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CHAPTER III
OF GENERATION
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
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