By Author [ A  B  C  D  E  F  G  H  I  J  K  L  M  N  O  P  Q  R  S  T  U  V  W  X  Y  Z |  Other Symbols ]
  By Title [ A  B  C  D  E  F  G  H  I  J  K  L  M  N  O  P  Q  R  S  T  U  V  W  X  Y  Z |  Other Symbols ]
  By Language
all Classics books content using ISYS

Download this book: [ ASCII | HTML | PDF ]

Look for this book on Amazon

We have new books nearly every day.
If you would like a news letter once a week or once a month
fill out this form and we will give you a summary of the books for that week or month by email.

Title: Schenk's Theory: The Determination of Sex
Author: Schenk, Samuel Leopold
Language: English
As this book started as an ASCII text book there are no pictures available.
Copyright Status: Not copyrighted in the United States. If you live elsewhere check the laws of your country before downloading this ebook. See comments about copyright issues at end of book.

*** Start of this Doctrine Publishing Corporation Digital Book "Schenk's Theory: The Determination of Sex" ***

This book is indexed by ISYS Web Indexing system to allow the reader find any word or number within the document.

                            SCHENK’S THEORY

                         DETERMINATION OF SEX

                          DR. LEOPOLD SCHENK

  Professor at the Imperial and Royal University, and Director of the
                   Embryological Institute in Vienna

                       _AUTHORIZED TRANSLATION_

                          THE WERNER COMPANY
                  CHICAGO    AKRON, OHIO    NEW YORK

                          Copyrighted, 1898,
                          THE WERNER COMPANY

                         [Illustration: logo]


The facts observed and recorded by others assisted me to advance so
far on the trodden path that I made an effort to snatch a secret from

What I succeeded in obtaining, though small, induced me to set forth in
the following pages the perhaps not unimportant results.

The labor was long, and engaged my attention for years. And yet, amidst
my continuous labors in the province of Embryology, it remained all the
time a matter of secondary importance, my principal attention being
engaged by far more extensive studies.

My desire is to stimulate others to wider observation. May the facts
which I here discuss prove of utility, and encourage further studies
in this direction with the assistance of modern science.

If we are not in a position to control the processes of Nature, we can
nevertheless exercise over them a more or less effective influence, so
as to obtain such results as are possible.

Whatsoever the question may be that we propose to discuss, it is
sometimes very difficult to reach any answer. And yet, when experience
and diligence have helped us over the difficulties, we succeed at last
in reaching the answer desired. The difficulties assume much less
formidable shapes when an individual is satisfied with shaking his
head and regarding the whole affair with mistrust. In that way the
inexperienced and lazy are at once able to launch their views without
further trouble. They believe or they disbelieve; and they like to have
their say. Any one can in this way easily win himself a place amongst
those who have written on a topic. The man who desires to obtain a
lasting place takes on his shoulders heavier responsibilities.

This book contains but a portion of the vast and wide-reaching
literature dealing with the subject in hand. That literature
extends back to the date of man’s earliest intellectual labors. The
observations that have been recorded by others are here followed by
methods of investigation, and by considerations which may serve to
elucidate the facts. In conclusion, a section has been dedicated to the
methods which I recommend for the artificial influencing of sex. Some
particular experiments are subjoined.

May my little book, then, go out into the world and make known my
views, which are founded exclusively upon facts.


In sexually differentiated individuals, the difference of sex is
already apparent in the embryonal state of existence, not only in
the exterior form, but also in the interior cellular rudiments which
subsequently form the genital organs. In both, the earliest forms are
of such a nature that, up to a certain period, it is impossible for
investigations conducted with the means at present at our disposal to
discover any distinction. Soon, however, after this, in such organisms
as have a distinction of sex, elementary male and female forms of
the organs of reproduction can be recognized developing themselves
in the embryo out of the substratum of formative elements. Some of
these remain in a rudimentary condition; others attain to complete

These processes take place at a relatively early period. They do not
seem to make their first appearance, as phenomena of vitality, in the
course of the life-development of the cells of the ovum. But it is
not improbable that, from the very outset, the ovule has a capacity
to transfer (during the process of segmentation) to a corresponding
cell-substance (out of which the generative organs will be subsequently
developed) the force contained in the ovule, so that the cell-substance
may afterwards take up the office of providing for the preservation
of the species. The cells of the ovum derive this power from the
protoplasma of the ovum, and retain it in a rudimentary form for
one sex, whilst for the other they possess it in full measure. This
energy is contained in the ovule itself in an unknown condition. In
it lies the basis of the formation and development of the future sex.
In close connection with this property of the ovule, lies another
faculty, included in the ovule, namely, that the other different
elements proceeding from the cell-body of the ovum, starting from the
protoplasma of the ovum, are endowed with certain vital peculiarities,
according as they belong to the future male, or female, organisms.

It will be plain from this that the germ of the future sex must be
sought in the first cell-segmentation of an ovum. As soon as some
of the cells derived from the primary protoplasm of the ovum have
developed themselves into genital cells, the other elements which have
originated from the same ovum are in such a manner conditioned that,
in the latter stages of their vitality, they adapt themselves, and, in
short, adapt the properties inherent in all the cells, to the sex of
the individual. According, as the ovum is male or female, so are also
the cells which originate from it either all male or all female.

It will be seen that not only do different cells for the different
sexes develop themselves out of an ovum, but that also, at the same
time with these, a peculiarity reveals itself in the other cells,
in accordance with which the sexually different organisms exhibit a
difference in their vital capacities, and take also different forms.
The distinction between male and female characteristics appears to
be determined before the fecundation of the ovum. The formation of
the ova in the ovary, and their further development, seem, however,
not to be independent of external influences. It is possible that
upon these circumstances depend the number of ova contained in the
ovary. But, apart from the question of quantity, it is possible that
many characteristics might so affect the quality of the ovum, as to
exercise an influence over its capacity for fecundation. We may here
mention an experiment which was made with the ova of a rabbit, from
which it was quite clear that the capacity of an ovum for fecundation
was immediately diminished when the surrounding elements attached
to the ovule, in consequence of the density of their investing
substance, offered a resistance to penetration by the spermatozoa.
(Schenk.) The penetration of a spermatozoon into the protoplasm of
the ovum becomes possible only when, in consequence of the movements
of the spermatozoon, the cells of the surface of the ovum can be
thrust aside. This is facilitated when the investing substance is
considerably relaxed, as is the case when the ovum is ripe. Other
circumstances, also, which can in some cases be easily detected, may
prove detrimental to fecundation and development. Indeed, they can even
exercise an influence over the sex which is to be developed out of the
ovum. Bee-masters (F. Gerstung) have frequently shown that the food
exercises a striking influence upon the formation of sex in the ova.
(v. Berlepsch.)

All evidence goes to support the view that such external influences
as would favorably affect the separate sexual individual might also
promote the production of one sex or the other. In Hensen’s valuable
work on generation, a number of instances are adduced, gathered from
various authors, which make it clear that the nutrition of the parents,
apart from any question of race, is capable of exercising an influence
upon the sex of the children. (Ploss.) In plants which produce separate
male and female blossoms (Lenkhart), the male blossoms are more
numerous when the temperature is relatively high, whilst in shaded
places and damp soils a greater number of female individuals will be

       *       *       *       *       *

Facts which might assist to explain the origin of sex have been
sought after from very early times, and have been also placed in very
different lights. The result on every occasion, when this subject
has been discussed, has been always a wide difference of opinion.
People have, in consequence, been induced to fall back upon theories
of different sorts, theories which have for varying periods, sometimes
long, sometimes short, been accepted as of some assistance towards a
scientific explanation. In all the theories which have been propounded,
the sex has been regarded as already determined in the ovum, or else
the origin of the sex has been assigned to some early stage of the

The earliest statements extend back into the ages of myth and fable, in
consequence of which any exact comparison of them is not an easy task.
All the different manuals which deal with the present question touch
upon these early views, and for this reason I am unwilling entirely
to ignore them here. I shall, accordingly, select a few of the more
important for mention.

The reproductive glands of the two sexes were supposed to contain
generative matter distributed in such a way, on the right and left,
that the right ovary and the right testicle contained the generative
secretions for the production of the males, and the left ovary and
left testicle those which produced females. It is immediately evident
that, according to this theory, it was impossible to exercise any
influence over the sex of the future individual. This primitive theory
is ever cropping up anew, always to be again rejected. Of various
other theories of the same kind, only those deserve any attention
which rest upon some basis of fact. Accordingly, recourse has been
had to statistics, and an attempt has been made to reach, from the
figures which they furnish, some certainty respecting which sex was
the more numerous, and what should be concluded to be the cause of
the greater prevalence of the one sex or the other. The fact was,
however, apparently overlooked that the available statistics, though
in many respects of the highest scientific value, could be of
real significance only when the numbers were gathered from widely
distributed peoples amongst whom there was none of that wandering about
the world which characterizes modern society.

I am at the same time unwilling to omit data, resting upon numbers
which have been gathered from statistics, and are not without value for
the determination of many important questions.

Ploss has in this way shown that in favorable years, when food was
cheap, the births showed an excess of girls. Under unfavorable
circumstances, more male individuals were born.

A comparison of statistics, however, soon led to another theory, which
culminated in this result, that in all countries an excess of male
individuals was born.

To what extent this relation between the numbers of the sexes can be
maintained, and may serve for a fixed rule, is at the same time a
question to be regarded with caution. An unimpeachable result of such
investigations is rendered more unlikely by the fact that comparisons
of numbers lead to a conclusion of an exactly contrary nature, making
the feminine sex the more numerous. These facts at once suggest that we
are not dealing with fixed or normally recurring numerical proportions,
which would repeat themselves at each numeration. And it is also
possible that external influences may in various ways affect such
numerical proportions.

We may add also that, in investigations of this kind, other circumstances
should be taken into consideration. Thus, in the case of endemic or
epidemic disease, the births which furnish the statistics fluctuate,
and the stability of the numbers, in consequence, is modified by these
exceptional occurrences.

The numbers (Oesterlen) which are based upon the population of half
Europe, are amongst the widest of statistical data, and furnish
information of the highest value.

They represent 59,350,000 births. These showed an excess of male
births. The proportions were 106.3 boys to 100 girls. Of course,
these numbers refer to the new-born, and must necessarily be very
much altered by the age of puberty. In fact, the powerful influences
which come into play in the life after birth would very considerably
affect the former of the above numbers. This is, however, a matter
for further statistical investigation, and of little importance in
our present inquiry. The numbers (Oesterlen) are in this respect very
remarkable: the average of the total number of births in the various
states corresponds very nearly with the numbers in the several states,
or at least shows no difference worthy of consideration. In the single
states, the proportion of boys to 100 girls varied from 105.2 to 107.2.
Thus the proportion of the number of male individuals born to the
number of females very nearly corresponded with the proportion shown
by the total of all countries enumerated. Statistics derived from the
genealogies of Court calendars gave (according to Kisch) 107.7 boys to
100 girls.

I am prompted here to quote also the statistical numbers given in
Hensen’s work, which have been taken from Darwin’s ‘Descent of Man.’ Of
pigs, rabbits, and pigeons, more males are born than females. For every
100 mares, 99.4 horses are born. In the case of greyhounds, 110 dogs
are born for every 100 bitches. Of horned cattle 94.4 males, of poultry
94.7 males are born for every 100 females. The degree of accuracy and
the limits of error which here remain undefined, make fluctuations
easily perceptible. The mistakes, also, which may be made in such
cases, are not always the same.

Statistics have been in many other ways called in to assist in the
discussion of the question before us. In the early decades of the
present century a question was raised--what was the effect upon the
relative number of births of male or female individuals when the
parents were of like or unlike ages?

Hofacker, in the year 1828, and Sadler (an Englishman), in the year
1830, attempted to solve this problem, and found adherents for their
theories based upon numerical returns. But the Frenchman, Girou (Paris,
1838), appeared as an opponent of their views, also supporting his
opinions by numbers obtained in the same manner, probably, as those of
Hofacker and Sadler.

I shall not here reproduce the tables which were constructed for the
discussion of this question. Any one who occupies himself with these
questions can refer to the respective technical works, and I shall
content myself with mentioning some of the results. If the man is older
than the woman, more boys will be born. According to Sadler, the
statistics showed even 121.4 boys for 100 girls.

If both the parents are of the same age, fewer boys than girls will be
born. According to Sadler, in this case for every 100 girls only 94.8
boys are born. But if the woman is older than the man, an excess of
girls in the family is the result. According to the two above-mentioned
authors, when the mother is older than the father the proportions are:
86.5 boys to 100 girls.

Similar numbers collected by other specialists differ not inconsiderably
from those given by Sadler. Regarding the proportions of male and female
births as affected by the respective ages of the parents, Sadler’s
numbers show the widest differences of all. Breslau and Noirot have
arrived at numerical results so different, though less than Sadler’s,
that no thoroughly reliable conclusions can be based upon them. Wall
confesses himself an adherent of this law, and lays down the principle
that in the intercourse of two quite young parents the male sex tends
to predominate. If, on the contrary, the age of the man is distinctly
greater than that of the woman, he insists on the excess of females
amongst the new-born. The French breeder Girou de Buzareingues is
disposed in many respects to support the theory of the influence of
difference of age in the parents upon sex of offspring; but, also, on
the strength of his own experiences in breeding, is partially opposed
to it. According to his theory, he also takes into consideration the
character, the food, etc., of the parents, and would have regard to
their size and strength. In this way he gave his theory a much wider
range. He mentions a great number of facts which he observed in the
human subject. He outlines the expenditure of force, mental and
physical, entailed on the parents by their occupation, and then sets
forth ten very precise particulars from which, in any given case, the
sex of the offspring which will result from the wedlock in question may
be known. The following cases from Girou may be mentioned. A vigorous
man married a corpulent, melancholy, elderly blonde. Seven daughters
were the result of the marriage, all of them resembling their father and
grandfather. Many similar cases are mentioned by Girou, all of which
may be found of interest to the reader, if he be inclined to regard
preponderance of temperament, or physical disposition for procreation
of the species as important factors. Included in his _repertoire_ of
anecdotes are many interesting and piquant details respecting the
results of the pairing of dissimilar temperaments which might be quoted,
were it not that this would lead us too far from our subject, and also
be of no service in the present inquiry.

Bidder is in many respects inclined to give his assent to the theories
of his predecessors, and states that women who bear their first child
between the ages of twenty and twenty-one produce more girls than boys
(Düsing). The older the woman is at the time of her first parturition,
the greater number of male births. An excess of male births will occur
in the case of those who first give birth to children between the
ages of thirty and forty (Eckhardt). Ahlfeld insists that this is a
universal rule in the case of women who become pregnant in later years.
A great number of specialists are of this opinion, and apply the data
afforded by statistics to support it in different ways.

The evidence of Stieda, Berner, and Birelli, and especially that of
Wilkens, respecting the domesticated mammals, leads, however, to this
conclusion, that the theories respecting the relative proportions of
male and female births set forth by Sadler and Hofacker must either be
given up or their value considerably discounted.

Specialists are also to be found who, in order to explain this theory,
have availed themselves of Darwin’s law, and in a certain measure the
results admit of this explanation.

The older parent, who evidently under such normal circumstances as
might be anticipated has a shorter time to live than the younger
individual, his consort, naturally in the struggle for life, makes
an effort for the preservation of his sex. Accordingly, the elderly
husband of a young wife, or _vice versâ_, the elderly wife of a young
husband, will make an effort to preserve the sex which is first
threatened with death, but which may at least be replaced by a majority
of births.

In so far as these theories are mere calculations and results which
have originated from comparisons of numbers (the numbers themselves
being in many cases of no practical value), the conclusions reached
may appear to be astonishing, and may be used to support either one
view or another, or to contradict them. Only one fact appears to be
certainly established, that, on an average, under normal circumstances,
the number of male individuals of our population that are born exceeds
the number of females. The difference amounts to a small and variable
number per cent., but in the case of the new-born, the excess is on the
side of the males. (Süssmilch.)

       *       *       *       *       *

Thus far we have given such data as statistics have furnished. These,
it is true, belong principally to past epochs, and no new results of
this sort have been used by statisticians. But it would be equally
impossible to deduce from new statistics, or from old, or from both
together, any law of nature affecting the question before us.

       *       *       *       *       *

I shall proceed next to examine the further theories on this subject
with which I have become acquainted from the perusal of the literature
treating of it. With some of the works which I am about to mention I
am acquainted at first hand. Others I know only from quotations found
in various technical publications. I have not attempted to arrange my
materials in any other way.

In the case of the most widely different branches of natural science,
and whether the author’s aim be descriptive or experimental, it is a
common practice to commence with a glimpse at what has been said by the
earliest writers. I shall begin in the same way. I shall, however, not
take into consideration what has been at various times mere folk-lore,
and is only traditionally known, but shall limit myself to such
traditions as have been preserved in writing. I have, besides, already
spoken above of suppositions respecting the origin of sex which appear
to partake of the nature of myths. To these it was impossible to attach
any importance. And the same must be said of other views which belong
to the epoch of the Greek or Latin writers on natural science, and are
so strange that they can be scarcely brought into any agreement with
modern knowledge.

In Ploss’s work ‘_Das Weib in der Natur and Völkerkunde_’ (Woman in
Nature and Popular Tradition), are to be found the various speculations
of different races respecting the origin of sex. Much of this folk-lore
is of a distinctly surprising character, and calculated to afford
the reader considerable amusement. For example, in Servia, if a man
has a stye on his eyelid he comes to the conclusion that his aunt is
pregnant. If the stye is on the upper eyelid, the child will be a male,
if on the lower, a female.

Amongst the Asiatic races religious ceremonies, prayers, and similar
expedients are considered efficacious, and capable of influencing the

What question is there of the present day, respecting which we can
consult the literature of the ancients, that does not take us back
to the writings of Hippocrates, Aristotle, or Galen, or to those of
the old authors of those oriental races whom we regard as the earliest
cultivated peoples? Hippocrates held that to produce a male, the
generative material must be of a stronger quality. The future destiny
of the male rendered it necessary that it should be constructed on
a stouter foundation. He must be capable of a stronger development,
and must, therefore, be a product of stronger elements alike on the
father’s and the mother’s side. A second hypothesis was soon added to
this primary one, but without any foundation of facts.

According to Aristotle, the woman supplied the primary material for
the development of the future individual. It was the function of the
man to give the impulse, in consequence of which the future individual
came into being. Next followed the purely mythical theory, already
mentioned, in which Anaxagoras believed. The much-sought-for origin of
the future difference of sex in the various individuals was assigned to
the right or left side of the organism. And Galen even concluded that
the right side of the body was the warmer, and the left the colder,
further claiming for the warmer side the privilege of producing male

       *       *       *       *       *

Various notions respecting the origin of sex have been also accommodated
to these primitive theories of the ancients, without resting upon any
positive foundation. No evidence exists to show from whom they
originated, nor how they were disseminated. Nevertheless, the historical
connection of these speculations justifies a reference to them, and
various hypotheses of this kind will be found in a little publication of
Dr. Heinrich Janke’s (Stuttgart, 1896). The older literature on the
subject of the generation of the sexes has been collected by His.
(_Archiv für Anthropologie, Vol. IV. V._) In ‘_Das Weib in der Natur
and Völkerkunde_’ (Leipzig), Ploss has collected ample information
concerning both ancient and modern ideas on this subject amongst the
different races of mankind. The procreative elements, furnished by the
male and female organs, after their mixture, compete with each other, by
virtue of their inherent forces, for the mastery. In this conflict, if
the male molecules are the more numerous, a male results. On the
contrary, if the female molecules are more numerous, the result is a
female. Nicholaus Venette ascribes the difference of sex to the
earliest phases of the life of the ovule.

