says that in the semen "the _pneuma_ included in the semen and in
foaminess"[426] is the vehicle of the generative heat, does not the
turn of phrase indicate that Aristotle's thought is ranging far,
that he is thinking not only of the foam of the semen but of other
widely different kinds of prolific foam as well? Does he not seem
to think that, in general, the power of bringing matter to life as
a new individual dwells typically in a bubble representing earth,
water, and air, and charged with soul and with generative heat, for
the presence of which the sun is responsible, heat other than that
of elemental fire?[320] It is not fanciful--for Aristotle himself,
we remember, has done so incidentally--to connect such speculation
with the ancient myth of Aphrodite, the goddess of love, who sprang
from the foam which had risen upon the sea, about the immortal
genitals of Uranus, which had been severed and cast therein; Uranus
being the heavens personified.[427]

Before the time of Aristotle important thinkers had held the
heavenly bodies, and even the heavens themselves, to be fire;[428]
and we have seen that after his time Cleanthes did the same, simply
setting apart the generative fire from the destructive. Aristotle
denied that the sun is fire, though he could not have denied that
its radiant generative heat produces no different sensation from
that of sterile fire kindled upon earth. He did not identify the
sun's heat with ether, the "body on high," though he styled the heat
of the semen a "body" analogous to the ether. How then did Aristotle
obtain heat from the ethereal sun? The point is crucial and he met
it; but in so doing he revealed a very weak place in his towering
fabric of speculation. In his treatise On Heaven, speaking of the
heavenly bodies, he says:--

     "The heat and light from these arise from the friction which the
     air undergoes by reason of their course. For it is the nature of
     motion to fire even wood and stone and steel."

He then speaks of projectiles, and says:--

     "These, then, are heated because borne onward in air which
     becomes fire from the shock of the motion. But each of the
     bodies on high is borne onward in its sphere, so that they
     are not fired; while the air, being beneath the sphere of the
     circling body,[429] is heated of necessity as this [body]
     is borne onward, and mainly where the sun is set in place.
     Therefore, when the sun approaches and rises and is above us,
     heat is generated. Be it said, then, of the heavenly bodies,
     that neither are they fiery nor are they borne on in fire."[430]

In his Meteorology Aristotle boldly says: "The sun, which is held to
be especially hot, appears white, but not to be like fire."[431]

Hardy thinker as he is, however, Aristotle nowhere undertakes to
tell how the heat of friction between the air and the circling
"first element" on high becomes generative, as opposed to the heat
of friction between the air and a projectile composed of the lower
elements. As to this the Aristotle who deals with the heavens does
not strike hands with Aristotle the biologist; nor is light thrown
by its author on the Aristotelian passage quoted by Harvey, in which
alone does the generative heat of animals figure as "the nature
which is analogous to the elements of the stars";[432] nor yet does
the Aristotelian dictum that "Man and the sun generate man"[338]
remain other than a great truth which awaits elucidation.

More than nineteen centuries after Aristotle's death Harvey
published the following, in his treatise On Generation:--

     "Thus the sun and man, that is, the sun through man as an
     instrument, generate. In the same way the Father of all and
     the cock generate the egg and the chick derived from the egg;
     namely, by means of the perpetual approach and withdrawal of the
     sun, which by the will of divine authority, or by fate if you
     choose, serves for the generation of all things.

     "Our conclusion, then, is that the male, although a prior and
     more important efficient cause than the female, is only an
     instrumental efficient cause; that he, no less than the female,
     receives his fecundity or generative power from the approaching
     sun; and that, accordingly, the art and providence which we
     discern in his works proceed not from himself but from God."[433]

Two pages farther on Harvey says, again:--

     "In fact, what the cock confers upon the egg to make it no
     longer a wind-egg but prolific, is the same that is bestowed by
     the summer fervor of the sun upon vegetable fruits, that they
     may reach maturity, and their seeds, fecundity; and the same
     that imparts fecundity to beings that arise spontaneously[434]
     and that produces caterpillars out of worms, chrysalides out of
     caterpillars, out of chrysalides, butterflies, flies, bees, and
     the rest."[435]

In a later Exercise of the same treatise Harvey says:--

     "As I have said, the product of conception in viviparous
     creatures is analogous to the seed and fruit of plants; as
     also is the egg in the ovipara; in creatures which come into
     existence spontaneously, the worm;[436] or some bubble of
     confined moisture[437] pregnant with vital heat. In all of the
     foregoing exists that which is the same in all, that in virtue
     of which they are called with truth seeds; that, namely, out
     of which and by which, preëxisting as matter, artificer, and
     instrument, every animal is in the first instance made and comes
     into existence."[438]

Despite emphatic denials of Aristotelian doctrine which Harvey
freely makes in his treatise On Generation, the Aristotelian
flavor of the foregoing passages is obvious. It is not easy to
make out from Harvey's writings the exact nature of his views as
to spontaneous generation. He sometimes seems to assume the truth
thereof; but it is by no means certain that he believed in it in the
same simple sense in which it had been accepted by Aristotle.[439]
Nothing, however, can be clearer than this: that, though for Harvey
the "innate heat" is not ethereal spirits nor even an analogue
of the ether, but is simply identical with the living blood;
nevertheless, for him as emphatically as for Aristotle the "heat in
animals" which "is not fire and does not take its origin from fire,"
derives its origin from the solar ray.

To Harvey, the lifelong thinker upon the meaning of the circulation,
the prodigious history of generation was but continued in the
history of the blood, with which he had identified the "innate heat"
and which he saw appear and live, before all other parts, in the
minute first rudiment of the embryo. We have seen him pondering
the cycle wherein unending life is transmitted from egg to fowl
and from fowl to egg beneath the sun's life-giving rays. So now
shall we see him pondering a cycle of life wherein, from generation
to generation, the circulating blood takes over and exercises
the generative powers of the semen from which it is derived, and
transmits them in turn to the semen evolved out of itself. He says:--

     "Further, since we have just seen the study of the semen to be
     so difficult; that is to say, the way in which the structure
     of the body is built up by the semen with foresight, art, and
     divine intelligence; why should we not equally admire the
     excellent nature of the blood, and make the same reflections
     upon it as upon the semen? Especially since the semen itself
     is made of blood,[440] as is proved in the case of the egg;
     and since the whole body is seen not only to take origin from
     the blood as from a generative part, but also to owe its
     preservation to the same."[441]

To this same theme Harvey returns in his Exercise On the Innate Heat
near the end of his treatise On Generation, saying:--

     "The blood, too, acts in like manner above the powers of the
     elements, because, when it has come into existence as the first
     generated part and the innate heat, as is brought to pass in the
     semen and spirits, the blood constructs the remaining parts of
     the whole body in order; and does so with the highest foresight
     and understanding,[442] acting to a certain end and as though by
     some use of reason.[443] Surely the blood does not accomplish
     these things because it is composed of elements and draws its
     origin from fire, but because by the grace of plastic power and
     vegetative soul it is made the first generated heat and the
     immediate and fitting instrument of life."[444]



The discoverer of the circulation would have been no fit pupil of
Aristotle if he had limited his ken to the microcosm; nor were such
limitations common in an age when astrology was not so far out of
countenance as now. We have found Harvey discussing "the element
of the stars" and reverently affirming the dependence of all life
upon the sun as well as upon its Creator. We have found him also,
in dealing with the powers of the blood, affirming that "lower and
corruptible things are subject to other higher and incorruptible
things," and in that connection paraphrasing a passage in which
Aristotle deals with "the Cosmos which is about the earth." Of
this--that is, of the sum of things between our globe and the moon's
sphere--the ancient philosopher says:--

     "Of necessity it is conjoined, in a way, with the courses on
     high, so that its entire power is governed thence; for that
     which originates motion in everything must be recognized as
     first cause."[445]

In "the courses on high" the divine living existences of heaven
circulated forever, ruling the lower Cosmos as cycle succeeded cycle
in endless series and the seasons endlessly recurred. In a few
pregnant words Aristotle had dealt with the results of this Cosmic
circulation, as follows:--

     "There is said to be a circle in the affairs both of mankind and
     of whatever else is possessed of natural motion and is subject
     to generation and corruption."[446]

It was in Harvey's lifetime that this stupendous circulation of
the heavens "and all that is in them" received its death stroke.
Throughout Harvey's years of study at Padua, Galileo had lectured
there with great acclaim; and after Harvey's return to London
discovery after discovery had followed Galileo's work with the
telescope, and had dealt blow after blow to the ancient astronomy.
The trial of Galileo had followed; and he had died in 1642, nine
years before the publication of Harvey's work On Generation. Yet
belief in the ancient astronomy died far harder than belief in
the ancient physiology of the movement of the blood. The ancient
astronomy was based on the evidence of every man's own eyes, and
flattered human vanity with the doctrine that the whole universe
was centered upon the globe of which the ordained possessor was
the creature made in the image of God. Milton had visited Galileo,
famous long before, near Florence in 1638; but in the "Paradise
Lost," published in 1667,[447] Milton expressly treated the question
between the ancients and the followers of Copernicus as an open one,
though Copernicus had died in 1543. Indeed, we find Harvey himself,
seven years after Galileo's death, speaking of "the reason why our
knowledge of the heavenly bodies is uncertain and conjectural";[448]
and saying of opponents of the circulation of the blood: "Nor do
they find it satisfactory to set up new systems, as in astronomy,
unless these explain all the phenomena."[449]

It need not surprise us, therefore, to find Harvey writing as
follows in 1628 in the very act of naming his own great discovery:--

     "I beg leave to call this motion circular in the same sense in
     which Aristotle said that air[450] and rain imitate the circular
     motion of the bodies on high.[451] For the earth, when wet and
     warmed by the sun, gives off vapor; the vapors are borne upward
     and condensed and, when condensed into rain, descend again and
     wet the earth. Thus, too, generation here below and, in like
     manner, the arising of tempests and meteors result from the
     circular motion of the sun, his approach and recession."[452]

In 1651, nine years after the death of Galileo, in the last words
about the moving blood which Harvey published, he drew a parallel
between the circulation of the microcosm and the mighty circulation
of the macrocosm. This parallel is drawn just before the end of his
final work, his treatise On Generation, in a passage of his Exercise
On the Innate Heat, in words which may serve to sum up what has gone
before. These words shall be quoted without further comment and
shall bring our present study of Harvey to an end:--

     "The following few points should be considered well by every
     diligent mind, and so the fact becomes established more clearly,
     that those remarkable virtues which learned men attribute to
     the spirits and the innate heat are appropriate to the blood
     alone; to say nothing of what is so wonderfully striking in the
     egg before aught of the embryo has appeared, and in the perfect
     and developed embryo also. To be sure, the blood, considered
     absolutely and by itself outside the veins and regarded as
     consisting of elements[453] and as composed of different
     parts,--some thin and serous, some thick and solidified,--is
     termed 'cruor' and is possessed of very few virtues, and those
     obscure. But the blood, when present within the veins as a part
     of the body, a generative part, too, and endowed with soul,
     being the soul's immediate instrument and primary seat--the
     blood, seeming also to have a share of another diviner body
     and being suffused with divine heat, certainly acquires
     extraordinary powers, and is analogous to the element of the
     stars. As spirits the blood is the hearth, the Vesta,[454] the
     household deity, the innate heat, the sun of the microcosm, the
     fire of Plato;[455] not because it shines, burns, and destroys,
     like common fire, but because it preserves and nourishes and
     increases its very self by its perpetual wandering motion.
     Moreover, the blood deserves the name of spirits because,
     primarily and before all other parts, it abounds in radical
     moisture, that is, in the final and most immediate form of
     nourishment; and the same fare wherewith the blood itself is
     nourished is made ready by it and given out to all other parts
     while it is coursing perpetually through the entire body.
     Indeed, the blood nourishes, fosters, and keeps alive all the
     parts which it constructs and adjoins to itself, even as the
     heavenly bodies above, especially the sun and moon, impart life
     to what is below, while they continue in perpetual circulation.
     Since, therefore, the blood acts beyond the powers of the
     elements and is potent with those virtues aforesaid, and also
     is the instrument of the supreme workman, no one ever will give
     praise enough to its wonderful and divine faculties."[456]

Let us end these studies by picturing to ourselves the memorable
figure of the small white-haired man ensconced in one of his
favorite nooks on the leads of his brother's house, musing upon the
mystery of the circulation, and linking it with that of

    "The shining powers, conspicuous afar
    Against the ether, which to mortals bring
    Winter and summer."[457]


[1] In the present paper frequent references will be made to the
writings of Harvey, Galen, Aristotle, and Hippocrates. Citations
from these authors will be made from the following editions:--

References to Harvey's finished writings will be made to two
editions, viz.: The Works of William Harvey, translated from the
Latin with a life of the author by R. Willis, M.D., London, 1847,
printed for the Sydenham Society, which will here be designated as
"Syd."; and Guilielmi Harveii Opera Omnia: A Collegio Medicorum
Londinensi Edita: 1766, which will be designated as "Op. Omn."
In the preparation of the text the present writer has used these
two editions and also the first editions of Exercitatio Anatomica
de Motu Cordis et Sanguinis in Animalibus, Frankfort, 1628, and
Exercitationes de Generatione Animalium, London, 1651. Willis's
translation of passages has been revised, often freely, where the
writer has judged this desirable; and sometimes the revision amounts
to a fresh translation. References to Harvey's lecture notes will be
made to Prelectiones Anatomiæ Universalis by William Harvey, edited
with an autotype reproduction of the original by a committee of the
Royal College of Physicians, London, 1886.

