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

Other anatomists, and among them Fabricius de Aquapendente, have supposed the fœtus quitted the matrix through the need of procuring refreshment by means of respiration. This cause appears to me still more remote than all the rest, because the fœtus can have no idea of respiration without having respired.

After having weighed all these explanations, I suppose the fœtus's quitting the matrix depends on a quite different cause. The flowing of the menstrua is periodical, and at determined intervals; and although conception suppresses its appearance, it does not destroy the cause; for notwithstanding the blood does not appear at the accustomed times, yet a kind of revolution takes place, like that which is made before conception. Thus it is, there are many women whose menstrua are not suppressed in the first two or three months. I imagine, therefore, that when a woman has conceived, the periodical revolution is made as regular as before; but as the matrix is swelled, the excretory canals cannot give issue to the blood, at least unless it arrives there with such force, and in such quantities, as to open a passage in spite of the resistance, that is opposed to it. In this case blood will appear, and if it flows in a great quantity abortion will ensue, and the matrix take the form it had before. But if the blood only forces one part of these canals, the business of generation will not be destroyed, although the blood appears, because the greatest part of the matrix still remains in the state which is necessary for that purpose.

When no blood appears, as is generally the case, the first periodical revolution is remarkable and felt by the same pains and symptoms. From the first suppression of the menses, therefore, a violent action on the matrix is made, and provided the action is augmented, it destroys the product of generation. It may from thence be concluded, that every conception which is made just before the useful return of the menses seldom succeeds, and that the action of that blood easily destroys the weak roots of a germ so tender and so delicate. The conceptions, on the contrary, which are made just after the periodical evacuations succeed the best, because the produce of the conception has more time to grow, strengthen, and resist the action of the blood, by the time the next revolution happens.

The fœtus having undergone this first trial, and having resisted it, receives more strength and growth, and is more in a condition to contend against the succeeding revolutions. Miscarriages may and do happen in all the periodical revolutions; but they are less frequent in the fourth and fifth months, than either at the beginning or near the end. We have assigned the reasons why they are more frequent at the beginning; it therefore only remains to explain why they are also more frequent towards the end.

The fœtus generally comes into the world during the tenth revolution. When it is born at the eighth or ninth it lives, and these deliveries are not looked upon as miscarriages, because the child, although not so perfectly formed, is still sufficiently so for the purpose of life. It has been pretended, that examples have been seen of children born at the seventh and even at the sixth revolution, that is, at five or six months, which have lived. There is, therefore, no difference between a birth and a miscarriage but what is relative to the living powers of the infant. In general the number of miscarriages in the first, second, and third months are very considerable for the reasons we have given ; and the number of deliveries of the seventh and eighth months are also very great, in comparison with the miscarriages of the fourth, fifth, and sixth months, because in this middle period the product of generation has received more solidity and strength, and having resisted the action of the four first periodical revolutions, a more violent force than the preceding is required to destroy it. The same reason subsists, with additional force, for the fifth and sixth months. But the fœtus, which till then is weak, and can act only by its own feeble strength, begins to get strong, and move with vigour; and at the eighth revolution the fœtus, uniting its efforts with those of the matrix, facilitates its exclusion, and it may come into the world in the seventh month, and be capable of living, especially if it happens, as is sometimes the case, to have more than ordinary strength for that period. But if it comes into the world only through the weakness of the matrix, which could not resist the action of the blood in this eighth revolution, the delivery would be regarded as a miscarriage, and the child would not live. But these cases are very rare, for if the fœtus has resisted the seven first revolutions, only particular accidents can prevent it from resisting the eighth. The fœtus, which has acquired this same degree of strength and vigour only a little later, will come into the world at the ninth revolution; and those which require nine months to obtain this same strength, will come at the tenth revolution, which is the most common and general term; but when the fœtus has not acquired in nine months this degree of perfection, it may remain in the womb till the eleventh, and even till the twelfth revolution; that is, till the tenth or eleventh month, as we have many examples.

This opinion, that it is the menstrua which is the occasional cause of delivery at different times, may be confirmed by many other reasons. The females of every animal which have no menses, bring forth at nearly the same terms, and there is but a very slight variation in the duration of their gestation. We may, therefore, suppose that this variation, which is so great in women, comes from the action of the menstrual blood, which is constantly exerted at every periodic return.

We have observed, that the placenta adheres to the papillæ, or the matrix, only by nipples; that there is no blood either in these nipples or in the vacuities they are niched into, and that when they are separated (which is easily done) a milky liquor only issues from them. Now, how happens it that delivery is always accompanied with a considerable hæmorrhage, at first of pure blood, and afterwards mixed with a watery liquor? This blood does not proceed from the separation of the placenta, as the nipples are drawn out without any effusion of blood. Delivery, which entirely consists, of this separation, should not, therefore, produce any blood. Is it not then more accordant with reason to suppose, that it is the action of the blood which causes delivery, and that it is this menstrual blood which forces the vessels as soon as the matrix is emptied, and which begins to flow immediately after delivery as it did before conception?

It is known, that in the first months of pregnancy that which contains the seed of generation is not adherent to the matrix. By the experiments of De Graaf it has been seen, that by blowing on the little ball we can make it move. The adhesion to the matrix is never very strong, and at first the placenta with difficulty adheres to the internal membrane of the viscera, and those parts are only contiguous, or joined by a mucilaginous matter, which has scarcely any adhesion. Why then does it occur, that in miscarriages of the first and second month this ball never escapes without a great effusion of blood? It is certainly not caused by the passage of the ball quitting the matrix, since it does not adhere to it; but it is, on the contrary, by the action of this blood that the ball is driven out. Must we not then conclude this blood to be menstrual, which by forcing the canals, through which it had been accustomed to pass before impregnation, destroys the product of conception by retaking its common road?