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Transcriber's note:
Text enclosed by underscores is in italics (_italics_).
_Barr's Buffon._
Buffon's Natural History,
CONTAINING
A THEORY OF THE EARTH,
A GENERAL
_HISTORY OF MAN_,
OF THE BRUTE CREATION, AND OF
VEGETABLES, MINERALS,
_&c._ _&c._
FROM THE FRENCH.
WITH NOTES BY THE TRANSLATOR.
IN TEN VOLUMES.
VOL. III.
London:
PRINTED FOR THE PROPRIETOR,
AND SOLD BY H. D. SYMONDS, PATERNOSTER-ROW.
1807.
T. Gillet, Printer, Wild-Court.
CONTENTS
OF
THE THIRD VOLUME.
_Page_
History of Animals 1
Chap. VI. _Experiments on the Method of Generation_ 81
Chap. VII. _Comparison of my Observations with those
of Leeuwenhoek_ 134
Chap. VIII. _Reflections on the preceding Experiments_ 159
Chap. IX. _Varieties on the Generation of Animals_ 208
Chap. X. _On the Formation of the Foetus_ 226
Chap. XI. _On the Expansion, Growth, and Delivery of
the Foetus_ 260
_Recapitulation_ 309
History of Man.
Chap. I. _Of the Nature of Man_ 317
Chap. II. _Of Infancy_ 334
_Directions for placing the Plates._
Page 88, Fig. 1, 2, 3, 4, 5, 6.
106, Fig. 7, 8, 9, 10, 11, 12.
140, Plate III.
148, Plate IV.
BUFFON'S
NATURAL HISTORY.
_HISTORY OF ANIMALS._
Aristotle admits, with Plato, of final and efficient causes. These
efficient causes are sensitive and vegetative souls, that give form to
matter which, of itself, is only a capacity of receiving forms; and
as in generation the female gives the most abundant matter, and it
being against his system of final causes to admit that what one could
effect should be performed by many, he concludes, that the female
alone contains the necessary matter to generation; and, as another of
his principles was, that matter itself is unformed, and that form is
a distinct being from matter, he affirmed that the male furnished the
form, and, consequently, nothing belonging to matter.
Descartes, on the contrary, who admitted but a few mechanical
principles in his philosophy, endeavoured to explain the formation
of the foetus by them, and thought it in his power to comprehend,
and make others understand, how an organized and living being could
be made by the laws of motion alone. His admitted principles differed
from those used by Aristotle; but both, instead of examining the thing
itself, without prepossession and prejudice, have only considered it
in the point of view relative to their systems of philosophy, which
could not be attended with a successful application to the nature of
generation, because it depends, as we have shewn, on quite different
principles. Descartes differs still more from Aristotle, by admitting
of the mixture of the seminal liquor of the two sexes; he thinks both
furnish something material for generation, and that the fermentation
occasioned by the mixture of these two seminal liquors causes the
formation of the foetus.
Hippocrates, who lived under Perdicas, a considerable time before
Aristotle, established an opinion, which was adopted by Galen, and a
great number of physicians who followed him; his opinion was, that the
male and female had each a prolific fluid, and supposed, besides, that
there were two seminal fluids in each sex, the one strong and active,
the other weak and inactive.[A] That a mixture of the two strongest
fluids produce a male child, and of the two weakest a female; so
that, according to him, they each contain a male and a female seed.
He supports this hypothesis by the following circumstance; that many
women, who produce only girls by their first husbands, have produced
boys by a second; and that men, who have had only girls by their first
wives, have had boys by others. It appears to me, that if even this
circumstance could be well established, it would not be necessary
to give to the male and female two kinds of seminal liquor for an
explanation; because it may easily be conceived, that women, who have
brought forth only girls by their first husbands, and produced boys
with other men, were only those who furnished more particles proper
for generation with their first husband than with the second; or that
the second husband furnished more particles proper for generation
with the second wife than with the first; for when, in the instant of
conception, the organic molecules of the male are more abundant than
those of the female, the result will be a male, and when those of
the female abounds a female will be produced; nor is it in the least
surprising that a man should have a disadvantage in this respect with
some women, while he will have a superiority over others.
[A] See Hippocrates, lib. de Genitura, page 129, & lib. de diæta, page
198, Lugd. Bat. 1665, vol. I.
This great physician supposes, that the seed of the male is a secretion
of the strongest and most essential parts of all that is humid in the
human body; and he thus explains how this secretion is made: "Venæ
& nervi, he says, ab omni corpore in pudendum vergunt, quibus dum
aliquantulum teruntur & calescunt ac implentur, velut pruritus incidit,
ex hoc toti corpori voluptas ac caliditas accidit; quum vero pudendum
teritur & homo movetur, humidum in corpore calescit ac diffunditur,
& a motu conquassatur ac spumescit, quemadmodum alii humores omnes
conquassati spumescunt.
"Sic autem in homine ab humido spumescente id quod robustissimum est ac
pinguissimum secernitur, & ad medullam spinalem venit; tendunt enim in
hanc ex omni corpore viæ, & diffundunt ex cerebro in lumbus ac in totum
corpus & in medullum; & ex ipsa medull proacedunt viæ, ut & ad ipsum
humidum perferatur & ex ipsa secedat; postquam autem ad hanc medullam
genitura pervenerit, procedit ad renes, hac enim via tendit per venas,
& si renes fuerint exulcerati, aliquando etiam sanguis defertur: a
renibus autem transit per medois testes in pudendum, proce dit autem
non qua urina, erum alia ipsi via est illi contigua, &c."[B]
[B] See Fæsius's Translation, vol. I. page 129.
Anatomists will no doubt discover that Hippocrates is not correct
in tracing the road of the seminal liquor; but that does not affect
his opinion, that the semen comes from every part of the body, and
particularly the head, because, he says, those whose veins have been
cut which lie near the ears only bring forth a weak, and very often an
unfertile semen. The female has also a seminal fluid, which she emits,
sometimes within the matrix, and sometimes without, when the internal
orifice is more open than it should. The semen of the male enters into
the matrix, where it mixes with that of the female; and as each has
two kinds of fluid, the one strong and the other weak, if both furnish
their strong, a male will be the result, and if their weak, a female;
and if in the mixture there are more particles of the male liquor than
the female, then the infant will have a greater resemblance to the
father than to the mother, and so on the contrary. It might here be
asked Hippocrates what would happen when the one furnished its weak
semen and the other its strong? I cannot conceive what answer he could
make, and that alone is sufficient to cause his opinion of two seeds in
each sex to be rejected.
In this manner then, according to him, the formation of the foetus is
made: the seminal fluids first mix in the matrix, where they gradually
thicken by the heat of the body of the mother; the mixture receives and
attracts the spirit of the heat, and when too warm part of the heat
flies out, and the respiration of the mother sends a colder spirit in;
thus alternatively a cold and a hot spirit enter the mixture, which
give life, and cause a pellicle to grow on the surface, which takes a
round form, because the spirits, acting as a centre, extend it equally
on all sides. "I have seen, says this great man, a foetus of six days
old; it was a ball of liquor surrounded with a pellicle; the liquor
was reddish, and the pellicle was spread over with vessels, some red
and others white, in the midst of which was a small eminence, which I
thought to be the umbilical vessels, by which the foetus receives
nourishment and the spirit of respiration from the mother. By degrees
another pellicle is formed, which surrounds the first; the menstrual
blood, being suppressed, abundantly supplies it with nutriment, and
which coagulates by degrees, and becomes flesh; this flesh articulates
itself in proportion as it grows, and receives its form from the
spirit; each part proceeds to take its proper place; the solid
particles go to their respective situations and the fluid to theirs:
each matter seeks for that which is most like itself, and the foetus
is at length entirely formed by these causes and these means."
This system is less obscure and more reasonable than that of Aristotle,
because Hippocrates endeavours to explain every matter by particular
reasons: he borrows from the philosophy of his times but one single
principle, which is, that heat and cold produce spirits, and that those
spirits have the power of ordering and arranging matter. He has viewed
generation more like a physician than a philosopher, while Aristotle
has explained it more like a metaphysician than a naturalist; which
makes the defects of Hippocrates's system particular and less apparent,
while those of Aristotle's are general and evident.
These two great men have each had their followers; almost all the
scholastic philosophers, by adopting Aristotle's philosophy, received
his system of generation, while almost every physician followed
the opinion of Hippocrates; and seventeen or eighteen centuries
passed without any thing new being said on the subject. At last, at
the restoration of literature, some anatomists turned their eyes
on generation, and Fabricius Aquapendente was the first who made
experiments and observations on the impregnation and growth of the eggs
of a fowl. The following is the substance of his observations.
He distinguished two parts in the matrix of a hen, the one superior
and the other inferior. The superior he calls the Ovarium, which is
properly no other than a cluster of small yellow eggs of a round form,
varying in size from the bigness of a mustard-seed to that of a large
nut or medlar. These small eggs are fastened together by one common
pellicle, and form a body which nearly resembles a bunch of grapes.
The smallest of these eggs are white, and they take another colour in
proportion as they increase.
Having examined these eggs immediately after the communication of the
cock, he did not perceive any remarkable difference, nor any of the
male semen in any one of these eggs; he therefore supposed that every
egg, and the ovarium itself, became fruitful by a subtle spirit, which
came from the semen of the male; and he says, that in order to secure
this fecundating spirit, nature has placed at the external orifice of
the vagina of birds a kind of net-work or membrane, which permits, like
a valve, the entrance of this seminal spirit, but at the same time
prevents it from re-issuing or evaporating.
When the egg is loosened from the common pellicle, it descends by
degrees through a winding passage into the internal part of the matrix.
This passage is filled with a liquor nearly similar to the white of
an egg; it is also in this part that the eggs begin to be surrounded
with this white liquor, with the membrane which occasions it, the two
ligaments (_chalazæ_) which passes over the white, and connects it
with the yolk and shell, which are formed in a very short time before
they are laid. These ligaments, according to Fabricius, is the part of
the egg fecundated by the seminal spirit of the male; and it is here
where the foetus first begins to form. The egg is not only the true
matrix, that is to say, the place of the formation of the chick, but
it is from the egg all generation depends. The egg produces it as the
agent: it supplies both the matter and the organs; the ligaments are
the substance of formation; the white and the yolk are the nutriment,
and the seminal spirit of the male is the efficient cause. This
spirit communicates to the ligaments at first an alterative faculty,
afterwards a formative, and lastly the power of augmentation, &c.
These observations of Fabricius have not given us a very clear
explication of generation. Nearly at the same time as this anatomist
was employed in these researches, towards the middle of the sixteenth
century, the famous Aldrovandus[C] also made observations on eggs; but
as Harvey judiciously observes, he followed Aristotle much closer than
experiment. The descriptions he gives of the chicken in the egg are
not exact. Volcher Coiter, one of his scholars, succeeded much better
in his enquiries; and Parisanus, a physician of Venice, having also
laboured on this subject, they have each given a description of the
chicken in the egg, which Harvey prefers to any other.
[C] See his Ornithology.
This famous anatomist, to whom we are indebted for the discovery of the
circulation of the blood, has composed a very extensive treatise on
generation; he lived towards the middle of the last century, and was
physician to Charles I. of England. As he was obliged to follow this
unfortunate prince in his misfortunes, he lost what he had written on
the generation of insects among other papers, and he composed what he
has left us on the generation of birds and quadrupeds from his memory.
I shall concisely relate his observations, his experiments, and his
system.
Harvey asserts that man and every animal proceed from an egg; that the
first produce of conception in viviparous animals is a kind of an egg,
and that the only difference between viviparous and oviparous is, that
the foetus of the first take their origin, acquire their growth, and
arrive at their entire expansion in the matrix; whereas the foetus of
oviparous animals begins to exist in the body of the mother, where they
are merely as eggs, and it is only after they have quitted the body of
the mother that they really become foetuses; and we must remark, says
he, that in oviparous animals, some hold their eggs within themselves
till they are perfect, as birds, serpents and oviparous quadrupeds;
others lay their eggs before they are perfect, as fish, crustaceous,
and testaceous animals. The eggs which these animals deposit are only
the rudiments of real eggs, they afterwards acquire bulk and membranes,
and attract nourishment from the matter which surrounds them. It is the
same, adds he, with insects, for example, and caterpillars, which only
seem imperfect eggs, which seek their nutriment, and at the end of a
certain time arrive to the state of chrysalis, which is a perfect egg.
There is another difference in oviparous animals: for fowls and other
birds have eggs of different sizes, whereas fish, frogs, &c. lay them
before they are perfect, have them all of the same size; he indeed
observes, that in pigeons, who only lay two eggs, all the small eggs
which remain in the ovarium are of the same size, and it is only the
foremost two which are bigger than the rest. It is the same, he says,
in cartilaginous fish, as in the thornback, who have only two eggs
which increase and come to maturity, while those which remain in the
ovarium are, like those in fowls, of different sizes.
He afterwards makes us an anatomical exposition of the parts necessary
to generation, and observes, that in all birds the situation of the
anus and vulra are contrary to the situation of those parts in other
animals; the anus being placed before and the vulra behind;[D] and
with respect to the cock, and all small birds, that they generate by
external friction, having in fact no intermission nor real copulation;
with male ducks, geese, and ostriches, it is evidently otherwise.
[D] Most of these articles are taken from Aristotle.
Hens produce eggs without the cock, but in a very small number, and
these eggs, although perfect, are unfruitful: he does not agree with
the opinion of country people, that two or three days cohabitation
with the cock is sufficient to impregnate all the eggs a hen will lay
within the year, but admits that he separated a hen from a cock for the
space of twenty days, and that all the eggs she laid during that space
were fecundated. While the egg is fastened to the ovarium, it derives
its nutriment from the vessel of the common pellicle. But as soon as
it is loosened from it, it derives the white liquor which fills the
passages in which it descends, and the whole, even to the shell, is
formed by this mode.
The two ligaments (_chalazæ_) which Aquapendente looks on as the shoot
produced by the seed of the male, are found in the infecund eggs
which the hen produces without the communication with the cock, as
in those which are impregnated: and Harvey very judiciously remarks,
that those parts do not proceed from the male, and are not those which
are fecundated; the fecundated part of an egg is a very small white
circle which is on the membrane that covers the yolk, and forms there
a small spot, like a cicatrice, about the size of a lentil. Harvey
also remarks, that this little cicatrice is found in every fecund or
infecund egg, and that those who think it is produced by the seed of
the male are deceived. It is of the same size and form in fresh eggs,
as in those which have been kept a long time; but when we would hatch
them, and when the egg receives a sufficient degree of heat, either by
the hen, or artificially, we presently see this small spot increase and
dilate nearly like the sight of the eye. This is the first change, and
is visible at the end of a few hours incubation.
When the egg has undergone a proper warmth for twenty-four hours,
the yolk, which was before in the centre of the shell, approaches
nearer to the cavity at the broad end; this cavity is increased by the
evaporation of the watery part of the white, and the grosser part sinks
to the small end. The cicatrice, or speck, on the membrane of the yolk,
rises with it to the broad end, and seems to adhere to the membrane
there: this speck is then about the bigness of a small pea, in the
middle of it a white speck is discernible, and many circles, of which
this point seems to form the centre.
