1.   THERE are two principal sentiments among the moderns, relative to the manner in which generation is effected. Some think that all the parts of the fetus are enclosed in miniature in those eggs contained in the ovaries of the female, which communicate with the womb by the Fallopian tubes; and that the seed of the male is only a sort of matter proper for detaching the egg, cherishing it, and conveying it into the womb, where the germ contained in the egg afterward unfolds its parts: this is the sentiment of Hervey, Redi, and many other celebrated physicians, who maintain that all animals are oviparous, and spring from eggs, which in the animal kingdom are what seed is in the vegetable.

2.   The other sentiment is that of Lewenhoek, that all animals, and even men, spring from little animals of extreme minuteness, contained in the seed of the male ; and he looks upon the eggs in the ovary of the female, only as little niduses fit to receive these animalculi, and to contribute to their developement and increase, by imparting to them the nourishment which comes from the vessels of the womb.

3.   The first of these systems was for a time generally received, and appeared to be founded on just observations. Those who maintain it. declare, that they have found eggs in the ovaries of every female that came under their notice, often to the number of more than twenty in each ovary, and of the size of a green pea. They draw another of their arguments from the analogy that nature every where observes in all operations, and particularly in the production of plants and animals. Now if this system deservedly confers glory on the inventor of it, it is but just that he should have it who is best entitled to it; and he to whom it appears primarily due is without doubt Empedocles, and next to him Hippocrates, Aristotle, and Macrobins.

4.   Plutarch, relating the different opinions of philosophers, as to the’ the generation of animals and productions of plants, says, that Empedocles thought they were all of them at first irregular and imperfect, but acquired afterward such a just form as distinguished them in shape and species from one another. And he concludes with saying, that animals are not produced like earth and water, from homogeneous bodies, but generate one another by the mixture of the sexes, and like plants, derive the principle of their origin from the particular seeds or eggs. This is the very same which Aristotle intended to indicate, as the doctrine of Ernpedocles, when he introduces him, as saying, “that whatever was born, was born of a particular seed ;“ and as calling the seeds of plants their eggs, which fall of themselves when they are come to maturity.

5.  Herodotus, who lived almost at the same time with Empedocles, relating that a land adjoining to the Nile had produced a great quantity of fish, gives a natural reason for it, upon the principles of Empedocles. What seems to me, says he, to have been the cause of this vast increase of fish, is this, during the time of the Nile’s overflowing, the fishes having left in the mud of its borders, a prodiguous quantity of sperm, or eggs, these disclose themselves after its retreat, covering. the land with a multitude of fish.

6.   Hippocrates, speaking of the formation of an infant, describes a fetus six days old, comparing it to a raw egg without the shell, round, and full of a red transparent liquor. In another place, he shows “how the same thing happens in the generation of an infant, as in the production of a plant.” He says “that nature is always the same, acting uniformly in the generating of men, and of plants, and of every thing else.”

7.  Aristotle, with still more precision, describes the egg containing the foetus. He says, “that all animals engender and conceive first a kind of egg, containing a liquor enveloped in a membrane or thin skin, resembling that of an egg shell. This, in another place, he plainly calls an egg; out of one part of which,” lie says, “the foetus is produced ; that is, out of the yolk ; whilst the white part, which is the other, serves to nourish it.”

8.  Nothing can be more clear than what Macrobius pronounces on this subject, who positively avers, that of all kinds of animals who copulate, an egg is the first principle of their generation; and in another place, that the egg is the solution or expansion of the seed.

9.   The system of animalcules or spermatic vermiculi has hindered that of generation by the means of eggs, from gaining the unanimous suffrage of the naturalists. Mr. de Plantades, secretary of the academy of Montpelier, was the first among the moderns who renewed this conjecture of the ancients. Lewenhoek and others confirmed this conjecture by observations so accurate, that they divided the sentiments of naturalists between their own opinion of men’s proceeding from spermatic animalcula, and that of Hervey, which derives all generation from eggs. We have already seen that this letter opinion sprung from Hippocrates, Aristotle, &c. And the other of the existence of spermatic vermiculi, is as clearly taught by Plato, Hippocrates, Aristotle, arid other ancient philosophers, as if they had seen them. We can never sufficiently extol the extreme penetration of those great geniuses, who, guided solely by reason, arrived so long before us, where we, after all our nice experiments and laborious researches, are glad to rest.

