u!4 ON GENERATION.
called " the form of forms," being itself immaterial and wholly without form ; it is, therefore, said to be possible or potential, but not passible.
This fluid, or one analogous to it, appears also to be the ultimate aliment from which Aristotle taught that the semen, or geniture, as he calls it, is produced. 1 I say the ulti- mate aliment, called dew by the Arabians, with which all the parts of the body are bathed and moistened. For in the same way as this dew, by ulterior condensation and adhesion, becomes alible gluten and cambium, whence the parts of the body are constituted, so, mutatis mutandis, in the commence- ment of generation and nutrition, from gluten liquefied and ren- dered thinner is formed the nutritious dew: from the white of the egg is produced the colliquament under discussion, the radical moisture and primigenial dew. The thing indeed is identical in either instance, if any credit be accorded to our observ ations ; and in fact neither philosophers nor physicians deny that an animal is nourished by the same matter out of which it is formed, and is increased by that from which it was engen- dered. The nutritious dew, therefore, differs from the col- liquament or primigenial moisture only in the relation of prior and posterior; the one is concocted and prepared by the parents, the other by the embryo itself, both juices, however, being the proximate and immediate aliment of animals; not indeed " first and second," according to that dictum, " con- traria ex contrariis," but ultimate, as I have said, and as Aris- totle himself admonishes us, according to that other dictum, " similia ex similibus augeri," " like is necessarily increased by its like." There is in either fluid a proximate force, in virtue of which, no obstacles intervening, it will pass spontaneously, or by the law of nature, into every part of the animal body.
Such being the state of the question, it is obvious that all controversy about the matter of animals and their nourish- ment may be settled without difficulty. For as some believe that the semen or matter emitted in intercourse is taken up from every part of the body, so do they derive from this the resemblance of the offspring to the parents. Aristotle has these words: "Against the opinion of the ancients, it may
1 De Gen. Anim. lib. i, cap. 18, et lib. iv, cap. 1.