At the end of the second day these circles are larger and more
visible; the streak also appears divided by these circles into two,
and sometimes three parts of different colours; a small protuberance
also appears on the external part, and nearly resembles a small eye,
in the pupil of which there is a point, or little cataract; between
these circles a clear liquor is contained by a very delicate membrane,
and the speck now appears more to be placed in the white than on the
membrane of the yolk. On the third day the transparent liquor is
considerably increased, as is also the small membrane which surrounds
it. The fourth day, a small streak of purple-coloured blood is observed
at the circumference of the speck or ball, at a little distance from
the centre of which a point may be seen of a blood colour, and which
beats like a heart. It appears like a small spark at each diastole, and
disappears at each systole; from this animated speck issue two small
blood vessels, which these small vessels throw out as branches into
this liquor, all of which come from the same point, nearly in like
manner as the roots of a tree shoot from the trunk.
Towards the end of the fourth day, or at the beginning of the fifth,
the animated speck is so much increased as to appear like a small
bladder filled with blood, and by its contractions and dilations
is alternatively filled and emptied. In the same day this vessel
very distinctly appears to divide into two parts, each of which
alternatively impel and dilute the blood in the same manner. Around
the shortest sanguinary vessel which we have spoken of a kind of cloud
is seen, which, although transparent, renders the sight of this vessel
more obscure; this cloud constantly grows thicker and more attached
to the root of the blood vessel, and appears like a small globe: this
small globe lengthens and divides into three parts, one of which is
globular, and larger than the other two; the head and eyes now begin to
appear, and at the end of the fifth day, the place for the vertebra is
seen in the remainder part of this globe.
The sixth day the head is seen more clearly, the outlines of the eyes
now appear, the wings and thighs lengthen, and the liver, lungs, and
beak, are distinctly observed; the foetus now begins to move and
extend its head, although it has as yet only the internal viscera; for
the thorax, abdomen, and all the external coverings of the fore part,
of the body are wanting. At the end of this day, or at the beginning
of the seventh, the toes appear, the chick opens and moves its beak,
and the anterior parts of the body begin to cover the viscera; on the
seventh day the chicken is entirely formed, and from this time until
it comes out of the egg, nothing happens but only an expansion of those
parts it acquired within these first seven days: at the fourteenth or
fifteenth day the feathers appear, and at the twenty-first it breaks
the shell with its beak, and procures its enlargement.
These observations of Harvey appear to have been made with the greatest
exactness; nevertheless we shall point out how imperfect they are,
and that he has fallen himself into the error he reproaches others
with, making experiments to support his favourite hypothesis, that
the heart was the animated speck which first appeared; but before we
proceed on this matter, it is but just to give an account of his other
observations, and of his system.
It is well known that Harvey made many experiments on hinds and does.
They receive the male towards the middle of September: a few days after
copulation the horns of the matrix become thicker, and at the same time
more lax. In each of the cavities five carunculas appear. Towards the
26th or 28th of the above month the matrix thickens still more, and the
five carunculas are swelled nearly to the shape and size of a nurse's
nipple; by opening them, an infinity of small white specks are found.
Harvey pretends to have remarked, that there was neither then, nor
immediately after copulation, any alteration or change in the ovarium,
and that he has never been able to find a single drop of the seed of
the male in the matrix, although he has made many researches for that
purpose.
Towards the end of October, or beginning of November, when the
females separate from the males, the thickness of the horns begins
to diminish, the internal surfaces of their cavities are swelled,
and appear fastened together; the carunculas remain, and the whole,
which resembles the substance of the brain, is so soft that it cannot
be touched. Towards the 13th or 14th of November, Harvey says, that
he perceived filaments, like the threads of a spider's web, which
traversed the cavities of the horns and the matrix itself: these
filaments shoot out from the superior angle of the matrix, and by
their multiplication form a kind of membrane, or empty tunic; a day
or two after this tunic is filled with a white, aqueous and glutinous
matter, which adheres to the matrix by a kind of mucilage; and in the
third month this tunic, or pouch, contains an embryo about the breadth
of two fingers long, and another internal pouch, called the amnios,
containing a transparent crystalline liquor, in which the foetus
swims. The foetus at first was but an animated speck, like that in
the egg of a fowl. All the rest is performed in the same manner as that
related of the chick; the only difference is in the eyes, which appears
much sooner in the fowl than in the deer. The animated speck appears
about the 19th or 20th of November, a day or two after which the oblong
body, which contains the foetus, is seen; in six or seven days more
it is so much formed that the sex and limbs may be distinguished; but
the heart and viscera are yet uncovered, and it is two days more before
the thorax and the abdomen cover them, which is the last work and
completion of the edifice.
From these observations upon hens and deer, Harvey concludes, that
all female animals have eggs, that in these eggs a separation of a
transparent crystalline liquor contained in the amnios is made, and
that another external pouch, the chorion, contains the whole liquors of
the egg; that the first thing which appears in the crystalline liquor
is the sanguinary and animated spirit; in a word, that the formation of
viviparous animals is made after the same manner as oviparous; and he
explains the generation of both as follows.
Generation is the work of the matrix, in which no seed of the male
ever enters; the matrix conceives by a kind of contagion, which the
male liquor communicates to it, nearly as the magnet communicates
its magnetic virtue to steel. This male contagion not only acts upon
the matrix but over all the female body, which is wholly fecundated,
although the matrix only has the faculty of conception, as the brain
has the sole faculty of conceiving ideas. The ideas conceived by the
brain, are like the images of the objects transmitted by the senses;
and the foetus, which may be considered as the idea of the matrix, is
like that which produces it. This is the reason that a child has a
resemblance to its father, &c.
I shall not follow this anatomist any farther; what I have mentioned
is sufficient to judge of his system; but we have some remarks to make
on his observations. He has given them in a manner most likely to
impose; seems to have often repeated his experiments, and to have taken
every necessary precaution to avoid deception; from which it might
be imagined he had seen all he writes upon, and observed them with
the greatest accuracy. Nevertheless, I perceive both uncertainty and
obscurity in his descriptions; his observations are related chiefly on
memory; and although he often says the contrary, Aristotle appears to
have been his guide more than experience; for he has only seen in eggs
what Aristotle has before mentioned; and that most of his observations
which may be deemed essential had been made before him, we shall be
perfectly convinced if we pay a little attention to what follows:
Aristotle knew that the ligaments (Chalazæ) were of no service to the
generation of the chicken. "Quæ ad principium lutei grandines hærent,
nil conferunt ad generationem, ut quidam suspicantur."[E] Parisanus,
Volcher, Coiter, Aquapendente, and others, remarked the cicatrice as
well as Harvey: Aquapendente supposed it of no use; but Parisanus
pretended that it was formed by the male semen, or at least that the
white speck in the middle of the cicatrice was the seed of the male
which would produce the chicken. "Est-que, says he, illud galli semen
alba & tenuissima tunica abductum, quod substat duabus communibus
toti ovo membranis, &c." Therefore the only discovery which properly
belongs to Harvey is, his having observed that this cicatrice is found
in infecund as well as fecundated eggs; for others had observed, like
him, the dilation of the circles, and the growth of the white speck;
and it appears that Parisanus had seen it much better; this is all
which he remarks in the two first days of incubation; and what he says
of the third day, is only a repetition of Aristotle's words. [F]"Per id
tempus ascendit jam vetellus ad superiorem partem ovi acutiorem, ubi
& principium ovi est & foetus excluditur; corque ipsum apparet, in
albumine sanguinei puncti, quod punctum salit & movet sese instar quasi
animatum; ab eo meatus venarum specie duo, sanguinei pleni, flexuosi,
qui, crescente foetu, feruntur in utramque tunicam ambientem, ac
membrana sanguineas fibras habens eo tempore albumen continet sub
meatibus illis venarum similibus; ac paulo post discernitur corpus
pufillum initio, ommino & candidum, capite conspicuo, atque in eo
oculis maxime turgidis qui diu sic permanent, sero enim parvi fiunt ac
considunt. In parte autem corporis inferiore, nullum extat membrum per
initia, quod respondeat superioribus. Meatus autum illi qui a corde
prodeunt, alter ad circumdantem, membranam tendit, alter ad luteum,
officio umbilici."
[E] Hist. Anim. lib. vi. cap. 2.
[F] Hist. Anim. lib. vi. cap. 4.
Harvey attacks Aristotle for saying that the yolk ascends towards the
small end of the egg, and concludes, that he had not seen any thing
himself, but had apparently received his information from some good
observer of Nature. Harvey was wrong in thus reproaching Aristotle, and
in asserting that the yolk always ascends towards the broad end of the
egg, for that depends on the position of the egg during the time of
incubation, for the yolk always ascends to the uppermost part, as being
lighter than the white, whether it be to the broad or the small end.
William Langley, a physician at Dordrecht, who made observations on the
hatching of eggs, in 1655, twenty years before Harvey, was the first
who made this remark.[G]
[G] See Wm. Langley Observ. edæ a justo Schradero, Amst. 1674.
But to return to the passage we have quoted. By that we see that the
crystalline liquor, the animated speck, the two circles, the two
blood vessels, &c. are described by Aristotle precisely as Harvey
had seen them. This anatomist also pretends that the animated speck
is the heart, that this heart is formed the first, and that the
viscera and other parts are joined afterwards. All this has been
spoken of by Aristotle, and seen by Harvey, and nevertheless it is
not conformable to truth. To be assured of this we need only repeat
the same experiments on eggs, or only read with attention those of
Malpighius,[H] which were made about 40 years after those of Harvey.
[H] Malpighii pullus in ovo.
This excellent observer of Nature examined, with attention, the
cicatrice, which is the essential part of the egg; he found it was
large in all impregnated eggs, and small in those which were not
impregnated; and he discovered in eggs which had never been sat upon,
that the white speck, spoken of by Harvey as the first which becomes
animated, is a small pouch or ball, which swims in a liquor inclosed
by the first circle, and in the middle of this ball he observed the
embryo. The membrane of this small pouch, which is the amnios, being
very thin and transparent, permitted him easily to see the foetus
it surrounded. Malpighius, with reason, concludes, from this first
observation, that the foetus exists in the egg before incubation, and
that its first outlines are then very strong. It is not necessary to
point out how opposite this experiment is to the opinion of Harvey,
for he saw nothing of a form for the two first days of incubation, and
it was the third day before the sign of the foetus appears, which is
the animated speck: whereas according to Malpighius, the outlines of
the foetus exist in the egg before incubation has commenced.
After being assured of this important matter, Malpighius examined, with
like attention, the cicatrice of unimpregnated eggs, which, as we have
observed, is smaller than those which have been impregnated; it has
often irregular circumscriptions, and sometimes differs in different
eggs. Near its centre, instead of the ball that encloses the foetus,
there is a globular mole, which does not contain any thing organized,
and which being opened does not present any thing formed or arranged,
but only some appendages filled with a thick but transparent fluid; and
this unshapen mass is surrounded with many concentric circles.
After six hours incubation the cicatrice is considerably dilated,
and the ball formed by the amnios is easily discovered; this ball is
filled with a liquor, in the middle of which the head of the chicken
and back-bone are distinctly seen. In about six hours more the little
animal is seen more distinctly; in another six hours the head is
grown larger, and the spine lengthened; and at the end of twenty-four
hours the neck begins to lengthen, the vertebræ of the back appears
of a white colour, and the head to turn to one side. The vertebræ are
disposed on each side of the spine, like small globules; and almost
at the same time the small wings begin to shoot, and the head, neck,
and breast are lengthened. After thirty hours nothing new appears,
but every part of the little animal is considerably increased,
especially the _amnios_. Around this membrane the umbilical vessels
are seen of a darkish colour. At the end of thirty-eight hours, the
chicken being grown much larger, its head is large, and in which
are distinguished three vessels surrounded with membranes, which
also cover the back bone, through which the vertebræ are still seen.
In forty hours, continues Malpighius, it was wonderful to see the
chicken alive, floating in the liquor; the back bone was increased,
the head was turned on one side, the vesicles of the brain were less
apparent, the first outlines of the eyes appeared, the heart beat, and
the circulation of the blood was begun. Malpighius then gives the
description of the vessels and course of the blood, and reasonably
supposes that, though the heart does not beat before thirty-eight or
forty hours incubation, it still existed before that time, like the
other parts of the chicken; but on examining the heart in a dark room,
he discovered not the least glimpse of light to proceed from it, as
Harvey insinuates.
At the end of two days the chicken is seen floating in the liquor of
the amnios; in which the head, composed of vesicles, is turned on one
side; the back bone and vertebræ are lengthened; the heart, which then
hung out of the breast, beat three times; for the fluid it contains
is impelled into the ventricles of the heart, from thence into the
arteries, and afterwards into the umbilical vessels. He remarks, that
having separated the chick from the white of the egg, the motion of
the heart still continued for a whole day. After two days and fourteen
hours, or sixty-two hours of incubation, the chicken, although grown
stronger, remained with its head bent downwards in the liquor,
contained by the amnios; the veins and arteries were seen among the
vessels of the brain; the lineaments of the eyes, and the spinal
marrow, also appear extending the length of the vertebræ.
At the end of the third day the head of the chicken appeared crooked;
besides the eyes five vessels were seen in the head filled with a
liquid matter; the first outlines of the wings and thighs were to be
distinguished, and the body began to gather flesh; the pupil of the
eye, and also the crystalline and vitreous humour were discernible. At
the fourth day the vesicles of the brain were nearer each other; the
eminences of the vertebræ were more prominent, the wings and thighs
assumed a greater solidity as they increased in length; the whole body,
covered with a jelly-like flesh, was now surrounded within the body by
a thin membrane, and the umbilical vessels that unite the animal to
the yolk, appeared to come from the abdomen. On the fifth and sixth
days the vesicles of the brain began to be covered; the spinal marrow,
divided into two parts, began to take solidity and stretch along the
trunk; the wings and thighs lengthened; the feet began to spread; the
belly was closed up and tumid; the liver was distinctly seen, and
appeared of a dusky white; the ventricles of the heart were discerned
to beat very distinctly; the body of the chicken was covered with a
skin, and the traces of the feathers were visible; the seventh day
the head appeared very large, the brain was entirely covered with its
membranes; the beak began to appear betwixt the eyes, and the wings,
the thighs, and the legs had acquired their perfect figure.
I shall not follow Malpighius any farther, as the remainder relates
only to the expansion of the parts till the twenty-first day, when the
chicken breaks the shell with its beak; though before that time it is
heard to chirrup in its imprisonment. The heart is the last part which
receives its proper form, for it is eleven days before the arteries
are seen to join, and the ventricles become perfectly conformable and
united.
We are now in a condition to judge of the value of Harvey's experiments
and observations. There is great appearance this anatomist did not
make use of a microscope, which in fact was not brought to perfection
in his days, or he would not have asserted there was no difference
between the cicatrice of an impregnated and an unimpregnated egg; he
would not have said the seed of the male produced no alteration in
the egg, especially in the cicatrice; he would not have affirmed that
nothing was perceptible till the third day, that the animated speck was
the first that appeared, and into which the white speck was changed.
He would have seen that the white speck was a ball which contained the
whole apparatus of generation, and that every part of the foetus are
there from the moment the hen has connection with the cock. He would
also have learnt, that without this connection it contains only an
unshapen mass, which could never become animated, because in fact it is
not organized like an animal, and because it is only when this mass,
which we must look upon as an assemblage of the organic particles of
the female semen, is penetrated by the organic particles of the male
semen, that there results from it an animal, which is formed at the
moment, but whose motion is imperceptible till the end of forty hours
after: he would not have asserted that the heart is first formed, and
that the other parts are joined to it by a juxta-position, since it
is evident from Malpighius's observations, that the outlines of every
part are all immediately formed, but only appear in proportion as they
dilate; on the whole, if he had seen what Malpighius saw, he would not
have affirmed that no impression of the male seed remained in the eggs,
and that it was only by contagion that they are fecundated, &c.