       *       *       *       *       *

The following aspect of the origin of sex is not without interest,
although the theory rests on somewhat insufficient foundations, and
is applicable, in the first instance, only to those creatures which
produce but a single individual at a birth. Many creatures, and
especially certain species of birds, present this phenomenon; they lay
in a single month two eggs. Of these, one is male, the other female. In
this way a provision is made for the equal increase, in each respective
month, of both sexes. In the case of man, it would, in accordance with
this, be anticipated that naturally an equal number of ova of either
sex would be produced by a single individual.

This would lead to the supposition that, in the case of the human
female, in one month a male ovule would reach its perfect development,
and in the next month, anterior to the occurrence of the menses, a
female ovule. Thus the ovary of the human female would contain in one
month a male ovum capable of fecundation, and in the following month
a similar female ovum. After a woman had once given birth to a child
it would then be possible to form a correct idea of the distribution
of the ova of the different sexes. The month of birth and the sex of
the new-born child would be known, and starting from the datum that it
would be the turn of the ovum of the next month to develop the opposite
sex, it would be possible to fix the given month in which an individual
of the male or female sex should be developed. (Dupuys.)

To these less general explanations of the origin of sex belong certain
very startling theories dealing with the question before us. These
notions are set forth at great length in theoretical explanations put
in the shape of popular expositions. According to these views a single
cell of the male or female reproductive glands is regarded as a sort of
complicated compound structure that might be compared to a spherical
world, in which thousands of primal individuals are contained, from
whose powerful and secret activity results the formation of male or
female individuals. (Hinz. Neusalz am Oder, 1897.)

       *       *       *       *       *

Another very common opinion is that the seasons (Düsing), the climate,
and other local circumstances, have an effect in determining the sex of
the embryo. If the data supplied by Birelli, Berner, C. F. Vilson, and
Felkin, and many other authors, be taken together, it appears that the
different zones of the earth’s surface are not without influence in the
reproduction of one sex rather than the other. More boys appear to be
born in the north; in the warmer south more girls.

Felkin and Vilson adduce the following instance from the south of
Egypt:--The Wagandas, a warlike race, kill the men and the old women
of their conquered foes. The children, girls, and young women they
lead into captivity. On one occasion 480 of the women gave birth to
children on their march. Of the new-born 79 were boys, 403 girls.
This incident led the author to pay further attention to the subject
on the east coast of Africa and in the Soudan. Everywhere he found the
anticipation of an excess of girls supported and confirmed. In fact his
investigations of the phenomenon led him to formulate and advocate a
law that the better nourished and superior parent tends to produce the
opposite sex.

In this case the women are in an inferior position, and in consequence
worse nourished and practically exhausted. Amongst other neighboring
races, where they live peaceably and domestically, the difference
between the number of new-born boys and girls is not a very great one,
although a small average appears in favor of the girls. The influence
of different phases of the moon has also been taken into consideration,
and has been described as so effective that some have even attempted to
prognosticate by these means the sex of a second child after the birth
of a first. (Lioy.)

       *       *       *       *       *

From Vilson’s statement that the sex of the worse-fed parent
perpetuates itself, a theory has been deduced which has been described
as _cross-heredity of sex_ (_Gekreuzte Geschlechtsvererbung_). In
accordance with this theory a prominent phenomenon would be that the
individual parents were not in a position to propagate their own sex,
but were yet under certain circumstances capable of reproducing the
opposite sex. If the father were the stronger, a girl would result from
the next impregnation; in the opposite case, a boy. A great number of
authors of renown, most of whom are mentioned in works dealing with
these questions, are supporters of this theory.

       *       *       *       *       *

We have already mentioned that there are some who regard the act of
generation as a conflict in consequence of which the sex of the elder
parent, whether father or mother, will be reproduced, so that the sex
in question may maintain its position. Similarly, in the case of the
so-called cross-heredity of sex there seems to be a conflict for the
preservation of the opposite sex. What conception we are to form of
this conflict seems a difficult question. Any measure of the greater
or less excitability of the centers during the act of generation
(which might be determined in the case of animals) is not easily to be
reached with any degree of probable correctness; and how much less any
numerical index which would express the differences of excitability, of
strength, and so forth, which might be developed during the conflict
of the opposite sexes. The theory of the cross-heredity of sex rests
upon the phenomenon that those female animals which are impregnated by
sexually inferior and older males, whose capacity for reproduction must
be considered as inferior to that of the females, produce more male
than female individuals.

       *       *       *       *       *

When a queen-bee lays male eggs, it is often asserted that these are
not yet fecundated. It is only after they have been impregnated by the
male that the female individuals appear. That is to say, after the male
influence has had its effect, the causes which lead to the development
of the female make themselves apparent, in accordance with the theory
of the cross-heredity of sex. Previously, this influence was wanting,
and, in consequence, only male individuals resulted from the eggs.

From the unfructified eggs of Daphnia (water-flea) many individuals
are at once developed, and in numbers so great as to be surprising.
According to Heincke, female individuals can be developed from eggs
which have not been fructified, but have been well nourished.

Dr. Clarke, a medical man of Detroit, is of opinion that in the
commixture of the elements, which serve as the basis of the future
individual, some external force is also embodied. Then the situation
would be something like this: there are two elemental forms, which, in
impregnation, are brought near each other, and their union actually
effected; of these the female ovum has the function of occasioning a
male offspring, and the male element that of occasioning a female.
In this act a conflict is supposed to take place, in which each sex
strives for the production of the opposite sex. But here there would
be also an expenditure of force on behalf of its own sex. This appears
to be a labor of love on the part of the sexually more ardent consort,
to which he or she finds himself or herself prompted by nature for the
sake of the weaker female or male sex, but at the same time without
any conscious volition of accomplishing an expenditure of power or
energy in this (reflex) act. Richarz affirms that it is the function
of the man to produce a higher degree of organization during the
development in the germ. But if the productive force of the mother is
more energetic, and exerts a greater influence, the result is a boy.
When, on the contrary, the generative force excited in the mother by
successful fecundation is weaker, the fecundated germ does not attain
the masculine sex.

Cases from married life are mentioned by different authors in which
the husband, partly in consequence of sexual debility, occasioned by
repeated seminal emissions on previous occasions, partly in consequence
of advanced age, and besides, also, through spermatic secretion
(_Samensecretion_), was scarcely capable of performing his conjugal
duties, nevertheless, pregnancy ensued, which after nine months
resulted in the birth of a boy. In these cases the mother would have
decided the sex of the child. But one is more inclined to explain
the origin and development of a boy in these cases by the law of
cross-heredity of sex. It may certainly be concluded from these cases
that a man, from whom it might have been supposed that no procreative
substance was to be had, although he can be reckoned amongst the
patriarchs of his species, may yet sometimes be able to boast that he
has left male offspring to be his direct heir.

On the other hand, Guttceit relates that a man, during the period
anterior to his having a mistress, and whilst he was entirely at the
service of his wife, begot only daughters. When, however, he limited
the time which he spent with his wife by devoting a part to a mistress,
his wife presented him with male offspring. This is a case which might
be explained by the law of cross-heredity of sex.

Serious surgical interference with the female certainly has an effect
upon fecundation. At least, pregnancy appears to be postponed after
the more difficult operations. If, however, impregnation takes place,
either male or female offspring may be anticipated. This contradicts
the theory of cross-heredity of sex, according to which only
individuals of one sex should appear, if one ovary has been removed.

Facts which have been brought to light by experiments with animals,
and by observation in the human subject, tend to give the theory of
cross-heredity of sex a higher value. But under the same circumstances,
other phenomena present themselves to observation which appear to
render some of the postulates of this theory untenable. Various
diseases which are diagnosed by medical men as organic disorders, but
which do not interfere with the power of reproduction, are apparently
without influence on the sex of the offspring, and also without
influence upon a striking prevalence of one or the other sex.

Richarz assigns all the power to the fecundated female individual. He
thus raises the culminating point of the female power of reproduction
to a height above that which other specialists will allow. In this
he is in complete disagreement with Roth, to whom he is also opposed
in other directions. Within certain individual limits (amongst which
is not to be included a diminution of capacity in consequence of
the necessary periodical functional impulses), the female organism
discharges its functions the more frequently and the more perfectly
the less often it is called into operation, and, _e contra_, the less
frequently and the less perfectly the more often it is called into
operation. According to Vernich, very long intervals between successive
pregnancies disturb the progressive increase in the weight of the
children less than very short ones.

One may, without being afraid of making any great mistake, at any rate
in the case of women who bear many children, make the same assertion
respecting the constantly increasing probability of male offspring, as
respecting the increase of weight.

The beneficial effect of a fairly long fallow season upon these
periodically acting organs is revealed in this way among others,
that, often enough, in consequence of prolonged rest and recovery of
strength, the female generative organs, after frequent still births,
became capable of producing healthy children. (Richarz.)

The fundamental law of crossing is supported by this author in every
direction. He recommends it as revivifying the blood and tissues,
in order to combat the evil effects of inbreeding, the exhaustion
of normal and healthy conditions, and as a preventative against the
appearance of degeneration and decay. A similar relation between the
sexes exists in their functions for the continuation of the species.

If an attempt be made (Richarz) to explain the different facts
observed, in accordance with the theory in question, no insuperable
contradictions will be met with. The general excess of male births,
their corresponding increase during the loss of many men in war (a loss
of distinctly stronger men), the high proportion of male births in the
case of mothers who produce their first-born at a comparatively late
age, the same high proportion where polygamy prevails, and, further,
the diminution of male births in the case of unmarried mothers, which
should not be overlooked,--all these phenomena are declared to be in
accord with Richarz’s views.

We will proceed here to give a brief sketch of Richarz’s opinion. Ribot
powerfully supports it in every particular from his own experience and
from historical data. The primary impulse upon which the whole process
of generation depends lies in the organs of the mother. Here lies also
the substratum in which is, as it were, the center of gravity of the
special generative process.

The function of the male sex is to evoke from the feminine substratum
an organism, or, more strictly speaking, to occasion a change in the
germ. If the mother’s generative capacity reaches the highest point the
result is a boy, who in external appearance resembles his mother.

If, however, it happens that the forces which act in the mother are
inferior to those of the father, the infant will be a female. She will
resemble her father, and will also inherit her father’s temperament.
Sex is not a transmissible attribute inherited directly from the
parents. Personal appearance and other characteristics will on the
whole correspond rather more with one of the parents than with the
other. Yet in every case the influence of the other parent will make
itself felt, and will in many respects exercise a modifying influence
over external appearance and other characteristics.

These views have been attacked by Roth, who declares himself against
Richarz’s hypotheses. His objections are contained in a work entitled
‘The Phenomena of Heredity’ (_Ueber die Thatsachen der Vererbung_). He
directly attacks the theory of cross-heredity of sex, and according to
his theory claims for each parent an equal share in the formation of
the future individual, at least in the earliest stages. Fecundation,
according to Roth, would at once be effective in determining the sex of
the future individual.

We shall have occasion hereafter to speak of the observations which
Mayerhofer has made upon the origin of sex. Here we shall mention only
a single fact. This is a result of his experiments with animals, and
seems to have a relation to the theory of cross-heredity of sex.

Ewes impregnated by a powerful ram bear more males than females, so
long as the ram is in possession of his full forces. After a time the
ram has to perform his functions repeatedly during a few days, as great
numbers of the ewes are rutting. The fatigued or exhausted ram then
begets only females.

Next the number of rutting ewes diminishes. The ram gradually recovers
his strength. Whilst constantly employing it with the remaining rutting
ewes he again begets male individuals. Now, according to the rule of
cross-heredity of sex, the number of females ought to be greatest at
the outset, because we here have a male of exceptional force. When the
ram is exhausted, according to the theory of cross sexual heredity the
males ought to be more numerous. It appears, therefore, that in this
experiment of Mayerhofer’s we have something which remains in want of
explanation. We shall presently have occasion to speak more fully of
the facts which this author communicates respecting the origin of sex
in man, and will then return to this subject.

The information which we have concerning a stallion (Sir Hercules)
belonging to the stud of Count Lehndorff deserves attention. This
stallion was twenty-six years old, and had to cover twenty-three mares.
The result was twenty-four foals of the male sex. This case of the
ardent mares and the old stallion can be explained by the theory of
cross-heredity of sex.

Particular attention should be here directed to a phenomenon which
seems to imply that a sexually exhausted individual always has
his advantage of propagating his own sex secured. It is a sort of
fulfilment of duty on the part of a strong female animal when her
litter shows a majority of male individuals, or male individuals
only. In this connection may be mentioned the facts communicated by
Settegast, Nathusius-Hundisburg, and De la Tellais, who arrived at
their results from experiments upon the proportions of the sexes of
the offspring of the domesticated mammalia.

       *       *       *       *       *

Attempts to solve the problem of the origin of difference of sex by
means of experiments have been numerous. So early as the last century
Platz attempted to carry out experiments with living animals.

The temperaments of the breeding couple ought to be concordant. Both
should be either of warm or cool temperament. Warmth and moisture are
primary conditions of fertility, not in plants alone, but amongst the
animals also; and (as Mayoor Zsigmond, of Kaschau, proclaimed in 1723)
represent the primary conditions of the possibility of a conception.

The warm element belongs to the man; the moist to the woman. Where both
qualities are to be found in both, offspring may also be anticipated.
But if this be not the case, for example, if the man’s warmth does not
accord with that of his wife, but is of a higher degree, then he can
beget boys. If he be not so warm, he must, if he wishes for sons, make
a distinct alteration in his diet. According to the prescription given,
he ought to lead a regular life and to limit himself strictly to warm
and dry aliments. The temperament of the woman is often ardent and dry.
In this state it must be regarded as unfitted for the development of
an embryo. Befitting food would not be without an influence upon the
alteration of temperament. Respecting this, experiments had proved this
much, that a suitable change of diet can exercise a salutary influence
over the temperament. A woman who was in the highest degree beautiful
in face and in every part comely had a temperament which would accord
with that of any man.

Then comes the theory of the allotment of the male and female in man,
and in all the vertebrata, to the right and left sides of organs of
generation. This is a theory which is being always brought forward,
even by the most recent writers, some of whom go so far as actually to
wish to support it by experiments.

Thus the excision of one or the other of the testicles of the male
is recommended in order that the owner may be able to breed the sex
which he desires. It still remains, in order to effect the artificial
determination of the sex, that the female should also play her part
correctly, so that the semen of the male may be conveyed to an ovule
from the required ovary. An effort was accordingly made to secure
intercourse in such a manner that the semen of the male might be
delivered in a certain direction in agreement with the anatomical
position of the duct which was to lead the seed into the required
ovary. But it was practically difficult to settle what position in the
intercourse was the right one. Experience proved that in a certain
case on two successive occasions male individuals were born when
the impregnation had been so contrived that the semen should enter
the right ovary. Therefore the left ovary was for female offspring.
It is not our concern to enter into further explanations of these
occurrences. Only this much may be said, that experiments have been
constantly made which might lead to some conclusive solution of these
questions, without any result having been obtained.

       *       *       *       *       *

A publication appeared in the year 1786 dealing with the above-mentioned
theory, and at the time attracted much attention. It has now become
difficult to procure, and is often mentioned on account of its containing
much that is valuable for influencing sex, both amongst men and animals,
that has been gathered from all the authors of the previous century, and
more especially from all the ancient authors who had written on this

The author was J. Ch. Hencke, organist at Hildesheim, and the title
of his book, ‘The Secret of Nature Completely Discovered, both in
the Procreation of Man, and for the absolute choice of the Sex of
Children.’ Brunswick, 1786. (_Völlig entdecktes Geheimniss der Natur,
sowohl in der Erzeugung des Menschen als auch in der willkürlichen Wahl
des Geschlechts der Kinder._ _Braunschweig, 1786._) The author relies
upon exploded theories, according to which the offspring is evolved,
as it were, out of a mixture of the generative secretions of the two
sexes, and can be induced to develop into either a male or female
individual. Thus the sex is not previously determined, only in the
course of its development out of the developing mass, which consists of
a mixture of male and female generative secretions, distinctive sexual
characteristics make their appearance, according to the predominance
of the male or female portion of the mixture. But here, also, the
old theory is set forth very precisely. The generative matter of the
right testicle serves to fructify ova from which males are developed,
that of the left testicle is used to fructify and develop female ova.
Similarly, the tenet is propounded that the right ovary contains male
ova and the left such only as will, when developed, produce female

       *       *       *       *       *

These doctrines, as a basis for the breeding of animals, Hencke had
discovered by castrating swine, dogs, and rabbits. Thus it happened
that a boar, who, after castration, had only the left testicle, twice
running bred with a sow female young only. Similar phenomena occurred
with other animals, so that this method was recommended by the author
to the breeders of his time. But it happened, also, that a surgeon
upon opening the body of a woman who had had sons only and never a
single daughter, found the left ovary very thin and withered, so that
it was hardly possible that it could serve for the development of
a new individual. On the contrary, the right ovary was in a normal
condition. It now remained only to discover some device for man,
by which he might be able, during the act of generation, to avail
himself of the discoveries thus made, so as to obtain the result of an
absolute choice of the sex of the offspring. The ligation of one of the
testicles was Hencke’s infallible remedy. When this severe proceeding
proved impracticable, in its place was substituted an elevation of
the testicle by means of its suspending muscle (the cremaster). Under
certain conditions this takes place of itself in particular positions,
and was accordingly recommended as an established proceeding for men.

One other conclusion of Hencke’s deserves particular mention. He was
bold enough not only to assert that the right and left sexual glands
served exclusively for the generation of male and female individuals,
respectively, but also asserted that the generative matter from the
right or left gland of one parent was productive only when united with
that of the same gland of the other parent. His counsels were not for
such persons as are too heated, too ardent. “For young, hot, hasty
men,” he says, “who are altogether without consideration, I am not
writing; but for chaste married people, and especially for those to
whom the production of a child of one or the other sex is a matter of

       *       *       *       *       *

Couteau established the fact that each seminal duct had its own
orifice, through which the semen was poured into the urethra. This
fact was in his days of the greatest importance, as it prevented any
mixture of the semen of a man’s two testicles. Hencke firmly insisted
that the semen was discharged by one testicle or seminal vesicle
alone, in the case when the testicle was raised up. But we need not
here follow further Hencke’s theories which he deduced from his own
experiments. In the present day these theories will satisfy no one.
Results which have been obtained either after ovariotomy, or after the
extirpation of testicles, have made us perfectly certain about the
value of one or the other generative gland for the production of the
male or female sex. The case of Schatz, which has been also pointed to
us as important in other specialist works, may not be uninteresting
here. The left ovary of a young girl was removed, together with a
portion of the left tube, and the right ovary, also, with the exception
of a margin of about two millimetres’ breadth. When she was married she
gave birth to a girl, whereas a boy should have been expected, seeing
that only male offspring were to be produced by the right ovary.

Scarcely any work that lies before us on this subject is so much
regarded as that of Hencke. At the same time, and although it had
in its day the widest circulation, it frequently met with the most
unqualified condemnation. Dr. von Seligson, in his discourse before the
Society of Medical Practitioners at Moscow (1895), on the subject of
influencing the development of sex, in connection with Hencke’s theory,
attached value to a great number of experiments tending to support the
old view. It was, however, admitted that by a departure of nature from
the ordinary law (somewhat resembling a transposition of the viscera)
male or female ova might occur in the respectively opposite ovaries.

