Of the Formation of the Foetus.
FROM the experiments of Verheyen, who found the semen of the bull in the uterus of a cow, and from those of Ruysch, Fallopius, and Leeuwenhoek, who discovered male semen in the uteri of women and many other animals, it seems to be a point fully ascertained, that the semen of the male enters into the uterus of the female. It is probable, that, during the time of coition, the uterus opens for the reception of the seminal fluid: But, though this should not happen, the active and prolific part of the semen may penetrate the membranes and substance of the uterus itself; for, as the seminal liquor, as formerly remarked, is almost entirely composed of organic particles, which are very active, and extremely minute, they may pass with the utmost facility through the membranes and substance of the uterus.
What proves that the active part of this fluid may pass through the pores and substance of the uterus, is the sudden change it undergoes immediately after conception. The menses are [271] obstructed, the uterus becomes flaccid, swells, and appears to be inflated. All these changes must be effected by an active external cause, by the penetration of part of the seminal fluid into the substance of the uterus. This penetration is not confined to the surface; it extends through all the vessels and parts of which the uterus is composed, like that penetration by which nutrition, and the expansion of the body is produced.
We shall more easily believe this to be the case, when we reflect, that, during the time of gestation, the uterus not only augments in size, but even in its quantity of matter, and that it possesses a species of life, or rather of vegetation, which continues till the child be delivered. If the uterus were only a sac, a reservoir for receiving the semen and retaining the foetus, it would extend and diminish in thickness, in proportion as the foetus grew larger. But the augmentation of the uterus is not a simple extension or dilation of its parts. It not only extends as the foetus enlarges, but it acquires, at the same time, an additional thickness and solidity; or, in other words, both its size and quantity of matter are greatly increased. This augmentation is a real growth or increase of substance, similar to the expansion of the body in young animals, which could not be effected but by an intimate penetration of organic particles analogous to the substance of those parts. As this [272] expansion of the uterus never happens but after impregnation, the seminal liquor must be the cause by which it is produced; for the uterus is considerably augmented before the foetus has acquired bulk enough to dilate it by pressing against its internal surface.
It appears, from my own experiments, to be equally certain, that the female has a seminal fluid, which begins to be formed in the testicles, and is brought to maturity in the glandular bodies. This fluid perpetually distills through the small apertures in the extremities of these bodies, and, like that of the male, enters the uterus by two different ways, either through the apertures at the extremities of the horns of the uterus, or by piercing through the substance of the uterus itself.
These two seminal fluids are extracts from all parts of the body; and a mixture of them is all that is necessary for the formation of a certain number of males and females. The more any animal abounds in this seminal fluid, or the more it abounds in organic particles, the number of young is the greater, as may be remarked in the smaller animals; and the number of young diminishes in proportion as the organic particles are less abundant, as is the case with the larger animals.
But, before taking any farther notice of other animals, we shall examine with attention the formation of the human foetus. In mankind, as well as in the larger species of animals, the [273] quantity of organic particles in the male and female semen is not great, and, accordingly, they very seldom produce above one foetus at a time. This foetus is either a male or a female, according as the number of organic particles predominates in the male or in the female fluid; and the child resembles the father or the mother most, according to the proportional quantities of male or female organic particles in the mixture of the two liquors.
I conceive, therefore, that the seminal fluids, both of the male and of the female, are equally active, and equally necessary for the purposes of propagation: And this, I think, is fully proven by my experiments; for I found in both fluids the same moving bodies; I discovered that the male fluid enters into the uterus, where it meets with the fluid of the female; that these two fluids are perfectly analogous; and that they are composed of parts not only similar in their form, but in their action and movements.* Now, I imagine, that, by the mixture of the two fluids, the activity of the organic particles proper to each is stopped; that the action of the one counterbalances the action of the other; that each organic particle, by ceasing to move, remains fixed in the place which corresponds to its nature; and that this place can be no other than that which it formerly occupied in the body of the animal from which it was extracted. Thus all the organic particles which were detached from the head [274] of the animal, will arrange themselves in a similar order in the head of the foetus. Those which proceeded from the back bone, will dispose themselves in an order corresponding to the structure and position of the vertebrae. In the same manner, the organic particles which had been detached from any part of the body, will naturally assume the same position, and arrange themselves in the same order that they observed before they were separated from that part. Of course, these particles will necessarily form a small organized body, entirely similar to the animal from which they originally proceeded.