References to Galen's writings will be made to two editions,
viz.: Claudii Galeni Opera Omnia. Editionem curavit C. G. Kühn,
Leipsic, 1821-1833, which will be designated by the letters "Kn.";
and Œuvres Anatomiques, Physiologíques et Medicáles de Galien,
Traduites avec Notes par C. Daremberg, Paris, 1854-1856, which will
be cited as "Dar." The former is the recognized working edition of
the Greek text of Galen; this is accompanied by a Latin translation,
to which is appended a serviceable Latin index. By the pages of
this edition the Greek text of Galen is commonly cited. None of the
treatises of Galen has been translated into English. Some of those
most interesting to physiologists may be read in the above French
translation of Daremberg. A critical edition of the Greek text of
Galen's treatise On the Doctrines of Hippocrates and Plato, Claudii
Galeni de Placitis Hippocratis et Platonis, with an amended Latin
translation by Johannes Müller, was published by Teubner, Leipsic,
1874; it will here be cited as "Mül."

References to Aristotle's writings will be made to Aristotelis
Opera: Edidit Academia Regia Borussica, Berlin, 1831-1870, which is
the commonly cited Greek text. Pages and lines of this edition will
always be found in the margin of a modern edition or translation.
The following works of Aristotle will be referred to in this paper:--

The Psychology and its appendices, viz.: the so-called "Lesser
Works on Natural Things (Parva Naturalia)." English translation by
W. A. Hammond, New York, 1902. The two last treatises of the Parva
Naturalia have also been translated by W. Ogle, M.D., London, 1897.

The History of Animals. English translation by R. Creswell. Bohn's
Classical Library. London, 1878.

On the Parts of Animals. English translation by W. Ogle, M.D.,
London, 1882.

On the Generation of Animals. There is no English translation. An
excellent German translation, with the Greek text, is that by Aubert
and Wimmer, Leipsic, 1860.

Physics. There is no English translation; Greek text and German
translation by C. Prantl, Leipsic, 1854.

On Heaven: On Generation and Corruption (In the Universe at Large).
There is no English translation; Greek text and German translation
by C. Prantl, Leipsic, 1857.

Meteorology. There is no English translation; French translation by
J. B. St. Hilaire, Paris, 1863.

Besides the foregoing, other treatises by Aristotle may be referred
to or cited briefly.

References to the Hippocratic writings will be made to Œuvres
Complètes d'Hippocrate, traduction nouvelle, par É. Littré, Paris,
1839-1861, which will be designated as "Lit." This is the standard
working edition of the Greek text of the Hippocratic collection, and
is the one now usually cited. The accompanying French translation
is complete. There is a translation into English of some of the
treatises, but it cannot be recommended. A new version of the Greek
text is now in slow course of publication by Teubner of Leipsic.

[2] John Aubrey: 'Brief Lives,' Chiefly of Contemporaries, etc.
Edited from the Author's Mss. by Andrew Clark; 1898, Vol. I, 300.

[3] Harvey: On Generation, Preface, Syd. 152, l. 34 to 153, l. 4;
Op. Omn. 168, l. 22-26.

[4] Galen: Is Blood Naturally Contained in the Arteries? Kn. Vol.
IV, 703-736.

[5] Harvey: On Conception, Syd. 575, l. 9-12; Op. Omn. 592, l. 8-11.

[6] Harvey: Letter to Hofmann, Syd. 595, l. 6-15; Op. Omn. 635, l.

[7] Harvey: Letter to Hofmann, Syd. 596, l. 3-7; Op. Omn. 636, l.

[8] Harvey: Exercise to Riolanus, II, Syd. 122, l. 31 to 123, l. 1;
Op. Omn. 122, l. 16-21.

[9] Harvey: On the Motion, etc., VIII, Syd. 47, l. 29-33; Op. Omn.
49, l. 28-30.

[10] Harvey: On the Motion, etc., IX, Syd. 48, l. 10-14; Op. Omn.
50, l. 8-11.

[11] Plato: Timæus, 70_a_ and _b_; 77_c_ to 78_a_; 78_e_ to 79_a_.

Aristotle: On the Parts of Animals, 668_a_, 4 to _b_, 6.

Galen: On the Natural Faculties, Kn. Vol. II, 210-212; Dar. Vol. II,

[12] Aristotle: On Sleep and Waking, 456_a_, 30 to _b_, 5.

Galen: On the Use of the Parts, etc., Kn. Vol. III, 269-270; Dar.
Vol. I, 280-282.

[13] Galen: On the Natural Faculties, Kn. Vol. II, 186-189; Dar.
Vol. II, 306-307.

[14] Harvey: On the Motion, etc., Syd. 72, l. 24 to 73, l. 12; Op.
Omn. 73, l. 26 to 74, l. 15.

[15] Harvey: On the Motion, etc., Syd. 75, l. 9-22; Op. Omn. 76, l.

[16] Joannes Riolanus, Filius: Encheiridium Anatomicum et
Pathologicum, etc., Paris, 1648, 298, l. 1-4. Harvey's quotation
does complete justice to the sense, but is by no means accurate

[17] Harvey: Exercise to Riolanus, I, Syd. 95, l. 4-21; Op. Omn. 97,
l. 6-23.

[18] Aselli: De Lactibus, sive Lacteis Venis, etc. Milan, 1627.

[19] John Aubrey: Brief Lives, etc., 1898, Vol. I, 302.

[20] Harvey's venous artery and arterial vein correspond
respectively to the pulmonary vein and the pulmonary artery of our

[21] Harvey: On the Motion, etc., VI, Syd. 39, l. 29 to 40, l. 15;
Op. Omn. 41, l. 20 to 42, l. 10.

[22] Compare Aristotle: History of Animals, 511_b_, 10-24.

[23] Harvey: On the Motion, etc., XVII, Syd. 85, l. 17-25; Op. Omn.
87, l. 5-12.

[24] Aristotle: On Youth and Old Age, On Life and Death, 469_b_,

[25] Aristotle: On Respiration, 473_a_, 8-10.

[26] Aristotle: On the Generation of Animals, 732_a_, 18-20.

[27] Aristotle: On Youth and Old Age, On Life and Death, 469_a_, 28
to 470_a_, 18. On Respiration, 474_a_, 25 to _b_, 24; 478_a_, 26 to
_b_, 21; 480_a_, 18 to _b_, 20.

[28] Aristotle: On Respiration, 478_a_, 21-30.

[29] διὰ τὴν σύναψιν.

[30] Aristotle: History of Animals, 496_a_, 27-32.

[31] Hippocrates: On the Heart, Lit. Vol. IX, 86 and 90-92.

[32] Hippocrates: On the Heart, Lit. Vol. IX, 86-88.

[33] Galen: On the Use of Respiration, Kn. Vol. IV, 487-493.

[34] ποιότητος.

[35] Galen: Is Blood Naturally Contained in the Arteries? Kn. Vol.
IV, 724-725.

[36] Galen: On the Use of Respiration, Kn. Vol. IV, 510.

[37] Galen: On the Use of the Parts, etc., Kn. Vol. III, 412; Dar.
Vol. I, 381.

[38] Galen: On the Use of the Pulse, Kn. Vol. V, 149-180.

[39] Harvey: On the Motion, etc., Preface, Syd. 9-14; Op. Omn. 9-14.

[40] Galen: On the Use of the Parts, etc., Kn. Vol. III, 636-656;
Dar. Vol. I, 541-552.

[41] Harvey: Prelectiones, 86 right.

[42] Compare Hippocrates: On Flatus, Lit. Vol. VI, 96.

[43] Harvey: Prelectiones, 86 right.

[44] Galen: On the Use of Respiration, Kn. Vol. IV, 470-471.

[45] Harvey: Prelectiones, 86 right.

[46] Aristotle: On Respiration, 473_a_, 15 to 474_a_, 24.
Hippocrates: On the Sacred Disease, Lit. Vol. VI, 368 and 372.

[47] Hippocrates: On the Sacred Disease, Lit. Vol. VI, 368.

[48] Passages which justify the statements here made are among those
cited in note 140.

[49] Galen: Is Blood Naturally Contained in the Arteries? Kn. Vol.
IV, 703-736.

[50] Galen: On the Use of the Parts, etc., Kn. Vol. III, 541-542;
Dar. Vol. I, 476.

[51] Plato: Timæus, 69_c_-_d_. Archer-Hind's Edition, 254, l. 13 to
256, l. 6.

[52] Aristotle: On Soul, 412_a_, 1 to 415_a_, 13.

[53] Galen: On the Doctrines of Hippocrates and Plato, Kn. Vol. V,

[54] Galen: On the Use of the Parts, etc., Kn. Vol. III, 696-703;
Dar. Vol. I, 575-579. See also Rapp: "Ueber das Wundernetz,"
Meckel's Archiv für Anatomie und Physiologie, 1827, 1-13.

[55] Galen: On Methods of Treatment, Kn. Vol. X, 839-840.

[56] On the subject of the spirits the following passages of Galen's
works should be consulted, viz.:--On the Natural Faculties, Kn.
Vol. II, 204, l. 11 to 206, l. 13; Dar. Vol. II, 315, l. 7 to 316,
l. 14; Kn. Vol. II, 214, l. 9-16; Dar. Vol. II, 320, l. 2-9. On the
Organ of Smell, Kn. Vol. II, 857-886. On the Use of the Parts of
the Human Body, Book VI: Kn. Vol. III, 412, l. 6-12; Dar. Vol. I,
381, l. 4-9; Kn. Vol. III, 487, l. 3 to 488, l. 13; Dar. Vol. I,
438, l. 1 to 439, l. 9; Kn. Vol. III, 490, l. 14 to 492, l. 8; Dar.
Vol. I, 440, l. 24 to 441, l. 16; Kn. Vol. III, 496, l. 5-16; Dar.
Vol. I, 444, l. 6-19. Book VII: Kn. Vol. III, 536-544; Dar. Vol. I,
472-477; Kn. Vol. III, 544-549; Dar. Vol. I, 477-480. Book VIII: Kn.
Vol. III, 636-651; Dar. Vol. I, 541-550; Kn. Vol. III, 651-656; Dar.
Vol. I, 550-552; Kn. Vol. III, 663; Dar. Vol. I, 557; Kn. Vol. III,
672-673; Dar. Vol. I, 563. Book IX: Kn. Vol. III, 684-691; Dar. Vol.
I, 569-572; Kn. Vol. III, 696-703; Dar. Vol. I, 575-579; Kn. Vol.
III, 750-751; Dar. Vol. I, 602-603. Book XIV: Kn. Vol. IV, 183, l.
7-10; Dar. Vol. II, 114, l. 23-25. Book XVI: Kn. Vol. IV, 323, l.
2-18; Dar. Vol. II, 189, l. 3-21; Kn. Vol. IV, 333, l. 18 to 335,
l. 10; Dar. Vol. II, 195, l. 6-36. Book XVII: Kn. Vol. IV, 349, l.
5-14; Dar. Vol. II, 202, l. 30-38. On the Causes of Respiration, Kn.
Vol. IV, 465-469. On the Use of Respiration, Kn. Vol. IV, 470-511.
Is Blood Naturally Contained in the Arteries? Kn. Vol. IV, 703-736.
On the Use of the Pulse, Kn. Vol. V, 149-180. On the Doctrines of
Hippocrates and Plato, Book II: Kn. Vol. V, 281, l. 3-15; Mül. 245,
l. 10 to 246, l. 6. Book III: Kn. Vol. V, 355, l. 18 to 356, l.
11; Mül. 325, l. 16 to 326, l. 9. Book VI: Kn. Vol. V, 524, l. 12
to 525, l. 16; Mül. 512, l. 3 to 513, l. 8; Kn. Vol. V, 571, l. 12
to 573, l. 2; Mül. 563, l. 12 to 566, l. 2. Book VII: Kn. Vol. V,
600-611; Mül. 596-608; Kn. Vol. V, 611-617; Mül. 608-615; Kn. Vol.
V, 628, l. 8-15; Mül. 626, l. 8-15; Kn. Vol. V, 641, l. 14 to 642,
l. 6; Mül. 641, l. 13 to 642, l. 6. Book VIII: Kn. Vol. V, 707,
l. 17 to 710, l. 15; Mül. 714, l. 14 to 718, l. 2. On Methods of
Treatment, Book IX: Kn. Vol. X, 635, l. 6 to 636, l. 12. Book XII:
Kn. Vol. X, 839, l. 10 to 840, l. 3.

[57] Harvey: Prelectiones, 83 right.

[58] Harvey: Prelectiones, 85 left.

[59] Harvey: Prelectiones, 83 right and 85 left.

[60] Compare R. Columbus: De Re Anatomica. Venice, 1559, 223-224.

[61] Harvey: Prelectiones, 85 left. The last line of page 85 left,
as deciphered and printed, reads as follows: "Galenus 7 & p. 8°."
It should read, however, "Galenus 7 u.p. 8°." That this is Harvey's
brief reference to Galeni Lib. 7, De Usu Partium, Cap. 8, is proved
by the text of the Galenic passage thus referred to, viz.: Galen: On
the Use of the Parts, etc., Kn. Vol. III, 539-540, Dar. Vol. I, 475.

[62] As no other claimant than Columbus to be the discoverer of the
pulmonary transit of the blood was known to Harvey, the question
whether Columbus was the true discoverer, or possibly owed the basis
of his doctrine to the unfortunate Michael Servetus, need not here
be discussed.

[63] Vesalius: De Humani Corporis Fabrica, Basel, 1543; Lib.
VI, Cap. II, 589, l. 9-24. Vesalius: Opera Omnia Anatomica et
Chirurgica, Leyden, 1725, Tom. I, De Hum. Corp. Fabr. Lib. VI,
Cap. 11, 511, l. 11-23; Cap. 15, 519, l. 42-54. Columbus: De Re
Anatomica, Lib. VII, 177, l. 17-24.