It is also just to remark, that what Harvey has said on the parts of
the generation of a cock is not exact; he asserts that the cock has no
genital member, and that there is no intromission; nevertheless it is
certain that this animal, instead of one has two, and that they both
act at the same time, and which action is a very strong compression, if
not a true copulation;[I] and it is by this double organ that the cock
emits the seminal liquor into the matrix of the hen.
[I] See Reyn. Graaf, page 242.
Let us now compare the experiments made by Harvey on hinds with those
of De Graaf on doe rabbits; we shall find that although De Graaf
supposes, with Harvey, that all animals proceed from eggs, yet there is
a great difference in the mode which these two anatomists have observed
in the first steps of formation, or rather expansion, of the foetuses
of viviparous animals.
After having exerted every effort to establish, by reasons drawn from
comparative anatomy, that the testicles of viviparous females are real
ovaries, De Graaf explains how the eggs are loosened from the ovaries
and fall into the horns of the matrix; he then relates what he observed
in a rabbit, which he dissected half an hour after copulation. The
horns of the matrix, he says, were more red than before, but no other
change in the rest of the parts: there was also no appearance of any
male seed, neither in the vagina, matrix, nor horns of the matrix.
Having dissected another six hours after copulation he observed the
follicules, or coats, which he supposes contained the eggs in the
ovary, ware become red, but found no male seed either in the ovaria or
elsewhere. He dissected another twenty-four hours after copulation,
and remarked in one ovarium three, and in the other five follicules
that were changed, the transparency being become dark and red. In one
dissected twenty-seven hours after copulation he perceived the horns
of the womb had become more red and strictly embraced the ovaries. In
another, that he opened forty hours after copulation, he found in one
of the ovaries seven, follicules, and in the other three that were
changed. Fifty-two hours after copulation he examined another and
found one follicle changed in one of the ovaries and four in another,
and having opened these follicules he found a glandular liquor, in the
middle of which there was a small cavity, where he did not perceive
any liquor, which made him suppose that the transparent liquor,
commonly contained in the follicules, and which, he says, is enclosed
in its own membranes, might have been separated by a kind of rupture:
he searched after this matter in the passages, and in the horns of
the matrix themselves, but he found none; he only perceived that the
internal membrane of the horns of the matrix was very much swelled. In
another, dissected three days after copulation, he observed that the
superior extremity of the passage, which communicates with the horns
of the matrix, strictly embraced the ovaries; and having separated it
he perceived three follicules, longer and harder than usual. After
searching with the greatest attention the passages above-mentioned he
found in the right passage one egg, and in the right horn of the matrix
two more, not bigger than a grain of mustard-seed: those little eggs
were each closed in double membranes, and the inner one was filled
with a very limpid liquor. Having examined the other ovarium he found
four follicules that were changed, three of which were white and had a
little liquor within them; but the fourth was of a darker colour, and
contained no liquor, which made him judge that from this the egg had
been separated. Pursuing his enquiries he found an egg in the superior
extremity of the other horn, and exactly like those he had discovered
in the right one. He says that the eggs which are separated from the
ovary are ten times smaller than those which are fastened to it; and
he thinks that this difference is occasioned from the eggs containing,
when they are in the ovaries, another matter, and that is the glandular
liquor he remarked in the molecules.
Four days after copulation he opened another, and found in one of the
ovaries four, and in the other three follicules, emptied of their eggs;
and in the horns corresponding to these he found an equal number of
eggs. These eggs were larger than the first that he found three days
after copulation, and were about the size of a small bird-shot; he also
remarked that the internal membrane in these eggs was separated from
the external, and appeared like a second egg in the first. In another,
dissected five days after copulation, he found five empty follicules
in the ovaries, and as many eggs in the matrix, to which they adhered.
These eggs were about the size of duck-shot, and the internal membrane
was more apparent than in the one he had observed before. In one which
he opened six days after copulation there were six empty follicules
in one ovaria, and only five eggs in the corresponding horn, and they
appeared in one mass; in the other ovaria were four empty follicules
and but one egg; these eggs were as big as swan-shot. He opened another
on the seventh day after copulation, and found seven empty follicules;
he also perceived several internal tumours in the matrix, from whence
he took eggs the size of a pistol-bullet. Its membrane was more
distinct than before, but contained only a very clear liquor. In one,
eight days after copulation, he found in the matrix tumours, or cells,
which contained the eggs, but they were very adherent, for he could not
loosen them. In another, nine days after copulation, the cells, which
contained the eggs, were greatly increased, and he saw that the liquor
inclosed by the internal membrane had now got a light cloud floating
upon it. He opened another ten days after copulation and the cloud was
thicker, and formed an oblong body, like a little worm. At last, on the
twelfth day after copulation, the figure of the embryo was distinctly
to be perceived, which two days before only presented the figure of an
oblong body; it was even so apparent that the different members might
be distinguished. In the region of the breast he perceived two red and
two white specks, and in the abdomen a mucilaginous substance, somewhat
reddish. Fourteen days after copulation the head of the embryo was
become large and transparent, the eyes prominent, the mouth open, the
rudiments of the ears appeared; the back-bone, of a whitish colour,
was bent towards the breast, and small blood-vessels came from each
side, whose ramifications ran along the back as far as the feet; the
two red specks, being considerably increased, appeared to be no other
than the ventricles of the heart; by the sides of these red specks
were two white ones, which were the rudiments of the lungs. In the
abdomen the outlines of the liver were seen of a reddish colour, and a
little intricate mass, like a ravelled thread, which was the stomach
and intestines. After this the process was no more than a growth and
expansion of every part till the thirty-first day, when the female
rabbit brings forth her young.
From these experiments De Graaf concludes, that all viviparous
females have eggs; that these eggs are contained in the testicles,
called ovaries; that they cannot disengage themselves till they are
impregnated, because, he says, the glandular substance, by means of
which the eggs quit their follicules, is not produced till after an
impregnation. He also insists, that those who suppose they have seen
eggs in only two or three days increased in size, must have been
mistaken, for these eggs remain a longer time in the ovary, although
fecundated, and instead of immediately increasing, they rather diminish
until they are descended from the ovaries into the matrix.
By comparing these observations with those of Harvey, we shall easily
perceive that the principal circumstances have escaped the latter;
and although there are many errors in the reasoning and experiments
of De Graaf, nevertheless this anatomist, as well as Malpighius, has
made better observations than Harvey. They agree in the principal
points, and are both contrary to Harvey; the latter had never seen
the alterations which happen to the ovary; he did not see the small
globules in the matrix which contain the apparatus of generation, and
which De Graaf calls _eggs_. He had not even a supposition that the
foetus existed in this egg; and though his experiments gave us nearly
an exact account of what occurs during the growth of the foetus,
they give us no information either of the moment of fecundation or of
the first development. Schrader, a Dutch physician, who held Harvey
in great veneration, owns that we must not put too great a reliance
in that anatomist in many things, and especially on what he says of
the fecundative moment, for the chicken in fact is in the egg before
incubation, and that Joseph de Aromatarius was the first who observed
it.[J] Although Harvey pretended that every animal proceeds from an
egg, he did not imagine that the testicles of females contained these
eggs, and has only repeated what Aristotle has said on this subject.
The first who speaks of having discovered eggs in female ovaries is
Steno, who says, in dissecting a female sea-dog he saw eggs in the
testicles, although that animal is viviparous; and he adds, that the
testicles of women are analogous to the ovaries of oviparous animals,
whether the eggs fall in any manner into the matrix, or whether there
only falls the matter they contain. Although Steno is the first who
discovered these pretended eggs, De Graaf claims the merit to himself,
and Swammerdam has disputed it with him, insisting that Van Horn had
perceived these eggs before De Graaf. It is true this last writer
stands charged with asserting many things experience has found to be
false. He pretended that a judgment might be formed of the number of
foetuses contained in the matrix by the number of cicatrices, or
empty follicules, in the ovary, which is not true, as we may see by the
observations of Verrheyen,[K] and by those of M. Mery,[L] and by some
of De Graaf's own observations, where he found fewer eggs in the matrix
than cicatrices in the ovaries. Besides, we shall make it appear that
what he says concerning the separation of the eggs, and the manner in
which they descend into the matrix, is not exact; that no eggs exist in
the female testicles; that what is seen in the matrix is not an egg;
and that nothing can be worse founded than the systems endeavoured to
be established on the observations of this famous anatomist.
[J] See Observ. Justi Schraderi, Amst. 1674.
[K] Vol. I. chap. iii. Brussels edit. 1710.
[L] Hist. of the Academ. 1704.
This pretended discovery of eggs in the testicles of females attracted
the attention of most anatomists; they, however, only met with small
bladders in the testicles of female viviparous animals, these they did
not hesitate to look on as real eggs: they therefore gave the name
of _ovaries_ to the testicles, and called the vesicles eggs, They
also said, with De Graaf, that there are eggs of different sizes in
the ovarium; that the largest in the ovarium of women was not above
the size of a small pea; that they were very small in the young,
but increased with age and intercourse with men; that twenty might
be counted in each ovarium; that these eggs are fecundated in the
ovarium by the spirited part of the seminal liquor of the male; that
afterwards they loosen and fall into the matrix, where the foetus is
formed, from the internal substance of the egg and the placenta of the
external matter; that the glandular substance, which does not exist
in the ovarium till after a fruitful copulation, serves to compress
the egg, and make it quit the ovarium, &c. But Malpighius having
examined things more minutely, detected many of their errors before
they were even received; yet most physicians adopted the sentiments
of De Graaf, without any attention to the observations of Malpighius;
which, notwithstanding, are very important, and to which his scholar
Valisnieri has given a great deal of weight.
Malpighius and Valisnieri, of all naturalists, speak with the greatest
foundation on the subject of generation. We shall therefore give an
account of their experiments and remarks, to which we cannot pay too
much attention.
Malpighius having examined a great number of the testicles of cows
and other female animals, affirms that he found vesicles of different
sizes in the testicles of all of them, whether young or adults; these
vesicles are inclosed by a thick membrane, in the inner parts of which
there are blood-vessels, filled with a kind of lymph, or liquor, which
hardens by the heat of the fire like the white of an egg.
In time a firm yellow body grows which adheres to the testicles. It
is prominent and increases to the size of a cherry, occupying the
greatest part of the ovarium. The body is composed of many little
angular tubes, and its position is irregular; it is covered with a
coat, or membrane, spread over with nerves and blood-vessels. The
appearance and form of this yellow body are not always the same, but
vary according to time. When not above the size of a millet seed,
it is nearly globular, and if divided appears composed of a kind of
variegated net-work. Very often an external covering is observed,
composed of the same substance as the yellow body, around the vesicles
of the ovarium.
When the yellow body is become nearly of the size of a pea, it is the
shape of a pear, in which is a small cavity filled with liquor; as is
also the case when grown to the size of a cherry. In some of these
yellow substances, when increased to their full maturity, Malpighius
says, a small egg, with its appendages, not bigger than a millet
seed, may be seen near the centre; when they have cast out their eggs
they are empty, resemble a cavernous passage, and the cavities which
inclose them are about the size of peas. He thinks this yellow and
glandular substance nature produces to preserve the egg, and assist
it in leaving the testicles, and perhaps to contribute towards the
generation of the egg itself; consequently, he says, the vesicles,
which are always observed in the ovary, and which are of different
sizes, are not real eggs that may be fecundated, but only serve for the
production of the yellow body where the egg is to be formed. On the
whole, although these yellow substances are not found at all times in
all testicles, we nevertheless always find the first traces of them,
and Malpighius having seen the marks of them in young heifers, cows
that were with calf, and in pregnant women, he reasonably concludes
that this yellow and glandular substance is not, as De Graaf has
supposed, the effect of fecundation, but what produces the infecund
eggs, which leave the ovary without any communication with the male, as
well as to those which leave it after communication. When the latter
falls into the tubes of the matrix, all the rest is performed as De
Graaf has described.
These observations of Malpighius shew that the testicles of females
are not real ovaries, as most anatomists believe; that the vesicles
they contain are not eggs; that these vesicles never fall into the
matrix; and that the testicles, like those of the male, are kinds
of reservoirs, containing a liquor which must be looked upon as an
imperfect seed of the female, that is perfected in the yellow glandular
body which fills the internal cavity, and is shed when the glandular
substance has acquired its full maturity. But before we decide on this
important point, we must relate the observations of Valisnieri; and we
shall perceive that, though Malpighius and Valisnieri have made good
observations, they have not carried them far enough, nor drawn those
consequences from them which their observations might naturally have
produced, because they were both prejudiced for the system of eggs, and
of the foetus pre-existing therein.
Valisnieri began his experiments in 1692, on the testicles of a sow,
whose testicles are not composed like those of a cow, sheep, mare,
bitch, female ass, she goat, nor most other viviparous females, for
they resemble a small bunch of grapes, whose seeds are round and
prominent outwardly. Between these seeds there are smaller, which have
not arrived to maturity. These seeds do not appear to be surrounded
with one common membrane; they are, he says, similar to those yellow
substances which Malpighius observed in cows; they are round, of a
reddish colour, their surface sprinkled over with sanguinary vessels
like the eggs of viviparous animals, and together form a mass larger
than the ovary; we may, with a little address, and by dividing the
membrane, separate these grains one by one, and draw them from the
ovary, where they each leave an impression.
These glandular substances are not of the same colour in every sow, in
some they are red, in others more clear; and they are of all sizes,
from the most minute point to that of a grape. On opening them we find
a triangular cavity filled with a limpid liquor, which coagulates
by the fire, and becomes white like that contained in the vesicles.
Valisnieri hoped to meet with the egg in one of those cavities, but
although he sought for it with the utmost assiduity in the glandular
substance of the ovaries of four different sows, and afterwards in
those of other animals, yet he could never discover the egg which
Malpighius asserts to have met with once or twice.
Below these glandular substances the vesicles of the ovary were
seen, and which were in a greater or lesser number as the glandular
substances are thicker or smaller, for in proportion as the glandular
substances increase, the vesicles diminish. Some of these vesicles were
the size of a lentil, and others as small as a millet-seed. In crude
testicles twenty, thirty, or thirty-five vesicles might be counted,
but when boiled a greater number are seen; and they are so strongly
connected by fibres and membraneous vessels, that it is impossible to
separate them without a rupture.
Having examined the testicles of a sow which never had littered, he
found there, as in the rest, glandular bodies, and their triangular
cavities filled with lymph, but never met with the egg either in the
one or the other. The vesicles of this sow which had never littered
were greater in number than in those which had littered or conceived.
In the testicles of another sow which had conceived, and whose young
were much expanded, he found two large glandular substances, that
were empty, and others smaller, in their common state. Having also
dissected many others when with young, he found that the number of
glandular substances was always greater than that of the foetus,
which confirms our observations on De Graaf's experiments, and proves
they are not exact; what he terms the follicules of the ovary being
only the glandular substances, whose number always exceed that of the
foetus. In the ovaries of a sow but a few months old, the testicles
were large, and sprinkled with vesicles pretty well tumefied: between
these vesicles there were four rising glandular substances in one of
the testicles, and more in the other.