       *       *       *       *       *

De Bay, who was opposed to the theory of the anteriorly-developed
sexual products of the right and left ovaries, asserts that the
quality of the generative products depends upon the quantity of
nitrogen existing in the chemical composition of the ovum and the
semen. A large proportion of nitrogen in the ovum occasions the
development of a girl. If, on the contrary, the semen contains a great
quantity of nitrogen, a male individual will result. To determine the
proportion of nitrogen, or to give it scientific value in such cases,
seems to be a difficult matter.

       *       *       *       *       *

Mention is also made of cases of tubal pregnancy in which the sex
was determined, and an effort has been made here, also, to find some
support for the theory of the existence of sex in the ovum whilst
in the ovary on the right or left side. Fourteen of these tubal
pregnancies, described by different authors, showed boys on the right
and girls on the left side. (Seligson.) In such anomalous cases where
the embryo has developed itself in the Fallopian tube, and has not
reached the uterine cavity, there is no doubt that the developed ovum
originated in the ovary of the side on which it was found.

Efforts are made to confute the different objections raised in many
quarters. The mention made by the traveler, Peter Kolben, of the
practice of cutting out one testicle, which is the custom of certain
African tribes (this is contradicted by Le Vaillant [1784], and by
Fritsch [1880]), and the accounts of Otto Finsch, may not deserve
credit, as they rest upon assertions made by other persons. Accounts
are further given, drawn from medical experience, of men who, after
prolonged orchitis, with consequent occlusion of the vas deferens,
begot only children of one sex, or in other cases were unable to induce
pregnancy. Also the discharge of semen was asserted not to take place
from both spermatic ducts at the same time. After many digressions,
Seligson in the end adheres to Hencke’s theory on no sufficient
grounds, and then bases on that theory a method, upon which I shall not
here pass judgment, but merely mention it without describing it.

At all events, there can be no question of a compression of the
spermatic cord in any way, for it could not be accomplished, either
manually or with the aid of various kinds of apparatus, without giving
rise to excessive pain.

In this case, as Hencke in his time explained, the cremaster muscle
raises the testicle up towards the inguinal canal. At complete erection
the testicle is drawn up and pressed against the inguinal ring. This
gives more favorable conditions for leading the semen forward from this
one of the two testicles; and this portion of the semen is used for
impregnation, to which end also a favorable attitude and a free passage
into the ovary must be provided. According to the views of the author,
this method, if adopted in procreation, will lead to the desired result
of producing a given sex. Exceptions are admitted. Exceptions occurred
in five families with twenty-three children. The author clings firmly
to his theory that each testicle possesses its own special spermatozoa
and each ovary its special ova, in which a given sex is already in
existence, and from which in fruitful intercourse male or female
individuals originate.

       *       *       *       *       *

Next after a number of theories which have been current on this
subject, we reach some others, to which more or less value has been
attributed. Morello attached weight to the concentration of the semen.
Thin, liquid semen was to be favorable to the production of females;
thick semen produced males. According to modern theories, based upon
observation of invertebrate animals (O. Hertwig, Balfour, Landois,
Minot, and others), it appears improbable that this position can
be maintained. The supporters of this theory assert that a single
spermatozoon suffices for the fertilization of an ovule, or to develop
the ovum into a so-called “oosperm,” that is to say, to form a really
fertilized ovum. (Perhaps the excess of semen serves for the earliest
nutritive processes of the ovum; which would, however, be difficult to
prove.) This fact has been also confirmed in the case of the higher
animals, and it might be in a similar manner brought to an issue in the
case of man. However, observations of this kind have not yet proved
possible with man. But in the case when several spermatozoa penetrate
the interior of a single ovum, anomalies in the process of development
result from the formation of several nuclei. Such ova, also, perhaps in
consequence of excess of semen, are very often aborted and perish.

In order to throw light on the causes determining sex, Pflüger (in
connection with results obtained by Born, which will be cited
later) attempted to determine the relative numbers of the sexes,
under normal conditions, in the case of the frog (_Rana fusca_). The
numbers were taken by his pupils, A. von Griesheim and Dr. W. Kochs.
The identification of the sex was made with a microscope under the
supervision of Pflüger. According to Pflüger the Graafian follicles
are easily identified with the aid of a microscope, if they are not in
their earliest stage. They contain an ovum with a scanty yolk and large
germinal vesicles with germinal markings. The whole is surrounded by
connective tissue.

According to Pflüger, the epithelium is wanting in such very young
follicles. In these frogs after their metamorphosis the testicle
consists of tubes, with multinuclear epithelia, and is easily
distinguishable from the always large ovaries of the tadpoles. By
different concentrations of semen, Pflüger attempted to influence the
proportion between the male and female sexes.

According to Pflüger, there are normally found amongst frogs in a
state of nature 36.3 per cent. males, and 63.7 per cent. females. With
thinner or thicker semen, the average number can be altered. With thin
semen Pflüger obtained 27.3 males and 72.7 females per cent. With
concentrated semen he obtained 39.4 males, and 60.6 females. Pflüger
carried out some other experiments, and came to the conclusion that the
concentration of the semen or the extract from the testicles exercised
either a very small influence or no influence at all upon the sex.
When he took an average result from all his experiments, he found that
out of 806 frogs which he raised, 288 were males. Whilst the normal
proportion of the males developed freely under natural conditions was
36.3 per cent., that reached by experiment was 35.7 per cent. It should
be here remarked that among the tadpoles many are found whose sex is
not yet determined. They are in a hermaphrodite condition, out of which
they develop into either males or females.

       *       *       *       *       *

Robin, the well-known French histologist, made the question of the
origin of sex the subject of an extensive inquiry. His investigations
start from the following point:--In warm climates the whole quantity of
blood in the inhabitants is less than in temperate zones. The process
of respiration in the inhabitants of warm climates is also not so free
as in the case of those who inhabit temperate or cold zones.

From this it would seem that some process connected with nutrition,
and with the passage of nourishment into the blood, is the cause of
the number of male births being greater in the cold zones than it is
in the temperate zones, or in the inhabited regions lying nearer
to the equator. It would follow from these considerations, that if
the women were subjected to such a régime as would materially affect
their respiration and the quality of their blood, more boys than
girls, or the contrary, might be bred. If so, breathing an atmosphere
containing more oxygen, with a corresponding diet, would be the right
receipt for producing in the woman such a basis that in the course
of development the male generative organs (which Robin considers the
anatomically more perfectly developed) might be evolved instead of the
female. According to Robin, the male sexual apparatus in comparison
with that of the female is provided with the more perfectly developed
character. Robin further insists that strong men will beget more male
individuals. Further, that a woman who indulges in sexual intercourse
somewhat seldom has female children; and that voluptuous women, who
are fruitful, generally bear boys. A number of experiments with
domesticated mammalia are adduced in support of this view.

       *       *       *       *       *

Hegar teaches that in the case of a merely rudimentary development of
the germinal gland either sex is developed.

With the views of Robin may be connected also other suggestions
regarding the food of the parents. These have been tried both with men
and animals. But we shall not here go further into them. Nor shall we
mention the different kinds of food or drink which have been employed,
whether by men or women, to produce a greater sexual activity.

       *       *       *       *       *

The eminent naturalist Born, of Breslau, made a long series of
experiments, which are of the highest interest in reference to the
doctrine of the origin of sex. It is easy to fertilize frogs’ eggs
artificially. The ripe eggs are taken directly from the female,
and the testicles of the male rubbed with water. This fluid, which
now contains spermatozoa, serves to fertilize the eggs. Spallenzani
had already undertaken artificial fructification. Born observed,
during his study of the course of development, that the effect of his
breeding as regarded sex was to produce 95 per cent. of females. This
number is evidently so remarkable that it ought to secure particular
attention. No such extreme contrast between the numbers of males and
females is to be found amongst the frogs that develop freely under
natural circumstances. It seemed to Born that his result was to be
referred to insufficient nourishment, and that the tadpoles, being
somewhat unfavorably circumstanced, had not been able to attain the
development of the stronger sex. In this experiment on the evolution
of sex it appeared that not only was there an excessive production
of females, but that the other organs of the embryo and its whole
constitution could be modified by means of nutrition. It is also to
be observed respecting this most interesting experiment that many of
the tadpoles perished of hunger. Now, the number of still-born males
of the human species very much exceeds the number of still-born girls.
The mortality amongst males is so great that the average is from 136
to 140 still-born boys to 100 still-born girls. An attempt has been
made (Pflüger) to explain this phenomenon in the human subject on the
ground that the tenacity of life in the female sex in the period of
embryonal existence exceeded that of the male. Consequently, boys would
more easily perish during development than girls. If this observation
made with respect to human beings were applied to the tadpoles, it
might also explain the high percentage which the females showed among
the frogs. Very likely the male tadpoles possessed less capacity of
resistance; or, in other words, were less tenacious of life than the
females. It will be understood that this view would apply only as a
partial explanation of the facts set forth by Born.

       *       *       *       *       *

In the artificial breeding of trout, which is conducted under cover, in
which process the embryos which have crept out of the ovarian follicle
are kept with the yolk-sacs in small reservoirs under a continuous flow
of water, it is observed that single individuals develop themselves
further. They lose their store of yolk with the yolk-sacs. In the
course of their further development and nutrition they arrive only
very slowly at the development of the internal generative organs. Even
in a very advanced stage the sex is not yet so plainly indicated as
in fish of the same size living free. Indeed, it is even affirmed by
many persons of experience that in the artificial breeding of trout
even those that have attained their full growth remain unfruitful and
cannot be used for further breeding. (D’Audeville and Arens raised, in
the case of trout, more females by dry impregnation.)

       *       *       *       *       *

Here might be adduced also many other doctrines of greater or less
interest respecting the theory of the origin of sexual distinction.
Only in order that I may not introduce too much literary matter, I
shall mention only a few of the more important and noticeable theories
before I return once more to the experiments upon the influence of food
upon the development of sex. Janke’s work (small edition), published at
Stuttgart in 1896, furnishes a synopsis of the literary work done, as
do other books which treat of this subject.

       *       *       *       *       *

Mons. Thury, professor at Geneva, published at Leipzig, in the year
1863, a book on the law of breeding the sexes, which, on account of
its contents, attracted great attention. In this work the author, after
a number of successful experiments and other investigations, shows how
an influence may be exerted over the sex of plants, animals, and men.

This work stirred me up to the endeavor to devote myself to this
question, so far as that might be possible. I shall give a short sketch
of Thury’s work, together with the critical revision of it by Dr. H. A.
Pagenstecher, of Heidelberg.

The doctrine respecting the origin of sex in cattle was laid down by
Thury from his own investigations. The principal point in his doctrine
of the origin of sex in animals he considers to be the condition of the
ovum at the time when it is fertilized. If the ovum has reached the
stage of ripeness, which may be described as an advanced stage, we may
expect to have, after fertilization has taken place, a male individual,
which will develop itself out of the ovum. If, however, the ovum
has reached only an imperfect state of ripeness when successful
impregnation takes place, then no such powerful and perfect specimen
of the race as the male is can be developed, and the result of such an
ovum is always a female.

       *       *       *       *       *

From this it follows that, according to Thury, the cause of sex lies in
the ovum developing itself in the ovary, and the degree of its ripeness
is the only factor in the development of one sex or the other.

It is not, however, shown what the systems are by which such an ovum
can be correctly judged, so as to determine the different degrees of
ripeness. We now know very well certain signs which appear upon the
maturation of the ovum, of which we shall not say more here. Of these
Thury could know nothing in 1863, because at that time they had not
been discovered.

Thus the sex depends upon the ripeness of the female’s ovum at the
time of its fecundation. In the case of its having reached the highest
degree of ripeness, a male is the result. It is impossible for the ovum
to attain a higher degree of ripeness. If the ovum of a human female
has arrived at this supreme degree of ripeness, it has reached that
stage in which it is capable of becoming the basis of the most perfect
living creature which exists upon our globe.

Rutting is an external sign of the maturity of the ovum amongst the
lower animals. When, during the rutting period, an ovum is detached
from the ovary, and passes through the Fallopian tubes to the cavity
of the uterus, the fructification can take place at the beginning of
the rutting period. At this period its ripeness is not so far advanced.
The result of the development of such an ovum is a female. But when
the fecundation has taken place at the end of the rutting period, the
ovum has reached its highest degree of development, and, if effectively
fecundated, it will become a male. It follows that the signs of rutting
should be carefully studied, as in fact is habitually done by practical
farmers. The duration of the rutting period and the influences which
affect fertilization should be accurately known in order to lead to any
practical result.

Females at their first conception would usually produce, or would be
particularly disposed to produce, female individuals. Experiments
succeed better with such as have often produced young. In their case
the symptoms which indicate the commencement or the conclusion of
the rutting are much more easily determined, so that they are better
adapted for these experiments.

       *       *       *       *       *

We know well that in the case of the lower animals when rutting, as
in the case of the human female during menstruation, an ovum is
liberated from the follicle in the ovary, and ordinarily passes away
in the menstrual discharge. In fact, a follicle of the ovary bursts,
and, to be precise, that one which protrudes most beyond the surface
of the ovary. This bursting of the follicle has not actually been
observed. But that this event takes place there can be no doubt, for
the locality of the fissure is perceptible, and the ovum is found
either at hand on the ovary, or else on the fimbria. The increase of
fluid in the follicle of the ovary, and the excessive charge of blood
in the vessels on the walls of the follicle, seem to be, without any
actual contraction taking place, the physiological causes of the
freeing of the ovum from the follicle, so that it may come in contact
with the semen. Ovulation can take place without intercourse. But
sexual intercourse can also favor ovulation; at least, it appears to
facilitate the separation of the ovum from the ovary.

Bischoff made known the fact of the separation of the ovum from the
follicle. He showed that the presence of sperm in the feminine organs
of generation of the animals was indifferent, that the rutting of the
animal was the index of the ripeness of the ovum. Eimer, Beneke, Van
Bamecke, and Hensen, call attention to the phenomenon which is observed
in the case of bats, who for a whole month before the detachment of the
ovum from the follicle have their uteri full of semen.

       *       *       *       *       *

These processes which take place at rutting time are attended with
sexual excitement and congestion of the external genitals. It is not,
however, necessary that these processes should in the case of all
animals occur at the same time as ovulation. If rutting animals are
restrained from sexual intercourse, the sexual excitement of the female
passes off; but the symptoms of rutting again make their appearance
after a time. These are the phenomena of the so-called rutting season.

This rutting season lasts with sheep fourteen days, with swine
fifteen to eighteen days; with cows, horses, and apes four weeks. It
corresponds to the menstruation of the human female (Hensen). Many
bitches admit the dog only when six or seven days have elapsed since
the issue of blood. In the case of many animals rutting is marked by a
flow of blood from the genitals. This is the case with apes, bitches,
swine, and many other mammalia.

       *       *       *       *       *

Under these circumstances, the symptoms of rutting are sufficiently
distinctly marked to make it possible, as Thury suggests, to determine
the advanced state of ripeness or its commencement in the ova. But it
is scarcely possible to say when the period of ripeness commenced in
this ovum or that. An ovum which had begun to ripen early may, at
the beginning of the rutting time, have attained to the condition of
a male-producing ovum. At the same time, others which are fertilized
at the conclusion of the rutting, but had begun to ripen comparatively
late, may, at the end of the rutting time, not yet have advanced far
enough to be able to develop male individuals.

       *       *       *       *       *

Thury bases his doctrine on a number of phenomena of the vegetable and
animal world, and upon various experiences in the case of man. He also
adduces many statistical data in explanation and support of his theory.

The observations on plants make it indisputably clear that all the
circumstances which favor growth and ripening are favorable conditions
for the development of male organs. If all these circumstances are
lacking, female organs are produced.

Dark and cold, for instance, cause the male organs to perish. In
recent times a great number of extended studies of the phenomena of
vegetable life in this direction have appeared. I may mention more
particularly the following experiments made by M. von Treskow in
Gorlitz with _Arisæma_ (Verhandlungen des Botanischen Vereins der
Provinz Brandenburg, 1895). This plant first produces male flowers. In
the later year, when it has become larger, it produces female flowers.
The transition from the male flowers of the early stage to the female
flowers of the later stage can be hastened at pleasure by planting in
rich garden mold and manuring with horn shavings. If, on the other
hand, the plant be placed in poor, sandy soil, it reverts to the male
flowers. The same author quotes in his essay a remark of Heyer’s
(Halle, 1884), who declares that no sufficient observations exist
respecting the influence which different situations exert over sex.

I adduce this instance, for the sake of remarking respecting it, that
on this subject also controversies exist, which must be settled by
wider studies of the life of plants.

Cornaz has tried to derive from cows evidence in support of Thury’s
theory. He had twenty-nine cows impregnated with attention to the
rutting time, and from twenty-nine births received twenty-two females
and seven males. Cornaz attested his experiment by a declaration, and
the experiment was repeated in the French state domains.

But the experiment alone was striking enough to invite repetition. It
also met with partial success. But the plan was afterwards entirely
given up, perhaps in consequence of disappointments.

In this case it very likely happened--as in such experiments it very
easily may happen--that, in consequence of insufficient practical
knowledge on the part of the experimenter, the actual commencement
of the rutting time was overlooked. In addition, it is well known
that animals, in consequence even of an amount of exercise not very
exhausting, and in many other ways, as well as in consequence of the
food they have taken, may exhibit variations in the activity of their
rutting. It is not, therefore, surprising if the results of experiments
show much that was unexpected.

I here pass over a great number of proofs which Thury gives in his
essay. Funcke (1866) made in his ‘Physiology’ the following remarks
on Thury’s theory:--“Although the origin and determination of sex is
not indisputably proved to depend upon the degree of ripeness of the
ovum, it appears to me that we have not reached the right time for
determining the factor upon which it does depend. These experiments
have been made to repose upon a fact, which fact certainly proves,
beyond the possibility of dispute, a relation between the fertilization
of the ovum and the subsequent sex. This fact is that, in the case of
certain creatures capable of parthenogenesis (unisexual procreation),
we find that, from unfertilized ova one sex always results, and from
fertilized ova the other. But any closer interpretation of this
function of the semen is rendered nugatory in advance by this, that it
is in some cases the male and in others the female that results from
the unfertilized ova.”

       *       *       *       *       *

Thury’s theory can be very suitably brought into agreement with the
theory of cross-heredity of sex, and explained by the assistance of
that view. The cow, at the beginning of her rutting, is not in a
condition of great sexual vigor. If the ovum be effectually fertilized,
it may be supposed that the bull, in procreative activity the superior
consort, will be fitted not to reproduce his own sex, but that of the
weaker cow. At the end of the rutting period the cow, which is brought
to the bull, has her ovum ripened to the highest possible degree, and
in consequence, when compared, from a sexual point of view, with the
bull, is distinctly the stronger and superior, and a male calf is in
this case the result of conception.

According to the theory of cross-heredity of sex, female creatures
should in the former instance be produced, and in the latter males,
which same result is reached in accordance with the theory of Thury.

Attempts have been also made to apply Thury’s theory to the human
species. The menstruation of women has been compared with the
rutting of the lower animals, and has been considered a protracted,
oft-repeated rutting. Now, as an ovum is specially developed every
month, it follows that this ovum requires a certain part of a month to
attain a more or less advanced degree of ripeness. According to this,
the ova which are fertilized a short time after menstruation will
develop only female individuals, whilst those which have had a longer
time in which to attain to ripeness would develop themselves into males.