It is worthy to remark, that this mixture of the organic particles of both sexes contains particles that are similar, and particles that are dissimilar. The similar particles are those which have been detached from all the parts that are common to the two sexes. The dissimilar particles are those which have been separated from the parts that distinguish the two sexes. In this mixture, therefore, there is a double portion of particles destined for the formation of the head, the heart, and such parts as are common to both sexes; while there are no more than what are necessary for the production of the sexual parts. Now, the similar particles may act upon each other without producing disorder; and they may unite in the same manner as if they had proceeded from the same body. But the dissimilar parts cannot act upon each other, nor form any intimate union, because they have no analogy or relation: Hence [275] these particles will preserve their original nature without any mixture, will first fix their position, without the necessity of being penetrated by others. Thus the particles which proceed from the sexual parts will be first fixed, and those that are common to the two sexes, whether they belong to the male or to the female, will then fix indiscriminately, and form an organized body, which, in its sexual parts, will perfectly resemble the father, if it be a male, and the mother, if it be a female, but, which, in the other parts, may resemble either or both.
If what I have advanced be properly understood, we shall, perhaps, be able to obviate an objection made to the system of Aristotle, and which might also be urged against the doctrine which I am now establishing. The question is, Why is not every individual, both male and female, endowed with the faculty of producing an animal of its own sex? I am aware of the difficulty of solving this question, which I have slightly mentioned in the fifth chapter, and I shall now proceed farther to illustrate.
From what is delivered in the first four chapters, and from the experiments I have described, it is apparent, that reproduction is effected by the assemblage and union of the organic particles, detached from every part of the animal or vegetable body, in one of several common reservoirs; that these particles are the same which serve for the nutrition and expansion of the [276] body; and that both effects are produced by the same matter, and by the same laws. I think I have established this point by so many facts and reasonings, that it is impossible to entertain a doubt concerning its truth. But, I allow, that the question may be put, Why every separate animal and vegetable produces not its own likeness, since every individual detaches from all its parts, and collects in a common reservoir, the organic particles necessary for the formation of a small organized body? Why is not this organized body formed? and why, in most animals, is a mixture of the fluids of both sexes necessary? If I were to reply, that in all the vegetable tribes, in all those animals that multiply by cutting, and in the vine-fretters, which produce without any sexual commerce, the general intention of Nature seems to be, that each individual should multiply its own species, and that reproduction by the intervention of sexes is only an exception to this general law, It might, with propriety, be rejoined, that the exception is perhaps more universal than the rule itself. To maintain that all individuals would have the faculty of reproducing, if they were endowed with proper organs, and if they contained the matter necessary for nourishing the embryo, is not removing the difficulty: for, in females, all these circumstances concur; and yet the influence of the male is indispensable to the production either of a female or of a male foetus. [277]
But, we come nearer a solution of the question, when we maintain, that, though the fluid in the testicles and seminal vessels of the male contain all the organic particles necessary for the formation of a male foetus, yet these particles cannot receive any local establishment or arrangement of parts, because a constant circulation of them goes on by means of absorption, and by the perpetual succession of new supplies from all parts of the body; and that, as the same circulation of the organic particles takes place in the female, neither of them can possibly multiply without the assistance of the other; because, in the mixture of male and female fluids, the different organic particles of which they consist have a greater affinity to each other than they have to the body of the female where the mixture happens. But, though this explication were admitted, why, it may still be asked, does not the ordinary mode of generation correspond with it? For, upon this supposition, each individual would produce, and, like snails, mutually impregnate one another, every individual receiving the organic particles furnished by the other power, would unite solely by the affinity between the particles themselves. If there were no other cause by which the organic particles could be united, perhaps this mode of generation would be the most simple. But it is contrary to the analogy of Nature. [278] Few animals are endowed, like snails, with both sexes; and, therefore, if this mode of propagating were the most simple, it would be more generally employed by Nature. This solution, of course, amounts to no more than a gratuitous supposition, that males produce not, solely because they have not organs proper for containing and nourishing a foetus.