After having finished his experiments on sows, Valisnieri repeated
those of Malpighius on the testicles of cows, and found that all he had
said was conformable to truth; only Valisnieri owns that he has never
been able to find the egg which Malpighius thought he had seen once or
twice in the internal cavity of glandular bodies. Valisnieri proceeded
in his experiments upon a variety of other animals to discover this
egg, but in vain; nevertheless his prejudice for that system induced
him, contrary to his experience, to admit the existence of eggs, which
neither he nor any other man ever did or ever will see. It is scarcely
possible to make a greater number of experiments, or better than he has
done. He observes, as something particular to a ewe, that there are
never more glandular substances in the testicles than foetuses in
the matrix. In young ewes, which have never been with the male, there
is but one glandular substance in each testicle, which when worn away,
another is found; and if a ewe has only one foetus in her matrix,
there is but one glandular substance in the testicles; if there are
two foetuses there will be two glandular substances. This substance
occupies the greatest part of the testicles; after it disappears
another is formed for the purpose of another generation.
In the testicles of a she-ass he perceived vesicles the size of small
cherries, which evidently prove they are not eggs, since, being of that
size, they could not enter into the horns of the matrix, which are too
narrow in this animal for their reception.
The testicles of a female dog, wolf, or fox, have a kind of cowl, or
covering, which is produced by the expansion of the membrane that
surrounds the horns of the matrix. In a bitch, whose heat was just
began, and had not been brought to a dog, Valisnieri found this cowl,
which is not adherent to the testicle, internally bathed with a
liquor like whey: he discovered also two glandular substances in the
right testicle, which run almost its whole length. These glandular
substances had each a small nipple, with a little orifice, from which
of itself issued a clear liquor like whey, and when pressed, a greater
quantity came out, which made him imagine, that this liquor was the
same as that found within the cowl: he blew into this orifice, by the
means of a small pipe, and immediately the glandular body was puffed
up; and having introduced a bristle, he easily penetrated to the end of
it: he opened this glandular substance the same way as the bristle was
entered, and found within a cavity which communicated with the orifice,
and which also contained a good deal of liquor. Valisnieri was also
in hopes to discover the egg, but, notwithstanding all his endeavours
and strict attention, he never could perceive it. He remarked, that
the extremity of these nipples, from which this liquor flowed, was
contracted by a sphincter, which served to shut up, or open the orifice
of the nipple: he found also in the left testicle two glandular bodies
with the like cavities, nipples, orifices, and liquor distilling from
them. Still not being able to find the egg, neither in this liquor,
nor in the cavity which contained it, he boiled two of these glandular
substances, hoping that by this means he might discover the object he
was in pursuit of, but it was all in vain.
Having opened another bitch, eight or nine days after she had been with
the male, he found no difference in the testicles; there were three
glandular substances like the preceding ones, and, like them, distilled
a liquor from the nipples. Here he also persevered in his fruitless
researches after the egg. By the help of a microscope, he perceived the
glandular substances were a kind of vascular net-work, formed by an
infinite number of small globular vesicles which served to filtre the
liquor that issues through the end of the nipple.
After this he opened another bitch whose heat was off, and having
introduced air between the testicle and its covering, he found it
dilated like a bladder by means of inflation; having raised this cowl,
he found three glandular substances on the testicle, but they had no
apparent nipple, nor orifice, nor did any liquor distil from them.
In another bitch that had pupped two months, and had five puppies, he
found five glandular substances, which were become very small, and
began to obliterate, without leaving any cicatrices: there still
remained a small cavity in the middle, but it was dry and empty.
Not content with these, and many more experiments, Valisnieri, who
would not give up his researches after the pretended egg, called
together the most expert anatomists of his country, among whom was M.
Morgagni, and having opened a young bitch at the time of her first
heat, and had been with a male three days before, they examined
the vesicles of the testicles, the glandular substances with their
nipples, orifice, and liquor which flowed from them, and in their
internal cavities, but not an egg was to be found. After this he made
experiments on female goats, foxes, cats, and a great number of mice,
&c. He always found vesicles in the testicles of all those animals,
and often the glandular substances, and the liquor they contained, but
never any egg.
At length, desirous of examining the testicles of a woman, he had an
opportunity of opening a farmer's wife, a young woman that was killed
by a fall from a tree. She had been married several years, but although
of a good habit of body, yet she had never borne a child. He sought if
the cause of her sterility was not discoverable in the testicles; and
he found the vesicles all replete with a blackish and corrupted matter.
In the testicles of a girl of eighteen, who had been brought up in a
convent, and, according to all appearances, was a virgin, he found
the right testicle somewhat larger than the left: its shape was oval,
and its surface a little unequal. This inequality was produced by the
protuberance of five or six vesicles of this testicle which advanced
forwards; one of which was more prominent than any of the rest. Having
opened this vesicle, a spirit of lymph issued out: around it there
was a glandular substance in form of a crescent of a yellowish colour
rather bordering on the red. He cut the remainder part of the testicle
transversely, and found many vesicles filled with a limpid liquor, and
remarked that the corresponding trunk to this testicle was very red and
a little longer than the other, as he had frequently observed in female
animals, when in their amorous season.
The left testicle was as round as the right, it was whiter, and its
surface more smooth; for although there were some vesicles a little
prominent, yet there were not any in form of a nipple; they were all
alike, without any glandular substance, and the corresponding trunk
was neither inflamed nor red.
In a little girl of five years old, he found the testicles with the
vesicles, blood vessels, fibres and nerves complete.
In the testicles of a woman sixty years of age, he found some vesicles,
and the vestiges of a glandular substance, which were as so many thick
points of matter of a dark brownish colour.
From all these observations Valisnieri concludes, that the business
of generation is carried on in the female testicles, which he looked
upon as ovaries, although he never found any eggs in them, but on the
contrary, evidently saw that the vesicles were not eggs. He also says,
that it is not necessary for the seed of the male to enter into the
matrix to impregnate the egg: he supposes that the egg comes from the
nipple of the glandular substance, after impregnation in the ovarium;
that from thence it falls into the trunk, and descends by degrees, till
at last it fastens to the matrix. He adds, he is persuaded that the
egg is concealed in the glandular substance, and that all the business
of generation is performed in the cavity, although neither he nor any
other anatomist, have ever seen or been able to find it.
According to Valisnieri the spirit of the male seed ascends to the
ovarium, forces its way into the egg, and gives motion to the foetus
that pre-exists therein. In the ovarium of the first woman were eggs,
which not only inclosed in miniature every child she brought forth,
but of the whole human race. That if we cannot conceive this infinite
chain of individuals contained in one, it is the fault of our minds,
the weakness of which is every day perceptible; but it is, upon that
account, no less true, that every animal which has been, is, and will
be, were created all at one time, and inclosed in the first females.
The resemblance of children to parents only proceeds, continues he,
from the imagination of the mother, the power of which is so great on
the foetus that it can produce on it spots, marks, disproportions,
and extraordinary births, as well as perfect resemblances.
This system of the eggs, which is unreasonable, and without foundation,
would, nevertheless, have obtained the unanimous suffrages of all
physicians, if, when it was first endeavoured to be established,
another system had not been formed on the discovery of spermatic
animals.
This discovery, for which we are indebted to Leeuwenhoeck and
Hartsoeker, has been confirmed by Andri, Valisnieri, Bourguet, and
many other observers of Nature. I shall relate what has been said
concerning the spermatic animals which are found in the seminal liquor
of all males: they are in such vast numbers that the semen seems to be
entirely composed of them; and Leeuwenhoeck pretends to have seen many
millions of them in a drop smaller than the smallest grain of sand.
Although we do not meet with any in female animals they abound in all
males, both in the semen emitted naturally and that in the testicles,
as well as in the seminal vesicles. If the semen of a man is exposed
to a moderate heat it thickens, and the motions of all the animalcules
immediately cease, but if allowed to cool it becomes thinner, and the
animals preserve their motion till the liquor thickens as it dries
away. The thinner the liquor becomes the more the animalcule increase,
and if water is added it will appear like a substance of small animals.
When the motion of these animalcule is nearly finished, whether from
heat, or any other cause, they seem to assemble closer together, and
have a whirling motion in the centre of a small drop which may have
been taken out for observation, and appear all to perish at one and the
same time, whereas in the larger portion of the liquor they are easily
seen to perish successively.
The animalculæ, say they, have different figures in different animals;
nevertheless they are all long, slender, without any appearance of
limbs, and move with rapidity. The fluid which contains them, as we
have already observed, is heavier than blood. The semen of a bull
afforded Verrheyen, by a chemical process, first phlegm, afterwards a
considerable quantity of foetid oil, but little volatile salt, and
much more earth than he could have thought.[M] This author appears
surprised that in rectifying the distilled liquor he could not draw any
spirit from it, and being persuaded it contained a great quantity, he
attributed the evaporation to its great subtility: but may it not be
more reasonably imagined that it contains very little or no spirits,
as neither its consistency nor smell announce any ardent spirit, and
which is only plentifully found in fermented liquors? besides, with
respect to volatile spirits, the horns, bones, and other solid parts
of animals, afford more than all the liquor of the animal body. What
anatomists have called animal spirits, _aura seminalis_, may possibly
not exist; and it is certainly not these spirits which agitate the
particles seen moving in the seminal liquors; but we will here relate
the principal observations that have been made on this subject.
[M] See Veerheyen, sup. anat. tom. ii. page 69.
Leeuwenhoeck observed, in the semen of a cock, animals which resemble
the figure of an eel, but so exceedingly minute, that he pretends fifty
thousand would not equal in size a grain of sand; and in that of a
rat many millions would be required to make the thickness of a hair,
&c. This observer imagined that the whole substance of the semen was
only a mass of these animalcules. He perceived these animalculæ in
the semen of men, quadrupeds, birds, fishes, insects, &c. In that of
grasshoppers they were long and slender. They are attached, he says, by
their extremities, and the inferior of which he calls the tail, had a
quick motion, like that of the tail of a serpent, when the upper part
is motionless. He further adds, that in the semen of young animals the
animalculæ are motionless, but as the age for reproduction comes on
they move about with great vivacity.
In the semen of a male frog he observed animalculæ, at first they
were imperfect and motionless, but some time afterwards he found them
living: they were so very small, he says, that ten thousand would
scarcely equal the size of a single egg of the female. It was only
those in the seminal liquor of the frog which had life and motion.
In the semen of a man, and that of a dog, he pretends to have seen two
kinds, which he looked upon as males and females. Having inclosed the
seed of a dog in a vial, he says, that numbers of the animalculæ died
the first day; the second and third there died still more, and very
few remained alive the fourth. But having repeated this experiment
on the semen of the same dog, he found, at the end of seven days,
live animalculæ, some of which swam with as much swiftness as in
fresh-extracted semen; and having opened a bitch which had been three
times with the same dog, he could not perceive by the naked eye any
seminal liquor of the male in either of the horns of the matrix; but
by help of a microscope he discovered the spermatic animals of the
dog in both horns of the matrix, and great numbers of them in that
part of the matrix adjoining to the vagina, which, says he, evidently
proves that the male semen enters the matrix, or at least that the
spermatic animals of the dog had got there by their own motion, which
is sufficient to carry them four or five inches in half an hour. In the
matrix of a doe rabbit, which had just received the buck, he likewise
observed an infinite number of spermatic animals; he says, that their
bodies are round, with long tails, and that they often change their
forms, especially when the humid matter in which they swim evaporates
and dries.
Leeuwenhoeck's experiments have been frequently repeated and found
conformable to truth. There have been some inclined to exceed him in
these discoveries. Dr. Dalenpatius having observed the seminal liquor
of a man, not only pretended to have discovered animals like tadpoles,
whose bodies appeared nearly the size of a grain of wheat, and their
tails four or five times longer than their bodies, and which moved
with great agility, but, what is still more marvellous, he observed
one of these animals quit its covering; upon which it was no longer an
animalcule, but had become a human body, the two legs of which, he
affirms, were very discernible, as were the arms, breast, and head.[N]
But by the figures which this author has given of this pretended
embryo, it is evident his assertion is false. He might suppose he
saw what he relates, but he was mistaken; for the embryo, such as he
describes, was more formed on quitting this covering, and the state
of a spermatic worm, than it would have been at the end of a month or
five weeks in the matrix of its mother; therefore this observation of
Dalenpatius, instead of having been confirmed by other observations,
has been rejected by every naturalist, the most exact and accurate of
which have only discovered, in the seminal liquor of man, round and
oblong bodies, which seemed to have long tails, but without any kind of
members.
[N] See Nouvelles de la Republique des Lettres, Ann. 1699, page 552.
It might be said that Plato had spoken of these spermatic animals
which become human forms; for he says, "Vulva quoque matrix que in
foeminis eadem ratione animal avidem generandi, quando procul a
foetu per ætatis florem, aut ultra diutius detinetur, ægre fert
moram ac plurimum indignatur, passimque per corpus oberrans, meatus
spiritus intercludit, respirare non finit, extremis vexat angustiis,
morbis denique omnibus premit, quosque atrorumque Cupido amorque quasi
ex arboribus foetum fructumve producunt, ipsum deinde decerpunt, &
in matricem velut agrem inspargunt; hinc animalia primum talia, ut nec
propter parvitatem videantur, necdum appareant formata, concipiunt: mox
quæ conflaverant, explicant, ingentia, intus enutriunt, demum educunt
in lucem, animaliumque generationem perficiunt." Hippocrates, in his
treatise _De Diæta_, seems also to insinuate, that the seed of animals
is replete with animalcules. Democritus speaks of certain worms which
take the human figure, and Aristotle says, that the first men came out
of the earth in the form of worms; but neither the authority of Plato,
Hippocrates, Democritus, Aristotle, nor the observation of Dalenpatius,
can make us receive the idea that these spermatic worms are small human
bodies, concealed under a covering; for it is evidently contrary to
experience and observation.
Valisnieri and Bourguet, whom we have quoted, discovered small worms
in the seed of a rabbit, one of whose extremities was thicker than
the other; they were very lively and active, struck the liquor with
their tails, and twisted and turned themselves like snakes. At last
(says Valisnieri) I clearly perceived them to be real animals, "e gli
riconobbi, e gli giudicai senza dubitamento alcuno per veri, verissimi
arciverissimi vermi[O]." This author, who was prejudiced with the
system of eggs, has, nevertheless, admitted of spermatic worms, and
taken them for real animals.
[O] Opere dell. Cav. Valisnieri, vol. II. page 105.
M. Andry having made observations on these spermatic worms of a man,
pretends that they are only found in the age proper for generation;
that in the younger years, and in old age, they do not exist: that in
those affected with venereal disorders there are very few, and those
are languishing, and for the most part dead: that in impotent persons
we do not see any alive; that these worms in the semen of men have
larger heads than in that of other animals, which agrees, he says, with
the figure of the foetus and the child; and he adds, those people who
too frequently enjoy female amours, have generally but few or none of
these animalcules in their semen.
Leeuwenhoeck, Andry, and many others, strenuously opposed the
egg system; they had discovered in the semen of all males living
animalcules; they proved that these animalcules could not be regarded
merely as dwelling in this liquor, since their bulk was greater than
that of the liquor itself; and that nothing like them was found
either in the blood, or in the other animal liquors. They asserted,
that females furnished nothing similar, nothing alive; and it was
therefore evident that the fecundity attributed to them belonged,
on the contrary, to males alone: and that the discovery of these
spermatic animals in the semen tended more to the explanation of
generation than all that had been before supposed; since, in fact,
what was most difficult to conceive in generation, was the production
of the living part, all the rest being only accessary operations,
and therefore no doubt could remain but these little animals were
destined to become men, or perfect animals of their kind. When it was
opposed to the partizans of this system, that it did not seem natural
to suppose that so many millions of animalcules, every one of which
might become a human being, should be employed for a purpose of which
one alone was to reap the advantage; when it was asked them, why this
useless profusion of the shoots of human beings? they answered, that
it was only consonant with the common munificence of nature: that
out of many millions of seeds which plants and trees produce, but a
very few succeed, and therefore we must not be surprised at the same
circumstance in spermatic animals. When the infinite minuteness of the
spermatic worm, compared to man, was objected to them, they answered,
by the example of the seed of trees; and they added, with some
foundation, metaphysical reasonings, by which they proved that great
and small being only relations, the transition from small to great, or
from great to small, was executed by nature with still more facility
than we can conceive.