The mucous membrane of the womb ought, about ten days before the
beginning of menstruation, to thicken itself distinctly in consequence
of a turgescence and dilatation of the vessels. In consequence it
appears swollen and loosened, and it has reached the culminating point
of swelling when the menstruation is at its highest. After menstruation
the swelling does not immediately decrease, but lasts on for about
nine days, until the mucous membrane returns to its normal condition.
(Hensen.) Thus it seems that the swelling and hyperæmia in the womb
appear at the same time as the conditions which lead to the ripening of
the ovum. The fertilization of the human ovum would be, therefore, most
efficacious at the time when the mucous membrane of the womb is also
most appropriately prepared, and it is probable that the same moment
is the one when all the other coincident factors are of a sort best
calculated for the reception, the fixing, and the protection of the
ovum. It is simultaneously with these processes in the mucous membrane
of the womb, and in the other parts of the generative organs of the
woman, that the ripening of the ovum is effected.

Now, it may appear not to be a matter of indifference (and may very
likely even have some connection with the development of sex) whether
the ovum is fertilized at a period during which the mucous membrane
is passing through its changes in order to reach its highest point of
swelling, or at the time, when, after menstruation, the mucous membrane
is, during so considerable a period (nine days), passing through a
retrograde metamorphosis in order to return to its normal condition.
This protracted process seems to correspond to the protracted rutting
in the form of a menstruation. If so, the human uterus, as Thury’s
theory would declare, would be prepared, to a certain extent, in
different ways, for the reception of the ovum, according to the
different sex-conditions of the future child.

       *       *       *       *       *

It is not sufficiently known to how great an extent the principles of
Thury’s theory have hitherto found their right application to the case
of man. They seem in practice to be applied in different ways.

It seems that in cases where a result was obtained it could be more
easily explained by the principles which have been already described
under the theory of cross-heredity of sex. The assumption of a greater
or lesser degree of ripeness of the ovum which was to be developed was
a very questionable one.

The different processes with which we have become, in more recent
times, acquainted as symptoms of the ripening of the ovum, are not
here intended. Such symptoms can be observed both in the ova of
the invertebrata and in those of the vertebrata. These symptoms,
which are such as the attainment of the normal size of the ovum of
the species in question, the protrusion of the orientation points
(_Richtungskörperchen_), the steps towards the formation of a female
anterior nucleus (_Vorkern_), etc., do not here apply, for the
recognition of that higher degree of ripeness in the ovum which is
necessary at the time of fructification for the development of a male

All the above symptoms occur alike in the ova destined for the male and
for the female sex. That ripeness of the ovum upon which Thury’s theory
insists, lies in the nature of the ovum apart from any anatomical
signs. It is a condition of the ovum which we can only attempt to
explain by laying down the principle that an ovum which has been for a
longer time prepared in the female generative organs previously to its
fertilization, must be riper than another which has had less time for
this preliminary process.

       *       *       *       *       *

We have mentioned above that on the occasion of Thury’s experiment,
the desired result was effected in twenty-nine cases. Pagenstecher,
Siebold, and Köll have dealt critically with Thury’s work. Coste was
not in a position to confirm these experiments, nor to verify them.
In order to test Thury’s results as applied to the human subject,
Schröder obtained the assistance of young women, who were in a position
to give him positive and accurate information respecting the time at
which they became pregnant. The women could name the day on which they
had had sexual intercourse, and knew the date of the last menses.
From careful calculation of the interval between these dates, it was
possible to ascertain approximately at what stage impregnation of the
ova took place, the degree of ripeness of the impregnated ova could
also be inferred from the space of time that had elapsed since the
last menstruation, and the sex of the fœtus was noted. Schröder found
that on an average of twenty-six cases in which boys were born, the
conception had taken place 10.08 days after menstruation; on an average
of twenty-nine cases in which girls were born, 9.76 days after. In
consequence, he was not able to confirm Thury’s theory in the case of
the human subject.

       *       *       *       *       *

The experiments of Albini in Naples (according to Kronecker’s report
‘_Centralblatt für medicinische Wissenschaft_,’ 1868), which he made
during four years in his great poultry-yard showed in the first place
that hens for eight days after being separated from the cock laid none
but fertile eggs. On the ninth and tenth day the fertile and infertile
eggs were of equal number. On the twelfth day all the eggs were
infertile. Nevertheless fertile eggs appeared even on the eighteenth
day. It is possible that they had been impregnated by spermatozoa which
had remained in the folds of the mucous membrane of the uterus.

Hens never yet impregnated, or such as had not been impregnated for at
least a month, in three days (after impregnation) laid fertile eggs,
which increased in number daily.

According to Albini, hens can in Naples leave the eggs which they
are hatching. The shell can be partly broken off and again replaced
without the embryos necessarily perishing. But care must be taken that
no fungoid growth reaches the germ, as this is easily fatal to it.
Indeed, it has been recently shown that new-laid or well-preserved eggs
are free from all micro-organisms. When these appear they have made
their way into the egg through the mechanically injured or otherwise
altered calcareous shell. They do not have their origin in the egg from
the mother. The egg of the bird is perfectly free from micro-organisms
when it is laid. If, however, only traces of pure cultivations of
micro-organisms be in a suitable way applied to such eggs externally
(Lenderer), they always have a fatal effect upon the developing germ,
even when they are not any of the so-called pathogenic microbes.

       *       *       *       *       *

And now the result of Albini’s breeding experiments upon poultry with
respect to the origin of sex.

From three to six days after intercourse with the cock the hens lay
eggs, from which on the average an equal number of males and females
are developed. In the warmer part of the year the number of males
appears to be greater.

_Better nourishment of parents seems also to exercise an influence over
the sex of the young._

Such eggs as were laid from ten to fifteen days after complete
separation from the cock, gave when hatched generally a distinctly
greater number of females. Albini found that the greater number of
these died of anæmia. He ascribed that to imperfect fertilization, and
considered that development of an excessive number of females was to be
ascribed to the same cause.

Albini inclines towards the theory of Thury, in accordance with which
the principal cause of the development of sex lies in the degree of
ripeness of the ovum. He is opposed to the theory of Coste and Gerbe,
which declares that the ova of the birds and mammals are fertilized
when they fall from the ovary. The place where this took place was,
according to their theory, exactly localized, at the opening of the
Fallopian tube, and not at any place in the length of the tube.

Fertilization in the Fallopian tube or uterus is allowed to be
possible, and it is admitted that, in exceptional cases, fertilization
of the hen’s egg is possible so long as it is not surrounded by the

This opinion, however, is in direct contradiction to that of Lenkart
and Newport and many others, who hold that the albumen, which gathers
around the yolk in the oviduct, hinders the penetration of the
spermatozoa into the yolk. When Albini had collected his facts he came
to the conclusion that, in the case of animals which bear many young,
the last are mostly male, and explains this by the hypothesis that the
ova passing through the Fallopian tube thrust the semen back, so that
the ova which come behind are therefore fertilized in a more advanced

       *       *       *       *       *

Meyer believes that he has incontestably proved against Ahlfeld that
the sex is determined at conception. He does not appear to be disposed
to admit the existence of male and female ova in the ovary; but he
thinks it absolutely certain that the sex is determined at conception
by the reciprocal action of the ovum and the semen. This view follows
from the fact that, as Thury’s theory demands, a fertilization and a
determination of the sex must necessarily take place as regards time
either at the beginning or the end of the mingling of semen and ovum.

The longer the ovum exists free from the ovary, the longer it remains
without the surrounding of those elements (contained in the ovary)
which are necessary to it. Apparently, in consequence of the absence
of these elements, it is all the time drawing nearer extinction, or
it may at least become gradually less capable of maintaining its own
sex--which is feminine. At least, it appears, before it is overtaken
by the total extinction which threatens it if it is not fertilized,
to lose the energy necessary, when fertilization ensues, to maintain
its sex, and so may become fitted to assume the opposite masculine
sex. This much, however, seems to be quite certain, according to
Mayerhofer, that the human ovary does not contain male and female
ova already possessed of sex. Equally impossible is it to imagine
male and female seminal filaments (spermatozoa) already existing in
the organism, and provided with distinct capacities for generating
definite sexes. We are unacquainted with any special anatomical signs
indicating any such distinction, and do not, even after microscopic
investigation, find ourselves prompted to assume the existence of
such distinct forms as would allow us to conclude the existence of
so fundamental a difference. It is true that in many of the lower
animals different forms of spermatozoa are known. These are developed
in one and the same testicle, and under the microscope whisk about
confusedly with vivacious movements. We find this in the case of a
kind of snail (_Murex brandaris_). If we observe a drop of the semen
of this creature diluted with sea water, the greater number of the
spermatozoa, possessing head, central portion, and tail, move about
very energetically. Amongst them are other spermatozoa, distinctly
larger and of different form, whose shape suggests spindle-like
elements, ending in thin thread-like tails. All these objects exhibit
a striking vivacity of movement. Whether these objects represent a
particular kind of spermatozoa (as some have supposed), exhibiting
definite sexual character, or whether they are not cells, striking on
account of their movements, out of which spermatozoa are developed (the
so-called spermatides or spermatogonia, transition forms out of which
spermatozoa are developed), is at present an open question.

H. A. Pagenstecher attempted an important readjustment of Thury’s
theory, and tried to show that it might be made concordant with what
had been elucidated by previous observations. He holds fast to the
axiom (Joh. Muller, Home, Geoffrey St. Hilaire, etc.), that the embryo
is at first sexless, and that the ovum after its fertilization still
has this character, and must possess the potentiality of developing its
sex in two different directions. The factors which determine sex must
be external to the embryo.

Pagenstecher remarks that the relations which have existed anterior
to the fertilization of the ovum, as well as its age (with which its
ripeness is connected), are from the outset without influence on sex.

The embryonal germ, before its fertilization, is an embryo whose sexual
development is undetermined. In this case fertilization acts as an
external factor in the direction of determining the sexual quality of
this indeterminate embryo.

The act of impregnation would be of influence upon the sex of the
embryo in accordance with the character of the father. That follows
from Pagenstecher’s explanations of Hofacker’s observations. According
to Hofacker we get from men of twenty-four years of age and upwards,
as also from sheep of a certain age, an average of a greater number
of males. In the case of mothers, also, as we have already pointed
out, the sexually-stronger age (Lenkart, Girou de Buzareingues,
Hofacker, Morel de Vindé, Sadler) and the food have an influence upon
the majority of births of female individuals. Here should be added the
experience of Nasse and Van den Bosch. The observations of Dzierzon,
von Siebold, Lenkart, and von Berlepsh, on the development of sex in
bees, and, according to von Siebold, among the Psychids, should also
be taken into consideration. When the females of certain Psychids are
not impregnated they lay only female ova. If they are impregnated,
male ova appear also. The tree-lice (Cestoni, Réaumur) give birth to
living young without impregnation. These are at first only female,
_afterwards males appear as well_. After this impregnation commences,
and the females begin to lay ova.

The experiments of Knight, who found that melons and cucumbers produce
male blossoms under higher temperature and female under lower (which
was verified by Mauz), demonstrate that, in this case, such external
factors as warmth, light, dryness, have an influence upon sex.
Pagenstecher, however, believes that the conditions of origin of sex
are not the same in animals and plants. We must not, he says, from
these observations draw conclusions off-hand respecting the sexual
propagation of plants nor of animals in general.

It must be further pointed out with regard to the thesis that ova which
are emitted last have had more time to ripen, that we must reflect
whether the process of ripening may not have also begun late.

Thury’s observation that the last egg laid by a singing bird developed
a male (communicated by O. Bourrit), and that in the case of hens the
majority of the later eggs were males, seemed to Pagenstecher not quite
certain. He mentions also a method by which, in poultry breeding, the
breeding experiments can be conducted on a regular principle, which I
shall quote word for word:--

“For this experiment a number of hens are taken which may be
anticipated to be “setters,” unless the use of incubators is preferred.
The hens are to be separated, and the eggs which each one lays in her
own particular nest are to be marked with numbers corresponding to the
days on which they were laid.

“The eggs of the different hens are now to be rearranged, so that the
eggs which each particular hen is given to hatch shall, as nearly as
possible, have the same numbers. For example, if the number of the hens
be six, and the period of laying up to the time when the hens begin to
set be thirty days, one hen will have eggs to hatch with the numbers 1
to 5, the next 6 to 10, the third 11 to 15, the fourth 16 to 20, the
fifth 21 to 25, the sixth 26 to 30.

“In this way the doubt will be avoided, which necessarily arises, if I
give the eggs of one hen, although marked, to be hatched by her alone.

“In the latter case, it can very seldom be known with certainty from
which egg-shell a cock or hen issued.

“In this experiment, on the contrary, one can quietly wait until the
cocks and hens in the growing broods of the different hens can be
clearly distinguished and numbered, seeing that each brood has numbers
(of the days of laying) of very nearly the same value. The experiment
is easier and less subject to the possibility of error when the eggs
belong to different varieties and are taken from known parents.”

Fertilization in many cases alters the future sex as soon as it affects
the germ in some corresponding manner. The germ develops itself, and,
in the case of creatures whose ova develop without fertilization,
evolves one, or the other, or both of the sexes. According to
Pagenstecher, fertilization often alters the determination of the sex
of the germs which attain to development in the ova. The point of time
in the life of an ovum, at which it has reached that degree of ripeness
which gives it such a character that the semen can no longer affect the
determination of the sex, cannot be absolutely settled. A more powerful
bull might beget female calves earlier in the late rutting time than an
older one.

After further explanations and critical expositions, which suggest
themselves in the course of the examination of the theory, Pagenstecher
lays stress upon the following important dicta of Thury’s teaching:--

1. Sex depends upon the ripeness of the ovum at the time of

2. The ovum which, at the moment of fertilization, has not yet reached
a certain degree of ripeness, produces a female. If this degree of
ripeness has been passed, the ovum, upon fertilization, produces a male.

3. If at the time of rutting a single ovum is detached from the ovary,
and descends slowly through the genital canal (animals which bear a
single offspring), fertilization taking place at the beginning of the
rutting suffices to produce a female, and at the end of the rutting to
produce a male, provided that the change in the condition of the ovum
takes place normally during its passage through the genital canal.

Both the theory as Thury stated it, and the critical remarks that have
been made upon it, have been further elucidated in many subsequent
works. Here Pictet, Chavannes, C. Vogt, De Philippi, and others, have
taken part. Pictet believes in the uniformity of the sexual life of
vegetables and animals, so that both would be subject to identical
fundamental laws.

The facts which stand in certain relations with the fundamental laws
are numerous, and the manner in which they tend to affect those
fundamental laws occasions various combinations in the variety of

For the animal kingdom Thury adduces a number of observations as the
foundation of his teaching. We shall here turn our attention to some of

We have already pointed out that in the case of the eggs of the singing
birds, which are laid by turns, the young which emerges from the last
strikingly smaller egg, the so-called “nest egg,” is always a male.

According to the theory of Thury, the ripeness of the ovum depends
also upon the place which, in the animals, it occupies in the ovary.
In consequence, according to this author, it is not improbable that
we shall find an irregularity in the successive production of male and
female ova.

If the activity of the generative apparatus of the female should be
increased by any circumstance, in the case of the animals the ripening
of the ovum would be accelerated. The consequence would be an earlier
detachment or emptying out of the ova from the ovary. In consequence,
the generative operations in the animal are of a more complex nature
than in plants, a fact which is of great significance for the
determination of sex.

The continuous intercourse of the male with the female increases
the capacity for accelerating the ripening of the ovum. According
to Burdach the mother animals who do not have frequent intercourse
with the male bear more females, because their ova do not, before
fertilization, attain so high a degree of ripeness as to be able to
develop into males. Also, it appears from observations on animals,
not to be improbable that the male chooses the time of intercourse.
The determination of the chosen time depends upon many influences. The
causes of choice may be sought in many factors. Some of these depend
upon external influences; others have internal causes. The causes may
be general or personal. They may depend upon external form, or be
occasioned by other phenomena of the animal world. It is always easy
for these phenomena, which in their nature are of the most different
kinds, to escape observation.

Amongst cattle and sheep the first-born are more often females.
(Girou.) Also in the human species a greater number of females are
observed amongst the first-born. Here, on the one hand, regular
intercourse with the male is to some extent unfamiliar; whilst, also,
according to Thury, the choice of the date of marriage might be of
importance. The constancy of the births may be explained by the
regularity of the intercourse of the two parents in consequence of the
reciprocal ties which surround family life.

From illegitimate births more girls result than from marriage.
The reason of this might be sought in the influence of the active
excitement of the female at the time at which the conception took
place, that is, shortly after menstruation, when the woman is most
easily excitable.

       *       *       *       *       *

The various theories respecting the explanation of the production of
sex which are known to us, from the earliest accounts down to the
modern predominance of natural philosophy, have been collected by W.
His. (‘_Archiv für Anthropologie_,’ Band 4, 5.)

Since then, it is true, during the course of successive studies, and
more especially of those which have been made during the present
century, many substantial alterations have appeared in the views held
respecting the cause of the different development of sex. We have seen
this above.

Thus, discoveries have been made which have exercised a very wide
influence, for example, that of the ovum in man and in the other
mammalia (Baer, 1828), or the penetration of the spermatozoa into the
protoplasm of the ovum as a necessary condition of fertilization. In
later times it has been made certain that the head of the spermatozoon
is a nucleus, and that only one spermatozoon penetrates into the
interior of the ovum. Afterwards its head as a nucleus unites with
a nucleus-part of the ovum, forming a new nucleus in the ovule,
which, together with the surrounding protoplasm, serves as the point
of departure of the further processes of development, and in this
condition is described as an oosperm. After this follow other extensive
details of the process of development, which will not be described
here. It may be already seen, from the few principal factors of the
process mentioned, that our theory respecting the development of the
sex in the embryo will have to be substantially altered. We shall here
adduce only the fundamental doctrines respecting the development of
the generative organs laid down by Waldeyer in his masterly work on
the ovary and the ovum. The teaching for which we are indebted to His,
Kölliker, Schäfer-Korschelt, Heider, Duval, Kollmann, Minot, Bonnet,
Bergh, Prénant, Balfour, Romiti, Kuppfer, and others, must also be well
remembered, as well as the acquisitions of new information connected
with the physiology of the embryo, and, of quite recent date, the
mechanism of development (Roux), which can acquaint us more especially
with the particulars respecting the states and processes in the ovule
during the earliest life-stages of its development.

The doctrines of the physiology of metabolism in men and beasts under
different circumstances have exercised so powerful an influence
over our comprehension of the relations of the individual during the
sexual-life, that we practically find in all these teachings a powerful
support, whence we may obtain many elucidations bearing upon the
question lying before us, and may discover the principles necessary to
complete our theory.

But, before entering upon the fundamental principles of the theory
which I have set forth, I wish to mention a treatise of Mayrhofer’s,
the principal results of which I shall briefly recapitulate. After that
I shall mention briefly such information as I have met with respecting
the nutrition of the mother.

Mayrhofer was led by critical notices and the observations of others,
and, further, by his own experiences, to conclusions which he set forth
in propositions, some of which I select here.

In the plants and the lower animals food plays a principal part in the
development of sex. The sex is not generated, but depends upon external
influences over the fruit which is in a state of development. And here
we have a stage which precedes the separate sex in man, in which stage
sexual neutrality must be regarded as normal, where also we find a kind
of hermaphroditism.

