ON GENERATION. 355 



EXERCISE THE FORTY-NINTH. 



The inquiry into the efficient cause of the chick is one of great 

 difficulty. 



The discussion of the efficient cause of the chick is, as we 

 have said, sufficiently difficult, and all the more in consequence 

 of the various titles by which it has been designated. Aris- 

 totle, indeed, recites several efficient causes of animals, and 

 numerous controversies have arisen on the subject among 

 writers, (these having been particularly hot between medical 

 authors and Aristotelians,) who have come into the arena with 

 various explanations, both of the nature of the efficient cause 

 and of the mode of its operation. 



And indeed the Omnipotent Creator is nowhere more con- 

 spicuous in his works, nowhere is his divinity more loudly 

 proclaimed, than in the structure of animals. And though all 

 know and admit that the offspring derives its origin from male 

 and female, that an egg is engendered by a cock and a hen, and 

 that a pullet proceeds from an egg, still we are not informed 

 either by the medical schools or the sagacious Aristotle, as to 

 the manner in which the cock or his semen fashions the chick 

 from the egg. For from what we have had occasion to say of 

 the generation of oviparous and other animals, it is sufficiently 

 obvious that neither is the opinion of the medical authorities 

 admissible, who derive generation from the admixture of the 

 seminal fluids of the two sexes, nor that of Aristotle, who holds 

 the semen masculinum for the efficient, and the menstrual 

 blood for the material cause of procreation. For neither in 

 the act of intercourse nor shortly after it, is aught transferred 

 to the cavity of the uterus, from which as matter any part 

 of the foetus is immediately constituted. Neither does the 

 " geniture" proceeding from the male in the act of union 

 (whether it be animated or an inanimate instrument) enter the 

 uterus ; neither is it attracted into this organ ; neither is it 

 stored up within the fowl ; but it is either dissipated or escapes. 