Besides, continue they, have we not very frequent examples of
transformation in insects? do we not see small aquatic worms become
winged animals, by only throwing off their coats, which were their
apparent and external forms? and may not spermatic animals, by a
similar transformation, become perfect animals? All therefore, they
conclude, concurs to favour this system of generation, and confuting
that founded on eggs; and if there are eggs in viviparous females,
the same as in the oviparous, these eggs will only be the necessary
matter for the growth of the spermatic worm, which enters into the
egg by the pedicle that adheres to the ovarium, and where it meets
with food ready prepared for it. All the worms which find not this
passage through the pedicle into the egg will perish, and that one
which alone has traced its way will arrive at its transformation. The
difficulty of meeting with the passage in the pedicle of the egg, can
only be compensated by the infinite number of spermatic worms. It is a
million to one that any particular spermatic worm will meet with the
pedicle of the egg, and therefore what at first appears a profusion is
highly necessary. When one has entered, no other can introduce itself,
because, say they, the first worm entirely shuts up the passage, or
there is a valve at the entrance of the pedicle, which is free when
the egg is not absolutely full; but when the worm has filled the egg,
the valve can no longer open although impelled by another worm. This
valve is very well imagined, because, if the first worm should chance
to return, it opposes its egress, and obliges it to remain and undergo
the transformation. The spermatic worm then becomes the foetus, the
substance of the egg its food, the membranes, its covering, and when
the nutriment in the egg is nearly exhausted, the foetus adheres to
the internal skin of the matrix, and thus derives nourishment from the
parent's blood, till by its weight, and augmentation of its strength,
it breaks through its imprisonment, and comes perfect into the world.
By this system it was not the first woman who inclosed all mankind, but
the first man who contained all posterity in his body. The pre-existing
germs are no longer embryos without light, inclosed in the eggs, and
contained one in another, ad infinitum; but they are small animals, the
little homunculæ organized and actually living, included in each other
in endless succession, and to which nothing is wanting for them to
become perfect animals, and human beings, but expansion, assisted by a
transformation similar to that which winged insects undergo.
As our present physicians are divided on these two systems of spermatic
worms and eggs, and as all those who have lately written on generation
have adopted one or the other of these opinions, it seems necessary to
examine them with care, and to shew that they are not only sufficient
to explain the phenomena of generation, but are also founded on
suppositions void of all probability.
Both suppose an infinite progression; which, as we have said, is not so
much a reasonable supposition as an illusion of the mind. A spermatic
worm is more than a thousand million times smaller than a man; if,
therefore, we suppose the body of a man as an unit, the size of the
spermatic worm can only be expressed by the fraction 1/1000000000; and
as man is with respect to the spermatic worm of the first generation,
what this worm is to that of the second generation, the size of the
last spermatic worm cannot be expressed but by a number composed of
nineteen cyphers; and so likewise the size of the spermatic worm of the
third generation will require 28 cyphers; that of the fourth generation
37; the fifth 46, and the sixth 55 cyphers. To form an idea of the
minuteness represented by this fraction, let us take the dimensions
of the sphere of the universe from Sol to Saturn, and supposing the
sun a million times larger than the earth, and about a thousand
solar diameters distant from Saturn, we shall perceive that only 45
cyphers are required to express the number of cubic lines contained
in this sphere; and, by reducing each cubic line into a thousand
millions of atoms, 54 cyphers are only required to express that
number; consequently a human being will be greater, with relation to a
spermatic worm of the sixth generation, than the sphere of the universe
is with relation to the smallest atom which is possible to be perceived
by the assistance of a microscope. What would it be if we were to carry
it to ten generations? The minuteness would be so great as to leave us
no mode of expressing it. The probability of this opinion, therefore,
evidently disappears in proportion as the object diminishes. This
calculation may be applied to eggs as well as spermatic worms, and the
want of probability is general to both; it will, no doubt, be said,
that matter being divisible, _ad infinitum_, there is no impossibility
in this diminution of size; and although it is not probable, yet we
must regard this division of matter as possible, since we can always,
by thought, divide an atom into a number of parts. But I answer, that
the same illusion is made use of on this infinite divisibility as
on every other geometrical and arithmetical infinity; they are only
abstractions of the mind, and have no existence in nature. If we look
on infinite divisibility of matter as an absolute infinity, it is easy
to demonstrate that in that sense it does not exist; for, if once we
suppose the smallest atom possible, by that supposition this atom will
necessarily be indivisible, since if it were divisible it would no
longer be the smallest atom possible, which would be contrary to the
supposition. It therefore seems to me, that every hypothesis where a
progress, _ad infinitum_, is admitted, ought to be rejected not only as
false, but as void of all probability; and as the system of eggs and
spermatic worms supposes this progress, they should not be admitted in
philosophy.
Another great difficulty against these two systems is, that in the egg
system the first woman contained the male and female eggs: the male
eggs contained only a generation of males; and that, on the contrary,
the female eggs contained thousands of generations, both of males and
females; insomuch that, at the same time, and in the same woman, there
was always a certain number of eggs capable of developing themselves to
infinity, and another number which would be unfolded but once. The same
circumstance must occur in the other system, and therefore I ask if
there is the smallest appearance of probability in these suppositions?
A third difficulty arises against these two systems, which is, the
resemblance that children bear, sometimes to the father and sometimes
to the mother, and sometimes to both; and the evident marks of
extraordinary difference in mules, &c. If from the spermatic worm of
the father the foetus is produced, how can the child resemble the
mother; and if the foetus is pre-existing in the egg of the mother,
how can the child resemble its father? or if the spermatic worm of a
horse, or the egg of a she-ass contains the foetus, how can the mule
participate in the nature and figure of both the horse and the ass?
These general difficulties, which are invincible, are not the only
ones that can be made against these systems; there are particular ones
which are no less potent. To begin with the system of spermatic worms,
may it not be asked of those who admit of it, how they think this
transformation is made? and object to them, that insects have not, nor
cannot have any relation with what they suppose. For the worm which is
to become a fly, or the caterpillar which is to become a butterfly,
passes through a middle state, and when it ceases to be a chrysalis,
it is completely formed and has acquired its full size, and is then in
a condition of engendering; whereas in the pretended transformation
of the spermatic worm into man, it cannot be said to be in a state of
chrysalis, and even if we should suppose one during the first days of
conception, why does not the production of this chrysalis, instead of
an unformed embryo, suppose an adult and perfect being? We plainly see
how analogy is here violated; and that far from confirming this idea of
the transformation of the spermatic worm, it is instantly destroyed by
examination.
Besides, the worm which is transformed into a fly proceeds from an egg;
the egg is the produce of the copulation of the male and female, and
includes the foetus, which must afterwards enter into a chrysalis,
before it arrives at its state of perfection, as a fly; in which form
alone it has an engendering power; whereas the spermatic worm has no
faculty of generation, nor proceeds from an egg. Even should we allow
the semen to contain eggs, from whence issue spermatic worms, the same
difficulty will still remain, for these supposed eggs have not the
copulation of the two sexes for their principle of existence, as in
insects; consequently the partizans of that opinion cannot pretend
any similarity, nor derive any advantage from the transformation of
insects; which rather destroys the basis of their explanation.
When the innumerable multitude of spermatic worms are opposed to those
physicians who are prejudiced by this system, they answer, as before
observed, by the examples of plants and trees. But this comparison
is not entirely just, because all the spermatic worms excepting one
perish by absolute necessity, which is not the case with the seeds of
a tree or plant, for those which do not become vegetables, serve as
food for other organized bodies, and for the expansion and reproduction
of animals; whereas we do not see any use for the spermatic worms, or
any end to which we can refer their prodigious superfluity. On the
whole, I only make this remark in reply to what is, or may be said on
this matter; for I own, that no arguments drawn from final causes will
either establish or destroy a physical system.
Another objection made against this opinion is, there being, to all
appearance, an equal number of separate worms in the seed of all kinds
of animals, for, say they, it is natural to imagine, that in those
kinds where foetuses are most abundant, as in fishes, insects, &c.
the number of spermatic worms should be more numerous than in those
where generation is least abundant, as in man, quadrupeds, birds, &c.
for if they are the immediate cause of production, why is there no
proportion between their number and that of the foetus? Besides,
there is no proportionable difference in the size of most kinds of
spermatic worms, those of large animals being as small as those of the
least. Those of a rat, and those of a man, are nearly the same, and
when there is any difference it is no ways relative to the size of
the individual. The Calmar, which is a very small fish, has spermatic
worms above one hundred thousand times larger than those of a man or a
dog. Another proof these worms are not the immediate and only cause of
generation.
The particular difficulties that may be raised against this egg system
are no less considerable. If the foetus exists in the egg before the
communication of the male with the female, why do we not perceive the
foetus as well in those eggs produced before as after copulation?
We have before recounted the observations of Malpighius, who says
he always found the foetus in those eggs produced by hens that had
received the cock, and only a mass or mole in the cicatrice of those
who had not; it is therefore very clear that the foetus does not
exist in the egg till after impregnation.
Another difficulty against this system is, that not only the foetus
is not seen in eggs before the junction of the sexes, but even the
existence of eggs in viviparous animals is by no means proved. Those
physicians who pretend that the spermatic worm is the foetus
enveloped in a covering, are at least assured of spermatic worms; but
those who affirm that the foetus is pre-existing in the egg, have no
proof of the existence of the egg itself; on the contrary, there is a
probability, almost equivalent to a certainty, that these eggs do not
exist.
Although the partizans of the egg system do not agree what must be
looked on as the true egg in the female testicle, nevertheless they all
think that impregnation is made in the testicle called the _ovarium_,
without paying any attention that if it was so most foetuses would be
found in the abdomen instead of the matrix, for the superior extremity
of the trunk being separated from the ovarium, the pretended eggs must
often fall into the abdomen. Now, it is certain that this case is
extremely rare, and, I believe, never happened, unless occasioned by
some accident.
The general difficulties and objections against these two systems
have been noticed by the author of _Venus Physique_, whose treatise,
although very short, has more philosophical ideas than there are in
many folio volumes on generation. As this book is very public, and
the accuracy with which it is written will not permit any extract, I
shall only observe, this author is the first who has returned into the
road of truth, from which we were farther strayed than ever, since the
supposition of the egg system, and the discovery of spermatic animals.
Nothing therefore remains farther to be said, and I shall conclude with
relating a few particular experiments, some of which have appeared
favourable, and others contrary, to these systems.
In the History of the Academy of Sciences of Paris, 1701, some
objections are proposed by M. Mery against the egg system. This able
anatomist supports, with reason, that the vesicles found in the female
testicles are not eggs, but are so adherent to the internal substance
of the testicle that they cannot be naturally separated therefrom;
that if they could separate themselves from this substance it would
be impossible for them to get out, because the common membrane, which
surrounds all the testicle, is a web of too firm a texture to admit of
a conception; that a vesicle, or round soft egg, could open a passage
in it; and as the greatest number of physicians and anatomists were
prejudiced in favour of the egg system, and, from the experiments of De
Graaf, believed that the number of cicatrices in the testicles marked
the number of foetuses, M. Mery mentions the testicles of a woman,
where there was such a quantity of these cicatrices, that, agreeable to
this system, would have supposed a fecundity almost beyond imagination.
These difficulties excited other partizans of the egg system to make
new researches. M. Duverney examined and dissected the testicles of
cows and sheep: he pretended that the vesicles were eggs, because there
were some less adherent to the testicles than others, and insisted it
was natural to believe, that when they came to perfect maturity they
were separated altogether, especially as by inflating the internal
cavity of the testicle the air passed between these vesicles and the
adjoining parts. M. Mery only answers that this not a sufficient proof,
since these vesicles have never been seen separate from the testicles.
M. Duverney remarked the glandular bodies on the testicles, but he did
not look on them as an essential and necessary part towards generation,
but merely as accidental exuberances, like gall-nuts, on the oak.
M. Littre, whose prejudice for the egg system was still greater,
pretended, not only that the vesicles were eggs, but even asserted
he had discovered in one of them a well-formed foetus, of which he
distinguished the head and trunk very perfectly, and even gave the
dimensions. But besides this wonder being only seen by that gentleman,
and no other naturalist, it is sufficient to read his Memoire[P] to
perceive how doubtful was the fact. By his own words we find the matrix
was schirrhous, that the testicle was corrupted, and that the vesicle,
or egg, which contained this imaginary foetus was smaller than the
other vesicles, or eggs, which did not contain any thing, &c.
[P] Anno 1701, page 3.
A famous experiment, in favour of the egg system, is supplied by De
Nuck; he opened a bitch three days after copulation; he drew out one of
the horns of the matrix, and made a ligature in the middle, so that the
upper part of the passage could have no communication with the lower;
after which he replaced this horn, and closed up the wound, with which
the bitch seemed but little incommoded. At the end of twenty-one days
he opened it again, and found two foetuses in the upper part, that
is between the testicles and the ligature; but in the lower part there
was no foetus. In the other horn of the matrix, which had not been
tied by a ligature, he found three foetuses, which were regularly
disposed, which proves, he says, that the foetus does not proceed
from the seed of the male, but exists in the female egg. Supposing this
experiment, which has only been made once, was always followed with the
same effect, we should not then be right in concluding that fecundation
is made in the ovary, and that eggs are detached therefrom which
contain the foetus completely formed. It would only prove that the
foetus may be formed in the upper parts of the horns of the matrix as
well as in the lower; and it seems very natural to imagine that the
ligature, compressing the middle of the horns of the matrix, impelled
the seminal liquors, which are in the lower parts, to issue out, and
thus destroy the business of generation in them.
Thus we have gone through the opinions of anatomists and physicians
on the subject of generation; and it now only remains for me to
recount what I have been enabled to draw from my own researches
and experiments, and it will then be seen whether my system is not
infinitely more agreeable to Nature than any of those I have given an
account of.
CHAPTER VI.
EXPERIMENTS ON THE METHOD OF GENERATION.
I often reflected on the above system, and was every day more and more
convinced that my theory was infinitely the most probable. I then began
to suppose that, by a microscope, I might be able to attain a discovery
of the living organic particles, from which I thought every animal
and vegetable drew their origin. My first supposition was, that the
spermatic animalcules seen in the seed of every male, might possibly be
these organic particles; on which I reasoned as follows:
If every animal and vegetable contain a quantity of living organic
particles, these particles would be found in their seed, and in a
greater quantity than in any other substance, because the seed is an
extract of what is most analogous to the individual, and the most
organic; and the animalcule we see in the seed of males are, perhaps,
only these same living organic molecules, or at least the first union,
or assemblage of them. But if this is so, the seed of the female must
also contain similar living organic molecules, and, consequently, we
ought to find moving bodies there as well as in the male: and since the
living organic particles are common both to animals and vegetables,
we should also find them in the seeds of plants, in the nectarium,
and in the stamina, which are the most essential parts of vegetables,
and which contain the organic molecules necessary for reproduction. I
then seriously thought of examining the seminal liquors of both sexes,
and the germs of plants, with a microscope. I thought, likewise, that
the reservoirs of the female seed might possibly be the cavities of
the glandular bodies, in which Valisnieri and others had uselessly
sought for the egg; and at length determined to undertake a course of
observations and experiments. I first communicated my ideas to Mr.
