Ernest Rumley Dawson.

The causation of sex in man; a new theory of sex based on clinical materials together with chapters on forecasting or predicting the sex of the unborn child and on the determination or production of either sex at will online

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entirely applicable to man are but assumptions, based on
observations made chiefly on the invertebrata, the round-
worm of the horse especially.

Indeed, very few if any men have even seen a free human
ovum, that is, one discharged naturally from its Graafian
follicle, and most observations have been made on ova
artificially removed from the follicles either after death or
while operating under chloroform, etc.

We are equally ignorant with regard to most animals,
and Dr. Eden 3 tells us:

" The beginnings of development have not yet been made out
with precision in any of the mammalia."

The actual contact of the spermatozoon with the nucleus
of the ovum not having been observed, it is impossible to
say how many human spermatozoa are required to fertilise
the human ovum.

From analogy it has been believed and dogmatically
taught that only one spermatozoon was necessary : this may
be so, but it is also open to doubt. One spermatozoon only
may be sufficient, but it is also quite possible that very often,
if not usually, many spermatozoa participate. And here it
is advisable to recall Dr. J. W. Ballantyne' s 4 warning that

1 Ballantyne, " Manual of Antenatal Pathology," p. 608.

2 Dr. T. W. Eden, " Manual of Midwifery," 4th ed. 1915, p. 10.

3 Eden in Playfair's " Midwifery," 1898, p. 88.

4 Ballantyne, op. cit., p. 24.


"it is not safe to conclude that what occurs in the lower
animals will occur in the human subject."

Fertilisation of the frog's egg and also of the transparent
ova of several of the invertebrates, e.g. thread-worms and
sea-urchins, has been actually watched. In them only one
spermatozoon has been seen to enter the ovum, through the
only opening, called the micropyle, in the tunic or wall of the
ovum; hence it has been assumed that only one likewise
enters the human ovum. Though the entrance of but one
spermatozoon is usual, according to among others Van
Beneden, he has actually, though on but few occasions, seen

GRAAFIAN FOLLICLE. (Diagrammatic.)

The spherical ovum has been cut vertically and horizontally, to show that the cell-wall is uni-
versally perforated by the porous canals for the entrance of the spermatozoa. The outer
surface of the ovum, 2, shows the minute puncta or orifices of the canals, which are shown
in i as radiating lines ; 3 shows the interior of the ovum from which the nucleus and the
liquid yolk have escaped.

two spermatozoa enter one ovum, while watching the fertili-
sation of the eggs of the ascaris.

Comparative embryology is at best a doubtful guide, and
that it is dangerous to argue from analogy is evident from
the fact that there are marked differences in the ova of
the mammalia, including the human ovum, and the ova of
the fishes, birds, or reptiles, the ova of the latter being mero-
blastic and telolecithal, while the human ovum is holoblastic
and alecithal.

A meroblastic ovum means that a portion only of the ovum
when fertilised divides or segments, and it contains more
food yolk than germ yolk, as it has to develop independently
of the mother; while in the holoblastic ovum the whole


substance divides and subdivides, it contains much more
germ yolk than food yolk, because the mammalian embryo
very early derives its food supply from the mother while
in utero.

It is possible that this initial fundamental difference in
the ova is sufficient to require the different number of
spermatozoa, more being required when the whole ovum
segments as does the human ovum.

There is no micropyle, or specialised " way in," provided
in the cell wall of the human ovum for the entrance of the
spermatozoa; on the other hand there are multiple openings,


The spherical ovum presents one large opening, the micropyle, " the only way." for
the spermatozoon.

actually many thousands, in the human ovum wall, so it is
only reasonable to suppose that at least hundreds, if not
thousands, of spermatozoa do enter the ovum by them and
so reach the protoplasm or yolk of the ovum, whence it is
possible that several also enter the nucleus of the ovum.

That the striae in the zona pellucida are for the passage
of the spermatozoa is stated by Gerrish, 1 who says :

" The zona pellucida is marked by numerous radiating striae. The
striae are supposed to be minute canals, through which nutrition
reaches the ovum while it is still in the Graafian follicle, and through
which the spermatozoa may afterwards pass in the process of

Cunningham 2 too says " they allow the spermatozoa to
reach the ovicell."