[64] Aristotle: On the Parts of Animals, 649_b_, 19-27.

[65] Harvey: Prelectiones, 85 right. Compare closely similar
passages in Harvey: On the Motion, etc., Introduction, Syd. 12, l.
9-15; Op. Omn. 12, l. 10-17. Exercise to Riolanus, II, Syd. 116, l.
26-33; Op. Omn. 116, l. 15-20. On Generation, LXXI, Syd. 504, l.
22-28; Op. Omn. 525, l. 23-29.

[66] The decipherer of Harvey's Ms. notes reads "_generatur_."

[67] Harvey: On the Motion, etc., Introduction, Syd. 18, l. 16-21;
Op. Omn. 18, l. 17-21.

[68] Compare Aristotle: On Respiration, 470_b_, 28 to 471_b_, 29.

[69] Harvey: Prelectiones, 86 left.

[70] Harvey: On the Motion, etc., Introduction, Syd. 16, l. 23-27;
Op. Omn. 16, l. 21-26.

[71] Harvey: On the Motion, etc., Introduction, Syd. 16, l. 28-39;
Op. Omn. 16, l. 27 to 17, l. 4.

[72] πνεῦμα.

[73] Aristotle: History of Animals: 496_a_, 27-32.

[74] Columbus: De Re Anatomica, Lib. VII, 178-180; Lib. XI, 223-224;
Lib. XIV, 259 and 261.

[75] Harvey: Prelectiones, 86 left.

[76] Galen: On the Doctrines of Hippocrates and Plato, Kn. Vol. V,
611-617; Mül. 608-615.

[77] Harvey: Prelectiones, 94 right: "_puto: spiritus Nervis non
progredi sed Irradiatos et actus fieri unde sensus et motus ut lumen
in aere: forsan ut fluxus et refluxus Maris_," etc.

[78] Harvey: Exercise to Riolanus, II, Syd. 118, l. 9-14; Op. Omn.
117, l. 29-32.

[79] Harvey: Prelectiones, 86 left.

[80] Columbus: De Re Anatomica, Lib. VI, 166-167; Lib. VII, 177-178;
Lib. XI, 22.

Harvey: On the Motion, etc., VII, Syd. 41, l. 7-14; Op. Omn. 43, l.

[81] Harvey: Exercise to Riolanus, I, Syd. 98, l. 16-23; Op. Omn.
100, l. 21-28.

[82] Harvey: Exercise to Riolanus, II, Syd. 113-121; Op. Omn.
113-121. On Generation, LXXI, Syd. 501-512; Op. Omn. 523-534.

[83] Harvey: On Generation, LXXI, Syd. 502, l. 33-37; Op. Omn. 524,
l. 5-7.

[84] Harvey: On Generation, LXXI, Syd. 504, l. 22-31; Op. Omn. 525,
l. 25-32.

[85] Harvey: Exercise to Riolanus, II, Syd. 118, l. 32-38; Op. Omn.
118, l. 16-19.

[86] Harvey: Exercise to Riolanus, II, Syd. 119, l. 3-5 and l.
10-17; Op. Omn. 118, l. 26-28 and 118, l. 30 to 119, l. 4.

[87] Harvey: Prelectiones, 86 right.

[88] Harvey: Exercise to Riolanus, II, Syd. 113, l. 28 to 114, l. 19
and 117, l. 35 to 118, l. 9; Op. Omn. 113, l. 22 to 114, l. 14 and
117, l. 19-29.

[89] Harvey: On Generation, LII, Syd. 388, l. 31-32; Op. Omn. 405.
l. 14-15.

[90] Harvey: On Generation, LII, Syd. 386, l. 11-12; Op. Omn. 402,
l. 24-26.

[91] Harvey: Prelectiones, 87 left.

[92] Galen: On the Doctrines of Hippocrates and Plato, Kn. Vol. V,
571-572; Mül. 563, l. 12 to 565, l. 9.

[93] Harvey: Exercise to Riolanus, II, Syd. 114, l. 26-29; Op. Omn.
114, l. 19-21.

[94] Harvey: Exercise to Riolanus, II, Syd. 114, l. 37-40; Op. Omn.
114, l. 28-31.

[95] Harvey: Exercise to Riolanus, II, Syd. 115, l. 18-21; Op. Omn.
115, l. 12-14.

[96] Harvey: Exercise to Riolanus, II, Syd. 136, l. 19-21; Op. Omn.
136, l. 12-13.

[97] Harvey: On the Motion, etc., XVII, Syd. 77, l. 24-29; Op. Omn.
79, l. 5-9.

[98] See J. C. Dalton: Doctrines of the Circulation, Philadelphia,
1884, 127-128.

[99] Columbus: De Re Anatomica, Lib. XI, 223, l. 11 to 224, l. 8.

[100] Galen: On the Use of the Parts, etc., Kn. Vol. III, 451-452;
Dar. Vol. I, 412, l. 5-8.

[101] Harvey: Letter to Slegel, Syd. 597, l. 14-23; Op. Omn. 613, l.

[102] Harvey: On Parturition, Syd. 530, l. 3-10 and l. 25-36; Op.
Omn. 549, l. 22-27 and 550 l. 11-20.

[103] Harvey: Letter to Hofmann, Syd. 596, l. 3-7; Op. Omn. 636, l.

[104] Harvey: Exercise to Riolanus, II, Syd. 123, l. 15-18; Op. Omn.
122, l. 31 to 123, l. 1.

[105] Harvey: On the Motion, etc., IX, Syd. 48, l. 21 to 50, l. 36;
Op. Omn. 50, l. 17 to 52, l. 23.

[106] Harvey: Prelectiones, 80 right.

[107] Hippocrates: On Wounds, Lit. Vol. VI, 430.

[108] Hippocrates: Epidemics, Lit. Vol. V, 114-116. Compare Galen's
Third Commentary on Epidemics, Kn. Vol. XVII, A., 433, l. 14 to 436,
l. 2.

[109] Harvey: Prelectiones, 79 right.

[110] Harvey: Exercise to Riolanus, II, Syd. 140, l. 30-39; Op. Omn.
140, l. 23-31.

[111] Harvey: Exercise to Riolanus, I, Syd. 98, l. 9-23; Op. Omn.
100, l. 14-28.

[112] Hippocrates: On the Heart, Lit. Vol. IX, 84, l. 11-12.

[113] Aristotle: On Youth and Old Age, etc., 469_b_, 6-20.

[114] Aristotle: On the Parts of Animals, 670_a_, 23-26.

[115] Galen: On the Use of Respiration, Kn. Vol. IV, 505, l. 15 to
506, l. 5.

[116] Harvey: On the Motion, etc., VIII, Syd. 46, l. 34 to 47, l.
16; Op. Omn. 49, l. 3-19.

[117] Aristotle: On Respiration; On the Parts of Animals, Books II
and III; and elsewhere. This reference is by Harvey himself.

[118] Aristotle: On the Parts of Animals, Book II. This reference is
by Harvey himself.

[119] Harvey: On the Motion, etc., XV, Syd. 68, l. 19 to 69, l. 17;
Op. Omn. 69, l. 22 to 70, l. 18.

[120] Harvey: On the Motion, etc., XV, Syd. 70, l. 17-25; Op. Omn.
71, l. 22-29.

[121] Harvey: On the Motion, etc., XVI, Syd. 72, l. 8-11; Op. Omn.
73, l. 13-16.

[122] Harvey: On the Motion, etc., XVII, Syd. 83, l. 9-27; Op. Omn.
84, l. 31 to 85, l. 14.

[123] Hippocrates: On the Nature of the Child, Lit. Vol. VII, 530,
l. 3-19.

[124] Aristotle: History of Animals, 561_a_, 4 to 562_b_, 2.

[125] Harvey: On the Motion, etc., XVII, Syd. 76, l. 3-10; Op. Omn.
77, l. 14-20. On Generation, XVII, Syd. 235, l. 21-26; Op. Omn. 249,
l. 9-13.

[126] Harvey: On the Motion, etc., IV, Syd. 30, l. 14-18 and 30, l.
31 to 31, l. 4; Op. Omn. 32, l. 8-10 and 32, l. 22-30.

[127] Aristotle: On the Parts of Animals, 666_a_, 8-13.

[128] _Principium._

[129] Harvey: On the Motion, etc., XVI, Syd. 74, l. 4-15; Op. Omn.
75, l. 9-19.

[130] It would be natural to conjecture that this Aristotelian
slighting of spirits derived from the air, taken in connection with
Aristotle's exaltation of the vital innate heat, may have had much
weight with Harvey, who, although he used the word "spirits" freely,
insisted that the blood and the spirits are one. But in this matter
the Aristotelian precedent cannot have had the same force for Harvey
that it would have for us, because he believed Aristotle to be the
author of two treatises in which the spirits are expressly treated,
not only as entities, but as entities of great physiological
importance, though their relations with the outer air are neglected
in one of the treatises and quite obscurely dealt with in the
other. (See Harvey: On the Motion, etc., IV, Syd. 29, l. 16-25;
Op. Omn. 31, l. 8-16. Do., VI, Syd. 38, l. 7-12; Op. Omn. 40, l.
2-5.) Indeed, Harvey in one of his references to Aristotle directly
affirmed that the philosopher had believed in "motor spirits" within
the animal body. (See Harvey: On the Motion, etc., XVII, Syd. 81, l.
8-12; Op. Omn. 82, l. 31 to 83, l. 3. Compare [Pseudo-] Aristotle:
On Spirits, 485_a_, 5-8; and the Latin translation of the same
"by an unknown interpreter," 249_b_, 13-18.) The two treatises in
question are entitled, respectively, "On the Motion of Animals" and
"On Spirits," and have been attributed to Aristotle and habitually
printed among his works, both before and since the time of Harvey.
Modern criticism, however, has made it clear that neither treatise
is a genuine work of Aristotle. It is especially plain that the
treatise "On Spirits" is by another hand and of another school;
among other reasons, because the author declares the skin to be
supplied with blood by the veins, and with spirits by accompanying
vessels which he calls "arteries." In this treatise the maintenance
of the spirits by respiration is discussed, but left uncertain
(483_b_, 15-19). It is but fair to the criticism of Harvey's
time to note that, glaringly at variance as the undoubted works
of Aristotle are with the treatise "On Spirits," the latter was
pronounced genuine, in 1839, by so eminent a scholar as É. Littré,
in his "Œuvres d'Hippocrate," etc., Vol. I, 203. Reasons why the
treatises in question are not by Aristotle, are given at length in
the essay in Latin by V. Rose, entitled "De Aristotelis Librorum
Ordine et Auctoritate Commentatio," Berlin, 1854, 162-171, and at
the end of 174.

[131] Compare the Iliad, Book XXI, 441.

[132] ἐν τούτῳ γὰρ ἡ φύσις ἐμπεπύρευκεν ἀυτήν. Aristotle:
On Respiration, 474_b_, 10-13.

[133] Aristotle: On Youth and Old Age, etc., 469_a_, 11-12 and 17-20.

[134] Plato: Timæus, 70_a_-_b_ and 77_d_-_e_.

[135] κίνησις.

[136] νεῦρα.

[137] Aristotle: On the Parts of Animals, 666_b_, 11-16.

[138] Harvey: On the Motion, etc., XVII, Syd. 81, l. 12-19; Op. Omn.
83, l. 3-8.

[139] Harvey: On Generation, XI, Syd. 207, l. 33-35; Op. Omn. 220,
l. 26-28.

[140] The foregoing statements and summaries of Aristotelian
doctrine are based upon the following portions of Aristotle's
works: Meteorology, 366_b_, 2 to 367_a_, 3. On Soul, 413_a_, 11 to
415_a_, 13; 416_a_, 9 to _b_, 31; 426_b_, 8 to 427_a_, 16; 429_a_,
10 to 430_a_, 9. The following five titles are of treatises among
the Parva Naturalia: On Sensation and the Sensible, 438_b_, 24 to
439_a_, 5; On Sleep and Waking, 455_a_, 4 to 458_a_, 32; On Dreams,
461_b_, 11-15; On Youth and Old Age, and On Life and Death, the
whole treatise; On Respiration, 473_a_, 9-10; 475_a_, 25 to _b_,
24; 478_a_, 11 to _b_, 21; 479_a_, 29 to _b_, 7; 479_b,_ 17 to
480_b_, 20. History of Animals, 496_a_, 4 to 497_b_, 2; 512_b_, 12
to 515_b_, 26; 535_a_, 26 to 536_a_, 4; 561_a_, 4 to 562_b_, 2. Of
the History of Animals Book X is clearly spurious; see V. Rose: "De
Aristotelis Librorum Ordine et Auctoritate Commentatio," 171-174.
Book VII is very probably spurious; see "Aristotelis Thierkunde,
etc.," Aubert and Wimmer, 1868, Vol. I, 7-11. On the Parts of
Animals, 647_b_, 29 to 648_a_, 13; 652_b_, 1-33; 659_b_, 13-19;
665_a_, 28 to 669_b_, 12; 670_a_, 23-27; 672_a_, 22 to _b_, 7;
677_b_, 36 to 678_a_, 3; 678_b_, 2-4; 689_a_, 29-31; 697_a_, 26-29.
On the Generation of Animals, 718_a_, 2-4; 728_a_, 9-11; 723_a_,
18-20; 735_b_, 32 to 736_a_, 9; 736_a_, 24 to 737_b_, 7; 737_b_, 27
to 738_a_, 9; 739_b_, 22-23; 740_b_, 2 to 741_a_, 5; 741_b_, 25 to
742_a_, 8; 743_a_, 3 to _b_, 29; 743_b_, 35 to 744_a_, 14; 744_a_,
26-31; 751_b_, 6; 752_a_, 1-4; 755_a_, 10-25; 762_b_, 6-9; 766_a_,
33 to _b_, 1; 768_b_, 15-36; 772_a_, 23-25; 781_a_, 14 to _b_, 29;
783_b_, 29-32; 789_b_, 7-12. Politics, 1336_a_, 34-39.