It may be still farther supposed, that the activity of the organic particles in the semen of each individual requires to be counterbalanced by the force or action of those of the other individual, in order to reduce them to a fixed state, or equilibrium, without which the formation of the foetus cannot be effected; and that the motion of the organic particles of the female cannot be counterbalanced by any other cause than a contrary action in the organic particles received from the male. But this answer is too general to be void of obscurity. However, when we attend to all the phaenomena, it may, perhaps, admit of some illustration. The mixture of the two seminal fluids produces not only a male or female foetus, but other organized bodies, which are endowed with the faculty of growth or expansion. The placenta, the membranes, &c. are produced at the same time, if not sooner, than the foetus. There are, therefore, in the seminal fluid of the male or female, or in the mixture of both, organic particles not only suited to the production of the foetus, but of the [279] placenta and membranes. Since there are no parts either in the male or female bodies from which they could be detached, whence do these particles proceed? It must be admitted, that the organic seminal particles of each sex being equally active, uniformly produce organized bodies every time that they can fix themselves, by their mutual action upon one another; that, of the particles destined to produce a male, those peculiar to the male sex will fix first, and form the sexual parts; that the particles common to both sexes may afterwards fix themselves indifferently, in order to from the rest of the body; and that the placenta and membranes are produced by the excess of organic particles which have not been employed in the formation of the foetus. If, as we have supposed, the foetus be a male, all the organic particles peculiar to the female sex, which have not been employed, as also the superfluous particles of both individuals which have not entered into the composition of the foetus, and which cannot be less than one half of the whole, remain for the formation of the membranes and placenta. If the foetus be a female, the same quantity of superfluous organic particles still remain, and are occupied in forming the placenta and membranes.
But it may be said, that the membranes and placenta, upon this supposition, ought to become another foetus, which would be a male, if the first was a female, and a female, if the first was [280] a male; because the first foetus consumed only the organic particles peculiar to the sex of one individual, and the half of those particles which were common to both sexes; and, of course, the sexual particles of the other individual, and the other half of the common particles, remain still unexhausted. To this I reply, that the first union of the organic particles prevents a second, at least under the same form; and that the foetus, being first formed, exerts an external force which destroys the natural arrangement of the organic particles, and throws them into that order which is necessary for the formation of the placenta and membranes.
From the experiments and observations formerly made, it is apparent, that all animated beings contain an amazing quantity of living organic particles. The life of an animal or vegetable seems to be nothing else than a result of all the particular lives (if the expression be admissible) of each of these active particles, whose life is primitive, and perhaps indistructible [sic]. These living particles we have found in every animal and vegetable substance; and we are certain, that all these particles are equally necessary to the nutrition, and consequently, to the reproduction of animals and vegetables. That the union of certain number of these particles, therefore, should produce an animated being, it is not difficult to conceive. As each particle is animated, a whole, or any assemblage of them, [281] must be endowed with life. These living organic particles being common to all animated beings, they are capable of forming particular species of animals, or of vegetables, according to the peculiar arrangement they assume. Now, this arrangement depends entirely on the form of the individuals which furnish the organic particles. If they are furnished by an animal, they arrange themselves under the form peculiar to its species, exactly agreeable to that arrangement they observed when they nourished or expanded the animal itself. But, does not this regular arrangement suppose the necessity of base or centre, round which the particles assemble in order to unite and form a foetus? This basis is furnished by the particles which form the sexual parts. I shall illustrate this point.
As long as the organic particles of either sex remain alone, their activity produces no effect, because it is not opposed by any resistance or reaction from particles of a different kind. But, when the male and female liquors are blended, the particles detached from the sexual parts being of a different kind, serve as a base to fix the activity of the other particles.
Upon this supposition, that the organic particles which, in the mixture of the two fluids, represent the sexual parts of the male, can alone serve as a basis to the particles which proceed from all parts of the female; and that those proceeding from all parts of the male can only be fixed [282] by the particles which are detached from the sexual parts of the female; we may conclude, that the sexual parts of the male foetus are formed by the organic particles of the father, and the rest of its body by the organic particles of the female; and, on the contrary, that the female foetus derives nothing but its sex from the mother, and the rest of its body from the father. Boys, therefore, excepting in the parts which distinguish their sex, ought to resemble the mother more than the father, and girls should resemble the father more than the mother.