1 Gerrish, " Text-book of Anatomy," 2nd ed. 1903, p. 852.

2 Cunningham, op. cit., p. 12.


Hcisler 1 also confirms this, and points out that these

" correspond in junction to the micropyle, a small aperture found in
the less easily penetrable egg envelopes of many invertebrates, and
of some fishes."

In the invertebrata, therefore, the supply is equal to
the demand viz. one micropyle for one spermatozoon.
Hence, in those cases where there is only the single
micropyle or special " way in " provided in the ovum
wall, we should expect that one spermatozoon enters
thereby only, because only one spermatozoon is needed.
Certciinly the provision in the human ovum of multiple
avenues of entrance looks as though multiple spermatozoa
are required to enter thereby, in order to fertilise the human
ovum ; or does the supply far exceed the demand thousands
of ways in for only one spermatozoon ! It would be more
rational to expect hundreds of spermatozoa for every
" way in "; which there probably are, as the total number
of spermatozoa in a single seminal ejaculation has been
estimated at several millions.

It is certainly evident, as stated by Dr . J. W. Ballantyne, 2
that " what took place in the chick did not necessarily occur
in the human embryo ' ' ; and even more truly what takes
place in the ova of worms and sea-urchins need not occur
in the human oosperm. Indeed, Dr. J. Teacher 3 says that
" each ovum seems to be a law unto itself."

Nature would hardly be so prolific in her supply of human
spermatozoa to the single ovum if one only were necessary ;
for certainly the enormous number of spermatozoa provided
each time, and their very frequent renewal, and their long life
in the Fallopian tubes, point rather to the necessity of
multiple spermatozoa.

Nature may well require only a single spermatozoon for
each ovum in those cases where sexual congress and fertilisa-
tion are an annual, or at most a half-yearly occurrence, and

1 Heisler, op. cit., p. 23.

2 Ballantyne, " Journal of Obstetrics and Gynaecology," 1902, vol. i.,
p. 698.

3 Dr. J. Teacher, " Journal of Obstetrics and Gynaecology," July, 1903,
vol. iv. p. 25.


the ova to be fertilised are numbered by thousands or even
hundreds of thousands.

Polyspermy, or the entrance of multiple spermatozoa into
the ovum nucleus, has been blamed for the production of
human deformities on no reliable evidence; for who sees the
fertilisation of the ovum when a monstrosity is produced ?
It has also been blamed for the production of twins and plural
births on equally inaccurate data, for we know that usually
when these occur multiple ova, as evidenced by multiple
corpora lutea, have been produced.

to believe that fertilisation usually takes place in the
Fallopian tube, and not in the uterus ; if the uterus were the
proper site for fertilisation, then tubal pregnancies should
not occur so frequently.

The discovery in utero of an early fertilised ovum is no
proof that that ovum was not already fertilised when it
first reached the uterus; on the other hand, tubal pregnancies
are so numerous that they must be looked upon as cases of
abnormal arrest of a normally fertilised ovum in its progress
along the tube, and not as cases of abnormal fertilisation
in an abnormal site.

We are forced, then, to the conclusion that the actual
site, where fertilisation normally takes place is the Fallopian
tube; probably it occasionally occurs in the body of the
uterus, as it undoubtedly also does, on very rare occasions,
in the recently ruptured (rraafian follicle on the surface of
the ovary; hence the site of fertilisation is not identical
in all cases.

Garrigues 1 says:

" The Fallopian tubes are the canals through which the ova pass
from the ovaries to the uterus, and in which probably, in most
cases, impregnation takes place by the union of an ovum and one
or more spermatozoids."

Halliburton 2 says :

" The spermatozoa make their way into the Fallopian tubes.
It is here that they meet the mature ovum."

1 Garrigues, " Diseases of Women," 3rd ed. 1900, p. 68.

2 Halliburton, op. cit., p. 881, 1915.


So usual is it for spermatozoa to be found waiting for
the ovum in the Fallopian tubes of women in whom sexual
congress regularly occurs, that the Fallopian tubes are now
regarded as receptacles for the semen.

Most often, then, the fertilisation of the ovum and its
conversion into an oosperm takes place in the Fallopian
tubes, both in women and the mammalia; it then safely
makes the journey down the Fallopian tube to the uterus,
which is, in fact, the incubator or nest for the fertilised egg.

On its arrival there, it finds a bed, or nidus, in the shape
of a thick vascular mucous membrane, into which the ovum
sinks, and thus secures a safe resting-place.