[141] Hippocrates: On the Heart, Lit. Vol. IX, 86-92.

[142] Galen: On the Doctrines of Hippocrates and Plato, Kn. Vol. V,
547-563; Mül. 537, l. 15 to 555, l. 11.

[143] The extant works of Aretæus the Cappadocian; edited and
translated by Francis Adams. London, printed for the Sydenham
Society, 1856. Therapeutics of Acute Diseases, Book II, Chapter 6,
[Greek text] 190; [English translation] 440-441; Chapter 7, [Greek
text] 193; [translation] 443.

[144] Hippocrates: On Nourishment, Lit. Vol. IX, 110. Galen:
Commentary IV on the foregoing, Kn. Vol. XV, 388-392; On the
Doctrines of Hippocrates and Plato, Kn. Vol. V, 529, 531-532 and
577-578; Mül. 517, l. 7-15, 520, l. 2 to 521, l. 4, 570-571.

[145] Galen: On the Use of the Parts, etc., Kn. Vol. III, 451, l. 16
to 452, l. 2; Dar. Vol. I, 412, l. 5-8.

[146] Among Galen's numerous works the following are the treatises
and parts of treatises which are most important for a student of
Galen's doctrines regarding the movement of the blood. A title
quoted without further specification indicates a treatise in one
book only, the whole of which should be read. Where no chapters of
a book are specified the whole book should be read. The order is
that of Kühn's edition: On the Natural Faculties, Book III, chapters
13-15, Kn. Vol. II, Dar. Vol. II. On Anatomical Manipulations,
Book VII, chapters 4, 14, 15, 16; Book VIII, chapter 8, Kn. Vol.
II. On the Dissection of the Veins and Arteries, chapters 1, 2, 8,
9, Kn. Vol. II. On the Use of the Parts of the Human Body, Books
IV, VI, VII, IX, Kn. Vol. II, Dar. Vol. I, Book XVI, Kn. Vol. IV,
Dar. Vol. II. On the Causes of Respiration, Kn. Vol. IV. On the Use
of Respiration, Kn. Vol. IV. Is Blood Naturally Contained in the
Arteries? Kn. Vol. IV. On the Use of the Pulse, Kn. Vol. V. On the
Doctrines of Hippocrates and Plato, Book I, chapter 7, Book II,
chapter 8, Book III, chapter 8, Book VI, Book VII, chapter 3, Kn.
Vol. V. On the Causes of Disease, chapter 3, Kn. Vol. VII. On the
Different Kinds of Pulse, Book IV, chapters 2, 6, 17, Kn. Vol. VIII.
On the Causes of the Pulse, Book I, chapters 3, 4, Book II, chapter
15, Kn. Vol. IX. On Prognosis by the Pulse, Book II, chapter 1, Kn.
Vol. IX. On Methods of Treatment, Book VIII, chapter 5, Book IX,
chapter 10, Book XII, chapter 5, Kn. Vol. X. Commentaries on the
Book on Nourishment of Hippocrates, Commentary III, chapters 8, 10,
23, Commentary IV, chapters 4, 6, Kn. Vol. XV. Commentaries on the
Book on the Humors of Hippocrates, Commentary III, chapter 31, Kn.
Vol. XVI. Commentaries on the Sixth Book of Hippocrates on Epidemic
Diseases, Commentary VI, chapters 1-3, Kn. Vol. XVII, Pars II.

[147] For the views of Columbus see his book: De Re Anatomica, Lib.
VI, VII, XI, cap. 1, 2, 4; XII and XIII.

[148] Columbus: De Re Anatomica, Lib. VII, 180, l. 1-6.

[149] Harvey: Prelectiones, 33 and 35 right; 74 and 75 left. On the
Motion, etc., XVI, Syd. 73, l. 12-17 and l. 24-28; Op. Omn. 74, l.
15-19 and l. 24-28; Do., XVIII, Syd. 83, l. 9-27; Op. Omn. 84, l. 31
to 85, l. 14. On Generation, LIII, Syd. 392, l. 14 to 393, l. 5; Op.
Omn. 409, l. 13 to 410, l. 5; Do., LX, Syd. 452, l. 20-28; Op. Omn.
472, l. 1-7. On Uterine Membranes and Humours, Syd. 568, l. 8-27;
Op. Omn. 587, l. 19 to 588, l. 5.

[150] Harvey: On the Motion, etc., Syd. 32, l. 39 to 33, l. 31; Op.
Omn. 34, l. 24 to 35, l. 19. In Galen's book, from which Harvey here
quotes, the quoted passage is preceded by a corrected statement of
the mechanics of the valves of the heart, and a declaration that
their mechanics were unknown to Erasistratus. Then follow these

     "If this be so, O followers of Erasistratus, let us omit all
     else and consider only what is in controversy. As to the vena
     cava, which conveys blood from the liver into the heart, in
     which of two ways are its membranes [i.e. the segments of the
     tricuspid valve] inserted: do they extend from the interior [of
     the ventricle] outward, or contrariwise, from without inward?
     But perhaps this is of no great moment!"

The preceding words are immediately followed by the words quoted
by Harvey. The context shows that the phrase "from without inward"
indicates the true insertion of the "membranes" of the tricuspid
valve, according to both Galen and the facts. Harvey himself refers
his quotation from Galen to the treatise "On the Doctrines of
Hippocrates and Plato, Book VI." It is from chapter 6 of that book.
The Latin text quoted by Harvey, and that from which the quotation
in this note has been translated, may be found in the Ninth Juntine
Edition of Galen's works, consisting of Latin translations by
various hands. This edition was published in Venice in 1625, three
years before the publication of Harvey's treatise. The title of the
edition is: Galeni Opera ex Nona Juntarum Editione, etc. Venetiis,
apud Juntas, MDCXXV, Cum privilegiis. The passage quoted in this
note is: "Prima classis," folio 264 D, l. 53-56. Harvey's quotation
is: folio 264 D, l. 56 to folio 264 (verso) E, l. 3. The Greek text
of the passage quoted in this note is to be found in Kn. Vol. V,
550, l. 9-15; Mül. 541, l. 4-9. The Greek text of Harvey's quotation
is in Kn. Vol. V, 550, l. 15 to 551, l. 6; Mül. 541, l. 10 to 542,
l. 2. The Latin rendering printed in the Juntine edition gives the
true meaning of the Greek text, but in a rather lumbering fashion.

[151] The transit of the blood from the right to the left ventricle.

[152] The Galenic work entitled: "Is Blood Naturally Contained in
the Arteries?" Kn. Vol. IV, 703-736.

[153] Harvey: On the Motion, etc., V, Syd. 32, l. 39 to 34, l. 22;
Op. Omn. 32, l. 24 to 36, l. 15. The second Galenic passage above,
which refers to the origin and contents of the arteries and to the
aortic valves, is printed in italics and with quotation marks in the
first edition of Harvey's treatise, and Harvey's own words regarding
this passage seem to mean that it is a verbal quotation from Galen.
But neither in Galen's treatise entitled "Is Blood Naturally
Contained in the Arteries?" nor in the sixth book of his treatise
On the Doctrines of Hippocrates and Plato, does more than the
last part of this seeming quotation occur. The rest appears to be
merely a sound statement by Harvey of Galenic doctrines, for which
abundant authority can be found in the two treatises aforesaid.
See especially for the origin of the arteries: On the Doctrines of
Hippocrates and Plato, Book VI, chapter 3, Kn. Vol. V, 524, l. 13 to
525, l. 3; Mül. 512, l. 4-13; and for the contents of the arteries:
chapter 4, Kn. Vol. V, 537, l. 1-7; Mül. 526, l. 1-7; and chapter 8,
Kn. Vol. V, 572, l. 12 to 573, l. 11; Mül. 565, l. 10 to 566, l.
12. Of the words relating to the aortic valves, the first part is a
statement justified by the words which occur in the Ninth Juntine
edition of Galen's works, Classis I, folio 264C, l. 41-43 and D,
l. 49-53. But the last part of the passage aforesaid is a verbal
quotation of words on folio 264 verso E, l. 9-11. This passage
relating to the valves is all in Galen's treatise On the Doctrines
of Hippocrates and Plato, Book VI, chapter 6. The Greek text may be
found as follows: Kn. Vol. V, 549, l. 3-8, 549, l. 18 to 550, l. 6,
552, l. 1-3; Mül. 539, l. 10 to 540, l. 1, 540, l. 11 to 541, l. 1,
543, l. 1-3.

[154] Harvey: Letter to Slegel, Syd. 598, l. 21-23; Op. Omn. 614, l.

[155] Aristotle: On Soul, 405_b_, 1-8.

[156] Harvey: Prelectiones, 80 right. Compare pp. 42-46 of this

[157] Harvey: Prelectiones, 79 right.

[158] That is, one may suppose, after development _in utero_ has

[159] _Anima._

[160] Harvey: Prelectiones, 33 left.

[161] Harvey: Prelectiones, 75 left.

[162] Harvey: Prelectiones, 76 right.

[163] _Non propria ratione._

[164] _Sanguinis multitudine._

[165] _Pullulare._

[166] The two words "household shrine" represent the one word

[167] Harvey: Prelectiones, 73 left. In the photograph of folio
73 left of Harvey's note-book, the 16th line of text consists, as
translated, of the words "Is there only a drop of blood in the
auricles?" This line has the appearance of an interlineation. If it
be really such, the words which follow it to the end of the passage
were meant, when jotted down, to refer to the heart and not to "a
drop of blood."

[168] _Rationem._ Compare Harvey: On Generation, LXXI, Syd. 507, l.
16-26; Op. Omn. 528, l. 21-29.

[169] Harvey: Exercise to Riolanus, II, Syd. 136, l. 37 to 137, l.
17; Op. Omn. 136, l. 25 to 137, l. 9.

[170] Harvey: On Generation, Introduction, Syd. 167, l. 2-5; Op.
Omn. 180, l. 23-26.

[171] Harvey: On Generation, XIV, Syd. 226, l. 38 to 227, l. 16; Op.
Omn. 240, l. 22 to 241, l. 3.

[172] _Animalis._

[173] Harvey: On Generation, XLVI, Syd. 341, l. 25-37; Op. Omn. 357,
l. 5-15.

[174] That is, the mammalian embryo.

[175] Harvey: On Generation, LIII, Syd. 392, l. 1-13; Op. Omn. 409,
l. 1-12.

[176] Harvey: On the Motion, etc., Dedication to the King, Syd. 3,
l. 2-3; Op. Omn. 3, l. 2. On the Motion, etc., VIII, Syd. 47, l.
7-9; Op. Omn. 49, l. 13-14.

[177] _Idque non solum in ovo, sed in omni fœtu, animaliumque
conceptu primo contingere, mox palam fiet._ Harvey: On Generation,
_Editio princeps_, 149, l. 33-35. In the Opera Omnia, 390, l.
1-3, a comma has been erroneously placed between "_conceptu_"
and "_primo_"; the latter word qualifies "_conceptu_," not
"_contingere_." Compare Op. Omn. 391, l. 4: _in primis animalium

[178] _In primis animalium conceptibus._

[179] Harvey: On Generation, LI, Syd. 373, l. 35 to 374, l. 27 and
374, l. 36 to 375, l. 8; Op. Omn. 389, l. 28 to 390, l. 22 and 390,
l. 30 to 391, l. 8.

[180] Harvey: Exercise to Riolanus, II, Syd. 137, l. 2-4 and 138, l.
12-13; Op. Omn. 136, l. 29-30 and 138, l. 6-7.

[181] Milton: Areopagitica, edited with introduction and notes by J.
W. Hales, Oxford, 1874, 38.

[182] The "point" is the embryonic heart, to which in its earliest
visible state the name of "_punctum saliens_," _i.e._, "leaping
point," had been given, this technical term having been coined no
doubt out of expressions used by Aristotle in speaking of the living
rudimentary heart as seen with the naked eye in the hen's egg and in
mammalian abortions. Compare Aristotle: History of Animals, 561_a_,
6-17; On the Parts of Animals, 665_a_, 33 to _b_, 2.

[183] Presumably the terminal sinus of modern embryology.

[184] The fourth day of incubation.

[185] _Per totum colliquamentum._ For Harvey's account of this clear
liquid see On Generation, XVI, Syd. 232, l. 15 to 234, l. 31; Op.
Omn. 246, l. 4 to 248, l. 17.

[186] Aristotle: History of Animals, Book VI, chapter 3. This
reference is Harvey's own. Aristotle's words are πόροι φλεβικοί
(561_a_, 13), which are given by Harvey as "_meatus venales_."

[187] Harvey: On Generation, XVII, Syd. 237, l. 16 to 238, l. 12 and
238, l. 25-35; Op. Omn. 251, l. 6 to 252, l. 3 and 252, l. 15-22.

[188] Harvey: On Generation, XIX, Syd. 252, l. 1 and l. 9-11; Op.
Omn. 266, l. 3 and l. 11-13.

[189] Harvey: On Generation, XVI, Syd. 415, l. 22-24; Op. Omn. 433,
l. 22-24.

