Buffon's Natural History, Volume 03 (of 10) / Containing a Theory of the Earth, a General History of Man, of the Brute Creation, and of Vegetables, Minerals, &c. &c.

by comte de Georges Louis Leclerc Buffon

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 fœtus, 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 fœtuses 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 fœtus? 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 fœtus exists in the egg before the communication of the male with the female, why do we not perceive the fœtus as well in those eggs produced before as after copulation? We have before recounted the observations of Malpighius, who says he always found the fœtus 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 fœtus does not exist in the egg till after impregnation.

Another difficulty against this system is, that not only the fœtus 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 fœtus enveloped in a covering, are at least assured of spermatic worms; but those who affirm that the fœtus 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 fœtuses 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 fœtuses, 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 fœtus, 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 fœtus was smaller than the other vesicles, or eggs, which did not contain any thing, &c.

[P] Anno 1701, page 3.