Needham, a gentleman well known for his microscopical observations,
and read to him the first part of this work; he seemed to approve of
these ideas, and did me the favour to lend me his microscope which
was infinitely superior to my own. At the same time I communicated my
system and project of experiments to Messrs. Daubenton, Gueneau, and
Dalibard, all of whom encouraged me to persevere in my determination,
and from whom, in the course of making those experiments, I received
much assistance, particularly from Mr. Daubenton.
Persons not experienced in the use of the microscope will not be
displeased that I here insert some remarks which will be useful to
them, if they repeat the following experiments, or make new ones.
We should give the preference to double microscopes, in which we
see objects perpendicularly, from their having a plain or concave
mirror, which shews the objects clear; the concave mirror is the
most preferable when the observations are made with the strongest
lens. Leeuwenhoek, who undoubtedly has been the greatest and most
indefatigable of all microscopical observators, is said to have
only made use of simple microscopes, with which he viewed objects
horizontally. If this is true, it is necessary to remark, that most of
the plates given by Leeuwenhoek of microscopical objects, especially
spermatic animals, represents them much thicker and longer than he
really saw them, which renders the microscopes we speak of preferable
to the horizontal, as they are more stable; the motion of the hand,
with which the microscope is held, producing a little trembling, which
causes the object to appear wavering, and never presents the same part
for any time. Besides, there is always a motion in the liquors caused
by the agitation of the external air, at least, if we do not put the
liquor between two plates of glass, or even fine talc, which diminishes
somewhat of its transparency, and greatly lengthens the experiment; but
the horizontal microscope, whose tables are vertical, has the still
greater inconvenience, that the most ponderous parts of the drop of
liquor fall to the bottom; consequently there are three motions, that
of the trembling of the hand, the agitation of the fluid by the action
of the air, and also that of the parts of the liquor falling to the
bottom: from the combination of which, certain small globules, which
we see in these liquors, may appear to move by their own motion and
powers, while they only obey the compounded power of those three causes.
When we put a drop of liquor on the table of the double microscope,
although horizontally placed, and in the most advantageous situation,
we still see one common motion in the liquor, which forces all what it
contains to one side. We must wait till the fluid is in an equilibrium
and at rest, before we make our observations; for it often occurs,
that this motion of the fluid hurries away many globules, and forms
a kind of whirling motion, which returns one of these globules in
a very different direction to the others. The eye is then fixed on
the globules, and seeing one take a different course from the rest,
supposes it an animal, or at least a body, which moves of itself,
whereas its motion is only owing to that of the fluid; and as the
liquor is apt to dry and thicken in the circumference of the drop,
endeavours must be made to fix the lens on the centre of it. The drop
should also be as large as possible, and contain as much liquor as will
permit a sufficient transparency, to see perfectly what it contains.
Before we begin to make observations, we should have a perfect
knowledge of our microscope. There is no glass whatsoever but in which
there are some spots, bubbles, threads, and other defects, which
should be nicely inspected, in order that such appearances should not
be represented as real and unknown objects: we must also endeavour
to learn what effect the imperceptible dust has which adheres to the
glasses of the microscope; a perfect knowledge of which may be acquired
by observing the microscope several times.
To make proper observations, the sight, or focus, of the microscope
must not precisely fall on the surface of the liquor, but a little
above it; as not so much reliance should be placed on what passes upon
the surface, as what is seen in the body of the liquor. There are often
bubbles on the surface which have irregular motions produced by the
contact of the air.
We can see much better with the light of two short candles, than in the
brightest day, provided this light is not agitated, which is avoided by
putting a small shade on the table, inclosing the three sides of the
lights and the microscope.
It will often appear as though dark and opaque bodies become
transparent, and even take different colours, or form concentrical and
coloured rings, or a kind of rainbow on the surface; and other matters,
which are seen at first sight transparent and clouded, become black and
obscure; these changes are not real, but only depend on the obliquity
the sight falls on the body with, and the height of the plain in which
they are found.
When there are bodies in a liquor which seem to move with great
swiftness, especially when they are on the surface, they form a
furrowed motion in the liquor, which appears to follow the moving body,
and which we might be inclined to mistake for a tail. This appearance
deceived me at first, but I clearly perceived my error, when these
little bodies met others which stopped them; for there was no longer
any appearance of tails. These are the remarks which occurred during
my experiments, and which I submit to those who would make use of the
microscope for the observation of liquors.
[Illustration: _PLATE I._]
EXPERIMENTS.
I. I took from the seminal vessels of a man, who died a violent death,
and whose body was still warm, all the liquor therein contained, and
put it into a small bottle; of this I put a drop on the table of the
microscope, without the addition of water or any other liquor. The
first thing which presented, was a vapour which steamed from the liquor
towards the lens, and obscured it. These vapours being dissipated, I
perceived large filaments, (_fig. 1._) which in some places seemed to
extend into different branches, and in others to intermingle together.
These filaments clearly appeared to be internally agitated by an
undulating motion, and looked like hollow tubes which contained some
moving substance. I distinctly saw two of these filaments (_fig. 2._)
were joined together, and had a vibration nearly like that of two
extended strings, which are tied at the two extremities, and pulled
asunder in the middle. These filaments were composed of globules which
touched each other, and resembled beads. I afterwards saw filaments
which swelled in certain parts, and I observed, that on the side so
swelled small globules came out, which had a distinct motion like that
of a pendulum; these small bodies were fastened to the filaments by
a small thread, (_fig. 3._) which lengthened gradually as the little
body moved; and at last I saw these little bodies entirely separated
from the large filament, carrying after them the small thread which
connected them. As this liquor was very thick, and the filaments too
near each other, I dilated another drop with rain water, in which
I was assured there were no animals. I then saw the filaments much
separated, and very distinctly perceived the motion of these little
bodies, which was now more free, and they swam much quicker; and if
I had not seen them separate from the filaments, and carry along
with them their thread, I should have taken the moving body in this
second observation for an animal, and the thread for its tail. I then
attentively observed one of these filaments, that was much thicker than
these small bodies, and I had the satisfaction of seeing two of those
bodies which separated with difficulty, drag along with them a long and
small thread, which obstructed their motion.
This seminal liquor was at first very thick, but by degrees it became
more fluid; in less than an hour it was almost transparent; and in
proportion as this fluidity increased, the phenomena changed, as I
shall relate.
II. When the seminal liquor attained more fluidity, the filaments were
no longer to be seen, but the little bodies appeared in great numbers;
they have for the most part a motion like that of a pendulum, and they
draw after them a long thread, which it may clearly be perceived they
want to get rid of; their motion forwards is very slow, vibrating to
the right and left. The motion of a boat fastened in the midst of a
rapid stream to one fixed point, pretty well represents the motion
of these bodies, excepting that the boat remains in the same place,
whereas they advance by degrees; but they do not always keep the
same parts in the same direction; but at each vibration they take a
considerable rolling motion; so that, besides their horizontal motion,
they have one of a vertical balance, which proves that these bodies
are of a globular figure, or, at least, that their lowest part is not
sufficiently extended to maintain them in the same position.
III. At the end of two or three hours, when the liquor was more fluid,
we saw a greater quantity of these moving bodies. They seemed to be
more free; the threads were shorter; their progressive motion was more
direct, and their horizontal motion was greatly diminished; for the
longer the threads are, the greater is the angle of their vibration;
and in proportion as these threads diminish in length, the vibratory
motion lessens, and the progressive motion increases. The vertical
balance still subsisted, and was always plainly perceptible.
IV. In five or six hours the liquor attained its utmost fluidity. Most
of these moving substances were entirely disengaged from their threads;
they were of an oval figure, (_fig. 4._) and moved progressively
with great swiftness, and by their various motions had a stronger
resemblance than ever to real animals. Those who had their threads
still adhering, were not so brisk as the others; and among these that
had not threads, some seemed to change their shape and size, some were
round, some oval, and others thicker at their extremities than in the
middle; the balancing and rolling motion was still observable.
V. At the end of twelve hours a kind of gelatinous matter was settled
at the bottom of the bottle: it was of an ash-colour, and of a
tolerable consistency; the liquor that swam above was almost as clear
as water, with a kind of bluish tint, resembling water in which a
little soap had been dissolved; nevertheless it still preserved its
viscidity. The moving bodies had then a great activity, were loosened
from their threads, and moved in all directions. I saw some of them
change their form, and from oval become round; and others separate,
and from one oval form two. As they became smaller, their activity
increased.
VI. In twenty-four hours the liquor had deposited a greater quantity of
gelatinous matter. I diluted it with water, but it did not readily mix,
and required a considerable time to dissolve. It then appeared composed
of an infinite number of opaque tubes that formed a kind of net-work,
in which no regular disposition nor the least motion could be seen:
in the clear liquor some few small bodies were still moving. The next
morning there were also a very few; but after that time I saw no more
in this liquor than in the globules, without any appearance of motion.
These experiments were repeated several times with the most possible
exactness; and I am persuaded that those threads above mentioned are
not tails, nor do they make any part of the individual body; for these
threads have no proportion with the rest of the body; they are of
different sizes, although the moving bodies are always nearly of the
same, at the same time. The globule appears embarrassed in its motion,
as its tail is longer or shorter; sometimes it cannot advance, but move
only from right to left, or from left to right, when the tail is very
long; and it is clearly seen that they use great efforts to get rid of
them.
VII. Having taken the seminal liquor from another man but just dead,
and still warm, I put a drop of it on the table of the microscope, and
it immediately liquified; it had at first a condensed appearance, and
seemed to form a compact web, composed of long and thick filaments,
which grew from the thickest part of the liquor. These filaments
separated in proportion as the liquor became more fluid, and at
length they divided into globules, which at first seemed not to have
sufficient power to set themselves in motion, but this power increased
as they separated from the filament, from which they made many efforts
to disengage themselves. Each of them in this struggle drew out tails
from the filaments of different sizes, some of which were so thin
and so long as to have no proportion with the bodies, which were all
so much the more embarrassed as these threads or tails increased in
length. The angle of their vibratory motion was also much greater as
those filaments were longer: and their progressive motion so much the
more remarkable as these tails were shorter.
VIII. Having continued these observations for fourteen hours, I
perceived that these threads, or tails, were continually lessening, and
became so fine, that at last their extremities were no longer visible,
and at length the whole entirely disappeared. At this time the globules
absolutely ceased their horizontal vibrations; their progressive motion
was direct, although they had always the vertical balancing motion,
like the rolling of a ship. When disencumbered of these threads, the
bodies were oval, transparent, and perfectly like those pretended
animals seen in the liquor of an oyster on the seventh day, and still
more to those found in the jelly of roast veal at the end of the fourth
day.
IX. Between the tenth and eleventh hour the liquor became extremely
fluid, and all the globules appeared to proceed in ranks from one and
the same side; (_fig. 5._) they passed over the table of the microscope
in less than four seconds; they were ranged seven or eight in front,
and moved on successively, as troops march in files. I observed this
singular instance for more than five minutes; and as their course
did not finish, I was desirous of finding the source: and, having
gently moved my glass, I perceived that all these moving globules came
from a kind of mucilage, (_fig. 6._) where the filamentary net-work
continually produced them more abundant and much quicker than the
filaments had ten hours before. There was still a remarkable difference
between these moving bodies produced in the thick liquor, and those
produced when the liquor became more fluid; these last had no thread
behind them, their motion was quicker, and they went in flocks like
sheep. I observed the mucilage from whence they issued for some time,
and perceived it diminished, and was successively converted into
moving globules, till the diminution of more than half the bulk; after
which, the liquor being too dry, this mucilage became obscure in its
middle, and all the environs were divided by the small threads which
appeared to be formed from the bodies of these moving globules which
were destroyed as it dried up, not in one single mass, but in long
threads, regularly disposed, with quadrangular intervals, forming a
net-work, very like to a cobweb, on which the moisture hung in an
infinite number of globules.
X. I perceived by the first experiment, that these little moving
bodies change their form, and I thought they in general diminished,
but of that I was not certain. In this last observation, at the
twelfth and thirteenth hour I observed it more distinctly; at the same
time remarking that though diminished considerably in size, yet they
increased in specific gravity; especially when their motion was nearly
finished, which generally happened all at once and they sunk to the
bottom, forming a sediment of an ash-colour, plainly perceptible to the
naked eye, and which appeared through the microscope to be composed of
globules adherent to on another, sometimes by threads, and at others
in knots, but always in a regular manner.
XI. Having procured the seed of a dog, emitted naturally, I observed
that this liquor was clear, and had but little tenacity. I put it in
a phial, and having examined it with a microscope, without diluting
it with water, I perceived moving bodies entirely like those I had
observed in the human semen; they had threads, or tails, perfectly
the same; they were also nearly of the same size; in a word, they
resembled, as perfectly as possible, those I saw in the human liquor,
liquified during two or three hours. I then sought for the filaments
which I had seen in the human liquor, but it was useless; I perceived
only some long threads entirely like those which served as tails to
the globules. These threads were not attached to any globules, nor had
they any motion. Those globules which were in motion, and had tails,
appeared to me to move quicker than those in the human semen: they had
scarcely any horizontal vibrations, but a rolling motion. They were not
in a great number; and, although their progressive motion was stronger,
they took more time to cross the microscope than those I had before
remarked. I observed this liquor for three hours, but perceived no
change: after which I examined it at another time for four hours, and
remarked, that the number of moving bodies diminished by degrees; the
fourth day there was still some, though they were very few, and often
I only found one or two in a drop of liquor. The second day most of
them were deprived of their tails; the third day very few retained
them, yet, at the last day, there still remained some which had them;
the liquor had then deposited a whitish sediment, which appeared to be
composed of immoveable globules, and many threads, that seemed to be
tails separated from the globules. There were also some attached to the
globules, which appeared to be the dead bodies of these little animals,
but whose forms were different from those that moved, for they appeared
larger than the moving globules, or the rest, which remained without
motion at the bottom of the liquor, and appeared to have a fissure or
opening.
XII. Another time, having taken the seminal liquor of the same dog, I
again perceived the fore-mentioned phenomena; and I saw, besides, in
one of the drops of this liquor, a mucilaginous part, which produced
moving globules, as in the ninth experiment, (_fig. 6._) and these
globules formed a current, and went in ranks like troops. This mucilage
appeared to me animated with an internal inflated motion, which
produced small bloated appearances in different parts, and from whence
issued these bloated forms, or moving globules, with a nearly-equal
swiftness, and in the same direction. The bodies of these globules were
not different from the rest, excepting they had no tails. I observed
that many of them changed their shape, and lengthened considerably,
till they became little cylinders, after which the two extremities of
the cylinders were bloated, and divided into two globules, both moving
and following the same direction as that before they were united.
XIII. The phial, which contained this liquor, having been broke by
accident, I, a third time, took the liquor of the same dog, but whether
the animal was wearied by too reiterated emissions, or by other
causes, the seminal liquor contained none of the above bodies, but was
transparent and viscous, like the serum of blood; I examined it then,
and at one, two, three, and even twenty-four hours afterwards, but it
presented nothing new: there was not a single moving body to be seen,
nor any mucilage; in a word, nothing that I had seen before.
XIV. I then opened a dog, and separated the testicles and the adherent
vessels, but I perceived no seminal vesicles, and apparently the seed
in those animals passes directly from the testicles into the urethra.