[190] Harvey: On Generation, LVI, Syd. 415, l. 32-38; Op. Omn. 433,
l. 31 to 434, l. 4.

[191] Harvey: On the Motion, etc., IV, Syd. 30, l. 14-22; Op. Omn.
32, l. 8-14.

[192] Harvey: On Generation, LI, Syd. 373, l. 35 to 374, l. 27; Op.
Omn. 389, l. 28 to 390, l. 22.

[193] ἡ ἀρχή.

[194] ἀλλὰ καὶ περὶ τὴν τελευτήν.

[195] ὤσπερ τῆς φύσεως διαυλοδρομούσης καὶ ἀνελιττομένης ἐπὶ
τὴν ἀρχὴν ὄθεν ἠλθεν.

[196] Aristotle: On the Generation of Animals, 741_b_, 15-24.

[197] In his lecture notes Harvey, in dealing with the heart, speaks
of the right auricle as "the last to pulsate." Prelectiones, 74
right, l. 17.

[198] Harvey: On the Motion, etc., IV, Syd. 28, l. 23-34 and 29, l.
6-16; Op. Omn. 30, l. 13-24 and 31, l. 1-8.

[199] Leviticus XVII, 11 and 14--Harvey's own reference.

[200] Harvey: On Generation, LI, Syd. 376, l. 14 to 377, l. 2; Op.
Omn. 392, l. 15 to 393, l. 6.

[201] Harvey: On Generation, XVII, Syd. 239, l. 32 to 240, l. 7; Op.
Omn. 253, l. 19-31.

[202] Harvey: On the Motion, etc., IV, Syd. 28, l. 15-21; Op. Omn.
30, l. 7-12.

[203] Harvey: On Generation, LI, Syd. 374, l. 28-35; Op. Omn. 390,
l. 23-29. Compare: On the Motion, etc., XVII, Syd. 76, l. 11-29; Op.
Omn. 77, l. 21 to 78, l. 9.

[204] Harvey: Exercise to Riolanus, II, Syd. 122, l. 31 to 123, l.
18, 124, l. 28-37, 130, l. 29 to 132, l. 25; Op. Omn. 122, l. 16 to
123, l. 2, 124, l. 11-17, 130, l. 15 to 132, l. 17. On Generation,
LXXI, Syd. 503, l. 15-18; Op. Omn. 524, l. 21-24. Letter to Morison,
Syd. 604, l. 13-19; Op. Omn. 620, l. 24 to 621, l. 3.

[205] Harvey: Exercise to Riolanus, II, Syd. 137, l. 15-16; Op. Omn.
137, l. 7-9.

[206] Harvey: Exercise to Riolanus, II, Syd. 136, l. 37 to 138, l.
16; Op. Omn. 136, l. 25 to 138, l. 10.

[207] Harvey: On Generation, LI, Syd. 375, l. 8-39; Op. Omn. 391, l.
9 to 392, l. 2.

[208] ἡ ζύμη.

[209] πνευματυμένου.

[210] Aristotle: On the Generation of Animals, 755_a_, 18-21.

[211] ζέσις.

[212] πνευματουμένου.

[213] Aristotle: On Respiration, 479b, 26-27 and 30-32.

[214] πρὸς τὸν ἔσχατον χιτῶνα.

[215] ἀναθυμίασις.

[216] διά τὸ ἠρτῆσθαι ἐκ τῆς καρδίας.

[217] ὄτε.

[218] πήδησις, _i.e._, the "palpitation" of modern medicine.

[219] πνευμάτωσις.

[220] Aristotle: On Respiration, 480_a_, 2-15.

[221] Aristotle: History of Animals, 521_a_, 6-7.

[222] Galen: On Local Affections, Kn. Vol. VIII, 429, l. 10-12;
Dar. Vol. II, 693, l. 35-37. Plutarch: On the Opinions of the
Philosophers, Book IV, chapter 22, Diels: Doxographi Graeci, Berlin,
1879, 412, l. 7-9.

[223] Galen: On the Motion of the Muscles, Kn. Vol. IV, 367, l. 1-3
and 382, l. 14 to 383, l. 2; Dar. Vol. II, 321, l. 1-3 and 330, l.

[224] Harvey: On the Motion, etc., XVII, Syd. 81, l. 20-31 and 82,
l. 29 to 83, l. 8; Op. Omn. 83, l. 9-18 and 84, l. 15-30.

[225] Harvey: Exercise to Riolanus, II, Syd. 137, l. 17-22; Op. Omn.
137, l. 27-32.

[226] _Cuius vero rei gratia? Aristotelis. Nullius sed passio ut
in pulte ebulliente WH sed vulneratum non flatum sed sanguinem
Emittit._ Harvey: Prelectiones, 79 right.

[227] _Non ab attractione aliqua._

[228] Harvey: Exercise to Riolanus, II, Syd. 140, l. 15-29; Op. Omn.
140, l. 11-22.

[229] Harvey: Letter to Morison, Syd. 604, l. 22-33; Op. Omn. 621,
l. 6-15.

[230] Harvey: Exercise to Riolanus, II, Syd. 132, l. 26 to 133, l.
14; Op. Omn. 132, l. 18 to 133, l. 11.

[231] Harvey: Exercise to Riolanus, II, Syd. 113, l. 24-25; Op. Omn.
113, l. 19-20.

[232] Harvey: On the Motion, etc., XVII, Syd. 80, l. 32; Op. Omn.
82, l. 15-16.

[233] Compare Harvey: Exercise to Riolanus, II, Syd. 122, l. 19-28;
Op. Omn. 122, l. 8-14.

[234] Harvey: On the Motion, etc., IV, Syd. 27, l. 25-27; Op. Omn.
29, l. 12-14.

[235] _Ad constitutionem suam._ Harvey: On the Motion, etc., XVII,
Syd. 80, l. 39 to 81, l. 3; Op. Omn. 82, l. 22-26.

[236] Harvey: Prelectiones, 79 left, l. 19 and 80 left, l. 8-10;
Columbus: De Re Anatomica, Lib. XI, 223, l. 37-39 and 224, l. 16-21.

[237] Harvey: Exercise to Riolanus, II, Syd. 132, l. 11-15; Op. Omn.
132, l. 4-7.

[238] _Quia non pulsant. sed potius attrahi._ The jotting would
seem to leave the verb "_videntur_" or the like, to be understood.
Harvey: Prelectiones, 80 left, l. 8-13.

[239] _Eodem tempore tactu sentitur pulsus Arteriae quasi attrahitur
vena cava._ Harvey: Prelectiones, 77 right, l. 11-12.

[240] Harvey: On the Motion, etc., Syd. 21, l. 23-27; Op. Omn. 23,
l. 16-19. Compare Exercise to Riolanus, II, Syd. 139, l. 26 to 140,
l. 29; Op. Omn. 139, l. 21 to 140, l. 22.

[241] _Auriculae pulsant post emotum cor sanguinis multitudine._
Harvey: Prelectiones, 73 left, l. 10.

[242] Harvey: Prelectiones, 77 right, l. 15.

[243] _Quorum radicale humidum glutinosum magis, aut pingue, et
lentum est, et non ita facile dissolubile._

[244] Harvey: On the Motion, etc., IV, Syd. 28, l. 4-14; Op. Omn.
29, l. 29 to 30, l. 6.

[245] Harvey: Exercise to Riolanus, II, Syd. 138, l. 9-11; Op. Omn.
138, l. 4-6.

[246] Galen: On Anatomical Manipulations, Kn. Vol. II, 614, l. 8-11.
On the Doctrines of Hippocrates and Plato, Kn. Vol. V, 238, l. 7 to
239, l. 1; Mül. 198, l. 4-16.

[247] Cicero: On the Nature of the Gods, Müller, Leipsic, 1903, 55,
l. 20-22. Harvey says in his lecture notes: "_Item_ Cicero [has]
much about the use of the parts in De Natura Deorum libro 2°."
Prelectiones, 98 left, l. 25.

[248] Vesalius: De Humani Corporis Fabrica, Lib. VI, cap. 8, 584, l.

[249] Harvey: On the Motion, etc., Syd. 53, l. 26 to 54, l. 15; Op.
Omn. 55, l. 21 to 56, l. 11.

[250] For the references to Galileo Galilei, Evangelista Torricelli
and Blaise Pascal, see J. C. Poggendorff, Geschichte der Physik,
Leipsic, 1879, 251-255, 319-325 and 328-334.

[251] S. Hales: Statical Essays, containing Hæmastaticks, etc. Vol.
II, London, 1733. Preface, pp. xvii, l. 13 to xviii, l. 22 and
Experiment III, 13, l. 13 to 17, l. 3. See also P. M. Dawson: The
Biography of Stephen Hales, D.D., F.R.S., Johns Hopkins Hospital
Bulletin, Vol. XV, No. 159, June, 1904, 185-192. Stephen Hales the
Physiologist, Do., Vol. XV, Nos. 160-161, July-August, 1904, 232-237.

[252] Harvey: Exercise to Riolanus, II, Syd. 134, l. 7-16; Op. Omn.
134, l. 8-15.

[253] Harvey: Exercise to Riolanus, II, Syd. 135, l. 12-16; Op. Omn.
135, l. 11-15.

[254] Harvey: Exercise to Riolanus, I, Syd. 93, l. 37 to 94, l. 5;
Op. Omn. 95, l. 29 to 96, l. 4.

[255] Harvey: Letter to Slegel, Syd. 598, l. 36 to 602, l. 34; Op.
Omn. 615, l. 10 to 619, l. 7.

[256] _Cacochymica._

[257] Harvey: Exercise to Riolanus, II, Syd. 124, l. 5-10; Op. Omn.
123, l. 25-29.

[258] Harvey: Exercise to Riolanus, II, Syd. 122, l. 9-12; Op. Omn.
122, l. 1-3.

[259] Harvey: Letter to Slegel, Syd. 602, l. 7-10; Op. Omn. 618, l.

[260] _Quasi versus principium._

[261] _Et contra spontaneum moveatur._

[262] Harvey: On the Motion, etc., XV, Syd. 70, l. 33 to 71, l. 11;
Op. Omn. 72, l. 4-17.

[263] _Lacuna._

[264] _Declinante sponte sanguine et, venarum motu, compresso ad
centrum._ Harvey: On the Motion, etc., IV, Syd. 27, l. 33-35; Op.
Omn. 29, l. 19-21.

[265] Malpighi: Letter II Regarding the Lungs, Bologna, 1661.
Marcelli Malpighii Opera Omnia, Leyden, 1687, Vol. II, 328.

[266] Harvey: Exercise to Riolanus, I, Syd. 96, l. 37 to 97, l. 13;
Op. Omn. 99, l. 2-15. The term "circulatory vessels" is one repeated
by Harvey from Riolanus, whose views he is here refuting. Riolanus
speaks of the region outside the liver, to which the branches of
the portal vein are distributed, as the "first region." The "second
and third regions" appear to comprise all the rest of the body. See
Harvey: Exercise to Riolanus, I, Syd. 90, l. 30 to 91, l. 23; Op.
Omn. 92, l. 21 to 93, l. 18. See also Joannes Riolanus, Filius:
Encheiridium Anatomicum et Pathologicum, 154, l. 1-13; 155, l. 17 to
156, l. 17; 297, l. 7-17.

[267] _Quibus absorptus et exhaustus traducitur._ Harvey: Exercise
to Riolanus, II, Syd. 133, l. 30-39; Op. Omn. 133, l. 25 to 134, l.

[268] _In sinistri ventriculi locum._ Harvey: On the Motion, etc.,
VII, Syd. 45, l. 5-9; Op. Omn. 47, l. 7-10.

[269] Harvey: Exercise to Riolanus, II, Syd. 133, l. 3-6; Op. Omn.
132, l. 30 to 133, l. 2.

[270] Harvey: Prelectiones, 86 left, l. 30-32.

[271] Harvey: Prelectiones, 33 left, l. 31.

[272] Shakspere: Hamlet, Act I, Scene IV, l. 70-73.

[273] ἀύτη γὰρ ὀυσία ὀφθαλμοῦ ἡ κατὰ τὸν λόγον.

[274] κίνησις. Cf. p. 52.

[275] δύναμις.

[276] ὅτι ἐστὶν ἡ ψυχὴ τῶν ἐιρημένων τούτων
ἀρχὴ καὶ τούτοις ὥρισται.

[277] θρεπτικῷ, ἀισθωτικῷ, διανοητικῷ, κινήσει.

[278] The foregoing passages from Aristotle's treatise On Soul occur
respectively as follows: 412_a_, 14-15; 414_a_, 12-14; 412_b_,
18-22; 413_a_, 26; 413_a_, 31; 413_a_, 20-26; 413_a_, 31 to _b_, 16.

[279]  ὀυθὲν γὰρ ἀυτοῦ τῇ ἐνεργείᾳ κοινωνεῖ
[σωματικὴ ἐνέργια.]