Whether sex in the human species is determined at conception, or only
develops itself afterwards, we must attempt to discover from obstetric

The twins and triplets contained by one chorion are of the same
sex, and have a common placenta in which the blood passages of both
umbilical cords communicate with one another. On this account, also,
many opine that the identity of sex is occasioned by the intermixture
of the blood, an opinion regarded, on the contrary, by others,
with incredulity, because the intermixture of the blood might very
possibly lead merely to a mixture and not to homogeneity, under which
circumstances dissimilarity of development would be possible enough.
We may here adduce the following facts also (Jhering): The armadilloes
produce a number of young in one litter, which are normally developed
in a single chorion, and are of the same sex, as in the case with man
when twins are developed in one chorion.

Heartless monstrosities (_Acardiaci_) are, in spite of imperfect
nutrition (the conditions of proper nutrition by the blood are wanting
in the embryo), of the same sex as normal offspring. Now, cases of this
kind demonstrate that, in the later periods of development, although
the conditions of nutrition are not alike, nevertheless the similarity
of sex in the twins is maintained; so the foundation of the future sex
would be laid at the period of conception. This rule which proves valid
for the twins found in a single chorion, would apply for all human ova
in general, because all possess the capacity of attaining their sexual
character at conception.

According to Mayrhofer, placentæ are rare in which, where there are
two chorions, communication is found between the vessels of the two
umbilical cords. In addition to what has been already mentioned,
Mayrhofer lays down the law, which we find frequently stated in many
quarters, that the older of the two parents has a greater preponderance
in favor of the propagation of his, or her, sex. Especially the
physical maturity on the man’s side enables him to propagate his own
sex, either in connection with younger or older women. A superiority on
the part of the woman produces girls.

Our author only partly supports Thury’s theory, and considers it an
open question whether the time of impregnation has any influence on the
origin of sex. But he lays down this principle, that an economy of the
semen by infrequent indulgence in intercourse is extremely favorable
to the production of males.

It may be possible to obtain more exact data respecting the origin of
sex from the artificial breeding of fish. In this case the properties
of the sperm, as well as of the ova, might be observed at an earlier
date by means of a fertilization effected externally. Attention might
be also paid to the age of the parents. In short, all the factors of
artificial influence upon the development of sex can in this case be
taken in hand and controlled by varying the process of artificial
fertilization. The author does not appear to know that the results
obtained by artificial breeding differ remarkably from those which are
the consequence of the natural multiplication of fish, nor that the
development of sex is unfavorably affected in many ways. The cause of
that lies very likely in the nutrition of the young fry, and perhaps,
also, partly in cross-breeding.

What influence the physical welfare of the parents, and especially
of the mother, has on the sex of the offspring in man, besides other
factors deserving of attention, ought to be discoverable from the
statistics of the lying-in hospitals. This is, in my opinion, hardly to
be expected.

       *       *       *       *       *

On various occasions, whilst taking into consideration the possibility
of an influence on the part of the parents over the sex of the child
(in such respects as have been placed before us in the literature
dealing with this subject), we often had occasion to direct attention
to the food of the parents. And especially the food of the mother
seemed to us to be of the highest importance.

Now, it is universally known that metabolism is increased during
pregnancy. The products of excretion in the case of pregnant women are
much smaller than the quantity of matter taken in, in the shape of
food. The difference, to a great extent, represents the matter taken
to form the bodily substance of the embryo, in accordance with the
anterior laws which have been fixed by the doctrines of the physiology
of metabolism. It will, then, be necessary to pay particular attention
to the investigation of metabolism. Suggestions are not wanting.
They will be found amongst the observations of leading specialists.
For example, Winckel observed that during pregnancy the temperature
was slightly raised. This increase of temperature must practically
be explained as due to the higher and more productive process of
oxidization, which has to be accomplished by the human female for the
sake of nourishing the fœtus.

During pregnancy the number of blood corpuscles suffers an observable
diminution. Still plainer is the reduction of the quantity of
hæmoglobin, when measured with Fleischl’s hæmatometer. This last
phenomenon is very likely connected with a greater consumption of
hæmoglobin, the substance being used up by oxidization.

Observations of setting hens are not without interest. In their case,
also, a diminution of hæmoglobin is observable during the period of
incubation. The hæmoglobin can sink to nearly 50 per cent. of the
normal amount. With the increase of hæmoglobin in the embryo and its
simultaneous diminution in the mother during incubation, it happens, at
a certain period in the process of development, that the embryo in the
egg and the setting hen possess a nearly equal measure of hæmoglobin
with a nearly equal number of blood corpuscles. An increase of the
quantity of hæmoglobin until the normal amount is reached may be
observed in both towards the end of incubation.

The Rhine salmon each year go up in a well-nourished condition from the
sea into the fresh-water streams to spawn. There they remain several
months. They lose much of their muscular substance. (Miescher.) On the
other hand, a great development of the sexual organs and of sexual
secretions takes place, produced, probably, at the expense of the
used-up muscular substance.

Many have paid particular attention to the nourishment of the maternal
organism. Investigations have also been published dealing with the
nutrition of the parent animals in cases when it was desired to
exercise an influence over the sex.

In fact, we have frequently touched upon such subjects, although only
lightly. Here, as we are about to proceed to the subjects of nutrition
and metabolism in the human female awaiting impregnation, we find
ourselves compelled to acquaint the reader with a number of facts which
permit us to assume a connection between the food supply (including
metabolism) and the development of sex.


According to St. Hilaire, the male sex is more common in the case
of scantily nourished (and therefore weakly) animals. Giron de
Buzareingues says that the same is sometimes the case with domesticated
mammalia. Martegoute has found that the sheep which bear female
offspring are, on the average, of a heavier weight. Furriers have
remarked that in fruitful regions more furs of female animals are
always to be had than in unfruitful districts. It would follow from
this that better nourishment assists the production of females.

This observation seems, however, to be concordant with the general
practice of farmers, according to which it is usual to keep a greater
number of the females of the domesticated animals, on account of
their utility. The males are kept only in such numbers as may be
absolutely necessary for breeding purposes, or for stronger beasts
of burden. The surplus is, by means of trade, disposed of in other
regions. In consequence, in poor unfruitful districts, the number of
males is pretty nearly the same as in fruitful regions, the actual
requisite number being in both cases about the same. The females, on
the contrary, can be much better kept in fruitful districts, where
there are rich and fertile meadows and better fodder, than in the poor
regions. In the latter the females are consequently rarer.

Wilkens attempted to apply diet to the production of sex in the
domesticated mammalia, and laid down the following principles: The food
must be of influence upon the embryo in the mother’s womb, and the
better nourishment favors the female, the worse the male sex.

We have already mentioned the views of Robin and Born respecting the
influence of food.

Düsing turned his attention to the effect of diet upon horses, with a
view to the development of sex.

The state of nutrition of the parents would have an influence upon the
development of the embryo. In this case, also, the better condition
produced females, the worse males.

According to Düsing, if the mother was well nourished, old semen
operating upon a young ovum would produce a majority of female
offspring. On the other hand, if the mother was insufficiently fed,
young semen operating upon an old ovum would produce a majority of male

According to Wappaens, richer or poorer nourishment in years of
different fruitfulness in Sweden has no effect upon the prevalence of
one or the other sex.

Ploss also tried to draw attention to the fact that better food, in
the case of the male as well as of the female parent, could have some
effect. Thus, a balance of the numbers of the two sexes depended upon
the better or worse harvests in different regions. If an excess of one
sex appeared in one year, in consequence of an abundance of food, in
the next year unfavorable circumstances raised the number of the other
sex, and thus a proportion was reached which represented the normal

According to Fiquet, female calves are born if the cow is poorly fed.
This diet should last some weeks, but the bull should be abundantly fed
before serving.

According to Landois, food plays a most important part in the
determination of sex amongst insects. If the germ be richly nourished,
females are principally developed. (Landois, ‘_Physiologie_.’)

A great number of different foods and drinks, and also substances
which have direct medical effects, are commonly known or held to
exercise an effect upon the activity of the generative organs, and of
these some are also recommended under medical advice.

Many of the medicinal substances should be carefully avoided. The use
of them may prove deleterious. Cantharides, or various preparations
of them, as well as other substances enumerated under this head
in pharmacology, are distinctly to be eschewed. Not only are they
absolutely incapable of exercising any influence over the sex of the
future offspring, but they can also be distinctly injurious to the
whole organism, or in any case to the urinary and generative organs in
this way, that, after having produced their effect, they occasion a
reaction, which leads to abnormal conditions and inflammation of the
kidneys. No expedient of this kind, no food of any sort, nor drink,
should ever be used, without medical advice. Most of all are these
expedients out of place where any question exists of determining the
sex of offspring.

All these nostrums, as well as the particular kinds of food or drink,
exercise only temporarily a certain influence over the activity of
the sexual organs, exactly as they do in general over the nervous
condition, the mental disposition, humor, etc., which are temporarily

Herewith may be classed the expedient of the injection of semen
recommended by Brown-Sequard, in consequence of which people of
advanced age enjoy a feeling of rejuvenescence. His first experiment
was tried upon himself, and, in spite of his advanced age, he felt
himself quite fresh and young. Originally the injection consisted of a
sort of watery extract made from the testicles of animals. Afterwards
preparations were used which had been more carefully prepared. These
extracts are employed by medical men under the name of spermin or

In a similar way an attempt was made to obtain extracts and pure
preparations from the ovaries of animals (oophorin), which were to be
used in the same manner.

       *       *       *       *       *

After having given ourselves the trouble to glance through the long
series of different views which have existed concerning the origin of
sex, we are struck with the fact, that scarcely a single objective
observation has been made that could lead to a positive result in the
development of sex in the new-born. Out of all these theories, however,
one hypothesis does seem to be tenable, and to that we shall find
ourselves compelled to give our adhesion here, after having set forth
the detailed explanations which shall presently follow. Now, we were
not led to the recognition of the truth of this teaching by previously
assumed theories. On the contrary, it was after we had completed our
experiments, and had been led by them to positive results, that we
found ourselves compelled, in order to find an explanation of the whole
process, to fall back upon the theory of cross-heredity of sex, and
to place it, by our own experience, upon firmer foundations. It must
be briefly remarked here that the literature of this subject is very
extensive, and to trace out all the literary results would lead us too
far. For which reason I have limited myself to the actual facts.

       *       *       *       *       *

In order to enter more fully into our theory, it will in the first
place be necessary to turn our attention to the products of excretion
which are eliminated from the bodies of animals, in a more or less
solid, fluid, or gaseous form, as the results of the transformations
of matter which have taken place in the bodies of the animals. The
chemical constituents of the evacuations are either such as it has not
been possible to convert to use in the body, or such as are evacuated
as the final product of the oxidation which has been effected in the
body by the process of combustion.

Of these the former are evacuated from the body as so much inert matter
which has not been affected by the digestive juice, nor altered in any
other way. The latter are given off from the animal’s body in various
states of oxidation in the urine, sweat, or dung, or else in a gaseous
form by the lungs.

A great number of the substances which have been hitherto exactly
examined are secreted by the kidneys and appear in the urine. In this
fluid are found nitrogenous products of secretion, others free from
nitrogen, and inorganic substances.

Amongst the substances free from nitrogen, I found myself prompted
_more particularly to select as an object of my attention the
carbo-hydrate (sugar) found in the urine_. Three groups of closely
connected compounds are reckoned amongst the carbo-hydrates. They
consist of carbon, hydrogen, and oxygen, which contain in the molecule
six, or a multiple of six, atoms of carbon. The hydrogen and oxygen are
in the same proportion as in water. (Arnold.)

The three groups are grape-sugar, cane sugar, and cellulose. In the
urine grape-sugar occurs normally among the products of excretion in
inconsiderable quantities. Under exceptional circumstances, in cases
of polyuria, inosite can occur. (H. Voll, Neumeister.) In addition we
find also a carbo-hydrate mentioned by E. Luther that would be of the
character of dextrine, and probably owes its existence to the secretive
activity of the urinary bladder.

Upon boiling the urine with mineral acids we obtain substances
which separate as brown flakes. We denote these “humin-substances”
(_Huminsubstanzen_, Udránsky, Salkowski). In addition to these must be
enumerated animal gum, isomaltose, pentaglycoses, lævo-rotary sugar,
the conjugate glycuronic acids, etc. In conclusion, the occurrence
of milk-sugar must be mentioned, which appears in the last days of
pregnancy. The last-mentioned substances occur in very insignificant
quantities, and are not to be enumerated among the ordinary constituent
parts of the urine.

       *       *       *       *       *

The carbo-hydrates may be, in many respects, of high interest for the
activity of the organism in its metabolism, as they are found amongst
the products of excretion only as final products of the completed
transformation and using-up of the food.

The excretion of a carbo-hydrate in the urine can be interpreted to
mean that the process of combustion in the organism in question has
not been complete. By some agencies, at present unknown to us, the
efficiency of the organism becomes impaired in such a way that it does
not fully use up all combustible substances.

A number of substances can be excreted from the body which are capable
of a further process of oxidation--for example, until they are
oxidized into carbonic acid and water. The heat which could be hereby
generated is withdrawn from the organism, and must be procured by
fresh nourishment, in order to replace that which has been lost by an
imperfect assimilation of the food.

One substance which occurs in the urine, about which much has been
written by various authors, by physiologists, by medical men, and by
chemists, is of high importance for our inquiry. That is the _sugar
found in normal urine_.

       *       *       *       *       *

When this substance occurs in the human organism, no matter in how
small a quantity, its presence always suggests the assumption that it
ought not to have been secreted in the form of grape-sugar. For, if
the organism possessed its full efficiency to deal with the necessary
quantity of food taken, then one might also suppose that a substance
such as grape-sugar, be the quantity never so small, would not be
secreted in an unaltered form, but must be further used up, seeing that
the sugar would be decomposed, oxidized, in short, burnt up.

The imperfect performance of an operation of this kind by the organism
is not to be taken for a symptom of pathological processes. In point of
fact, it has been impossible to recognize, in the case of individuals
afflicted with this imperfection, any symptoms of processes of such a
character as would furnish the remotest occasion for the appearance of

       *       *       *       *       *

When small quantities of saccharine matter are excreted, derived from
carbo-hydrates which have been swallowed, or, on the other hand,
formed within the human body, say from albuminous principles, it might
be expected that this excretion, occurring repeatedly in different
individuals, ought to be regarded as a normal metabolic process. Such
an occurrence must be interpreted, in fact, in much the same way as
other small anomalies which affect the organism, whose presence leads
to no further consequences.

But our attention must be directed, not to the sugar alone, but to
a number of other so-called reducing substances, because these, as
regards certain reactions, resemble grape-sugar, and have to be
distinguished from it.

       *       *       *       *       *

In the year 1858 my highly-revered master, E. Brücke, drew attention
to the presence of grape-sugar in normal urine. The foundation of the
theory of normal glycosuria was laid by his obtaining the potassium
compound of sugar (_zuckerkali_) from large quantities of urine. His
theory has been since much elaborated, and a great deal written both
for and against it. When this symptom in the urine reaches a certain
proportion per cent., the condition of the individual must be described
as diseased.

If we apply qualitative chemical tests for sugar, we soon find that
they are disturbed by a number of reducing substances which exist in
the urine, and it is often difficult to determine whether the processes
used to discover the sugar do not produce more reducing substances than
the sugar itself.

Bence-Jones agrees with Brücke’s opinion respecting the presence of
sugar in normal urine, and insists upon its power to rotate the plane
of polarization to the right. More recent authors, Ivanof, Huizinga,
Pavy, Abeles, have stated this fact in different ways, and it yet
remains to be verified. The fact existed, but not without meeting with
contradiction. Maly, Seegen, Friedländer, and many others sought to
oppose the view.

Although in many cases with the commonly used reactions it is
impossible to demonstrate the presence of sugar in samples of urine,
nevertheless, the sugar has been isolated in considerable quantities,
by means of precipitation with acetate of lead and ammonia, and by
subsequent decomposition of the precipitate with sulphuretted hydrogen
(E. Ludwig), after which it has been successfully tested and recognized
by characteristic reactions.

       *       *       *       *       *

We shall here concern ourselves principally with the appearance or the
increase of the sugar, so far as its presence according to the views
hitherto held is normal.

We are acquainted with a so-called alimentary glycosuria, which is
occasioned by this, that the individual in question, after having eaten
an excessive quantity of sugar, easily recognizes an increase of the
quantity of sugar in the urine. But there are also individuals, who,
though they may have eaten a very large quantity of sugar, cannot
afterwards discover a trace of it in the urine. In these cases
complete combustion has taken place.

But here we must also next direct our attention to the fact that
there are persons who, in the digestion of their food under all
circumstances, excrete sugar, though perhaps in very small quantities.
Others, after eating proportionately much larger quantities, excrete no
perceptible sugar in the urine. Hoppe-Seyler, after having eaten 225
grammes of sugar, could find no trace of it in his urine. (Moritz.)
Frerichs admits exceptions, and relates that in the case of two men he
could always discover sugar in the urine after they had eaten sugar,
although he considered both healthy. Then we find specialists like
Budge, C. Schmidt, Mosler, Schiff, Vogel, C. Ludwig, Voit, etc., who
admit, after their experiments with men and beasts, an artificial
glycosuria, which is normal. Seegen, after feeding dogs with cane
sugar, found inverted sugar (_invertzucker_) in the urine. The sugar
which he was able to identify was of two kinds, one of them turning the
polarization plane to the right, and the other turning it to the left.

Experiments with champagnes, various other wines and sweetmeats, which
contain great quantities of sugar, gave as a regular result perceptible
sugar in the urine of many individuals. As a consequence of greater
quantities being taken, an excessive glycosuria set in. Its duration
depended upon the occasioning causes alone. On their removal, the
quantity of sugar either returned to a minimum or entirely disappeared.

       *       *       *       *       *

The presence of sugar in normal human urine is therefore possibly in
accordance with all the above-mentioned observations. This fact must be
considered a physiological axiom as regards the constituents of normal
urine. The quantity of sugar contained can be increased by a condition
of alimentary glycosuria. But, when there is no such artificial cause,
and yet the sugar is recognizable, without the ordinary régime of life
being altered, still its presence is no symptom of a pathological
process going on. Even the continuation of the insignificant excretion
of sugar, when it continues for many years, appears to exercise no
influence over the health. _But as one finds many individuals in whose
urine not even the minimum quantity of sugar is discoverable, it seems
not improbable that in a perfectly normal condition of the organism
it is possible for many individuals completely to burn up the whole
of the carbo-hydrates either taken into the organism or formed within
it._ Such persons, in consequence of their metabolism being normal,
are able to carry out the process of combustion to the full, and
their excretions are of such a nature as should represent the normal

But, if this condition of the excretions cannot be attained in a given
individual in the desired degree, the organism is suffering from an
imperfection that occurs in a normal manner (an excretion of sugar) to
a certain degree and extent, such as the physiological potentialities
of a living organism permit.

In one connection only, in which it afforded me practical assistance
for my observations, this question has not yet been fully elucidated.
Sex had not been taken into consideration during the examination of
the excretion of sugar within normal physiological bounds. Whilst I
was looking through the experiments of the specialists whom I have
mentioned, it struck me that most of the inquiries respecting the
presence of sugar in normal urine had been made in the case of men
alone, and that, so far as regarded the presence of sugar, the urine
of the human female had been little observed, and never quantitatively
and qualitatively compared with that of man. Nicolai Ivanoff, in his
dissertation (Dorpat) on the question of glycosuria in the case of
pregnant women, lying-in women, and suckling women, arrived at the
following final results: “A physiological glycosuria in the case of
the pregnant, or of those who are lying in, has, so far as present
investigations have gone, never been established, and certainly not
to the extent which Blot asserts. Sugar occurs in human urine more
frequently than has been hitherto supposed, but absolutely never _in
constant and increased quantities in that of pregnant and lying-in

If, however, it has been in many cases asserted that there was an
increased quantity of sugar in the urine of pregnant and lying-in
women, and that this has been proved, these statements have originated
from mistaking for a previously developed sugar one which has during
the experiments come into existence from the action of alkalies and
acids on an extractive substance which requires further examination.