Considering generation by sexes under this light, we should conclude it to be the most common manner of reproduction, as it is in reality. Beings of the most perfect organization, as animals, whose bodies make a whole that is incapable of division, and whose powers are all concentrated into one point, cannot be reproduced in any other way; because they contain only particles that are perfectly similar, and cannot be united but by means of different particles furnished by another individual. But vegetables, which are less perfect in their organization, and which can be divided without destruction, are capable of being reproduced in different ways: 1. Because they contain dissimilar particles; 2. Because the form of these bodies is less fixed and determined than that of an animal, different parts supply the functions of each o- [283] ther, and vary according to circumstances: The roots of a tree, when exposed to the air, push out branches and leaves; and thus the organic particles of vegetables obtain a local establishment, become fixed, and produce individuals in many different ways.
The same phaenomenon is exhibited in animals whose organization is less perfect, asx in the fresh water polypus, and others, that are capable of reproducing by the division of their parts. These organized bodies, instead of single animals, may be considered as bundles of organized beings united by a common membrane, as trees are composed of an infinite number of minute trees.* The vine-fretters, which propagate individually, likewise contain dissimilar particles; because, after producing their young, they change into barren flies. Snails mutually communicate dissimilar particles to each other; and, therefore, each individual is fruitful. Thus, in every mode of generation with which we are acquainted, we find, that the necessary union of the organic particles cannot be effected but by the admixture of different particles, to serve as a common basis, and to fix or destroy their activity.
According to this general idea of sexes, we may suppose, that the distinction of sex extends through all Nature; for sex, in this sense, is nothing but that part of bodies which furnishes [284] organic particles of a different kind from those of the common parts, and which serve as a basis for their union., But it is , perhaps, useless to reason on a question which can be solved at once, by saying, that, as God has created sexes, animals must necessarily be produced by their intervention. We are not in a condition, as I formerly remarked, to explain why things exist; we are unable to explain why Nature almost universally employs sexes for the reproduction of animals, or why sexes exist. We ought, therefore, to content ourselves with reasoning concerning things as they are. If we attempt to rise higher, we lose ourselves in the regions of fancy, and forget the narrow limits of our knowledge.
Leaving, therefore, all farther subtleties, I shall adhere to nothing that is not founded on facts and observation. I find that the reproduction of bodies is effected in many different modes: But, at the same time, I clearly perceive, that animals and vegetables are reproduced by the union of the organic particles detached from all parts of their bodies. I am certain that these active organic particles exist in the seeds of vegetables, and in the seminal fluids of animals, both male and female; and have no doubt that every species of reproduction is accomplished by the union and admixture of these particles. It is equally unquestionable, that, in the generation of man, and other animals, the organic [285] particles of the male and female mix at the time of conception; because we often see children who resemble both father and mother: And, what confirms this theory is, that all the particles common to the two sexes mix together promiscuously, but that the particles peculiar to the sexes never mix; for we daily perceive children with eyes resembling those of the father, while their mouth and front resemble those of the mother. But we never see any such mixture of resemblances in the sexual parts; we never find, in the same individual, the testicles of the father and the vagina of the mother.
The formation of the foetus, therefore, is effected by the mixture of the organic particles of both sexes; and this mixture fixes or gives a local establishment to the particles, because it is made according to the laws of affinity which take place between the different parts, and which determine the particles to arrange themselves in the same order they observed when they existed in the individuals who furnished them. The particles which proceed from the head, for example, cannot, according to these laws, take up their station in the legs, or in any other part but the head of the foetus. All the particles are in motion when they first unite; and this motion must be round the point or centre of union. This basis or central point, which is necessary to the union of the particles, and which, by its reaction and inertia, fixes and destroys their ac- [286] tivity, is probably the first assemblage of particles that proceed from the sexual parts, because they are only the only particles in the mixture that differ from those common to both sexes.