[280] Aristotle: On the Generation of Animals, 736_a_, 24 to 737_b_,
7. The quoted passage is 736_b_, 28-29. Compare On Soul, 413_b_,

It was not Greek philosophy alone in which in ancient times the word
corresponding to "soul" was used in a wider sense than that of the
quotation from "Hamlet." In the English Authorized Version of the
Old Testament, first published in 1611, we read in Genesis II, 7:
"Man became a living soul." The reading is the same in the Revised
Version of 1885. In Genesis I, 30, we read in both versions: "And
to every beast of the earth, and to every fowl of the air, and to
every thing that creepeth upon the earth, wherein _there is_ life,
_I have given_ every green herb for meat." In both versions it is
noted in the margin that the expression translated by the single
English word "life" is, in the Hebrew, "a living soul." Accordingly
we find this Hebrew expression of Genesis I, 30, rendered "a soul
of life"--ψυχὴν ζωῆς,--in the ancient translation of
the Old Testament into Greek, known as the "Septuagint," which was
probably completed less than two hundred years after the death of
Aristotle and more than one hundred and fifty years before the
Christian era. In the early Latin translation of the Scriptures
which was finished in A.D. 405, and is largely embodied in the
"Vulgate" of to-day, we read in the same verse--Genesis I, 30,
"_anima viviens_"--"a living soul." In Genesis II, 7, where the
reference is to man himself and the English Bible reads "a living
soul," the Vulgate reads "_animam viventem_," using the same Latin
words as for the lower creatures of I, 30. In like manner the
Septuagint reads in Genesis II, 7, ψυχὴν ζῶσαν, as it
reads in I, 30, ψυχὴν ζωῆς. Other instances from the Book
of Genesis could be cited of the wide significance given therein to
the expression which corresponds to "soul."

[281] _Domi._ Compare Aristotle: On the Generation of Animals,
736_a_, 24 to 737_b_, 7.

[282] Harvey: On Generation, LXXI, Syd. 511, l. 1-24; Op. Omn. 532,
l. 9-29.

[283] _Neque sanguinis vim, virtutem, rationem, motum, aut calorem,
ut cordis domum, habet._ Harvey: Exercise to Riolanus, II, Syd. 137,
l. 16-17; Op. Omn. 137, l. 8-9.

[284] Hippocrates: On the Nature of Man, Lit. Vol. VI, 44, l. 7-10.

[285] Harvey: On Generation, XVII, Syd. 239, l. 13-23 and l. 29-31;
Op. Omn. 253, l. 3-11 and l. 15-18.

[286] Harvey: On Generation, LVII, Syd. 430, l. 23-33; Op. Omn. 449,
l. 11-21.

[287] _Promanat._

[288] Harvey: On Generation, XLVII, Syd. 347, l. 26 to 348, l. 3;
Op. Omn. 363, l. 18 to 364, l. 2.

[289] _Primigenia._

[290] Harvey: On Generation, LI, Syd. 375, l. 40 to 376, l. 8; Op.
Omn. 392, l. 3-10.

[291] Leviticus XVII, 11 and 14--Harvey's own reference. Not these
two verses merely, but the whole of chapter XVII, should be read,
not only in the Authorized Version, but in the Revised Version also.

[292] Harvey: On Generation, LI, Syd. 376, l. 19-21; Op. Omn. 392,
l. 20-22.

[293] Harvey: On Generation, LI, Syd. 377, l. 3-11; Op. Omn. 393, l.

[294] Harvey: On Generation, LII, Syd. 380, l. 14-16; Op. Omn. 396,
l. 18-20.

[295] Harvey: On Generation, LII, Syd. 381, l. 26-35; Op. Omn. 398,
l. 1-8.

[296] Harvey: On Generation, LII, Syd. 391, l. 11-30; Op. Omn. 408,
l. 8-22.

[297] Aristotle: On Soul, Book I, chapter 2--Harvey's own reference.
For Thales, Diogenes, Heraclitus, Alcmæon, and their views, see
also Zeller, Die Philosophie der Griechen, I Theil, 5 Auflage,
Leipsic, 1892. For Critias, see William Smith, Dictionary of Greek
and Roman Biography and Mythology, Vol. I, London, 1880, 892.

[298] Aristotle: History of Animals, I, chapter 19--Harvey's own
reference. This should read III, chapter 19, 520_b_, 14-17 and
521_a_, 6-9. The reference to Book I is an error of the press which
has been copied without correction from the _Editio Princeps_ in
both the Opera Omnia and the Sydenham translation. Aristotle: On the
Parts of Animals, II, chapter 3 (Harvey's own reference), 650b, 2-8.

[299] Harvey: On Generation, LII, Syd. 380, l. 37 to 381, l. 20; Op.
Omn. 397, l. 8-27.

[300] Plato: Phædo, 96_b_: Platonis Dialogi, Hermann-Wohlrab, Vol.
I, 142, l. 2-3.

[301] Censorinus: De Die Natali, chapter VI, § 1, Edition Hultsch,
1867, 10.

[302] Empedocles: Fragment 105, l. 3; Diels, Poetarum Philosophorum
Fragmenta, Berlin, 1901, 146, constituting Vol. III of Wilamowitz-
Moellendorf, Poetarum Græcorum Fragmenta. See also Zeller, Die
Philosophie der Griechen, I Theil, 5 Auflage, 1892.

[303] Theophrastus: Opera Omnia: On Sensation and Sensible Things,
II, (10), Edition Wimmer, 323_a_, Paris, Didot, 1866.

[304] Compare Aristotle: On Soul, 404_b_, 27-30.

[305] Aristotle: History of Animals, 520_b_, 14-17.

[306] Harvey: On Generation, LII, Syd. 382, l. 18-21; Op. Omn. 398,
l. 24-27.

[307] Harvey: On Generation, LII, Syd. 380, l. 3-6; Op. Omn. 396, l.

[308] Harvey: On Generation, LII, Syd. 390, l. 35 to 391, l. 2; Op.
Omn. 407, l. 25-30.

[309] See Harvey: Letter to Hofmann, Syd. 595, l. 6-15; Op. Omn.
635, l. 10-17.

[310] See J. B. Meyer: Aristoteles' Thierkunde, 1855, 411, l. 14 to
413, l. 2.

[311] _Calor animalis._

[312] Harvey: On Generation, LXXI, Syd. 501, l. 29 to 502, l. 16 and
502, l. 38 to 503, l. 20; Op. Omn. 523, l. 1-16 and 524, l. 8-24.

[313] Harvey: On Generation, LXXI, Syd. 504, l. 6-10; Op. Omn. 525,
l. 13-16.

[314] Harvey: On Generation, LXXI, Syd. 504, l. 16-34; Op. Omn. 525,
l. 20 to 526, l. 2.

[315] Aristotle: On the Generation of Animals, Book II, chapter 3
(Harvey's own reference), 736_b_, 29-31.

[316] The Latin translation of this passage which is quoted by
Harvey reads: "_Omnis animae sive potentia_, etc." The Greek text of
Aristotle reads: "πάσης μὲν ὀῦν ψυχῆς δὺναμις," κ.τ.λ.,
meaning "the faculty of every soul." In the part of the chapter
which just precedes this passage Aristotle discourses of "the
nutritive soul," "the sensory soul," and "the intellectual soul";
and the context makes it clear that the words of the passage quoted
by Harvey refer to the faculty of every kind of soul, and not simply
to the faculty of the soul of every living being.

[317] ἑτέρου σώματος ἔοικε κεκοινωνηκέναι, κ.τ.λ. The
Latin translation of these words, which is quoted by Harvey, reads:
"_corpus aliud participare videtur_." Regarding the significance
of κεκοινωνηκέναι in this passage compare Aristotle:
Economics, 1343a, 10-12; although this treatise is now believed to
be not by Aristotle himself, but by a later member of his school.

[318] Aristotle: On the Generation of Animals, 736_b_, 33 to 737_a_,

[319] πνεῦμα (_Pneuma_).

[320] The following are the words of Aristotle which Harvey omits
from his quotation:--

     "and, moreover, as the souls differ one from another in nobility
     and ignobleness, so too does the nature aforesaid differ."
     (Aristotle: On the Generation of Animals, 736_b_, 31-33.)

If these words be read in their proper connection, it becomes clear
that "the nature which is analogous to the element of the stars"
is the same as "the nature aforesaid" (ἡ τοιαύτη φύσις),
which is the "body other than the so-called elements and more
divine." Fire is repeatedly styled a "body" by Aristotle, it being
one of the four "simple bodies" (ἁπλᾶ σώματα) or elements.
Compare Aristotle: On Generation and Corruption, 330_b_, 1-3. We
shall find that Harvey in his turn styles fire a "body" (_corpus_).
See Harvey: On Generation, LXXI, Syd. 506, l. 26-31; Op. Omn. 527,
l. 28 to 528, l. 1.

The Latin translation of Aristotle which Harvey quotes reads, in
dealing with the "spirits": "_spiritus qui in semine spumosoque
corpore continetur, et natura quae in eo spiritu est proportione
respondens elemento stellarum_." (Aristotle: On the Generation of
Animals, Vol. III, 360_b_, 4-5.) The Greek text reads: τὸ
ἐμπεριλαμβανόμενον ἐν τῷ σπέρματι καὶ ἐν τῷ ἀφρώδει πνεῦμα καὶ ἐν τῷ πνεύματι φύσις,
ἀνάλογον ὀῦσα τῷ τῶν ἄστρων στοιχείῳ (736_b_, 35 to 737_a_, 1). Two
manuscripts omit "ἐν" before "τῷ πνεύματι."

In the chapter immediately preceding Aristotle says:--

     "Not only does a liquid become thick which is made of water and
     earthy matter, but also one made of water and spirits; even as
     foam thickens and whitens; and the smaller and less conspicuous
     the bubbles are, the whiter and stiffer does the mass appear.
     Oil, too, is affected in the same way; for it becomes thick when
     mixed with spirits, so that, as it whitens, it thickens; what
     is watery within it being separated by the heat, and becoming
     spirits.... For the reasons aforesaid the semen, too, is stiff
     and white as it issues from within, since it contains much hot
     spirits due to the interior heat. But after the exit of the
     semen, when its heat has exhaled and its air has cooled, it
     liquefies and darkens. For in drying semen, as in phlegm, the
     water remains and perhaps some little earthy matter. The semen
     then is a combination of spirits and water, the spirits being
     hot air; so the semen, being derived from water, is naturally
     liquid.... The cause of the whiteness of the semen is that the
     generative medium (ἡ γονή) is foam, and that foam is
     white.... It seems not to have escaped even the ancients that
     the nature of semen is foamy; at all events they named from this
     property (δυνάμεως) the goddess who rules coition."
     (Aristotle: On the Generation of Animals, 735_b_, 8-16; 735_b_,
     32 to 736_a_, 2; 736_a_, 13-14 and _a_, 18-21.)

A very ancient poem, ascribed to Hesiod, relates the myth of
Aphrodite and says that she was so called by gods and men "because
she was produced in foam." (Theogony, l. 197-198.) The "air"
ἀήρ o f one of the foregoing passages from Aristotle
is of course not atmospheric air, but something aëriform produced
by heat, as the context shows. In the same treatise he speaks of
the presence, within the early embryo which has never breathed,
of spirits (πνεῦμα) due to heat and moisture, "the one
active, the other passive." (On the Generation of Animals, 741_b_,
37 to 742_a_, 16.)

[321] The Latin translation quoted by Harvey renders the Greek words
"ὀυδὲ φαίνεται συνιστάμενον πυρουμένοις ὀύτ' [ἐν]
ὑγροῖς ὀύτ ἐν ξηροῖς ὀυθέν" (737a, 1-3) by the misleading
words "_neque constitui quidquam densis vel humidis vel siccis
videntur_." Therefore, in translating this passage into English, it
has seemed necessary to make it intelligible by giving to the word
"πυρουμένοις" its proper meaning, rather than by rendering
literally the earlier translator's ill-chosen Latin word "_densis_."

[322] The Latin quoted by Harvey, viz.: "_qui semine continetur_,"
scarcely gives the force of the original Greek "ἡ διὰ τοῦ
σπέρματος" (737_a_, 3-4), which Greek words, rather than the
Latin, are rendered in the present English translation.

[323] ἀλλὰ κἄν tι περίττωμα τύχῃ τῆς φύσεως ὂν ἕτερον.
κ.τ.λ. (737_a_, 4-5). Compare the construction of this passage with
that of the following: διά τὸ πλησιαίτερα ἡμῶν ἐῖναι καὶ
τῆς φύσεως ὀικειότερα. κ.τ.λ. Aristotle: On the Parts of Animals,
645_a_, 2-3.

[324] Aristotle: On the Generation of Animals, 736_b_, 33 to 737_a_,
7. In translating into English the foregoing Aristotelian passages
the present writer has sought rather to indicate than to smooth away
the ruggedness of the original Greek. Harvey quotes these passages
verbatim from a Latin translation which may be found in Volume III
of the Berlin Academy's quarto edition of Aristotle's works. This
translation was made in the fifteenth century by Theodore Gaza, a
learned Greek of Thessalonica, who had fled from the conquering
Turks to Italy, where he learned Latin not long before his thirtieth
year. Gaza was neither physician nor biologist. In view of these
facts we need not wonder that his Latin version of Aristotle On the
Generation of Animals is occasionally unsatisfactory, as we have
seen. In the edition of the Greek text of Aristotle's History of
Animals, published by Teubner in 1907 (Aristotelis De Animalibus
Historia, textum recognovit Leonardus Dittmeyer, 1907, Leipsic,
p. XXII, l. 1-5), the editor says in his Latin preface, regarding
Gaza's Latin Translation of the History of Animals: "There is
need of caution, if we wish to unearth the Greek text from his

[325] _Respondens_, not _proportione respondens_.

[326] Harvey: On Generation, LXXI, Syd. 505, l. 18 to 506, l. 16;
Op. Omn. 526, l. 20 to 527, l. 20.

[327] Harvey: On Generation, LXXI, Syd. 508, l. 22-38; Op. Omn. 529,
l. 24 to 530, l. 5.