The site where it anchors or embeds itself is usually either
the anterior or posterior wall of the uterus, but may be at
any part of the uterine wall, even low down near the cervix,
as in cases of placenta prsevia. To whatever part it attaches
itself, the now living and growing ovum practically eats or
bores its way into the substance of the congested mucous
membrane, and the result of the activity displayed by the
growth and the fixation of the oosperm is that the mucous
membrane does not degenerate and wither, but maintains
its integrity and position, and thus menstruation is arrested :
the woman is pregnant.

If the ovum set free be not fertilised, menstruation occurs
that is, haemorrhage occurs from the congested superficial
vessels, and portions of the epithelial lining of the congested
uterine mucous membrane degenerate and are shed.

The site of attachment of the oosperm, the future placental
site, is usually in the corresponding half of the uterus to
the Fallopian tube it has just travelled down. Garrigues*
says: "The fertilised ovum is, as a rule, arrested near
the internal opening of one of the Fallopian tubes " i.e.
it is more to one or other side of the mid-line of the anterior
or posterior uterine wall; it may be quite on the lateral
wall; or it is in the corresponding cornu, or uterine horn,
if the uterus be a double one. In the uniparous mammalia,
too, the site of attachment (placental site) is usually in the
corresponding horn to the ovary from which the ovum was
derived, but not invariably so.

1 Garrigues, " Obstetrics," 1902, p. 29.


The site may, however, be more to the opposite side of
the uterus, or even in the opposite cornu or horn if the uterus
is double; or again, it may be low down near the cervical
orifice. We know not what determines its precise spot of
anchorage; it can undoubtedly travel to any part of the
uterine wall.

This occurrence of implantations of the oosperm in the
horn of the uterus of the opposite side to the ovary from
which the ovum was derived, has long been known; it
occurs both in women and in mammals.

It may be due either to the ovum passing through the
uterus from one side to the other, or else to its not entering
the Fallopian tube on its own side, but passing along the
surfaces of the intestines to the other side of the uterus,
where it thus enters the opposite Fallopian tube. This is
known as the migration of the ovum, internal and external
respectively. I reserve the full discussion of the matter to
Chapter XIII.

It is to be recalled that fertilisation of the ovum is more
correctly fertilisation of the ovum nucleus. An account of
the minute details after fertilisation, " not yet proved for
human beings," 1 but as studied in starfish, worms, and sea-
urchins, by which the single male nucleus and female
nucleus approach and coalesce, and how the oosperm thus
formed divides or segments, to form the primary embryonic
structures, is not necessary to the task of solving the cause
of sex in man, and so I do not describe them.

1 Whitridge Williams, " Obstetrics," 1913, p. 94.


THERE being, as we have seen, two ovaries, a right and a
left, it follows that the ova produced are either right or
left ova, also that as the right ovary is larger than the left,
more right-sided ova are usually produced.

If, as must and does sometimes occur, the two ovaries
each happen to have equally matured a Graafian follicle,
we get a simultaneous, or nearly so, rupture of the follicles
and discharge of the contained ova; that is, we get two
ova to be possibly fertilised for, of course, this does not
necessarily always occur.

Should fertilisation of both occur, we get two foetuses, or
twins, owing their origin to the fertilisation of ova from
different ovaries, the sexes differing, as we shall see later.
This is not, however, the only mode of origin of twins,
though it is the commonest; but I will refer to the subject
of twins further on.

Much more frequently only one ovary matures a follicle,
and a single ovum only is produced : if, now, as the result of
the unilateral ovulation, the single ovum be fertilised, we
get what is normal in mankind, viz. a single birth ; if double
or bilateral ovulation were the rule, and there were always
two ova shed, surely both would usually be fertilised, and
twins would become the rule and single pregnancies the
exception, for it would not be expected that if two ova
were always provided, one only would be fertilised and the
other left.

This brings me now to the dominant influence of the
supplying ovary over the sex of the resulting foetus. The
supplying ovary is in reality the ESSENTIAL FACTOR IN


This, then, is my theory, that the sex of the foetus is



not due to the male parent, but depends on which ovary
supplied the ovum which was fertilised, and so became that

I find that a male foetus is due to the fertilisation of an
ovum that came from the right ovary, and a female foetus
is due to the fertilisation of an ovum that came from the
left ovary.