I imagine, therefore, that, in the mixture of the two fluids, the organic particles which come from the sexual parts of the male fix themselves first, and cannot unite with those which proceed from the seminal parts of the female, because they are of a different nature, and have less affinity to each other than the particles that come from the eye, the arm, or any other part of the female. Round this centre, or point of union, the other organic particles successively arrange themselves in the same order they formerly existed in the body from which they were derived; and, according as the particles of the one or of the other individual most abound, or nearer this central point, they enter in greater or less quantities into the composition of the new being, which, in this manner, is formed in the middle of a homogeneous fluid; at the same time, vessels begin to shoot, which increase in proportion to the growth of the foetus, and furnish it with proper nourishment. These vessels, which have a peculiar species of organization, are probably formed by the excess of the organic particles which have not been admitted into the composition of the foetus; for, as these particles are both active, and furnished with a base or point of union from the organic particles pecu- [287] liar to the sexual parts of the other individual, they must arrange themselves in the form of an organized body, but not in the form of another foetus; because their position with respect to each other has been changed by the different movements of the particles which entered into the composition of the first foetus. From the union of these superabundant particles, therefore, an irregular body must arise, which will resemble the foetus in nothing but its growth and expansion; because, though this body be composed of the same organic active particles with the foetus, their position and form must be different, as they were thrown aside from the centre or point of union, which served as a basis for the formation of the foetus.
When the quantity of seminal fluid of both individuals is great, or, rather, when these liquors abound with organic particles, different centres of attraction are formed in different parts of the mixture; and, in that case, by a mechanism similar to what has been mentioned above, several fetuses are formed, some of them males, and others females, according as the particles of the one sex or of the other are most active. But, from the same centre of attraction, two fetuses can never originate; because two centres are requisite for this purpose. Besides, if this were to happen, no particles would be left for the formation of the placenta and membranes; because they would all be employed in constituting the [288] second foetus, which would necessarily be a female, if the other was a male. All that could happen in such a case would be, that some of the particles common to both individuals, being equally attracted by the first centre of union, must arrive there at the same time, and produce a monster, or a foetus with superfluous parts; or, if some of the common particles should fix at too great a distance from the first centre, or be constrained by the attraction of the second, round which the placenta is formed, a monster, defective in some part, would be the consequence.
That the organic particles peculiar to the sexual parts serve for a basis or centre of union to the other particles of which the embryo is formed, I pretend not to demonstrate: But, as they are the only particle which differ from the rest, it is more natural to imagine that they should answer this purpose that those which are common to both individuals.
I formerly detected the errors of those who maintained, that the heart, or the blood, were first formed. The whole is formed at the same time. We learn from actual observation, that the chicken exists in the egg before it is sit upon. The head, the back-bone, and even the appendages which from the placenta, are all distinguishable. I have opened a great number of eggs, both before and after incubation, and I am convinced, from the evidence of my own eyes, that the whole chicken exists, in the middle of the [289] cicatrix, the moment the egg issues from the body of the hen. The heat communicated to it by incubation, only expands the parts, by putting the fluids in motion. But we have never been able to determine, with certainty, what parts of the foetus are first fixed, at the moment of its formation.
I have always maintained, that the organic particles were fixed, and that they united in consequence of their motion being suspended. Of the truth of this fact I am fully convinced; for, if the male and female semen be separately examined, we find in both a great number of moving particles; but, when these fluids are mixed, the motion of the particles is totally destroyed, and a certain degree of heat is necessary to renew their activity; for the chicken, which exists in the centre of the cicatrice, has no motion before incubation; and, even 24 hours, or two days afterwards, when we begin to perceive it without the microscope, it has not the smallest appearance of motion. During the first two or three days, the foetus is only a small white mucilaginous mass, which gradually acquires consistence and magnitude. But this progress is exceedingly s low, and has no resemblance to the rapid movements of the organic particles in the seminal fluid. Besides, it was not without reason that I maintained that the motion of the organic particles was entirely destroyed; for, if eggs be kept without exposing them to the de- [290] gree of heat that is necessary for the expansion of the chicken, the embryo, though compleatly [sic] formed, will remain without any motion, and the organic particles of which it is composed will continue fixed, without being able to give life and motion to the embryo which was formed by their union. Thus, after the motion of the organic particles is stopped, and after they have united in such a manner as to form a foetus, some external cause is still necessary to give them life and motion. This cause, or agent, is heat, which, by rarifying the fluids, obliges them to circulate: This circulation makes all the organs act; and nothing farther is necessary for the growth and expansion of the parts than the continuation of this heat.