10.   Democritus is the first of the Grecian philosophers, who bath spoken of certain worms, which assume at length the human form; but no author transmitted to us, has entered into a detail of this opinion; though Epicurus, Diodorus, Siculus and Euripides, seem to hint at it. Epicurus thought that the generation of animals was effected by the continual transformation of one into another. Anaxagoras, had said the same, as well as Euripides, quoted by Plutarch, Galen, Eusebius and Philo. But Democritus, in explaining himself more precisely, taught that men, in their first original, appeared in the form of small worms, which, in all probability, he conceived to be contained in the seminal juice of the male; for it is natural to suppose, that in this idea he agreed with Hippocrates, who insinuates, that the “seed of animals is filled with animalcula, whose parts unfold themselves and grow all at a time.”

11.   That illustrious physician, without all doubt, held conferences upon this subject with Democritus, whom he found engaged in the dissection of animals, when be went first to visit him, and long enjoyed the utmost satisfaction in his company upon matters entirely philosophical. Aristotle seems to hint at Democritus, when treating of the first formation of men, he says, that some have thought that “the first men,” after having sprung out of the earth, “began their existence in the form of little worms ;“ and in another place, he speaks of Democritus as having believed, that “in the generation of man, the exterior parts of the foetus are first formed ;“ so that it is even then of human shape, and therefore even in that condition may be looked upon as a “little man.”

12.  Hippocrates advanced, that nothing in nature absolutely perished; “that nothing, taking it altogether, was produced anew nothing born but what had a prior existence ;“ that what we call birth is only “such an enlargement as brings from darkness to light,” or renders visible” those small animalcula which were before imperceptible." He says a little farther, it is impossible that what is not, should be born, there being nothing that can contribute to the generation of what has no existence. But he maintains, “that every thing increases much as it can, from the lowest to the highest degree of magnitude." These principles he afterward applies to human generation. Re says, that “the largest sizes arise out of the lesser ;“ that “ all the parts successively expand themselves, and grow and increase proportionally in the same series of time ; that none of them in reality takes the start of another, so as to be quicker or slower in their growth; but that those which are naturally larger, sooner appear to the eye than those which are smaller, though they by no means preceded them in existence.” In short, in the beginning of this book of Hippocrates, we meet with a train of reasoning entirely just and solid, the natural consequences of which is, that at the beginning of the world, the seeds containing the first lineaments of plants and animals came into existence, though their extreme minuteness hinders them from being seen. Whence he concludes, as we have already had occasion to observe, that “the birth of animals is only such an enlargement of them, as makes them pass from darkness into light.”

13.  It may be objected, that we have already represented Hippocrates and Aristotle as favouring the system of generation by eggs; and that we now seem to ascribe a contrary opinion to them. But it ought to be remarked, that in reality, these two philosophers favoured the former system: for Aristotle only relates the other opinion as introductory to the establishment of his own; and Hippocrates contents himself with insinuating the notion, that there may be animalcula in the male seed, without taking it upon him ‘to establish it as a truth. Besides, he might have admitted of spermatic vermiculi in the sense that some moderns do, in order to reconcile the two systems, regarding the eggs as niduses proper for the reception of the spermatic vermiculi, and containing matter necessary for contributing to their growth. In this case, the spermatic worm will be the real foetus, the substance of the egg its nourishment, and the membranes of it its wrappers.

14.   Plato bath still more clearly spoken of those small animals which become men; for after having compared “the womb to a fertile field,” in which the scattered seed produces fruit; he says, that “the animalcula, which there receive their growth, are at first so extremely small as not to be perceptible to the eye, but coming gradually to unfold themselves and expand, by means of the food prepared for them in the womb, they afterward spring firth into day in all the perfection of birth.” Nor can it be denied, that Seneca had a very distinct idea of this system of human generation by animalcula. when we find bins teaching, that “ the human form before birth, Was comprised in the seed, where all the members of the body were con-centered and shrouded up in a little indiscernible place.” Which Tertullian bath expressed in few words, when he says, “the seed bath life in it from the very first.”

15.  The discovery respecting the multiplicity of animation of which the polypus is capable, is what nobody makes any difficulty of regarding as due to the moderns, though Aristotle and St. Augustine speak of it as clearly as any of the moderns, as a thing which they knew from their own experience. The latter relates in his book concerning “the dimension of the soul," that one of his friends performed the experiment before him, cutting a polypus in two; and that immediately the two parts thus separated betook themselves to flight, moving the one, one way, and the other another. That great man adds, that this experiment suddenly threw him into such amazement, that for some time he knew not what to think of the nature of the soul. Aristotle, speaking of insects, says almost the same thing; for without naming the creature he speaks of, he observes, that “there are of these animals or insects, as well as of plants and trees, that propagate themselves by shoots :“ and as what were but the parts of a tree before, become thus distinct and separate trees: so in cutting one of these animals, says Aristotle, the pieces which before composed but one animal, become of a sudden so many different individuals.

Chapter 4 - Of the Sexual System of Plants

Chapter 4