       *       *       *       *       *

For the detection of sugar in the urine several methods exist, which
are more or less sensitive.

If we mix a few cubic centimetres of urine with an equal quantity of
10 per cent. solution of caustic potash, and warm a portion of this
in a test-tube, we observe that the fluid in the event of a sensible
quantity of sugar being present, acquires a color varying from dark
yellow to yellowish brown. We can most easily assure ourselves of this
if we warm only the upper part of the fluid contained in the test-tube,
whereupon the upper part of the fluid will appear darker than the rest.

This test will give a distinct result only in presence of a minimum of
1 per cent. of sugar.

A much more sensitive test consists in the reduction of a salt of
bismuth in an alkaline solution of urine sugar. This test, given by
Böttcher, was modified in the following manner by Nylander. Four
grammes of Seignette salts are dissolved in 100 cubic centimetres of
soda lye of the sp. gr. 1.119, and 2 grammes of bismuth subnitrite are
added to the fluid warmed in a water-bath. This solution represents
Nylander’s reagent.

In order to use the test we mix five cubic centimetres of the urine to
be examined (which, if possible, ought not to have a specific gravity
higher than 1.020) with 0.5 cubic centimetre of Nylander’s reagent in
a test-tube. The mixture is now boiled for two minutes. If more than
0.5 per cent. of sugar is present in the urine, the originally white
precipitate of earthy phosphates becomes deep black; with 0.05 per
cent. of sugar it shows a clear, brown color.

If this test is not the most sensitive of all, it provides us with a
process for recognizing sugar in the urine, and not a number of other
reducing substances mixed with it. (Neumeister.)

       *       *       *       *       *

Amongst the various tests for sugar used in practice, that of Trommer
is one of the most common.

We mix some 5 cubic centimetres of urine with an equal volume of 10 per
cent. solution of potash or soda, and add to the mixture, drop by drop,
a 10 per cent. solution of sulphate of copper, so long as the resulting
hydrated oxide of copper is dissolved by the sugar.

In this way we get, according to the quantity of sugar contained, a
more or less ultramarine-blue fluid. If we warm this, the result, in
consequence of the reducing action, is a reddish-yellow precipitate of
hydrated suboxide of copper which, after a short time, adheres to the
sides of the test-tube, somewhat in the fashion of a mirror.

This test can be applied fairly simply, and it gives good results in
presence of more than 0.5 per cent. of sugar. But at the same time we
cannot use it to detect extremely minute quantities of sugar such as
normally occur in human urine, because the urine, as we have already
remarked, contains a number of substances which reduce alkaline
solutions of copper.

The effect of these substances is sometimes such as to produce the
illusion that from 0.3 to 0.5 per cent. of saccharine matter is
present. (Neumeister.)

In recent times, for qualitative and quantitative investigation of the
grape-sugar, much use has been made of graduated fermentation-tubes.

For this experiment we mix about 10 cubic centimetres of urine with
a small quantity of yeast of ascertained weight, and fill the
fermentation-tube with the mixture. After the lapse of twenty-four
hours, during which the whole is kept in an incubator at a temperature
of 30° centigrade, all the grape-sugar will be completely fermented.

From the gaseous fermentation-products of the grape-sugar, which rise
into the longer branch of the U-tube, and consist of carbonic acid, we
detect the presence of sugar in the urine.

By means of the graduation of the longer branch, we can at once read
off the percentage of the sugar. This test is sensitive enough to
detect 0.05 per cent. of sugar. It is useful first of all to boil
the urine to be tested, in order to remove from it the carbonic acid
contained in solution. It is also advantageous to acidify the urine, so
that the yeast fungus which flourishes more easily in the acid medium
may overpower any gas-producing bacteria, and so avoid a false result.

In 1884, E. Fischer discovered phenylhydrazin, and pointed out the
fact that it might be used as a valuable reagent for the sugar in urine.

This preparation has the characteristic peculiarity of forming
crystalline compounds with aldehydes and ketones. These crystals,
in the cases of the different kinds of sugar, which, as is known,
represent the aldehydes and ketones, respectively, are needle-shaped,
of a yellow color, with difficulty soluble in water, have a high
melting-point, and are called glycosazone.

Jaksch used this property of phenylhydrazin for his phenylhydrazin
test. For this experiment he dilutes the urine with an equal
quantity of distilled water in a test-tube, and adds twice as much
phenylhydrazin hydrochloride as can be taken up on the end of a knife,
and double that quantity of sodium acetate. The mixture is well shaken
together and left from half an hour to an hour in a boiling water-bath.

Then, if the test-tube and its contents be slowly cooled, at the end of
about twelve hours the sediment is found to consist partly of spherical
resinous lumps, and partly of microscopical tuft-shaped crystals.

These crystals are nothing else than glycosazone-compounds. (Moritz.)
In normal urine this reaction is very often observed as distinctly
evident as if we had to do with a urine containing as much as 1 to 2
per cent. of sugar.

In reality besides the extremely minute traces of grape-sugar, a whole
number of aldehydes and ketones are present in urine, which can form

Amidst all these substances those which, according to the investigations
of Flückiger chiefly interfere with these tests are the glycuronic acid
compounds, as they give crystals of the same form in the course of the
reaction. Flückiger detected these compounds by their property of
rotating the polarization-plane to the left, and reducing alkaline
solutions of copper after long boiling. More accurate investigations
enabled him to identify these substances with acetone compounds.

Moritz recommends the following method of discovering whether we have
to deal with grape-sugar, glycuronic acid compounds, or other (azone)
crystal-forming substances.

Several litres of normal urine are precipitated with lead chloride and
filtered; the filtrate is precipitated with ammonia and again filtered;
the residue on the filter is washed and then dried on a clay slab. It
is after this decomposed with oxalic acid, mixed with acetate of lead
in excess, and the filtrate is deprived of its lead by hydrosulphuric
acid. As a result is obtained a perfectly clear fluid to which the
phenylhydrazin test described above is applied.

The precipitate obtained is filtered off, repeatedly washed with
chloroform and alcohol, several times crystallized, and finally the
melting-point of the needle-shaped crystals, which can be seen with
the naked eye, determined. If sugar is present, the melting-point
of the crystals will be at a temperature of 205° centigrade. If the
melting-point lies below this temperature, we have to do with other
substances (azones).

_Hence it appears that we possess in the phenylhydrazin test, applied
in the manner above described, a certain method of detecting even the
faintest traces of sugar in the urine._

Although hitherto it has been often ascertained that sugar was present
in normal urine, that was demonstrated only by the other methods
with which we have been hitherto acquainted, and not by means of the
phenylhydrazin test in the manner in which we have explained its use.
This seems to have been the reason why different authors have not been
able to speak unanimously on this subject.

       *       *       *       *       *

It frequently happens that the sugar is present in such quantities that
we are able to observe its power to rotate the plane of polarized light.

For this purpose we generally use Soleil-Ventzke’s penumbra-polarization
apparatus, a description of which will be found in the hand-books on the

This apparatus suffices to investigate the dextro-rotatory and
lævo-rotatory substances in the urine. With its assistance it is also
possible to determine the quantity of sugar in the urine. In addition
for the determination of the quantity of sugar in the urine a number of
chemical processes can be employed, such, for instance, as Fehling’s
method with Worm-Müller’s modification, Knapp’s method, and various

If we add to normal urine a dilute solution of potassium permanganate
it at once loses its color. From this we perceive that the urine
contains a great quantity of oxidizable or so-called reducing

It has been already mentioned that Trommer’s test gives positive
results after protracted boiling, even in the case of normal urine,
without any corresponding quantity of grape-sugar being present.
In this case the reducing substances interfere with the test in
consequence of their tendency to become oxidized.

We find a number of them in the urine. Foremost among them are uric
acid, creatinine, and the coloring-matter. Also the substances
mentioned above in the description of the carbo-hydrates have reducing

       *       *       *       *       *

Different statements have been made as to the quantity of reducing
substances existing in the urine. According to Flückiger they form
from 0.15 to 0.25 per cent.; according to Salkowski an average of 0.4
per cent., and according to Munk an average of 0.3 per cent.

Moritz found the quantity of reducing substances range between 2.93
and 4.1 grammes per diem in a grown man. His investigations were made
with the collected urine of 24 hours, and were applied to that of men,
women, and children. The result showed that men always excreted a
greater quantity of reducing substances than women of the same age who
used the same food.

The quantity of these substances depends upon the food taken. An
increase is also possible when certain benzoin compounds are taken
into the system. Moritz also found that the ratio of the quantity of
reducing substances to the food was a constant, which is the case also
with the nitrogen evacuated. An increase of the daily excretion of
reducing substances follows the free use of albumen.

       *       *       *       *       *

If, in the case of an ordinary diet, such as men take in youth, the
body performs its labors without fatigue, it must be assumed that the
several food stuffs have been selected from the classes of albuminous
bodies, carbo-hydrates, fats, and inorganic elements in suitable
portions and are provided in sufficient quantity.

According to the statements of Pettenkofer and Voit the total
metabolism is greater during labor than during rest. The food requisite
for a normal grown man while in a state of rest may be reckoned at
30 units of heat for each kilogramme of weight. In the case of a
full-grown working man, whose weight was 70 kilogrammes, the necessary
food represented about 2,000 units of heat. For a person whom we,
following Voit, will describe as an average working man, the requisite
food supply consists of 118 grammes of albumen, 56 grammes of fat, and
500 grammes of carbo-hydrates, equivalent to 3,055 units of heat gross,
or 2,749 units of heat net.

As a woman is generally smaller than a man, and the weight of her body
also less in comparison with his, and her labor also less than that
of a man, if we compare men and women of the same age, it is obvious
that in her case a less provision of force, and in consequence less
food, under similar circumstances, is necessary than for the man. Voit
assigns to a working woman a food supply of 94 grammes albumen, 45
grammes fat, and 400 grammes carbo-hydrates, which correspond to 2,444
units of heat gross, and 2,200 units of heat net, whilst the whole of
the food taken by an average working man, according to Voit, is fixed
at 118 grammes albumen, 56 grammes fat, 500 grammes carbo-hydrates,
equivalent to 3,035 units of weight gross, and 2,749 units of weight

Many consider that the quantity of albumen is placed too high. For this
reason Munk assigns a lower quantity of albumen for the food. Yet the
numbers which he gives do not vary much from those of Voit.

In youth several very marked differences appear in the metabolism,
and especially in the quantity of carbonic acid given off, and these
differences appear in both sexes. (Tiegerstedt.)

In the case of a male individual from fourteen to nineteen, the
quantity of carbonic acid given off is greater than in the case of
those who are younger or older of the same sex. During the same years,
also, a more rapid increase of weight takes place, and a marked
increase in height. This shows an increased metabolism, which is
occasioned by the greater addition of substance to the body.

In the case of the female individual this increased excretion of
carbonic acid does not occur at the same age. A girl of eleven gives
off nearly the same quantity of carbonic acid as a grown woman.

The quantity of carbonic acid given off by both sexes shows that, at
like ages and under like circumstances, the quantity given off by men
in their younger years is considerably greater than that given off by

When the time of the increase of the body is completed, at the end
of the period of growth, with both sexes there is little difference
between the ingesta and the egesta. The difference also between the
sexes is much less, and in advanced life completely vanishes.

       *       *       *       *       *

It will be seen from the above brief statements respecting metabolism
in both sexes that a difference is perceptible, and this implies the
possibility of carrying out an attempt to express that difference
numerically. It would lead us too far were we here to set forth all
the consequences connected with these facts in the case of both
sexes, with reference to growth, physical condition, etc. These are
sufficiently known from the data given in other technical works which
treat of the characteristic differences between man and woman in
different ages.

I shall here call attention to one peculiarity only of the human
female, which is this, that the female organism, in consequence of the
less abundant formation of tissue, is on a smaller scale than that of
the male, and yet the amount of sugar given off in the urine is, under
normal circumstances, nearly the same in quantity as in the case of the

Where there is less abundant formation of tissue there must be
evidently less strength. Consequently a weakness in the organism, such
as is present where we find the normal excretion of sugar, will have a
more marked influence upon the work done than a greater weakness of the
same kind would have where the mass of the body was greater and the
matter taken for combustion greater also. In other words, the sugar
excreted in a normal way in the urine of the man does not indicate so
significant a loss of the heat produced by combustion as it indicates
in the case of the woman.

_When, in addition to this, a woman is in the earlier period of her
life, at which time an ovulation takes place regularly every month_,
it is not a matter of indifference whether a good and complete use is
being made or not being made of the matter taken as nourishment.

Also, though the excretion of sugar in insignificant quantities in a
normal way is not detrimental to the whole organism, yet it appears, as
we shall see presently, not to be a matter of indifference as regards
the ovum forming itself and ripening in the human female.

Now, if we take further into consideration the observation which I made
many years ago, that sugar often occurs in the urine of women, and
also in larger quantities than we observe in the case of men, it is
obvious that this symptom ought to arrest our attention. Certainly we
often meet with female urine which shows us clearly that the process
of combustion in the organism in question is being perfectly effected.
Practically in such urine no sugar is detected by the reactions which
have been mentioned above, not even by the phenylhydrazin test. Yet,
in the case of many of these women, although no change has been made
in the diet, sugar is found in the urine temporarily in inconsiderable
quantities shortly before and shortly after menstruation. The methods
of investigation which we have applied gave at these epochs a positive

       *       *       *       *       *

The appearance of sugar in the urine does not occur only amongst women
of the upper classes, who enjoy a better and varied diet, but also
amongst those of the poorer classes, who are obliged to subsist chiefly
upon vegetable food.

Indeed, in the case of vegetarians who take concentrated albuminous
substances only in the form in which they occur in eggs, and get animal
fat and sugar from milk alone, the urine, as regards the occurrence of
sugar, is of the same character as that of those who do not adhere to
vegetarianism. Women, who, in other climes, are not within the reach of
our investigations, might also be included in the same category so far
as their diet is concerned.

It follows that the individual does not excrete sugar only in
consequence of the character of the diet, but that the _processes
of combustion_ manifest themselves in the results derived from the
digestion of the different nutriments.

Now, an indispensable condition of the ripening of the ovum in the
female organism is that the metabolic process shall be normal. When
these changes are being effected as perfectly as possible, sugar
is entirely absent from the urine. The female individual may have
arranged and chosen her diet from the different groups of food in
any conceivable way, and she may belong to this or that class of the
community, but the metabolic processes--that is to say, the combustion
processes--are, nevertheless, those which deserve most attention in
connection with the development of the ovum.

Ovulation is never in any case altogether independent of the influences
of diet and metabolism. In those cases where the combustion is of such
a kind that unoxidized remains of bodies still capable of producing
heat are found in the urine, the ovum in process of development in the
human female is never so highly developed as in the cases where no
sugar, or at least no recognizable trace of it, can be found in the

_In the first case we shall have not only a less ripe ovum, but very
likely also a less well-nourished ovum. An ovum of this sort has not
so fully attained to all the characteristics and powers inherent in
its protoplasm, and, in consequence, seems fitted to develop only a
female individual. In such an ovum the several cell-products of the
ovum, which have to develop themselves into the future embryo, will
be arranged for the growth of a female. Not only will female organs
of generation be developed from it, but also all the elements of the
future individual will be feminine._

On the contrary, if in the mother-individual all the substances
developed in, or taken into, the organism _undergo combustion in
such a manner that no sugar is found in the urine, not even in the
smallest quantities, then an ovum can be developed such as is required
to produce a male individual. Out of its protoplasm in the course of
evolution elements form themselves, whence male cells are developed,
which correspond to the development of tissues and forms of the male
individual. Some of the cells--viz.: those which ultimately become the
elements for the continuation of the species, are planned for the male

It follows from all this that the result depends to a great extent both
upon the diet chosen, and upon whether it has been rightly chosen to
suit the organism, whether it is possible to exert such an influence as
may so support the ovum in its maturation that in its development it
may form itself into a male individual. It must be observed in advance
that such an influence as may be effective for the production of sex
must not be applied to an already fertilized ovum, but must be applied
to an ovum in development before its fertilization.

Indeed, it is even of greater importance to know that the mother
individual has been for a considerable period anterior to the
fertilization of the ovum provided with the requisite food. Care must
also be taken that _after_ conception a similar befitting diet is
continued for the mother, which diet should resemble that previously

       *       *       *       *       *

Of what sort must the chosen diet be which can favor the ripening of
the ovum? Always only such a diet as can so modify the process of food
assimilation in the organism that no excretion even of the most minute
quantity of sugar discoverable by the application of the phenylhydrazin
test can be detected.

The quantity of sugar is small, but what has to be taken into
consideration here is not so much the amount of the sugar, as the fact
that this substance is being excreted.

Now, it has been proved by experience that when in an organism
a symptom appears, as the evidence of disease, in the form of a
considerable excretion of sugar in the urine, it is in many cases
possible, by the means of fitting diet, to produce a diminution of
the excretion of sugar, either bringing it down to a small amount or
causing it to disappear altogether.

Investigation of the urine according to recognized methods must
accompany this system of diet, and, under normal circumstances, we
soon meet with the phenomenon, at which we have been aiming--that the
quantity of sugar has diminished to a no longer perceptible amount.
When this has been attained, it may be presumed that, by a further
perseverance with the same diet, the metabolism will be so regulated
that, if no pathological accident supervenes, the excretion of sugar
will cease. In fact, in consequence of an alteration of diet and the
taking of no excessive quantities of starch and sugar, the excretion of
sugar in the urine ceases for a considerable time, and only makes its
reappearance after a long interval.

When, in consequence of having observed the minute normal quantity of
sugar in the urine, my attention was attracted to the fact that the
determination of the future sex was connected with the presence of this
sugar, my endeavors were directed to exercising such an influence over
its presence as might enable me to get rid of it. Experiments with
the most diverse diets gave me in the case of women most remarkable
results. In this way I found women, using an almost exclusively flesh
diet (which was, of course, especially rich in nitrogen), whose
urine showed greater quantities of sugar--according to approximate
estimations--than when they used a diet of carbo-hydrates, that is,
sugar, fatty substances, alcohols, etc. Others, again, showed an
exactly opposite result. In many cases I did not succeed in getting rid
of the normal sugar in the urine; in others it disappeared soon after
the beginning of the treatment. It follows that, in every case where
the question is one of so influencing the sex that a male offspring
may be obtained, the very first thing to be determined is whether
the normal quantity of sugar is present in the woman’s urine or not.
If none can be detected after repeated and painstaking search, and
if reducing substances are plentifully present, we do not require to
arrange the diet, but can recommend immediate impregnation, as every
probability points to a male embryo. But in all cases where the normal
“urine-sugar”--if I may so call it--is present, even if only traces of
it are to be found, it will then be our task, by various alterations
of diet, to discover that one which seems suited to the organism in
such a way that it will occasion the disappearance of every trace of
the “urine-sugar.” In these experiments the remarkable phenomenon
is observable, that the reducing substances which I have already
mentioned, and amongst these especially the lævo-rotatory glycuronic
acid compounds, show alterations in respect of quantity.