Before the action of this external heat, there is not the smallest appearance of blood; and I never could perceive any change of colour in the vessels till about 24 hours after incubation. In the vessels of the placenta, which communicate with the body of the foetus, the blood first appears. But, it would seem that this blood loses its red colour, as it approaches the body of the animal; for the chicken is entirely white; and, during the first, second, and third days after incubation, we can with difficulty perceive a few red particles near the animal’s body, but which seem not to make any part of it, though these red particles are destined for the formation of the heart. Thus the formation of blood is an effect produced by the motion communicated [291] to the fluids by heat; and even this blood is formed without the body of the animal, the whole substance of which consists of a white mucilage.
The foetus, as well as the placenta, receive the nourishment that is necessary for their expansion by a species of absorption; and they assimilate the organic particles of the liquor in which they swim: For, it is an equal impropriety to say that the placenta nourishes the animal, as that the animal nourishes the placenta. If the placenta nourished the foetus, the former would diminish in proportion to the growth of the latter, which by no means happens; for both augment together. I have indeed observed, that, in eggs, the placenta at first grows much more in proportion than the foetus, and, consequently, it may nourish the animal; or, rather, it conveys nourishment to it by means of absorption.
What we have said concerning the chicken, admits of an easy application to the human foetus, which is formed by the union of the organic particles of the two sexes. The membranes and placenta are produced by the superabundant particles that enter not into the composition of the foetus, which is now inclosed in a double membrane, containing also a quantity of fluid. This fluid is at first, perhaps, nothing but a portion of the seminal liquors of the father and mother; and, as the foetus is not thrown out of the uterus, it enjoys, from the moment of its forma- [292] tion, as much external heat as is sufficient for its expansion. This heat communicates motion to the fluids; it gives play to all the organs; and the blood is formed in the placenta, and in the body of the foetus, solely by the motion excited by the heat. We might even maintain, that the formation of the blood in a child is an independent of the mother, as that which arises in the egg is independent of the hen that covers it, or of the furnace which heats it.
It is certain that the foetus, the membranes, and the placenta, are all nourished and expanded by absorption; for, at first, the sack [sic] that contains the whole product of generation does not adhere to the uterus: And we have seen, from the experiments of De Graaf upon female rabbits, that he made the globules which contained the fetuses roll about in the uterus. They could receive no nourishment, therefore, but by absorbing the fluids that constantly bedew the uterus, to which they afterwards begin to adhere by means of a mucilage that gradually gives origin to small blood-vessels, as shall afterwards be more fully explained.
But to return to the formation of the foetus, concerning which we have to make several remarks, both as to its situation, and to the different circumstances that may prevent or alter the mode of its production.
In the human species, the semen of the male enters into the uterus, the cavity of which is [293] considerable; and, when it meets with a sufficient quantity of female semen, the two instantly mix, and the organic particles unite and form the foetus. The whole is, perhaps, performed in a moment, especially if the two fluids be in an active state. The cavity of the uterus is the proper place for the formation of the foetus; because the semen of the male has an easier admission into the uterus than into the Fallopian tubes or ovarium; and, as the uterus has only a small aperture, which is always shut, excepting when opened by the ardor of love, the materials of generation remain there in safety, unless they be disturbed by some rare and accidental circumstance. But, as the male fluid moistens the vagina, before it penetrates the uterus, and, as the organic particles are exceedingly active, it may penetrate as far as the Fallopian tubes and ovarium. In the same manner, as the female fluid is already perfected in the glandular bodies of the testicles, from which it distills and moistens the Fallopian tubes, before it descends into the uterus; and, as it may escape through the lacunae round the neck of the uterus, it is not impossible that the mixture of the two liquors may take place in all these different places. Foetuses, therefore, may frequently be formed in the vagina, and instantly fall out of it, having nothing proper for their retention. They may also be sometimes formed in the Fal- [294] lopian tubes; but instances of this kind must be rare.