[328] The sources, contained in Aristotle's own works, of the
foregoing brief sketch of his conception of the universe, are as
follows: On Heaven, the whole of the treatise; On Generation and
Corruption, the whole of the treatise; Physics, Book IV, chapter 14,
223_b_, 15 to 224_a_, 2; Meteorology, Book I, chapters 1, 2, 3, and
9; Metaphysics, Book XI, chapter 7, 1072_b_, 28-30, and chapter 8;
Nicomachean Ethics, Book VI, chapter 7, 1141_a_, 33 to _b_, 2; On
the Parts of Animals, Book I, chapters 4 and 5, 644_b_, 20-25; Book
II, chapter 10, 656_a_, 3-8; On the Generation of Animals, Book IV,
chapter 10. The treatise entitled "On the Universe: To Alexander,"
is not a genuine work of Aristotle. See V. Rose: De Aristotelis
Librorum Ordine et Auctoritate, 90-100. Besides the foregoing
Aristotelian texts, see Prantl's note, number 37, on pages 303-307
of his edition of Aristotle's treatise On Heaven and On Generation
and Corruption, and the references to other writers contained in the
said note.

[329] Aristotle: On Heaven, 269_a_, 5-7.

[330] Aristotle: Meteorology, 339_b_, 25-26.

[331] Aristotle: On Heaven, 269_a_, 30-32.

[332] Aristotle: On Heaven, 269_b_, 15-17.

[333] Aristotle: On Heaven, 270_b_, 1-5 and 20-24. Aristotle accepts
the derivation of αἱθέρα from ἀεὶ θεῖν. Modern
philology rejects this.

[334] Aristotle: Meteorology, 339_b_, 17-19.

[335] Aristotle: On Heaven, 289_a_, 13-16.

[336] Milton: Paradise Lost, III, l. 716-721.

[337] See pp. 119-121.

[338] Aristotle: Physics, 194_b_, 13.

[339] Aristotle: On the Generation of Animals, 731_b_, 35 to 732_a_,
1. This is a small part of a passage of which the whole should be
read, viz.: 731_b_, 24 to 732_a_, 6. Compare On Generation and
Corruption, 337_a_, 34 to 338_b_, 19.

[340] Aristotle: History of Animals, 511_b_, 1-4.

[341] Aristotle: On the Parts of Animals, 652_b_, 23-26. On the
Generation of Animals, 742_b_, 35 to 743_a_, 1.

[342] Compare Aristotle: On the Parts of Animals, 645_a_, 26 to
645_b_, 14.

[343] Aristotle: On the Generation of Animals, Book II, chapter
3--Harvey's own reference.

[344] Harvey: On Generation, XXVIII, Syd. 285, l. 22-36; Op. Omn.
300, l. 9-21.

[345] Compare Harvey: On Generation, LXXI, Syd. 502, l. 25-37; Op.
Omn. 523, l. 24 to 524, l. 7.

[346] _E.g._ Harvey: On Generation, LXXI, Syd. 507, l. 32-36; Op.
Omn. 529, l. 2-5.

[347] See pp. 119-121.

[348] Cicero _et al._

[349] See Aristotle: On Heaven, 269_b_, 18 to 270_a_, 12. Compare J.
B. Meyer: Aristoteles' Thierkunde, II Abschnitt, § 2, 407, l. 20 to
413, l. 27.

[350] Aristotle: On the Parts of Animals, 645_a_, 26 to _b_, 14;
especially 645_b_, 6-10. See also Poetics, 1457_b_, 16-19.

[351] See p. 120.

[352] See pp. 119-121.

[353] See p. 120.

[354] Harvey: On Generation, LXXI, Syd. 507, l. 37 to 508, l. 13;
Op. Omn. 529, l. 6-16.

[355] Harvey: On Generation, LXXII, Syd. 513, l. 1-24 and 516, l.
14-17; Op. Omn. 534, l. 12 to 535, l. 6 and 537, l. 26-28.

[356] Harvey: On Generation, LXXII, Syd. 517, l. 19-22; Op. Omn.
539, l. 3-5. For the views of Empedocles and Democritus, see Zeller:
Philosophie der Griechen, 1 Theil, 2 Hälfte, 5 Auflage, 750-777 and
837-898. For the views of the chemists, see Roscoe and Schorlemmer:
A Treatise on Chemistry, Vol. I, 1878, 3-11.

[357] Harvey: On Generation, LXXII, Syd. 517, l. 27-32; Op. Omn.
539, l. 9-14. The words at the end of the quotation read, in
Harvey's text: "_aut principia esse corporum similarium_." The
"_corpora similaria_" or "_partes similares_" are the ὁμοιομερῆ
of Aristotle, which in anatomy answer, nearly, to the "tissues"
of modern parlance. See Aristotle: On the Parts of Animals, 646_a_,

[358] See p. 105.

[359] See p. 116.

[360] See p. 117.

[361] See pp. 119-121 and notes 321-324.

[362] Harvey: On Generation, LXXI, Syd. 507, l. 32-36; Op. Omn. 529,
l. 2-5.

[363] _Sanguinis calor est animalis, quatenus scilicet in
operationibus suis ab anima gubernatur_; etc.

[364] Harvey: On Generation, LXXI, Syd. 508, l. 14-17; Op. Omn. 529,
l. 17-20.

[365] Compare Aristotle: Meteorology, 339_a_, 11-32.

[366] κόσμος means both "order" and "ornament."

[367] Harvey: On Generation, LXXI, Syd. 508, l. 22-29; Op. Omn. 529,
l. 24-30.

[368] Compare Aristotle: On the Generation of Animals, 737_a_, 16 to
_b_, 7, especially _a_, 30-34; 741_a_, 3-32; 750_b_, 3-26; 757_b_,
14-19, and _b_, 23-27.

[369] Harvey: On Generation, LII, Syd. 381, l. 20-25; Op. Omn. 397,
l. 27-30. Compare the same, LIV, Syd. 402, l. 10-27; Op. Omn. 419,
l. 23 to 420, l. 8.

[370] See p. 121.

[371] _Fateatur._

[372] Harvey: On Generation, XLVII, Syd. 350, l. 2-16; Op. Omn. 365,
l. 31 to 366, l. 11.

[373] See pp. 122-123.

[374] See p. 119. See also Aristotle: On the Generation of Animals,
736_b_, 30.

[ 375] Harvey: On Generation, LXXI, Syd. 506, l. 26-29; Op. Omn.
527, l. 28-31. Compare Aristotle: On Generation and Corruption,
330_b_, 1-3, and elsewhere.

[376] Harvey: On Generation, LXXI, Syd. 506, l. 17 to 507, l. 15;
Op. Omn. 527, l. 21 to 528, l. 20. Do., Syd. 508, l. 30 to 509, l.
24; Op. Omn. 530, l. 5-27.

[377] Harvey: On Generation, LXXI, Syd. 506, l. 29-30; Op. Omn. 527,
l. 32.

[378] _Participare._

[379] Harvey: On Generation, LXXI, Syd. 507, l. 6-15; Op. Omn. 528,
l. 13-20.

[380] Aristotle: On the Generation of Animals, 736_a_, 24 to 737_b_,
7. Gaza's Latin translation of this chapter may be found on page 350
of the third volume of the Prussian Academy's edition of Aristotle's

[381] Compare p. 120.

[382] Aristotle: Meteorology, 382_a_, 6-7.

[383] Aristotle: Meteorology, 340_b_, 22-23.

[384] Harvey: On Generation, LXXII, Syd. 518, l. 15-36; Op. Omn.
540, l. 1-17.

[385] Harvey: Prelectiones, 98 left.

[386] Cicero: On the Nature of the Gods, Mül. 60, l. 23 to 61, l. 2.

[387] Aristotle: On Youth and Old Age and on Life and Death, 469_b_,

[388] Aristotle: On Respiration, 474_a_, 26-28.

[389] συναίτιον.

[390] τῶν δὲ φύσει συνισταμένων σάντων.

[391] λόγος.

[392] Aristotle: On Soul, 416_a_, 9-18.

[393] See pp. 119 and 140.

[394] Compare Aristotle: History of Animals, 539_a_, 15-25; 550_b_,
30 to 551_a_, 13: On the Generation of Animals, 761_a_, 12 to
763_b_, 16.

[395] κινοῦσα.

[396] Aristotle: Meteorology, 364_b_, 20-23.

[397] κινοῦντα.

[398] Aristotle: Metaphysics, 1071_a_, 11-17. Compare Physics,
194_b_, 29-32 and On the Generation of Animals, 716_a_, 4-7.

[399] τὸ δημιουργοῦν. Aristotle: On the Generation of
Animals, 738_b_, 20-21.

[400] Aristotle: On the Generation of Animals, 762_b_, 2-4.

[401] Aristotle: On the Generation of Animals, 738_b_, 25-26;
Compare 716_a_, 4-7.

[402] Aristotle: On Respiration, 479_a_, 29-30.

[403] Aristotle: On the Generation of Animals, 741_a_, 3-32, 757_b_,

[404] Aristotle: On the Generation of Animals, 716_a_, 13-17.

[405] Strictly speaking, it is left uncertain by the Greek text
whether the verb translated by the words "when ... inclusion ...
has taken place" refers to "heat," or to "soul," or to both. This
uncertainty, however, does not affect the sense, as both the
expression "psychical heat," and the words which follow it, imply
the association of heat and soul with one another. A line or two
beyond this quoted passage, Aristotle speaks of "the inclusion of
the psychical principle."

[406] Owing to the vagueness of the word συνιστάται this
must be translated here by a periphrasis such as "an individual
is formed." The verb συνιστάναι is used by Aristotle to
express not only the immediate result of spontaneous generation,
or the production of the embryo in sexual generation, but also the
curdling of milk, the condensation of vapor into water, and even the
constitution of the universe.

[407] θερμαινομένων τῶν σωματικῶν ὑγρῶν.

[408] Aristotle: On the Generation of Animals, 762_a_, 18-24.

[409] ἡ δὲ θάλαττα ... σωματώδης, πολλῷ μᾶλλον τοῦ ποτίμου
... ἐστί. Aristotle: On the Generation of Animals, 761_b_, 8-12.
Compare 761_a_, 33 to _b_, 2.

[410] περίττωμα.

[411] _I.e._, the female animal.

[412] _I.e._, in the higher animals.

[413] συνίστησιν.

[414] κίνησιν ἐντίθησιν.

[415] Aristotle: On the Generation of Animals, 762_a_, 35 to _b_, 19.

[416] Aristotle: On the Generation of Animals, 729_a_, 34 to _b_,
21; and the passages cited on p. 145.

[417] Compare Aristotle: On the Generation of Animals, 743_a_, 26 to
_b_, 5.

[418] φρόνησισ Hippocrates: On the Sacred Disease, Lit.
Vol. VI, 390, l. 10 to 394, l. 8.

[419] Genesis: II, 7.

[420] Aristotle: On Soul, 410_b_, 27 to 411_a_, 2.

[421] Aristotle: On the Generation of Animals, 736_a_, 22 to 737_b_,

[422] Aristotle: On Soul, 410_b_, 16 to 411_a_, 22.

[423] Aristotle: On the Generation of Animals, 728_b_, 21-32.

[424] Aristotle: On the Generation of Animals, 728_a_, 9-11.

[425] Aristotle: On the Generation of Animals, 763_a_, 24 to _b_, 4.

[426] Aristotle: On the Generation of Animals, 736_b_, 35-37.
Gaza translates the foregoing as follows: _spiritus qui in semine
spumosoque corpore continetur_. Aristotle: Op. Ed. Acad. Reg.
Boruss. Vol. III, 360_b_, l. 4.

[427] Hesiod: Theogony, l. 188-200. Compare Aristotle: On the
Generation of Animals, 736_a_, 18-21, and see note 320. The same
myth is referred to by Harvey in his turn: On Generation, L, Syd.
368, l. 1-7; Op. Omn. 383, l. 18-22.

[428] Aristotle: On Heaven, 289_a_, 11-19. The derivation now
accepted of the word "ether," αἰθήρ, is from ἄθω, "I kindle"; which
substantiates Aristotle's account of the view which he combats.
Indeed, Aristotle himself says: "Anaxagoras, however, has not
employed this word correctly; for he uses the word 'ether' in place
of 'fire.'" On Heaven, 270_b_, 24-25.

[429] The ether.

[430] Aristotle: On Heaven, 289_a_, 19-22 and 26-35.

[431] Aristotle: Meteorology, 341_a_, 35-36.

[432] See pp. 119 and 140.

[433] Harvey: On Generation, L, Syd. 368, l. 12-25; Op. Omn. 383, l.
26 to 384, l. 4.

[434] _Quod sponte nascentibus fæcunditatem affert._

[435] Harvey: On Generation, L, Syd. 370, l. 27-34; Op. Omn. 386, l.
14-20. See note 439.

[436] _In sponte nascentibus vermis._

[437] _Conclusae humiditatis._

[438] Harvey: On Generation, LVI, Syd. 414, l. 32 to 415, l. 9; Op.
Omn. 433, l. 5-11.

[439] Compare Aristotle: History of Animals, 539_b_, 17-25. Harvey:
On the Motion, etc., XVII, Syd. 75, l. 23-29; Op. Omn. 77, l. 1-6.
Harvey: On Generation, I, Syd. 170, l. 32-36; Op. Omn. 182, l.
20-23; Do. L, Syd. 367, l. 30-36; Op. Omn. 383, l. 10-15; Do. LXII,
Syd. 457, l. 18-27; Op. Omn. 477, l. 4-12. Harvey: On Parturition,
Syd. 524, l. 31-39; Op. Omn. 544, l. 13-19. T. H. Huxley:
Encyclopædia Britannica, 9th ed., Vol. VIII, Article on "Evolution,"
746, especially 746_a_, 43 to _b_, 2. W. K. Brooks: William Harvey
as an Embryologist, Johns Hopkins Hospital Bulletin, Vol. VIII,
1897, 169_a_, 7 to 170_b_, 26.