       *       *       *       *       *

In fact, I found that the urine of most women who had male offspring
contained, during the first months of pregnancy, more reducing
substances than the urine of women who had female offspring. It is,
therefore, also necessary that the diet should not only occasion a
disappearance of the normal urine-sugar, but should also produce an
increase of the reducing substances. This end can be accomplished
certainly also by the use of different medicines, such as chloroform,
turpentine, salicylic acid, etc. But, apart from the fact that
medicinal influences are distinctly to be discouraged, these substances
do not seem to produce the same effects as diet. Besides, it is still
a question of what kind these efficient substances are. And another
question is whether they are themselves effective. It will be
sufficient for us to recognize them as a symptom.

It is known that the male sex possesses a distinctly greater amount of
albumen than the female. In age this difference disappears; in youth
it is greater. It might be expected that male offspring would result,
in consequence of a more albuminous diet, by which a greater increment
of albumen would be made possible; the thing, however, is not quite so
simple as this. Investigations in various cases showed me that women
in whom an increased amount of albumen could be detected, but in whom
either sugar was present to a small extent, or, on the other hand, only
very small quantities of reducing substances could be detected, almost
always had female offspring.

In spite of many endeavors to elucidate this phenomenon, I was forced
to have recourse to the symptoms alone, and to hope for the production
of the male sex only from the disappearance of the sugar and the
increase of the reducing substances. Certainly, further investigations
showed that the same diet which was the most favorable to the
production of the condition which I have named (the disappearance of
the sugar from the urine and the simultaneous increase of the reducing
substances), also effected the best albuminous increment in the body.
Key’s statements teach us that male individuals put on more albumen
than females, and that this is especially the case during the period
of growth. Very likely the male embryo also requires a greater amount
of albumen than the female, in the same way as this difference exists
between the boy and girl.

       *       *       *       *       *

We know as a universal rule that where there is rest there must be
a balance of forces. If the ovum, the accumulator of the balanced
forces in a state of rest, is to divide itself so as to produce in
this way the future individual, some stimulant impulse, some energy
is absolutely necessary to disturb the balance of forces, and to
induce the development of the cells. This impulse may be such a one as
occasions destruction. But it may also be one that gives occasion to
new growth, to tissue formation. (W. Haacke.) We must describe this
impulse as functional, and recognize in it a peculiarity which belongs
to the organic world alone, the vegetable and animal kingdom. Every
movement, every use of an organ, may serve as a stimulant impulse,
and contribute to its development. Thus we find, in the case of
great thinkers and poets, of celebrated generals, etc., a powerfully
developed brain. Oarsmen, gymnasts, and swimmers have far stronger
muscles than men who follow less fatiguing callings. In all these
cases there are impulses leading to increased growth of the organs.
In the growth of the fertilized ovum we have to deal again with a
phenomenon of impulse, a part of which is the property of the ovum
itself, a part, however, also dependent upon external influences. We
call the former autoplastic, the latter xenoplastic impulse. (Haacke.)
It is easy to understand that a purely autoplastic development (_eine
reine Autoplasie_, a pure autoplasia) cannot exist. Out of an ovum
alone, without the agency of new impulses, without the taking up of new
matter, no new individual could develop.

       *       *       *       *       *

The stomach furnishes the gastric juice. It is stimulated to do so by
the food. The food is digested, undergoes absorption in the intestine,
and becomes lymph. Blood is formed. The blood passes through the
several organs and tissues, nourishes them, and replaces the substances
used up by work. As soon, therefore, as the stomach and intestine,
with the intestinal glands, fail in their functions, all the organs,
which stand in physical relation with them, suffer; because they are
constantly during their work consuming matter, and are now receiving no
fresh supplies. The case of the other juices of the body is the same.
The thyroid glands supply the body with a principle without which a
person cannot be in a normal condition. Similarly the testicles, as
glands, supply the body with a principle the want of which gives a man
distinctly female qualities, as we perceive in the case of eunuchs.

       *       *       *       *       *

There is no doubt that the males and females of a race of animals
develop out of the same germinal-matter. Its development depends
upon two important factors, the impulse, and the capacity to take up
matter conditioned thereby. By taking up matter the substance of the
newly developed cells is increased, and this in turn prompts them to
repeated division, until at last an organ is developed. The new organ
again furnishes new impulses, and so influences the development of
other organs. The impulses are of themselves physical and chemical.
(Haacke.) In the ovule and the embryo the impulses are what chiefly
bring about new growth. These impulses the ovum receives from the
mother whose product it is. Now, as of the most different impulses now
one and now another comes to the front, the embryo will acquire at this
time rather these qualities, and at that time those. The impulse will
occasion now a greater addition of matter to this organ, and now a
greater addition of matter to that. According to observations made up
to the present time, there is hardly any doubt that the development of
the organs of sex requires an impulse as does the development of all
the other organs. These sex-determining impulses originate, like the
other development-determining influences, from the mother, since it
is she that supplies to the embryo, as agencies of impulse, the juices
derived from the food which she has taken. In addition to these, the
embryo receives also from the mother such products as are required for
the growth that follows the impulse. If the mother gives the child
no material for growth and no impulse, then the child, since it is
dependent upon the mother, must perish. Now, according as a developing
ovum or an embryo either receives the juice, the means of impulse, for
the acquisition of the male sex, or for the acquisition of the female
sex, so will a male or a female result.

       *       *       *       *       *

Of what kind the means of impulse are, the juices are, which occasion
this I do not know. I can only supply the conditions requisite for
them; I can see only whether they are present. And so I again come
back to this, that we may expect a male individual from the ovum
when the juices are developed which serve as a functional means of
impulse for the male sex. These juices can come into existence in the
organism under the most different circumstances. But they certainly
do come into existence, if we can so feed the mother that we cannot
find in her urine even the faintest trace of sugar, but instead of
it an increased excretion of reducing substances, _accompanied by a
relatively high exchange of nitrogenous substances_. These facts can,
therefore, serve us only as a symptom of processes taking place in the
organism. In consequence our task will be to follow up in the various
cases the conditions of this symptom, _in order that we may try so to
feed the mother individual that she may attain to giving the effective
impulse_; and this we have certainly accomplished by the increased
excretion of the reducing substances and the disappearance of the
normal urine-sugar.

When we have brought a woman into such a condition that she excretes no
sugar, and by the continuation of the same diet keep her permanently
in that condition, the ovule which is being developed in her organism
will develop itself correspondingly. Also with this diet the different
qualities of the organism may not be altogether without influence on
the course of the ovum’s development.

In many cases the quantity of sugar in the urine excreted does not
diminish. The most different kinds of diet may be tried, and yet the
phenylhydrazin test will always show the presence of sugar. Individuals
of this sort exhibit a certain obstinacy in resisting the attempt to
procure an alteration of the metabolism. In such cases no influence has
been exerted over the development of the ovum.

In these experiments which are made with the mother, not only is the
ovum influenced which is being developed for fertilization in the
maternal organism, but it is also possible for the mother herself, in
consequence of the alteration of diet, to experience many changes with
regard to the physical peculiarities of the elements which compose her

The treatment may prove highly beneficial to the mother herself,
so that not ovulation alone is subjected to an alteration, but the
activity of the processes of the tissues of the other organs of the
body may be also simultaneously in some way changed. And here may come
into consideration many other factors which may produce a particular
fitness for procreation and for the development of the ovum, and, if
they once make themselves felt, may be of the greatest advantage to the

The formation of the insignificant quantity of sugar in the body goes
on of itself regularly, without it being possible to perceive any
consequent striking alterations in the organism. The manner in which
sugar is formed in the body under normal conditions has in recent years
been thus explained.

The sugar contained in the blood in healthy persons is reckoned as not
higher than about 0.15 per cent. In those who suffer from diabetes it
may rise to 0.44 per cent. If sugar is present in the blood, that it
passes thence into the urine can be easily explained, seeing that the
excreted products of decomposition from the blood pass into the urine.
Thus the sugar results from a portion of the food which is transformed
into sugar, and so passes into the portal vein. (Strümpell.)

There exists also in the liver and muscles a non-nitrogenous substance,
glycogen, which is detected also in other organs. This glycogen
probably arises partly from the carbo-hydrates of the food, but
certainly from the albuminous substances taken with the food, which,
when broken up, separate into nitrogenous products and glycogen.

When the glycogen is once formed, we may regard it as an intermediate
substance which is changed into sugar, probably by a saccharine
fermentation, and then can reach the blood. How glycogen is transformed
into sugar within the organism is unknown. Normally occurring sugar
results from glycogen.


When, years ago, my attention was first attracted by the idea that,
for the solution of our problem, we ought to turn our attention to the
sugar in normal urine, no very exact tests for sugar were possible.
The reactions were not very sensitive, the fact being that the surest
evidence of the presence of sugar was obtained not from the reduction
processes but from the method used by Brücker for preparing a potassium
compound of sugar.

Every investigation which I undertook in his times for the confirmation
of my theory was very arduous. The few cases which I at first had under
observation presented formidable difficulties. The occasion of my first
turning my attention to sugar in the urine was a case of a woman who
had borne five children, and, after violent and continuous mental
excitement, was suddenly seized with diabetes mellitus. I frequently
examined her urine, and always found an abnormal amount of sugar. She
had twice given birth to children whilst suffering from diabetes, and
on each occasion the child was a female. This fact struck me, because
previously, whilst she was strong and well, she had borne sons only.
But, on the appearance of the disease mentioned, she had two daughters
in succession, of whom the first one lived and the other was still-born.

I numbered amongst my acquaintances a family, of whom, in the course
of years, I was acquainted with the grandmother, a daughter, and two
grand-daughters. The grandmother had, including the third generation,
fifteen descendants, of whom twelve were girls and three were boys.
Two of the boys were the sons of the grandmother, and the first two
children she had borne. She was under medical treatment, and the
analysis of the urine showed a considerable quantity of sugar. She had
six daughters. One of these daughters, who survived the others, had
five children, amongst them one boy, who soon died.

Two of the grand-daughters of this family became mothers, each bearing
one daughter. I had the opportunity of examining the urine of all the
mothers of this family, and always found sugar in it. Sometimes the
saccharine contents reached a remarkable quantity, and yet were not
such as could be diagnosed to indicate an unhealthy condition.

Amongst the acquaintances of my youth was a young lady of good family.
Carefully reared, she was, as a child, too much sheltered from the
influences of the open air, and in later years much imprisoned in-doors
by hard study in different branches of art and science. As a young lady
she was fairly tall and well nourished, but pale and possessed of
little color.

It happened that I had an opportunity of examining this young lady’s
urine. As I found a considerable quantity of sugar, I was led to the
conclusion that the girl (she was engaged) would have principally
female offspring.

Many years had elapsed. The young lady had ripened into a stately
matron, and told me that she had the happiness to be the mother of five
daughters and a son. I am altogether without the statistics necessary
to deduce from a great number of similar cases the average relative
number of the sexes born of women suffering from diabetes. But this
must be pointed out, that, notwithstanding the high percentage of sugar
excreted in the case of women suffering from pronounced diabetes,
female offspring do not necessarily always appear. They will probably
be in a very striking majority when compared with the males, but the
complete disappearance of the male sex is not to be anticipated,
because male individuals, though in the minority, can appear. And this
was to be anticipated, seeing that in the so-called slighter cases of
this complaint the abnormal metabolism can be sensibly improved by
attention to diet.

       *       *       *       *       *

Diabetes amongst women has a marked influence upon the functions of the
sexual organs. Thus, for example, the menses cease, a condition which,
according to gynæcologists, is occasioned by an abnormal condition of
the womb and of the ovaries which become atrophied. (Schauta.) On the
other hand, diabetes may also result from diseases of the reproductive
organs. (Imlach.) When the cause of the complaint is removed from the
female genitals the sugar also disappears from the urine.

From both of these facts, which rest upon medical observation, it
follows that the excretion of sugar has some definite connection with
the processes at work in the female generative organs. In the cases
when the excretion of sugar continues for a considerable time, it is
of greater significance, and indicates chronic derangement of the
metabolism, in connection with which a serious change comes over the
internal organs of generation.

       *       *       *       *       *

Now, if there is a possibility that disturbances so extensive can be
set up in the female genital tract when there is an excretion of sugar,
it is also very possible that certain modifications may be produced
by a small _constant_ excretion of sugar. These changes can show
themselves in the ovum to this extent, that they may be of considerable
significance and not without influence upon the development of sex.

Women who suffer from pronounced diabetes frequently miscarry. In what
way the disease influences ovulation I cannot here discuss.

       *       *       *       *       *

The connection of the development of sex with an imperfect physiological
combustion of the food can only be considered as demonstrated, if it is
possible, by means of certain exact experiments in this direction to
reach results which incontestably make for the possibility of influencing
sex. Cases of this kind, in which the work of observation was conducted
by myself alone, and in families closely connected with me, where there
were exceptional wishes in this direction, I shall mention presently.

Most striking of all are the cases where a number of daughters have
come into the world one after another as the results of a marriage.

The condition of a woman in a well-regulated married state, _when,
as we will suppose, five or six girls are born, one after another,
must be considered to be of a kind that departs more or less from the
normal_. The human female, if we regard the general statistical data,
ought to bring forth approximately the same number of male and female
individuals. If we find so remarkable an excess in the direction either
of males or females, that six or seven of the same sex follow one
another, there must be a reason for this. In my opinion that cause is
now to be ascertained only from the results of analysis of the urine
for sugar, mentioned above.

In the cases where we have to deal with an excessive predominance of
female offspring, Trommer’s test will show us the presence of sugar.
But it is safest, as I have already said, to use the phenylhydrazin
test in the manner described. If it be demonstrated that in any such
case sugar practically exists in the urine, in never so small a
quantity, dietetic treatment is to be resorted to, until even the
minutest trace of sugar has been made to disappear.

The treatment consists in giving the mother a highly nitrogenous diet
with fat, and adding only so much carbo-hydrate as is absolutely
necessary to prevent its want being felt.

This diet should be continued for a considerable time, even although
the sugar in the urine may have disappeared. It is best to begin the
change of diet a good while (about 2 or 3 months) before impregnation.
During the menstruations which fall within this period, the ripened ova
will be voided unfertilized, and new ova which have been influenced by
the altered conditions of nutrition in the organism will ripen in their

(If we follow such information as we have concerning the development
of sex in man, we thence conclude that the difference in sex appears
at the beginning of the third month of pregnancy, and is definitely
expressed in the fourth month. From this it would appear not to be
superfluous if the recommended alteration of diet was maintained until
the beginning of the third month.)

When the ovule of a human female, dieted in this way, becomes
fertilized, it has been so far ripened by the process of nutrition
conducted in the organism of the mother, that when it attains the stage
of development, it resolves itself into cells which compose an organism
containing male characteristics.

After impregnation it is still advantageous that whilst the condition
of the urine is examined at intervals of a few days, the corresponding
diet should be continued during the advancing stages of the development.

Although I do not here take the trouble to illustrate these diet
processes by explanations, every one can have regard to these
particulars for himself, and conduct the diet even after impregnation
has taken place in accordance with the information given above.

In a case like that mentioned, where, after marriage, female ova
were successively formed and developed, practically a process of
physiological combustion was going on in the mother which did not
suffice for deriving all the advantage possible from the food, so that
the available elements might be all oxidized. In consequence, only
female ova were fertilized and only female individuals born. This
condition of things remained the same for a number of years.

In such a case the question is not alone one of a small residuum of
sugar, but in addition to this it is probably not impossible that other
substances also were evacuated from the body, to make use of which was
not within the power of the process of combustion.

With a rational diet, these substances also might be withheld from
evacuation and, as well as the sugar, be made available for combustion
with a corresponding increase of nourishment.

In experiments of this kind metabolic activity will show itself in the
organism, as it may be perceived from the nitrogenous constituents of
the urine that a greater exchange of nutritive matter is taking place,
a thing that happens also with normal individuals.

Under these circumstances the specific gravity of the urine is also
increased, and it may sometimes become relatively considerable (1030 to

In consequence of the influence which the altered diet, if commenced a
sufficiently long time before conception, exerts both over the mother
and over the ovum which is being prepared for fertilization, it is
possible that this ovum may develop itself into a male individual.

It also sometimes happens that, even with careful dieting, the
conditions which are necessary for our purpose are not realized--viz.:
that the sugar does not disappear from the urine, that the mother
cannot accommodate herself to a diet of the kind required. She finds
the situation intolerable, because she cannot do without an abundance
of starchy substances and sugar, and in consequence all hope of a
satisfactory result falls to the ground.

There are persons who from their youth upwards have lived principally
on vegetable food, and are therefore not accustomed to take the
nitrogenous substances of their diet in the concentrated form in
which they are presented in the albuminous constituent of meat. They
obtain the necessary nitrogen for the body from large amounts of food
containing a great quantity of water, and it may happen that they
cannot easily submit themselves to such a change of diet without
pernicious consequences. To this class belong the women who live in the
rural districts of many of the mountainous regions of central Europe,
where little flesh is eaten. With them it might often be a difficult
matter to make an abrupt change of diet of the desired kind. Such
individuals can be reconciled to the kind of diet we recommend only by
a gradual advance in the quantity of concentrated nitrogenous food. But
in such cases it might very likely prove possible to attain our end by
a corresponding vegetable diet.

       *       *       *       *       *

The following case, which was conducted under my control with the
greatest care, and was also a case of an intelligent woman, who showed
the greatest willingness to do anything, in order that she might have
male offspring, is of the highest interest for our theory.

This woman was of a family in which principally female children had
been born. Although all its members were fruitful, no great number
of descendants seemed to have been reached. It is not unlikely that
the multiplication of descendants was restrained. The existence of a
tendency to provide female ova for fertilization was also proved by
testing the urine for sugar.

In the case of this woman, who wished to have male offspring, the
examination of the urine each time showed, as with the other women of
the family, traces of sugar. With her ordinary diet sugar was found
in the urine (that of twenty-four hours being collected) in minute
quantities. The unoxidized minute traces of sugar signified imperfect

When the diet is to be altered, it is necessary to select it in
such a way that the nitrogenous substances may predominate and that
the carbo-hydrates may be excluded as far as possible. Of course a
sufficient quantity of fat must be added to the food.

The food to be taken was regulated on these principles, and the dieting
began. After eight days the last traces of sugar in the urine had
disappeared. The woman’s health was good, and she at once showed
herself contented with the highly nitrogenous diet.

The menses lasted five days, and after them, five more days having
elapsed, impregnation took place, the same diet continuing. After about
eight weeks of pregnancy the food was gradually altered. The state of
the woman’s health during pregnancy presented no remarkable features.
She had taken all necessary care of herself, and her condition during
the pregnancy, in like manner as before it, when she had to alter her
diet until the sugar disappeared from the urine, was satisfactory. She
was in due course confined of a boy.

A year and a half passed. The woman bore, after similar treatment as on
the former occasion, a second boy. In the interval no further control
was exercised over her way of living, but a few weeks before she
conceived means were taken to regulate her diet, so that no perceptible
trace of sugar resulted from its physiological combustion.

During five years this woman did not conceive. The results of
examinations of the urine, which were made from time to time, showed
quite clearly that sugar was always normally present. The quantity was
not determined. At the end of this period the woman, after a long rest,
and a similar preliminary dieting, once more became pregnant. This time
also the result was a boy. After two years another boy followed. In
this case also a similar process of dieting had preceded.

After such occurrences it was sufficiently demonstrated that it could
be only the influence of the diet that showed itself in this way;
because in this case one would be convinced that it was not a mere
accident that the woman here spoken of produced only male offspring.