Anatomists mention, that fetuses have been found, not only in the Fallopian tubes, but likewise in the ovaria. M. Theroude,* a surgeon in Paris, showed to the academy a rude mass which he found in the right ovarium of a girl of 18 years of age. Two open fissures, garnished with hair like the eye-lids, were perceived in it. Above these eye-lids was a kind of front, with a black line in place of eye-brows. Immediately above the front, there were several hairs collected into two separate pencils, one of them about seven inches long, and the other three. Below the angle of the eye, two large, hard, white dentes molares [sic] appeared, together with their gums: These teeth were about three lines long, and about a line distant from each other. Several other teeth appeared, situated at different distances. In the same volume,+ M. Mery is reported to have found in the ovarium of a woman an upper jaw-bone, with several teeth in it, so perfect that they appeared to be at lest of ten years growth. In the Medical Journal, published by the Abbé de la Roque,3 we have the history of a woman, who died of her ninth child, which had been formed in or near one of the ovaria; for, from the description, it is not clear whether the child was within the o- [295] varium, or only adjacent to it. This foetus was about an inch thick, and compleatly [sic] formed. In the Philosophical Transactions, examples are recorded of teeth, hair, and bones being found in the ovaria of women. If all these facts can be credited, the seminal liquor of the male must be supposed sometimes, though rarely, to mount up to the ovaria. But there are many considerations which render this point extremely doubtful: 1. The facts which seem to support it are few: 2. the only instance of a perfect foetus found in the ovarium, is narrated in a very suspicious manner by M. Littre. Neither is it impossible that the seminal fluid of the female alone may sometimes produce organized masses, as moles, cists [sic] full of hair, of bones, or of flesh. Besides, if we are to believe anatomists, fetuses may be formed in the testicles of men as well as in those of women; for, we are told by a surgeon, in the 2d volume of the history of the old academy,* that he found a foetus, with its membranes, in which the head, the feet, the eyes, the bones and cartilages, were distinguishable in the scrotum of a man. Were all these facts equally worthy of credit, we must necessarily adopt one of the two following hypotheses; either that the seminal fluid of each sex can produce nothing without being mixed with the other; or, that either of the fluids alone is capable of producing irregularly organized masses. If we maintain the for- [296] mer hypothesis, to explain the facts above related, we shall be obliged to admit, that the male fluid sometimes ascends to the ovarium, and, by mixing there with the female fluid, forms organized bodies; and also, that the female fluid, by being copiously effused in the vagina, may, in the time of coition, penetrate as far as the scrotum of the male, in the same manner as the venereal virus often reaches that part; and, consequently, than an organized body may be formed in the scrotum by a mixture of the male and female fluids. If the other hypothesis, which is the most probable, be adopted, namely, that the seminal fluid of each individual may separately produce organized masses, then all these osseous, fleshy, and hairy bodies, which sometimes appear in the ovaria of females, and in the scrotum of males, may derive their origin from the seminal fluid of the individual in which they are found. But it is needless to speculate farther concerning facts which seem to be more uncertain than inexplicable; for I am inclined to think, that the seminal fluid of each individual may singly produce something; and that young girls, for example, may produce moles, without any intercourse with the male, in the same manner as hens lay eggs without intervention of the cock. I might support this opinion with observations equally credible as those we have just now quoted. M. de la Saone, a physician and anatomist, published a treatise on this subject, in [297] which he assures us, that nuns, though strictly cloistered, sometimes produce moles: And why should this be impossible, since hens produce eggs without any communication with the cock, and since we find, in the cicatrices of these eggs, instead of a chicken, a mole with its appendages? The analogy here is sufficiently strong to make us at least suspend a rash determination. Whatever be in this, it is certain, that a mixture of the two fluids is necessary for the formation of a foetus, and that this mixture cannot be properly effect but in the uterus, or in the Fallopian tubes, where anatomists have sometimes discovered fetuses: And it is natural to imagine, that those which have been found in the cavity of the abdomen, have escaped by the extremity of the tube, or by some accidental rupture of the uterus; and that they never fall into the abdomen from the ovarium, because I think it next to impossible that the seminal fluid should ascend so far. Leeuwenhoek has computed the motion of his pretended spermatic animals to be four or five inches in 40 minutes; so that, if the whole fluid moved at this rate, in an hour or two the animalcules might proceed from the vagina into the uterus, from the uterus into the Fallopian tubes, and from the Fallopian tubes into the ovaria. But, how is it possible to conceive, that the organic particles, whose motion ceases whenever they are deprived of the fluid part of the semen, should arrive at the ovarium, [298] unless they were accompanied with the liquor in which they swim? The moving particles cannot give a progressive motion to the fluid which contains them. Thus, whatever activity may be ascribed to these organic particles, we cannot conceive how they should arrive at the ovarium, and there form a foetus, unless, by some unknown power, the fluid is absorbed by the ovarium, a supposition which is not only gratuitous, but contrary to probability.
