Let us suppose, it may be said, as you have attempted to prove, that the superfluous organic molecules are sent back into the testicles and seminal vessels of the male, why, by the power of your supposed attracting forces, do they not form small organized beings, perfectly resembling the male? and for the same reason similar beings in the female? If you answer, that there is an appearance that the liquor of the male contains only males, and that of the female only females, but that all these perish for want of the necessary means for expansion, and that there are only those formed by the mixture of both which can expand and come into the world; may we not be asked why this mode of generation, which is the most complicated, difficult, and least abundant, is that which Nature prefers in so striking a manner, that almost all animals multiply by this mode of communication of the male with the female? I shall content myself at present with answering, that the fact is such as we have represented it; the objection becomes a fact question; to which, as we have observed, there is no other solution to be given than that of the fact itself. It may be insisted, it is the most complicated mode of production; yet this mode, which appears the most complicated to us, is certainly the most simple for nature, because, as we have remarked, what happens the most often, however difficult it may appear to our ideas, must in reality be the most simple; which does not prevent us from conceiving it to be complex, as we judge of it according to that knowledge which our senses and reflections can give us thereon. The assertion of the Aristotelians, that females have no prolific fluid, must fall to the ground, if we pay attention to the resemblance of children to their mothers, of mules to the female that produces them, of mongrels and mulattos, all of which resemble more the mother than the father. If, besides these, we consider the organs of females are, like those of the males, formed so as to prepare and receive the seminal fluid, we shall be readily persuaded that such a fluid must exist, whether it resides in the spermatic vessels, the testicles, or in the matrix: or whether it issues, when provoked, by the passages of de Graaf, situated at the neck, and near the external orifice of the urethra.