[440] Compare Aristotle: On the Generation of Animals, 724_a_, 14 to
727_b_, 33.

[441] Harvey: On Generation, LII, Syd. 381, l. 36 to 383, l. 7; Op.
Omn. 398, l. 9-16.

[442] _Intellectu._

[443] _Ratiocinio._

[444] Harvey: On Generation, LXXI, Syd. 507, l. 16-26; Op. Omn. 528,
l. 21-29.

[445] Aristotle: Meteorology, 339_a_, 21-24.

[446] Aristotle: Physics, 223_b_, 24-26.

[447] Milton: Paradise Lost, Book VIII, l. 15-178.

[448] Harvey: Exercise to Riolanus, II, Syd. 132, l. 9-11; Op. Omn.
132, l. 2-3.

[449] Harvey: Exercise to Riolanus, II, Syd. 123, l. 21-33; Op. Omn.
123, l. 15-17.

[450] _Aërem_; _i.e._, aëriform vapor.

[451] Compare Aristotle: On Sleep and Waking, 457_b_, 29 to 458_a_,

[452] Harvey: On the Motion, etc., VIII, Syd. 46, l. 25-33; Op. Omn.
48, l. 28 to 49, l. 2.

[453] _Quatenus est elementaris._

[454] The goddess of the domestic fire.

[455] Compare Plato: Timæus, 48_e_ to 50_a_; 54_c_ to 62_c_, and
76_c_ to 80_d_; Plato: Philebus, 28_e_ to 30_a_.

[456] Harvey: On Generation, LXXI, Syd. 510, l. 5-40; Op. Omn. 531,
l. 12 to 532, l. 9.

[457] Æschylus: Agamemnon, l. 5-6.


  Air, and fire, 14;
    and respiration, 15, 23, 31, 40;
    and spirits, Harvey on, 29;
    soul in, 147.

  Alcmæon, 111.

  Ancients, Harvey and, 2, 3.

  _Anima_, 23, 103, 147.
    See also Soul.

  Animal spirits, 22, 25, 127.

  Animals, Aristotle on, 105.

  Aorta, 62.

  Aphrodite, 149.

  Aretæus, 55.

  Aristotle, 2;
    on air and fire, 14;
    on animals, 105;
    and "artery," 49;
    on causes of man, 144;
    on cosmos, 121;
    on chick's heart, 48;
    on ether, 123, 125;
    on faculties, 104;
    on fire and soul, 143;
    onmfunction of heart, 48, 113;
    on heart as psychological center, 50;
    on heart as seat of motion, 52;
    ignorant of function of muscle, 53, 84;
    on innate heat, 14, 44, 139;
    as leader of Harvey, 48, 53, 67;
    on life, 104; on movement of blood, 53;
    on pulsation of heart, 82;
    on respiration, 15, 30;
    on semen, 120, 128;
    on sexes, 145;
    on soul, 51, 104, 114;
    on spirits, 21;
    on spontaneous generation, 143, 145;
    on sun and fire, 150;
    on sun and generation, 151.

  Arterial vein, 57.

  Artery, Aristotle's use of word, 49;
    bronchial, 38;
    flow in, 99;
    Galen's demonstration of blood in, 3;
    venous, 30, 57.

  Aselli, Gasparo, 10.

  Aubrey, John, 2, 12.

  Auricles, action of, 75, 87;
    fibrillar contractions of, 75.

  Automatic generation, 143.

  Avicenna, 2.

  Blood, as arising in liver, 56, 60;
    Aristotle on movement of, 53;
    arterial and venous, 35;
    color of, 35;
    as constructor, 153;
    as divine, 156;
    as the first to live, 68, 69, 75, 109;
    Galen on movement of, 56;
    Harvey on arterial and venous, 35;
    as innate heat, 116;
    as the last to die, 73, 109;
    life in, 76;
    palpitation of, 75;
    primacy of, 64, 81;
    the seat of soul, 103, 105, 156;
    as source of heat, 80, 109;
    and spirits, 117, 120, 127.

  Bloodletting, Harvey on, 110.

  Blood pressure, Hales on, 96;
    Harvey on, 97.

  Bronchial arteries, 38.

  Capillaries, circulation of blood in, 98.

  Chemistry, Harvey on, 12.

  Chick, development of, 47, 71.

  Chyle, 9.

  Cicero, 2, 141.

  Circulation of blood, in capillaries, 98;
    and circulation of heavens, 154;
    according to Columbus, 58;
    and feeding of tissues, 7;
    first announcement of, 4, 42;
    Harvey on use of, 1, 43;
    opposition to, 5, 62;
    and primacy of blood, 64;
    and primacy of heart, 42;
    pulmonary, 27, 38, 58, 101;
    physicians and philosophers on, 55, 60;
    and respiration, 11;
    use of, 1, 5, 8, 43.

  Circulation of heavens, 154.

  Cleanthes, 141.

  Columbus, Realdus, on pores of septum, 27;
    and pulmonary circulation, 27, 38, 58;
    on spirits, 27, 30.

  Copernicus, 118, 155.

  Cosmos, 121, 154.

  Critias, 112.

  Cruor, 76, 117, 156.

  Democritus, 132.

  Descartes, 85.

  Diastole as caused by heat, 80.

  Diogenes, 111.

  Empedocles, 20, 112, 132.

  Empyema, 29.

  Erasistratus, and valves of heart, 55;
    and Galen, 61;
    on spirits, 21.

  Ether, 123, 125, 129.

  Fabricius ab Aquapendente, 1.

  Faculty, intellectual, 105;
    motor, 105;
    nutritive, 104;
    sensory, 105.

  Female, function of, 145.

  Fernel, Jean, 118;
    on innate heat, 117.

  Fever, Harvey's view of, 46.

  Fire, and air, 14;
    not the source of innate heat, 119, 139;
    and soul, 143;
    and sun, 150.

  Galen, 2, 3;
    circulation opposed by followers of, 62;
    demonstration of blood in arteries by, 3;
    and Erasistratus, 61;
    on function of muscle, 84;
    and Harvey, 61;
    on innate heat, 17, 44;
    on mitral valve, 58;
    on movement of blood, 56;
    on net-like plexus, 24;
    on respiration, 16, 22, 27;
    on spirits, 22, 27.

  Galileo, 96, 155.

  Generation, automatic, 143;
    causes in human, 144;
    eternity in, 126;
    spontaneous, 143, 145, 152;
    and sun, 145, 151.

  Hales, Stephen, 96.

  Hamlet, 103.

  Harvey, William, and ancients, 2, 3;
    on arterial and venous blood, 35;
    on blood-letting, 110;
    on blood pressure, 97;
    on cause of heart-beat, 79, 81, 86, 90;
    on chemistry, 12;
    on development of chick, 47, 71;
    on eternity in generation, 126;
    on fever, 46;
    first announcement of circulation by, 4, 42;
    on flow in arteries, 99;
    on flow in veins, 95, 100;
    as follower of Aristotle, 48, 53, 67;
    on functions of blood, 114;
    on function of heart, 45;
    on function of muscle, 84;
    and Galen, 61;
    and "heart," 56, 92;
    on heart as seat of sensation, 107;
    on innate heat, 19, 33, 39, 44, 116;
    Lecture Notes of, 4, 18;
    on mechanism of heart-beat, 86;
    on moderns, 2;
    on nerve impulse, 32;
    as observer, 6, 70, 78;
    at Padua, 1, 155;
    publications of, 3, 4, 18, 66, 67;
    on pulmonary circulation, 38, 101;
    on respiration, 12, 18, 26, 28, 31, 39;
    on soul, 103, 106;
    as speculator, 6, 7;
    on spirits, 28, 31, 33, 127, 133;
    on spontaneous generation, 152;
    on sun and generation, 151;
    on use of circulation, 1, 5, 8, 43;
    on venous return, 95.

  Heart, action of excised, 92;
    action of heat on, 76;
    Aristotle on function of, 48, 113;
    Aristotle on pulsation of, 82;
    Aristotelian primacy of, 42;
    of chick, 47, 71;
    as common sense-organ, 51;
    as the first to live, 47;
    Harvey's use of word, 56, 92;
    as origin of life, 45;
    pores of septum of, 27, 57;
    primacy of, 42;
    as psychological center, 50;
    the seat of motion, 52, 107;
    the seat of sensation, 107;
    the seat of soul, 51, 114;
    the source of innate heat, 43, 49, 113;
    valves of, 15, 16, 55, 58, 62.

  Heart-beat, cause of, 79, 81, 90;
    mechanism of, 81, 86, 89.

  Heat, action of, on heart, 76;
    in semen, 119, 124, 128, 140, 143.

  Heat, innate, Aristotle on, 14, 44;
    blood as, 116;
    blood as source of, 80, 109;
    as cause of diastole, 80;
    as cause of pulse, 81, 93;
    Fernelius on, 117;
    Galen on, 17, 44;
    Harvey on, 19, 33, 39, 44, 116;
    heart as source of, 43, 49, 113;
    not from fire, 119, 139;
    and respiration, 14, 15, 16, 18, 33, 39;
    Scaliger on, 117;
    and spirits, 126, 129.

  Heavens, 121, 149;
    circulation of, and circulation of blood, 154.

  Heraclitus, 111.

  Hibernating animals, 77.

  Hippocrates, on respiration, 15, 20;
    on spirits, 20;
    works of, 15.

  Hofmann, Caspar, 5.

  Intellectual faculty, 105.

  Intellectual soul, 105.

  Lacteals, discovery of, 10.

  Laurentius, 29.

  Life, Aristotle on, 104;
    in blood, 76.

  Ligature, 42.

  Liver as source of veins and blood, 56, 60.

  Male, function of, 145.

  Milton, 70, 124, 155.

  Mitral valve, 58.

  Moderns, Harvey on, 2.

  Motor faculty, 105.

  Motor soul, 105.

  Muscle, function of, 84;
    function of, unknown to Aristotle, 53, 84.

  Natural spirits, 25, 27.

  Nerve impulse, 26, 32.

  Nervous system and spirits, 31.

  Net-like plexus, 22, 24.

  Nutritive faculty, 104.

  Nutritive soul, 50, 105, 145.

  Oxyhæmoglobin, 26.

  Paracelsus, 118.

  Pascal, Blaise, 96.

  Philosophers _versus_ physicians, 55, 60, 65.

  Physicians _versus_ philosophers, 55, 60, 65.

  Planets, 122.

  Plato, 23, 51, 112.

  _Pneuma_, 20, 23, 127, 147, 148.
    See also Spirits.

  Pores of septum, 27, 57.

  Porosities of tissues, 98, 100.

  Portal vein, 8.

  Powers of the elements, 130.

  Primitive moisture, 131.

  _Psyche_, 23, 104, 147.

  Psychical spirits, 23.

  Pulmonary circulation, 27, 38, 58, 101.

  Pulse, as caused by heat, 81;
    as dependent on heart, 83.

  Quintessence, 124.

  Respiration, and air, 15, 23, 31, 40;
    Aristotle on, 15, 30;
    and circulation, 11;
    Galen on, 16, 22, 27;
    Harvey on, 12, 18, 26, 28, 31, 39;
    Hippocrates on, 15, 20;
    and innate heat, 14, 15, 16, 18, 33, 39.

  _Rete mirabile_, 24.

  Scaliger, Julius Cæsar, 118;
    on innate heat, 117.

  Semen, Aristotle's view, of, 120, 128;
    heat in, 119, 124, 128, 140, 143;
    spirits in, 119, 128, 140, 148.

  Semilunar valves, 15, 16, 55, 62.

  Sensory faculty, 105.

  Sensory soul, 51, 105, 145.

  Sexes, Aristotle on, 145.

  Socrates, 112.

  Soul, in air, 147;
    Aristotle on, 51, 104, 114;
    in the blood, 103, 105, 156;
    as cause of vital activity, 143;
    and fire, 143;
    Harvey's view of, 103, 106;
    in the heart, 51, 114;
    intellectual, 105;
    motor, 105;
    nutritive, 50, 105, 145;
    sensory, 51, 105, 145.

  Spirits, 20, 23, 127, 147, 148;
    and air, Harvey, on, 29;
    animal, 22, 25, 127;
    Aristotle's view of, 21;
    and blood, 117, 120, 127, 133;
    Columbus on, 27, 30;
    Erasistratus's view of, 21;
    Galen's view of, 22, 27;
    Harvey's view of, 28, 31, 33, 127;
    Hippocrates's view of, 20;
    and innate heat, 126, 129;
    natural, 25, 27;
    and nervous system, 31;
    psychical, 23;
    in semen, 119, 128, 140, 148;
    vital, 22, 24, 27.

  _Spiritus_, 20, 147.

  Spontaneous generation, 143, 145, 152.

  Sun and fire, 150.

  Sun and generation, 145, 151.

  _Taenia_, 42.

  Thales, 111.

  Tissues, feeding of, and circulation, 7.

  Torricelli, Evangelista, 96.

  Tricuspid valve, 55.

  Universe of Aristotle, 121.

  Uranus, 149.

  Valves of heart, 15, 16, 55, 58, 62.

  Veins, arising in liver, 56, 60;
    flow in, 9, 95, 100.

  Vena cava, as distributer of blood, 55;
    Galen's view of, 56.

  Venous artery, 30, 57.

  Vesalius, 118;
    on pores of septum, 27.

  Vital spirits, 22, 24, 27.

  Wind-egg, 135, 145, 151.


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Minor typographical and punctuation errors have been corrected
without note. Irregularities and inconsistencies in the text have
been retained as printed.

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