The difficulty attending this supposition confirms the opinion, that the male fluid enters the uterus, either by its orifice, or by penetrating its substance. The female fluid may likewise find its way into the uterus, either by the aperture at the extremity of the Fallopian tubes, or by penetrating the substance of the tubes and uterus. M. Weitbrech, an able anatomist of the academy of Petersburg, has clearly proved that the seminal fluid can penetrate through the substance of the uterus: “Res omni attentione dignissima,” says he, “oblata mihi est in utero seminae alicujus a me dissectae; erat uterus ea magnitudine qua esse folet in virginibus, tubaeque ambae apertae quidem ad ingressum uteri, ita ut ex hoc in illas cum specillo facile possem transire ac flatum injicere, sed in tubarum extreme nulla debater aperture, nullus aditus; simbriarum enim ne vestigium quidem aderat, sed loco illarum bulbus aliquis pyriformioos material subal- [299] bida fluida tergens, in cujus medio fibra plana nervea, cicatriculae aemula, apparebat, quae sub ligamentuli specie usque ad ovarii involucra protendebatur.”
“Dices, eadem a Regnero de Graaf jam olim notata. Equidem non negaverium illustrem hunc profectorem, in libro suo de organis mulieribus, non modo similem tubam delineasse, Tab. xix. Fig. 3. sed et monuisse, ‘tubas, quamvis, secumdum ordinariam naturae dispositionem, in extremitate sua notabilem simper coarctationet habeat, praeter naturam tamen aliquando claudi;’ verum enimvero cum non meminerit auctor an id in utraque tuba ita deprehenderit, an in virgine, an status iste praeternaturalis sterilatem inducat, an vero conception nihilominus fieri posit, an a principio vitae talis structura suam originem ducat, sive an tractu termporis ita degenerare tubae possint, facile perspicimus multa nobis relicta esse problemata, quae, utcumque solute, multum negotii facescant in exemplo nostro. Erat enim haec foemina maritata, viginti quator annos nata, quae silium pepererat quem vidi ipse, octo jam annos natum. Dic igitur tubas ab incunab ulis clausas sterilitatem inducere: Quare haec nostra foemina peperit? Dic concepisse tubis clauses: Quomodo ovulum ingredi tubam potuit? Dic coaluisse tubas post partum: Quomodo id nosti? quomodo adeo evanescere in [300] utroque latere simbriae possunt, tanquam nunquam adfuissent? Si quidem ex ovario ad tubas alia daretur via, praeter illarum orificium, unico gressu omnes superarentur difficultates; sed fictions illectum quidem adjuvant, rei veritatem non demonstrant; praestat igitur ignorationem fateri, quam speculationibus indulgere.”* These difficulties, which occurred to this acute observer, are insurmountable, according to the ovicular system. But the fact he records is alone sufficient to demonstrate, that the female fluid may penetrate the substance of the uterus; and it is not to be doubted that the male fluid is capable of entering it in the same manner. The change which the male fluid produces in the uterus, and the species of vegetation or expansion which it occasions in that viscus, is sufficient to demonstrate the truth of the fact. Besides, the fluid which issues through the lacunae of De Graaf being of the same nature with that of the glandular bodies, it is evident that this liquor proceeds from the ovaria; and yet there are no vessels through which it could pass. We must therefore conclude, that it penetrates through the spongy substance of the parts, and that it not only enters the uterus, but may even issue out of it, when the parts are irritated.
But, though this penetration should be regarded as impossible, it cannot be denied, that the female fluid, which distills from the glandu- [301] lar bodies of the ovaria, may fall into the uterus, by entering the apertures at the extremities of the Fallopian tubes, as the male fluid enters by the orifice of the uterus itself; and, consequently, that the foetus may be formed in the cavity of the uterus, by the mixture of the two fluids, in the manner already explained. [302]
* See chap. VI [back to page 274].
* See Chap. II [back to page 284].
* See mem. de l’acad. des sciences, tom. 2. p. 91.
+ P. 244.
3. January 1683 [back to page 295].
* P. 298 [back to page 296].
* See Comm. Acad. Petropol. vol. iv. pag. 261. and 262 [back to page 301].