I found but a small quantity of liquor in the testicles, although the
dog was adult and vigorous. In the small quantity I could collect I
could not discover any bodies that were in motion. I only perceived a
great quantity of very small globules, most of which were motionless,
and some of the smallest had some trifling approximating motion, which
I could not follow, because the drops I gathered were so exceedingly
minute that they dried in two or three minutes after they were placed
in the microscope.
XV. Having cut the testicles of this dog into two parts, I infused
it in water, and closely sealed up the vessel. Three days after I
examined this infusion, which I made with the design of discovering
whether the flesh did not contain moving bodies, and I saw a great
quantity of moving bodies of a globular and oval form, like those I
had seen in the seminal liquor of the dog, excepting they had not any
threads. They moved in all manner of directions with great swiftness. I
observed these bodies, which appeared animated for some time, and saw
many change their form; I perceived some to lengthen, and others to
contract, while some swelled at both extremities: there were numbers
that were smaller and thicker than the rest; but they were all in
motion, and were about the size and figure of those I have described in
the fourth experiment.
XVI. The next morning the number of these globules were increased,
but they appeared smaller; their motion was more rapid and irregular;
they had also another appearance with respect to their form and manner
of moving, which seemed confused; the next and several days after,
till the fifteenth day, there were moving bodies in the water, whose
size gradually diminished till they were no Longer visible. The last,
which I perceived with great difficulty, was on the nineteenth and
twentieth days, and they moved with greater rapidity than ever. Upon
the water a kind of pellicle was formed, which appeared to be composed
of the coverings of those moving bodies, small threads, scales, &c. but
entirely motionless; this pellicle, and the moving bodies could not
come into the liquor by means of external air, since the bottle had
been kept carefully sealed.
XVII. I then successively opened ten rabbits, on different days, to
examine their seminal liquors; the first had not a drop, either in the
testicles or seminal vessels. In the second I was no more successful,
although I was assured he was the father of a very numerous progeny.
I succeeded no better in the third. I then imagined that the presence
of the female might be requisite; I therefore put males and females
into cages so contrived that it was impossible for them to copulate. At
first these endeavours did not succeed; for, on opening two, not a drop
of seminal liquor was to be found; however, in the sixth that I opened,
a large white rabbit, I found, in the seminal vesicles, as much liquor
as could be contained in a teaspoon; this matter resembled calves'
jelly, was nearly transparent, and of a citron colour. Having examined
it with the microscope, I perceived it to resolve, by slow degrees,
into filaments and thick globules, many of which appeared fastened to
each other; but I did not remark any distinct motion in them, only
as the matter liquefied, it formed a kind of current by which these
filaments and globules seemed to be drawn all to one side. I expected
to find this matter take a greater degree of fluidity, but that did not
happen, for, after it was a little liquefied, it dried, and I could
perceive nothing further than what is above mentioned. When this matter
was mixed with water, the latter did not appear to have power to dilute
it.
XVIII. Having opened another rabbit, I only found a very small quantity
of seminal matter, which was of a colour and consistency entirely
different from the former; it was scarcely tinctured of a yellow hue,
and was much more fluid. As there was but very little, I feared it
would dry too hastily, and therefore mixed it with water: from the
first observation, I did not perceive the filaments I had seen in the
other, but I discovered three globules, all in a trembling and restless
motion; they had also a progressive motion, but it was very slow; some
moved round the others, and most appeared to turn upon their centres. I
could not pursue this observation because the liquor so soon got dry.
XIX. I opened another of these rabbits, but could not discover any of
this matter; in the seminal vessels of another, I found almost as much
congealed liquor as in XVIIth Experiment: I examined it in the same
manner as the rest, but it afforded me no greater discovery. I infused
the whole I had collected, in almost double the quantity of water, and
after briskly shaking them together, I suffered them to settle for ten
minutes; after which, on inspecting this infusion, I saw the same large
globules as before; there were but few and those very distant from each
other. They had approximating motions with respect to each other, but
they were so slow, as to be scarcely discernable; two or three hours
after, these globules seemed to be diminished, their motion was become
more distinct, and they appeared to turn upon their centres. Although
this trembling motion was more than their progressive, nevertheless
they were clearly seen to change their situation irregularly with
respect to each other. Six or seven hours after the globules were
become still less, and their action was increased: they appeared to me
to be in much greater numbers, and all their motions distinct. The next
morning, there was a prodigious multitude of globules in motion, which
were at least three times smaller than those that at first appeared.
I observed these globules for eight days, and observed that many of
them seemed to join together, after which their motion ceased; this
union, however, appeared to me only superficial and accidental. Some
were larger than others; most were round and spherical, and some of
them were oval. The largest were most transparent, and the smallest
were almost black. This difference did not proceed from the light, for
in whatever situation these small globules were in, they were always of
the same appearance; the motions of the small were much more rapid than
the large ones, and what I remarked most clearly and most generally
in all, was their diminution of size, so that at the eighth day they
were so exceedingly small as to be hardly perceptible, and at last
absolutely disappeared.
XX. At length having obtained, with no small difficulty, the seminal
liquor of another rabbit, as it would have been conveyed to the female,
I remarked it to be more fluid than that which had been taken from
the seminal vesicles, and the phenomena which it offered were also
very indifferent; for in this liquor there were moving globules and
filaments without motion; and also a kind of globules with threads or
tails, resembling those of a dog or a man, but only appearing smaller
and brisker (_fig. 7._) They passed over the microscope in an instant,
their tails appeared shorter than those of other spermatic animals,
and I own I am not certain whether some of those tails were not false
appearances, produced by the furrows which these moving globules formed
in the liquor, as they moved with too great a rapidity to admit of my
clearly observing them; besides, the liquor, though sufficiently fluid
at first, very speedily dried away.
XXI. After this I resolved to examine the seminal liquor of a ram; I
applied to a butcher, who supplied me with the necessary parts of at
least twelve or thirteen, directly after they were killed, but I could
not find liquor sufficient for any experiment, either in the epididymis
or seminal vesicles. In the little drops I was able to collect, I only
perceived globules which had no motion. As I made these experiments in
March, I supposed by repeating them in October, the season of female
attachments, I should discover more seminal liquor in these vessels.
I cut many of these testicles in two longitudinally, and collected a
small quantity of liquor, but found nothing more in them.
[Illustration: _PLATE. II._]
XXII. I took three of these testicles, of three different rams, cut
each of them into four parts, and put them into separate bottles, with
as much water as was sufficient for them. Securing these bottles from
the admission of air I suffered the infusion to remain for four days,
after which I examined the liquor of each by the microscope, and found
them all replete with an infinity of moving bodies, most part of which
were oval, and the rest globular; they were pretty thick, and resembled
those described in the VIIIth experiment; their motion was neither
brisk, uncertain, nor very rapid, but equal, uniform, and in all
directions. These moving bodies were nearly of the same size in each
liquor, but differed one bottle with the other. They had no tails, nor
were there any filaments or threads in this liquor; during the fifteen
or sixteen days they were retained, they often changed their form, and
seemed successively to throw off their external coverings; they also
became every day smaller, and on the sixteenth day, they were no longer
perceptible.
XXIII. In the month of October I opened a ram, and found a great
quantity of seminal liquor in the epididymis; having examined it with
the microscope, I perceived an innumerable multitude of moving bodies,
so numerous, that all the liquor seemed to be entirely composed of
them; as it was too thick, I diluted it with water, but I was surprised
to see the motion of these bodies suddenly stop, though I perceived
them very distinctly; having many times repeated the same observation,
I perceived that the water which diluted the seminal liquors of a man,
a dog, &c. seemed to coagulate that of a ram.
XXIV. I then opened another ram, and in order to prevent the seminal
liquor from coagulating, I permitted the parts of generation to remain
in the body of the animal, and covered it over with warm clothes. By
these precautions I observed the seminal liquor in its fluid state;
it was replete with an infinity of oblong moving bodies, (_fig. 8._)
traversing in various directions; but as soon as the liquor grew cold,
the motion of all these bodies immediately ceased. I diluted the
liquor with warm water, when the motion of the small bodies remained
for three or four minutes. The quantity of these moving bodies was so
great in this liquor, that although diluted, they nearly touched each
other. They were all of the same size and form, but none of them had
tails. Their motion was not very quick, and when it stopped by the
coagulation of the liquor, they did not change their form.
XXV. As I was persuaded, not only by my own theory, but also by the
observations of all those who had made experiments before me, that the
female, as well as the male, has a seminal and prolific liquor; and,
as I had no doubt, but the reservoir of this liquor was the glandular
body of the testicle, where prejudiced anatomists attempted to find the
egg, I purchased several dogs and bitches, and some male and female
rabbits, which I kept separate from each other; and in order to have a
comparative object with the liquor of the female, I again observed the
seminal liquor of a dog, and discovered there the same moving bodies as
described in the XIth experiment.
XXVI. While I was thus occupied, a bitch was dissected which had been
four or five days in heat, and had not received the dog. The testicles
were readily found, and on one of them I discovered a red, glandular,
prominent body, about the size of a pea, which perfectly resembled
a little nipple; on the outside was a visible orifice formed by two
lips; one of which jutted out more than the other. Having introduced a
small instrument into this orifice, a liquor dropped from it, which we
carefully caught to examine with the microscope. The surgeon replaced
the testicles in the body of the animal, which was yet alive, in order
to keep them warm. I then examined this liquor with a microscope, and,
at the first glance, had the satisfaction to see moving bodies with
tails, exactly like those I just before saw in the seminal liquor
of the dog. (_fig. 9._) Messrs. Needham and Daubenton, who observed
them with me, were so surprized at this resemblance, that they could
scarcely believe but that these spermatic animals were the same,
and thought I had forgotten to change the table of the microscope,
or that the instrument with which we had gathered the liquor of the
female, might before have been used for the dog. Mr. Needham then
took different instruments, and having obtained some fresh liquor,
he examined it first, and saw there the same kind of animals, and
was convinced, not only of the existence of spermatic animals in the
seminal liquor of the female, but likewise of their resemblance to
those of the semen of the male. We repeated it ten times at least, in
different drops of the same liquor, without perceiving the smallest
variation in the phenomena.
XXVII. Having afterwards examined the other testicle, I found a
glandular body in its growing state; it had not any external orifice,
was much smaller, and not so red as the first. Having opened it, I
found no liquor; but only a small fold in the internal part, which I
judged to be the origin of the cavity that was to contain the liquor.
This second vesicle had some very small lymphatic vesicles externally.
I pierced one of them with a lancet, and a clear and limpid liquor
flowed out, which I examined with the microscope; it contained nothing
similar to that of the glandular body; it was a clear matter, composed
of small globules, which were motionless. Having often repeated this
observation, I was assured, that this liquor in the vesicles was only
a kind of lymph, which contains nothing animated, or similar to that
seen in the female seed, which is formed and perfected in the glandular
bodies.
XXVIII. Fifteen days after I opened another bitch that had been in
heat seven or eight days, but had not received the dog. I found the
testicles contiguous to the extremities of the horns of the matrix;
these horns were very long, their external tunic surrounded the
testicles, and they appeared covered with that membrane like a cowl.
In each testicle I found a glandular body in its full maturity. The
first was half open, and there was a passage which penetrated into the
testicle, and which was replete with seminal liquor; the second was
somewhat more large and prominent, and the orifice, or canal, which
contained the liquor was below the nipple. I took these two liquors,
and having compared them, found them perfectly alike. The seminal
liquor of the female is at least as liquid as that of the male. Having
afterwards examined the two liquors with the microscope, I perceived
the like moving bodies, (_fig. 10._) and the same phenomena, as in the
seminal liquor of the other. I saw besides many globules which moved
very briskly, and endeavoured to disengage themselves from the mucilage
that surrounded them: there was a great quantity of them as in the seed
of the female.
XXIX. From these glandular bodies I pressed out all the liquor, and
having collected it, I found enough to last for four or five hours
observations. I remarked that it deposited somewhat to the bottom, or
at least began to thicken. I took one drop of this, which was thicker
than the rest, and having put it on the microscope, perceived that the
mucilaginous part of the seed was condensed, and formed a continued
net-work. On the external border of this net-work, there was a torrent,
or current, composed of globules, which moved with rapidity. These
globules were lively, active, and appeared to be disengaged from their
mucilaginous covering, and their tails. This stream perfectly resembled
the course of the blood in small transparent veins; for they appeared
not only to be animated by their own powers, but also to be impelled
by a common force, and constrained to follow in a herd. From this
experiment, and the XIth and XIIth, I concluded, that when the fluid
begins to coagulate and thicken, these active globules break and tear
their mucilaginous coverings, and escape by that side where the liquor
remains most fluid. These moving bodies had then neither threads nor
tails; they were for the most part oval, and appeared to be flat at the
bottom, for they had no rolling motion.
XXX. The horns of the matrix were externally soft; I opened them
longitudinally, and only found a very small quantity of liquor, which,
upon examination, appeared to contain the same as that pressed from the
glandular substance of the testicle. These glandular bodies are placed
so as easily to sprinkle this liquor on the horns of the matrix; and
I am persuaded that, as long as the amorous season remains, there is
a continual dropping of this liquor from the glandular substance into
the horns of the matrix; that this dropping remains till the glandular
substance has emptied the vesicles; it then becomes fluid by degrees,
is effaced, and only leaves a little reddish cicatrice on the external
part of the testicle.
XXXI. I took this seminal liquor of the female, with the same quantity
of that just emitted from the male, and mixed them together, and having
examined this mixture with the microscope, I perceived nothing new, the
liquor remaining the same, and the moving bodies were so similar, that
it was impossible to distinguish those of the male from those of the
female; I only thought their motion appeared a little slackened.
XXXII. Having dissected a young bitch that had never been in heat, I
only discovered a small protuberance on one of the testicles, which
I supposed to be the origin of a glandular body. The surface of the
testicles was smooth and even, and the lymphatic vessels could scarcely
be seen externally, until the tunic, which covered the testicles, was
separated; but these vesicles were not considerable, and contained but
a small quantity of liquor, in which I could only perceive some little
globules without any motion.
XXXIII. In another bitch, which was younger, and only three or four
months old, there was no appearance of glandular bodies on the
testicles; they were white, smooth, and covered with a cowl like the
rest. There were some little vesicles which contained little or no
liquor; and it was with great difficulty we could perceive any vesicles
externally. I compared one of these testicles with that of a young
dog of nearly the same age, and they appeared internally of a fleshy
nature, and perfectly similar. I do not mean to contradict what some
anatomists have said concerning the testicles of dogs, but only that
the appearance of the internal substance of the female testicles is
like that of the males, when the glandular substances are not yet
grown.
XXXIV. The genital parts of a cow, which had been just killed, was
sent to me, covered over with hot cloths, and put into a basket with
a live rabbit, which likewise squatted on a cloth at the bottom, so
that I received them almost as warm as when taken out of the body. I
immediately inspected the testicles, and found them of the size of
a hen's, or, at least, a pigeon's egg. One of these testicles had a
glandular body, about the size of a pea, protuberating outwardly like a
small nipple, but it was not pierced, nor had any external orifice: it
was close and hard. I pressed it with my fingers, but no liquor issued
from it. I observed, before this testicle was dissected, there were
two other glandular substances at a distance from the other; but these
were just begun to grow; their colour was a whitish yellow, whereas
that which seemed to have pierced the membrane of the testicle was of
a rose colour. I opened this last, and examined it with the greatest
attention, but could not discover that it contained any liquor, I
therefore judged that it was far distant from its maturity.