I will explain the theory more in detail.

FIRST, then, my theory maintains that the male parent
or father has no influence in the causation of sex, which
rests entirely with the female or woman. She has in her
two ovaries the already definitely sexed ova ready only for
the fertilising action of the male semen, so that though man
or the male fertilises the ripened ovum, he does not (to
coin a word) sexify it or cause its sex.

No theory which I can discover has hitherto entirely
dissociated the male parent, as 1 do; hence it is entitled to
be called a new theory.

Every theory in which the father is credited with being
even partly responsible for sex causation differs materially
from mine.

In this category come a great many of the old and mythical
theories. These in differing methods and ways ascribed
to the two testicles, if not the chief, at least a great part in
the sexify ing of the ovum.

I do not propose to enter fully into these theories, none
of which were based on clinical facts or cases, but will only
shortly mention their chief points.

One maintained that sex was entirely due to the male
that the spermatozoa not only fertilised, but also gave the
sex to the ovum.

Hippocrates thought that the future sex was determined
by the relative prevalence of the male or female semen,
either as to the quantity of it, or else the relative strength
of it.

Leeuwenhoek went so far as to suppose he could see a
difference of sex in the spermatozoa upon which depended
the sex of the future fcetus.

Another theory maintained that fertilisation coul'd only
.take place by the junction of the spermatozoa and ova of


the same side of the body, so that a left-sided ovum could not
be fertilised by a right-sided spermatozoon, and vice versa.

This theory received the support of Hencke, who in 1786
wrote a book based on this assumption, also claiming that
males were derived from the union of right spermatozoa
with right ova only, and girls from the union of left sper-
matozoa only with left ova only. This theory differs there-
fore widely from mine, in spite of several critics, because
I say the spermatozoa do not influence sex at all.

I fully discuss the question of the paternal influence on
the sex of the future child in Chapter VII.

SECONDLY, my theory maintains that male ova are re-
stricted to and come only from the right ovary, and female
ova only from the left ovary.

It matters not from which testicle the spermatozoon is
derived which fertilises the ovum, the essential point being
that sex is due to the ova always having their definite and
unalterable sex prior even to ovulation.

It follows that directly an ovum is fertilised, a boy or a
girl has begun to be developed, and no external or other
influence brought to bear on the mother can alter the sex
of the future child.

To inquire why the ovary of the right side should have
been chosen for the production of boys rather than the other
side seems as fruitless and as useless as to inquire why the
liver should have been placed to the right and the spleen
to the left of the body.

Galen said it was due to the right side being warmer than
the left, but how this can rank as cause and effect I know

It is, however, reasonable to suppose that the association
of the left ovary with the production of the female sex is
due to the fact that the muscularly weaker sex should arise
from the muscularly weaker side of the body.

That the left side of the body is the weaker of the two
is manifestly true, for as Herman 1 says:

" The left side is weaker than the right, not only in muscular
strength, but in power of resistance to painful impressions. This
is illustrated by the fact that in cancer, which has no preference for

1 Herman, op. cit., p. 71,


the left side rather than the right, pain is more common on the left
side. So it is in displacements of the uterus, although the changes-
in this condition have n'o unilateral character ; and in the pain dowfl)
the thigh from haemorrhoids."

So that the muscularly weaker sex are derived ftOIH the
ovary of the left or weaker side, while the larger and stronger
males come from the larger right ovary. Dr. T. G. Moor-
head 1 has shown that a child even at birth begins its "exist-
ence with a marked right-sided bias."

Taking it for granted, then, that only one ovum is pro-
duced at a time, the question comes, from which ovary
does it arise ? There can be but little doubt that it is pro-
vided more or less alternately by first one ovary and then
the other; for although there are two ovaries, and both are
normally active, they do not work synchronously : one ovary
only discharges an ovum at a time, so that double or bi-
lateral ovulation is not normal. Ne'grier* says :

" The ovaries perform alternately, for I find in one ovary a recently
ruptured follicle, and in the opposite ovary one coming forward."

Further, he says that :

" In women, having double uterus and vagina, the menses have
come from each side alternately."

A case published recently by Jurinka proves this, as also
does a case of Engel's (cf. pp. 170, 171).

