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. 