XXXV. The other testicle had no glandular body which had pierced the
common membrane that covered the testicle, there were only two small
ones, which began to form a little protuberance below this membrane.
I opened both of them but no liquor issued therefrom: they were hard,
whitish, and with a little yellow tint; each of them had four or five
lymphatic vesicles, very easily distinguishable on their surface, and
appearing transparent. I judged they contained a quantity of liquor,
and having pierced them with a lancet, the liquor issued out to some
inches distance. I collected a sufficient quantity of this liquor to
observe it easily; I only saw some very minute immoveable globules; and
although I continued my examination for two days, I neither discovered
alteration, change, nor motion, therein.
XXXVI. Eight days after, two more genital parts were brought to me
in the same mode as the last. I was assured that one was taken from
a young cow that had never calved, and the other from one that had
had several, but was not old. I first examined the testicles of the
latter, and on one of them I found a glandular substance, as large and
as red as a cherry, which appeared a little soft towards the nipple. I
distinguished three small holes, in which a hair might be introduced.
Having pressed this substance with my fingers a small quantify of
liquor issued, which I placed on the table of a microscope, and had the
satisfaction to see some moving globules there, but quite different
from those which I had seen in other seminal liquors (_fig. 11._).
These globules were obscure and little; their progressive motion,
although distinct, was, nevertheless, very slow. The liquor was not
thick; the little globules had no appearance of threads, or tails, and
they were not all in motion. This is all I was able to perceive in the
liquor this glandular substance afforded me, for although I pressed
it again, it only afforded a less quantity, mixed with blood. I again
discovered it in the small moving globules, but they seemed to be at
least four times smaller than the sanguinary globules.
XXXVII. This glandular body was situate at one of the extremities by
the side of the horn of the matrix, and the liquor, which it prepares,
must fall upon this horn; nevertheless, on opening this horn I found
no material quantity of liquor. This glandular body penetrated very
forward in the testicle, and occupied more than a third of its internal
substance. I opened them longitudinally, and found a pretty large
cavity, but entirely void of any liquor. At some distance from this
glandular body there was a small one of the same kind, about the size
of a lentil. There were also two small cicatrices, about the same size,
which formed two small indentations, of a deep red colour: they were
the remains of obliterated glandular bodies. Having afterwards examined
the other testicle, I counted four cicatrices and three glandular
bodies; the foremost of which had pierced the membrane, was of a flesh
colour, and the size of a pea. It was solid, and without any orifice
or liquor: the two others were smaller, harder, and of a deep orange
colour. On the first testicle only two or three apparent lymphatic
vesicles remained. I counted eight on the external part, and having
examined the liquor of these vesicles I perceived only a transparent
matter, without any moving bodies.
XXXVIII. I then examined the testicles of the young cow which had not
calved, which, notwithstanding, were something larger than the other,
but it is true there were no cicatrices on either of them; the one
was smooth and very white, and a number of lymphatic vesicles were
sprinkled about it, but there was not the least mark of a glandular
body. On the other testicle I perceived the marks of two glandular
substances, the one had just began to grow, and the other was the size
of a pea; there was also a great number of lymphatic vesicles, which I
pierced with a lancet, but the liquor did not contain any thing; having
pierced the two small glandular bodies some blood alone issued thereout.
XXXIX. I divided each testicle of both cows into four parts, and,
having put them into separate phials, I poured as much water on as
would cover them, and after having closely corked them up, I suffered
to infuse for six days; I then examined these infusions, and discovered
an innumerable quantity of living moving bodies (_fig. 12._); they
were all, in these infusions, extremely small, moved with a surprising
rapidity in all directions. I observed them for three days, and they
always appeared to diminish, till at last, on the third day, they
entirely disappeared.
XL. The following day they brought to me the genital parts of three
more cows. I immediately searched the testicles to find one where the
glandular substance was in perfect maturity; but in two of them I
only discovered some growing glandular substances on the testicles.
I could not learn whether these cows had calved or not, but there
was a great appearance they had all been in season, for there were
a great number of cicatrices on all these testicles. In the third I
found a testicle, on which was a glandular substance, as thick and as
red as a cherry; it was inflamed, and seemed to be in full maturity.
Its extremity was a nipple, with a small hole; I pressed it a little
between my fingers, and a quantity of liquor issued out. I found in
this liquor moving globules, exactly like those in the liquor pressed
from the glandular body of the other cow, I have before spoken of in
experiment XXXVI. They appeared to be more numerous, their progressive
motions were not so slow, and their size larger. Having observed them
for some time I perceived some to lengthen and change their form. I
then introduced a very fine instrument into the little hole of the
glandular substance, and having opened it I found the internal cavity
replete with liquor; this liquor offered me the same phenomena, and the
same moving globules, as I before observed in experiment XXXVI. with
either filaments, threads, or tails attached to them. The liquor of
the vesicle presented me with nothing more than nearly a transparent
matter, which did not contain one moving thing.
XLI. At different times they brought me the genitals of several other
cows. In some I found the testicles loaded with an almost mature
glandular substance; in others they were of different growths, and
I remarked nothing new, excepting that in the two testicles of two
different cows I perceived the glandular substance in a decayed state;
the base of one was as broad as the circumference of a cherry; the
extremity of the nipple was soft, wrinkled, and shrivelled; the two
small holes were very perceptible, from whence the liquor had flowed.
With some difficulty I introduced a small hair, but there was no liquor
in the canal, nor in the internal cavity, which was still to be seen.
The flaccidity of these glandular substances begins, therefore, at
the most external part, or extremity of the nipple. They diminish at
first in height, and afterwards in breadth, as I observed in another
testicle, where this glandular substance had diminished more than three
fourths.
XLII. As the testicles of doe rabbits, as well as the glandular bodies
formed there, are very small, I could observe nothing very exactly
with respect to their seminal liquor. I only discovered, that the
testicles of doe rabbits are different, and that none of those I saw
resembled what De Graaf represents in his engravings; for the glandular
substances did not enclose the lymphatic vesicles; and I never saw a
pointed end, as he has depicted them.
XLIII. I found on the testicles of some cows a kind of bladders,
replete with transparent liquor. I remarked they were of different
sizes, the largest about that of a pea; they were fastened to the
external membrane of the testicle by a strong membraneous pedicle,
as was also another, still smaller; and a third, nearly of the same
size as the second, appeared to be only a lymphatic vesicle, much
more apparent than the rest. I imagined these bladders, which the
anatomists have called _hydatides_, might possibly be of the same
nature as the lymphatic vesicles of the testicles, for having examined
the liquor they contained I found it to be perfectly similar; it was a
transparent and homogeneous liquor, which did not contain one moving
substance.
XLIV. At the same time I made observations on the liquor in an oyster;
on the water in which pepper had been boiled; on the water wherein
pepper had been only infused; and on the water wherein I had put some
vegetable seed; the bottles which contained these waters were firmly
closed, and in two days I perceived in the oyster liquor a great
quantity of oval and globular substances, which seemed to swim like
fish in a pond, and had all the appearance of being animals; however
they had no limbs nor tails, but were very large, transparent, and
visible. I perceived them change their forms, and become smaller for
seven or eight days successively; and at length I and Mr. Needham
observed animals similar to those in an infusion of jelly of roast
veal, which had been also very exactly corked; so that I am persuaded
they are not real animals, at least according to the received
acceptation of the words, as we shall hereafter explain.
The infusion of the seed presented an innumerable multitude of moving
globules which appeared animated like those of the seminal liquors,
and in the infusions of the flesh of animals: these were also large,
and in violent motion during the first days, but they diminished by
degrees, and disappeared only from their minuteness.
I perceived the same thing, but later, in the liquor wherein pepper
had been boiled, and the like, though still later, in that which had
not boiled; from hence I supposed that what is called fermentation may
possibly be only the effect of the motion of these organical parts
of animals and vegetables; and in order to see what difference there
was between this kind of fermentation and that of minerals, I placed
a little powdered stone on the microscope, and sprinkled thereon a
drop of aquafortis, which however produced a different phenomena,
consisting of great balls, which ascended to the surface, and almost
instantaneously obscured the focus of the microscope: this was a
dissolution of the grosser parts, which being completed it became
motionless, and had not the smallest resemblance to the other infusions
I had observed.
XLV. I examined the seminal liquor in the roes of different fish; such
as carp, tench, barbel, &c. which I took out while they were living,
and having observed three different liquors with great attention, I
perceived a great quantity of obscure globules, all in motion. I took
several more of these fish alive, and with my fingers gently compressed
that part of the belly where this liquor is emitted; and in that which
I obtained, I perceived an infinity of moving globules therein, very
black and very small.
XLVI. Before I finish this chapter I shall relate the experiments of
Mr. Needham on the seed of a kind of cuttle fish, called calmar. This
able naturalist having sought for spermatic animals in the milts of
many different fish, found them in the roe of a calmar, apparent to
the naked eye. During the summer he dissected calmars at Lisbon, but
found no appearance of any roe, nor any reservoir which appeared to be
destined for the reception of the seminal liquor; and it was in the
middle of December that he began to discern the first traces of a new
vessel replete with a milky juice. This reservoir increased, and the
seed which it contained was diffused very abundantly. By examining this
liquor with the microscope, he perceived only small opaque globules,
which floated in a kind of serous matter, without the least appearance
of life. But some time after, in the milt of another calmar, he found
these organic parts completely formed; they seemed like spiral springs
shut up in a kind of transparent case. They appeared as perfect at
first as they did at last, excepting that by degrees they contracted
and formed a kind of screw. The lid of the case was a species of
valve that opened outwardly, and by which all the contents might
issue; it contained another valve, a barrel, and a spongy substance;
therefore the whole machine consisted in an external, transparent, and
cartilaginous case, whose upper extremity is terminated by a round
head, formed by the case itself, and which performs the office of a
valve. In this external case is contained a transparent tube, which
encloses the spring, piston, or valve, barrel, or spongy substance.
The screw occupies the upper part of the tube and case, the piston and
barrel are placed in the middle, and the spongy substance occupies
the lower part. These machines pump up the lacteal liquor, of which
the spongy substance is full; and before the animal spawns, the whole
milt is no more than a composition of these organic parts, which have
absolutely pumped up the lacteal liquor. As soon as these little
machines are taken from the body of the animal, and deposited either
in water, or held in the air, they begin to act; the spring ascends,
followed by the piston, the barrel, and the spongy substance which
contains the liquor; and as soon as the spring and the tube which
contain it begin to quit the case, the spring folds up; and all that
remains within begins to move, till the spring, the sucker, &c. are
entirely come out: as soon as that is done, the remainder immediately
follow, and the lacteal liquor, which has been pumped out, and which
was contained in the spongy substance flows out by the barrel.
As this observation is very singular, and incontestibly proves that
the moving bodies found in the milt of the calmar are not animals, but
simple machines, a kind of pumps, I have deemed it necessary to give
Mr. Needham's own words.[Q]
[Q] See New Discoveries made with the microscope by Mr. Needham, chap.
vi. Leyden, 1747.
"When the small machines, he says, are arrived to their perfect
maturity, many of them act the moment they are in the open air;
nevertheless most of them may be commodiously placed, so as to be
seen with a microscope, before their action begins; and even to make
them act, the upper extremity of the external case must be moistened
with a drop of water which then begins to expand, while the two small
ligaments which issue from the case twist and turn in different
manners: at the same time, the screw ascends slowly, the volutes, which
are at its upper end, approach and act against the top of the case:
those at the bottom also advance, and seem to be continually followed
by others which come from the piston. I say, they seem to be followed,
because I do not think they are so effectually, but only a deception
produced by the nature and motion of the screw. The piston and barrel
also follow the same direction, extend lengthways, and at the same time
move towards the top of the case, which is perceived by the vacuum
at the bottom. As soon as the screw, with the tube in which it is
enclosed, begins to appear externally from the case, it folds, because
it is retained by its two ligaments: nevertheless, all the internal
contents continue to move gently and gradually, until the screw,
piston, and bladder, are entirely come out. When that is done, the rest
follow directly after. The piston separates from the barrel, and the
apparent ligament, which is below the latter, swells and acquires a
diameter equal to that of the spongy substance which follows it. This,
although much larger than when in the case, becomes still five times
longer than before. The tube which incloses it all is straightened in
its middle, and forms two kinds of knots, about a third of its length
distant from each extremity: the semen then flows through, and is
composed of small opaque globules, which float in a serous matter,
without shewing any signs of life, and which are precisely such as I
have said to have seen them when they were diffused in the reservoir
of the milt. In the figure, the part between the two knots seems to
be broken: when it is examined attentively, we find that what causes
it to appear as such, is, that the spongy substance with in the tube
is broken in nearly equal pieces, which the following phenomena will
clearly prove. Sometimes it happens, that the screw and the tube break
by the piston, which remains in the barrel; then the tube closes in
a moment, and takes a conical figure, by contracting, as much as it
is possible, above the end of the screw, which demonstrates its great
elasticity in that part: and the manner in which it accommodates itself
with the figure of the substance it incloses, when it receives the
least change, proves, that it is equal in every other respect."
Mr. Needham from this conceives that we might imagine the actions
of all this machine were owing to the spring of the screw, but he
proves, by many experiments, that the screw, on the contrary, only
obeys a power which resides in the spongy part. As soon as the screw
is separated from the rest, it ceases its action, and loses all its
activity. The author afterwards makes this reflection on this singular
machine:
"If, says he, I had seen the animalcule pretended to be in the semen of
living animals, perhaps I might be in a condition to determine whether
they are really living creatures, or simple machines prodigiously
minute, and which are in miniature, what the vessels of the calmar are
in the great."
By this, and some other analogies, Mr. Needham concludes, there is a
great appearance that the spermatic worms of other animals are only
organized bodies and machines, like to those of the calmar, whose
actions are made at different times; "for, says he, let us suppose,
that in the prodigious number of spermatic worms seen on the table
of a microscope, there are some thousands which act at the same time,
that will be sufficient to shew us, they are all alive. Let us also
conceive, adds he, that the motion of these spermatic worms remains,
like that of the machines of the calmar, about half a minute; then the
succession of action of these small machines, will remain a long time,
and the pretended animals will appear to decrease successively. Besides
why should the calmar alone have machines in its seed, whereas every
other animal has spermatic worms, and real animals? Analogy is here
of such great weight, that it does not appear possible to refuse it."
Mr. Needham likewise very justly remarks, that even the observations
of Leeuwenhoek, seems to indicate that the spermatic worms have a
great resemblance with the organized bodies in the seed of the calmar.
"I have, says Leeuwenhoek, speaking of the cod, taken those real
substances for hollow and extended animalcule, because they were four
times as large as the living animalcule." And in another part, "I have
remarked, he says, speaking of the seed of a dog, that the animalcules
often change their form, especially when the liquor in which they
float evaporates. The progressive motion does not extend above the
diameter of a hair."[R]
[R] See Leeuwenh. Arch. Nat. page 306, 309, 310.
After considering all these circumstances Mr. Needham conjectures,
that the supposed spermatic animals might possibly be only natural
machines, substances much more simply organized than the bodies of
animals. I have seen with the microscope, these machines in the calmar,
and the description he gives of them, is very faithful and exact. His
observations then shew us, that the seminal liquor is composed of
parts which seek to be organized; that it, in fact, produces organized
substances, but that they are not as yet, either animals or organized
substances, like the individual which produced them. We might suppose,
that these substances are only instruments which serve to perfect the
seminal liquor, and strongly impel it; and that it is by their brisk
and internal action, that it most intimately penetrates the seminal
liquor of the female.