In the case of this woman it was evidently the diet that affected the
development of sex, and exerted such an influence that, under the
improved conditions, the metabolism both in the mother and in the
ripening ovum preparing for fecundation, took such a form that a male
individual was developed.

She again became pregnant after a lapse of two years. Before her
pregnancy the same system of diet was followed as on the previous
occasions. She miscarried in the fifth month. Violent emotions and
mortifications, accompanied by anxious cares, were, together with other
coincident unfavorable circumstances, the cause of the miscarriage. The
offspring was male.

Soon after, some four months after the miscarriage, she again became
pregnant. Also on this occasion dieting had preceded, such as I have
frequently carried out for the development of a male individual. But a
miscarriage again supervened. The fœtus was obviously male.

       *       *       *       *       *

But what was now wanting was an experiment that could be added to the
preceding, and would serve to show that a human female, who, under the
influence of our method of dieting, invariably bore sons, would, in the
case of paying no attention to diet, bring a female into the world.

The evidence was forthcoming, for the woman in question again became
pregnant without any consideration being bestowed on her bodily
condition, and without anything being done to remove the traces of
sugar from the urine. After having seven times borne males she became
this time mother of a female, which, born before the due time, soon
died. After that she was not again pregnant. Probably some change
supervened in consequence of which she became permanently unfruitful.

       *       *       *       *       *

This incident shows sufficiently that the ovum in the case of the woman
who served for our experiment possessed an inherent tendency to develop
into a female, and was also ripe enough to be fertilized. As we had
exercised no influence upon it so as to effect any change in the ovum
(in the same way as we had previously been able to affect the others
by the diet in order to procure the ovum of a male) the result was a

The female tendency was therefore already present in the ovum,
and indeed the mother supplied convincing evidence of the female
constitution of the ovum whilst it was yet unfertilized, because sugar
existed in her urine. The previous determination of the sex could
also in this case present no difficulty. In the earlier cases, when
male individuals followed one another, we always aimed, by means of
our support given by means of the nourishment of the mother, not only
at the ripening of the ovum which was to be fertilized, but also at
the development of a male individual. In the last case the ovum was,
without any assistance, capable of being fertilized, but it developed
into a female.

A ripe, fertilizable ovum in the ovary of a woman whose urine
habitually contains sugar has a tendency, when the proper conditions
are supplied, to develop into a female. In consequence, it is in such
cases from the outset possible, without exercising any influence
over the mother, without adopting any diet, to anticipate after a
conception, the birth of a female individual. But if these conditions
do not exist, if no sugar can be detected in the urine, the use of
the same influence in order to obtain a male individual is still not
superfluous. In this case also there is a need of an alteration of
diet, although the individual in question accomplishes the process of
physiological combustion in a manner which must be called the most
favorable possible, seeing that with a mixed diet all the oxidizable
materials are completely used up.

Supposing that a mother of this sort wished for female offspring,
one would not be in a position to give any advice. In this case
one cannot, according to the facts which have been mentioned above,
exercise any influence over an alteration in the course of the
development of the ovum which would occasion the birth of a female.
Such a mother is, up to the present time, beyond the reach of an
influence that can affect the development of the future sex.

       *       *       *       *       *

Two other cases follow in which male children were desired, several
females having so far been the offspring of the marriage. The
corresponding arrangements for the regulation of the diet, which led to
the complete disappearance of sugar from the urine, showed themselves
effective in the ripening of the ovum, and, after conception had taken
place, in both cases a male individual was formed and developed.

In addition to this, four other cases were under observation, in
which no influence was exercised on sugar occurring in the urine in
quantities, such as correspond to a normal healthy state. Without any
kind of influence of diet, three females were born.

In a fourth case I had a negative result. In three cases the result was
positive. In the last three cases I was able to examine the urine as
often as I wished, whilst in one case I was allowed to do so only at
long intervals as a favor.

       *       *       *       *       *

Let us now in conclusion endeavor to make some short reflections on the
results which we are able to attain.

First of all one would say that in certain regions and among certain
peoples, where meat forms the principal diet, only male, or principally
male, offspring would be anticipated.

The nutrition of the mother certainly plays a leading part in the
development of the ovum within her body. The different experiments
which breeders have made, and the observations which have repeatedly
shown in the case of the invertebrata (v. Berlepsch, ‘_Die Biene und
ihre Zucht_,’ second edition; Landois, ‘_Physiologie_’), a connection
between food and the development of sex leave no doubt that, in the
case of the human subject also, a certain diet of the mother would not
be without influence on the ovum developing within her. Here, however,
in the case of the ripening of the ovum, according to my opinion, the
result does not depend on the diet alone, but rather on the process of
metabolism in the mother.

How the physiological combustion goes on in the organism, and what
changes take place in it, in consequence of the altered diet, until
the sugar entirely disappears, is in the case of human beings of the
highest importance, and furnishes an index of the consequences.

In individual cases the diet is directed in accordance with the results
that show how the food has been assimilated and does not depend upon
these alone. In other words, whether the mother eats much meat is a
secondary consideration. Whether and how the food taken is completely
made use of in the process of combustion--that is a matter of
importance for the purpose we have in view.

Any one, who keeps before him the fundamental principles of this
theory, will see plainly that it is possible, under certain
circumstances, to procure male progeny by means of the influence we
have indicated. _The wish to have female progeny is a desire for the
gratification of which it is not at present possible to give any

       *       *       *       *       *

In connection with all that I have already said I will here mention
that the method which I employed to procure the ripening of an ovum
for male progeny in cases where I had previously found sugar normally
present, which served as an indication for the application of my
treatment, I attempted to apply also in the case of individuals with
whom no trace of sugar was to be found. The method of proceeding,
judging by my experiences thus far, should be as follows.

First of all, it must be elicited whether any special disease exists,
and especially any that indicates anomalies in the metabolism. Of
course capacity for generation and the possibility of conception are

If the history of the case shows no circumstances that would hinder the
application of the method, we inform the patient that she must furnish
us with the urine necessary for the occasional examination. It is best
to use for this purpose a urine glass marked in grammes and containing
two litres, in which the urine of twenty-four hours is to be collected.

It is well at the beginning of the procedure to put a few drops of
formaline into the measuring-glass, so that the urine may not, in
consequence of standing, decompose, and so become unfit for accurate
analysis. Of the collected quantity of twenty-four hours, about 200
grammes should be poured into a small phial, well corked, and used
for analysis. In making the analysis it is best to proceed in the
following order: First, we determine the _reaction_ of the urine with
litmus paper. In normal urine the reaction is generally acid. Next
the _specific gravity_ is determined. This is most easily done with
Ultzmann’s urometer, by means of which the density of the urine can
be easily determined. That varies in normal urine generally between
1015 and 1020. In exceptional cases it may sink very low, which often
happens after much fluid has been taken. In other cases it rises
under pathological circumstances enormously high, as, for example, in
diabetes. In the case of a thorough preparation of the organism by the
use of a great quantity of concentrated nitrogenous food with a view to
influencing sex, the specific gravity very often reaches 1030 and more.

After the specific gravity we measure next the _quantity of urine_
collected in the twenty-four hours.

       *       *       *       *       *

We proceed next to determine the normal _urine-sugar_, and for
this purpose use a number of the well-known tests--Nylander’s, the
fermentation test, and Trommer’s test--which have been already
described. If these give a positive result, we proceed to a quantitative
examination by means of the polariscope. If the quantity of sugar found
is very small, we exert ourselves to get rid of it by a suitable diet,
because otherwise no certain influence over the embryo in the direction
of the production of male offspring can be exercised. If, however, we
find no sugar by any of the above tests, we seek for it by means of the
phenylhydrazin test also described above. A few experiments on the
melting point of the phenyl-glycosazon crystals will easily give us
certain information. In the analysis we observe particularly whether the
positive result of the phenylhydrazin test has originated from the sugar
or from the reducing substances. With the polarization apparatus we
determine the quantity of lævo-rotatory substances, _the optical
rotation_, in per cents., as these stand in a certain relation to the
reducing substances. We make these experiments with urine that has not
been decolorized. The former becomes greater as the quantity of the
latter increases.

       *       *       *       *       *

_The determination of the reducing substances_ can be effected by
Salkovski’s gravimetric method, but I prefer Moritz’s volumetric
method, on account of its simplicity. For the experiment we prepare
the following solutions: 1. A solution of sulphate of copper of 80.78
grammes Cu S O{4} + 5 H{2} O, in a litre; 2. Solution of caustic soda
of 120 grammes Na H O, in a litre; 3. Watery solution of ammonia, of
7.1 per cent. N H{3}, specific gravity 0.9722. For conducting the
volumetric analysis we place in one of Erlenmayer’s flasks, containing
about 250 cubic centimetres, about 2 cubic centimetres each of the soda
solution and the solution of sulphate of copper, and add 140 cubic
centimetres of the ammonia solution. We thus obtain a dark blue fluid,
which we now boil. During the boiling we allow the urine to be analyzed
to flow in from a burette until the fluid becomes colorless. A table
given by Moritz in the forty-sixth volume of the ‘_Archiv für klinische
Medizin_,’ shows us in per cents. the quantity of reducing substances
contained in the urine we have used.

In conclusion we investigate the condition of metabolism by _determining
the excreted nitrogen_. Nitrogen is excreted both by the urine and the
fæces. The greater part is found in the urine, whilst, on the contrary,
the quantity of nitrogen excreted in the fæces amounts to more than 1
gramme per day. If, then, we determine the quantity in the urine alone
and add 0.94 gramme as a correction for the nitrogen excreted with the
fæces, the resulting error will be unimportant. The best and at present
most useful method of determining the nitrogen is that of Kjeldahl. I
generally use it in my analyses as one that can be conveniently carried
out. For this purpose we place 5 cubic centimetres of filtered urine in
a long-necked flask, add about 3 decigrammes of yellow oxide of mercury
and 10 cubic centimetres of chemically pure sulphuric acid. We then
carefully warm the brownish-black mixture over the flame of a Bunsen
burner until it has become colorless. We now allow it to cool. The
mixture is now poured into an Erlenmayer flask containing three-quarters
of a litre of water, is neutralized with 30 per cent. soda-lye, and then
40 cubic centimetres of a 4 per cent. solution of potassium sulphide is
added. The whole is next subjected to distillation. Decinormal sulphuric
acid contained in the receiver takes up the ammonia which distils over.
The acid still remaining free after the completion of the distillation
is titrated with decinormal caustic soda. As 1 cubic centimetre of
decinormal sulphuric acid corresponds to 0.0014 gramme of nitrogen, we
can easily reckon the quantity excreted daily. We know how much nitrogen
is contained in 5 cubic centimetres of urine, and can easily find to how
much the daily quantity amounts by multiplying by it and dividing by

The nitrogen found in the urine can be expressed as albumen by
multiplying it by 6.25 (Neumeister), at the same time making a
correction for the nitrogen in the fæces as described above.

This is all that there is to say about the analysis of the urine, which
is of so much importance for our experiments. In order to show the
practical application, I will add the following analyses, as actually
made in exercising an influence over sex to obtain male offspring.

       *       *       *       *       *

1. Case of a woman twenty-three years old, who, before anything was
done to influence the sex of her offspring, had been married five
years, and had given birth to two girls. The urine was collected
from eight in the morning until the same hour of the next day in a
measuring-glass. The quantity in twenty-four hours was 1,650 cubic
centimetres. Analysis gave the following results:--


    _Reaction_: Acid.

    _Specific gravity_: 1017.

    _Quantity in 24 hours_: 1650.

    _Color_: Light yellow, fairly pale.

    _Sugar_: None perceptible with Trommer’s test, the fermentation
       test, and Nylander’s test.

    _Phenylhydrazin test_: Negative.

    _Optical rotation_: Very slight, not determinable.

    _Reducing substances_: 0.135 per cent.

    _Nitrogen_: 12.76 (Correction 0.94).

    _Nitrogen as albumen_: 79.75.

I recommended that more meat should be taken, and that sugar and
other forms of carbo-hydrate should be avoided. After the lapse of
eight days, I again procured urine for examination. Analysis gave the
following results:--


    _Reaction_: Acid.

    _Specific gravity_: 1018.

    _Quantity in 24 hours_: 1050.

    _Color_: Somewhat darker than on 17, 1.

    _Sugar_: None perceptible with Trommer’s test, the fermentation
       test, and Nylander’s test.

    _Phenylhydrazin test_: Negative.

    _Optical rotation_: Not determinable.

    _Reducing substances_: 0.15 per cent.

    _Nitrogen_: 13.5 (Correction: 0.94).

    _Nitrogen as albumen_: 84.37.

The result was that the reducing substances and the nitrogen (expressed
as albumen) had increased. The diet of this woman was constantly
altered in the direction of increasing the amount of albumen, until,
after the lapse of about three weeks, the following results were


    _Reaction_: Acid.

    _Specific gravity_: 1030.

    _Quantity in 24 hours_: 1000.

    _Color_: Dark, brownish-yellow.

    _Sugar_: Cannot be determined by Trommer’s test, the
       fermentation test, and Nylander’s test.

    _Phenylhydrazin test_: Positive; the glycosazon-crystals have
       melting-point 110° cent., therefore do not result from sugar.

    _Optical rotation_: 0.2 per cent. lævo-rotatory.

    _Reducing substances_: 0.32 per cent.

    _Nitrogen_: 21.9 grammes (Correction: 1 gramme).

    _Nitrogen as albumen_: 136.8 grammes.

The woman was kept in this condition four weeks. In the meantime
menstruation took place. It lasted four days, during which time no
change appeared in the analysis. An analysis was made every week.
Another menstruation occurred, lasting four days, and impregnation took
place six days later. After this the menses ceased. As I mentioned
above, the sex of the embryo is already determined in the third month
of pregnancy, for which reason I kept the patient under dietary
influence up to that time. In the interim I made ten analyses at short
intervals, the average results of which I shall now give.

                       AVERAGE of TEN ANALYSES.

    _Reaction_: Acid.

    _Specific gravity_: 1028-1032.

    _Quantity in 24 hours_: 750 cubic centimetres, to 1200.

    _Color_: Golden yellow, always dark.

    _Sugar_: None could ever be detected.

    _Phenylhydrazin test_: Positive (owing to the presence of
       glycuronic acid compounds; melting-point of crystals 105°
       cent. to 120°).

    _Optical rotation_: 0.2-0.3 per cent. lævo-rotatory.

    _Reducing substances_: 0.29-0.35 per cent.

    _Nitrogen_: 17.9 grammes to 22 grammes (Correction 1 gramme).

    _Nitrogen as albumen_: 111.8-137.5 grammes.

When after 5 analyses the nitrogen (expressed as albumen) had reached
its highest point, it fell suddenly. Some immediate experiments proved
that it was necessary to give more carbo-hydrates and less albuminous
food, in order to re-establish the previous relations.

The woman was subsequently allowed to follow whatever course she
preferred, and bore a fine boy at full term.

The task still remains of examining many facts and theories already
known which may apparently be contradictory to our teaching.

And here should be first of all taken into consideration the
experiments in diet made by various stockbreeders (Bellingers, Wilkens,
etc.). In them, however, the results of the analysis of the products
of excretion are not given, and in particular there is no information
respecting the combustible and useable sugar evacuated from the
organism, or any other substances from the organism which might have
been of importance for the evaluation of the food. It is possible
that in experiments with diet, without reference to the excretion of
sugar, the results may be sometimes in favor of the male and sometimes
in favor of the female sex, upon which latter no active influence is
exercised. Herr U. P., a nobleman resident in a country district of the
Russian Baltic provinces, informed me by letter that in his herds the
greater number of calves are born in February. The February calves are
principally male. The cause in this case may be as follows:--Conception
takes place in the May of the previous year. After having been kept
some six months in the cow-houses, the beasts are turned into the
spring meadows, and are impregnated at a period when metabolism is
active in consequence of their altered mode of life. All the cows are
in heat. The notable result obtained in the ensuing February may be
explained as the consequence of the better physiological combustion of
the food.

According to statistics more boys than girls are born in the years with
a poor harvest. Bad harvest years are those which favor a flesh diet,
as the food-stuffs from the vegetable kingdom do not suffice for the
cattle, nor for the people either; in consequence of which the cattle
are killed, and more flesh enters into the diet of the women who are
fructified. If people in general had the normal aptness for procreation
in such famine years, the flesh-diet might turn the scale in favor
of the male sex; it being presupposed that the other conditions were

If Thury’s law be considered, Thury also held the ripeness of the ovum
to be of importance for male or female ova. The ova were regarded
by this author, as being more or less ripe, or as male and female,
according to the time, whether it happened to be at the beginning or
at the end of the rutting. To me, however, the ripeness seems to
depend upon the process of physiological combustion in the organism of
the mother. According to Thury no attention need be paid by us to the
ripeness for fructification, as this ripeness is attained independently
of our interference. But, on the other hand, our influence has the
effect of producing a male ovum out of the ovule ready to be fructified.

If the dieting of a woman in the way we recommend is practicable and of
definite effect upon the development of the future sex, we arrive at
a conclusion which may be summed up as follows:--If a woman be dieted
according to our method, she can reach a stage in which she becomes
sexually superior to the man, and her offspring will then be male, in
accordance with the law of the cross-heredity of sex.

 Transcriber’s Notes:

 --Text in italics is enclosed in underscores ( _italics_ ).

 --Subscripted text is enclosed in braces ( {subscripted character(s)} ).

 --Obvious punctuation and spelling inaccuracies were silently corrected.

 --Archaic and variable spelling has been preserved.

 --Variations in hyphenation and compound words have been preserved.

 --The Chapter headers for Chapters I, II and III were misprinted as
   Chapters I, III, and IV (respectively). Subsequent printings have
   corrected the error, and have been adjusted here.

*** End of this Doctrine Publishing Corporation Digital Book "Schenk's Theory: The Determination of Sex" ***

Doctrine Publishing Corporation provides digitized public domain materials.
Public domain books belong to the public and we are merely their custodians.
This effort is time consuming and expensive, so in order to keep providing
this resource, we have taken steps to prevent abuse by commercial parties,
including placing technical restrictions on automated querying.

We also ask that you:

+ Make non-commercial use of the files We designed Doctrine Publishing
Corporation's ISYS search for use by individuals, and we request that you
use these files for personal, non-commercial purposes.

+ Refrain from automated querying Do not send automated queries of any sort
to Doctrine Publishing's system: If you are conducting research on machine
translation, optical character recognition or other areas where access to a
large amount of text is helpful, please contact us. We encourage the use of
public domain materials for these purposes and may be able to help.

+ Keep it legal -  Whatever your use, remember that you are responsible for
ensuring that what you are doing is legal. Do not assume that just because
we believe a book is in the public domain for users in the United States,
that the work is also in the public domain for users in other countries.
Whether a book is still in copyright varies from country to country, and we
can't offer guidance on whether any specific use of any specific book is
allowed. Please do not assume that a book's appearance in Doctrine Publishing
ISYS search  means it can be used in any manner anywhere in the world.
Copyright infringement liability can be quite severe.

About ISYS® Search Software
Established in 1988, ISYS Search Software is a global supplier of enterprise
search solutions for business and government.  The company's award-winning
software suite offers a broad range of search, navigation and discovery
solutions for desktop search, intranet search, SharePoint search and embedded
search applications.  ISYS has been deployed by thousands of organizations
operating in a variety of industries, including government, legal, law
enforcement, financial services, healthcare and recruitment.