That unilateral ovulation is the rule is proved post mortem
by cases where only a few and definite number of menstrual
periods have occurred. We are then able to see and count
the cicatricial pits or scars, the remains of the corpora
lutea, and find them in the two ovaries together to equal the
number of periods passed. We do not find that each ovary
has pits or scars equal in number to the number of menstrual
periods; but that if, for example, as in one of the following
cases, only three periods had been experienced during life,
each ovary has not three pits or scars, but the two ovaries
have three scars between them.

1 Dr. T. G. Moorhead in " Transactions of Royal Academy of Medicine-
Ireland," 1902.

2 Negrier, " Anatomical and Physiological Researches on the Human
Ovary." Paris, 1840.


The following cases support and prove this:

Mr. Girdwood 1 exhibits a preparation taken from a young

unmarried female who he knew had menstruated about

thirty-six times.

"The ovaries presented several indentations or small cicatrices
about the size of mustard seeds. From thirty-two to thirty-four
of these marks could be detected about eighteen in one, and
sixteen in the other ovary."

" A young woman died under my care. She had menstruated
three times. The surfaces of one ovary presented two cicatrices;
that of the other, one."

" Jane C , aged eighteen, died of consumption. She had

menstruated only six times. We could readily detect five depres-
sions or cicatrices three on one, two on the other ovary; of a sixth
we were doubtful."

I.e. there were not six ovulation scars in each ovary, but
six in the two ovaries together.

" Miss G - had been regular for two years previous to her
sudden death. In her I found post mortem about twenty-two of
the usual marks on the ovaries."

That is to say, there was definite proof of twenty-two
ovulations by the two ovaries together, not by each ovary, as
there would have been had ovulation been bilateral every

" Emma Bull died yesterday. Two years ago she menstruated,
this being the first and only time she had ever had that secretion.
I opened the body. The ovaries were plump and rather larger than
usual, soft to the touch, and glistening. There was no mark or
scar whatever on the right ovary; but on the left there existed a
reddish part about the size of a mustard seed, which had quite the
appearance of an ulceration skinned over."

That is, one menstruation, one ovulation scar in one ovary

In the following cases, examination of the ovaries
during menstruation reveals only one ovary as having
just ruptured a Graafian follicle that is, one ovary only
has ovulated.

1 Braithwaite's " Retrospect of Medicine and Surgery," vol. vii, 1843,
pp. 261-3.

2 R. Lee, " Braithwaite's Retrospect," vol. i. 1840, p. 397.


Dr. R. Lee z

" examined the body of a young woman who died during menstrua-
tion from inflammation of the median basilic vein. The left ovary
was larger than the right, and at one point a small circular opening
was observed in the peritoneal coat, which led to a cavity of no great
depth in the ovary. The right ovary was in the ordinary state."

' ' A woman under twenty years of age died suddenly from acute
inflammation of the lungs while menstruating. A red, soft, elevated
portion of the right ovary was observed, and at one part the peri-
toneal coat to a small extent had been removed. Under the open-
ing was an enlarged Graafian vesicle filled with transparent fluid.
The left ovary presented a natural appearance."

Sir J. Bland-Sutton 1 says :

" The evening before the operation the patient commenced to
menstruate. When the cyst was drawn up from the pelvis a small
rounded aperture was noted in the peritoneal covering, from which
a few drops of blood issued. Examination of the parts showed this
to be a recently ruptured follicle."

That is, one ovary only, though in this case partially
occupied by a tumour, had ruptured a Graafian follicle,
coincidently with the onset of menstruation.

Dr. John Phillips 2 describes a case of a woman dying
during menstruation from purpura haemorrhagica :

" In the right ovary, at the site of the corpus luteum, there was
a haemorrhagic infarct the size of a marble."

In this case, therefore, menstruation had been accom-
panied by unilateral ovulation and the formation of a single
corpus luteum, not one in each ovary.

Garrigues 3 says:

" The fact is, we, as a rule, find only one fully developed or rup-
tured follicle corresponding to a menstruation."

We are therefore justified in saying that the number of
pits, scars, or cicatrices in the two ovaries being nearly equal,

1 2 4 6 7 8 9 10 11 12 13 14 15 16 17 18

Online LibraryErnest Rumley DawsonThe causation of sex in man; a new theory of sex based on clinical materials together with chapters on forecasting or predicting the sex of the unborn child and on the determination or production of either sex at will → online text (page 4 of 18)