344 ON GENERATION. 



To escape from such a labyrinth of " efficient causes," it were 

 necessary to be furnished with Ariadne's thread, composed 

 from observations on almost every animal that lives ; on this 

 account the subject is deferred till we come to our more general 

 disquisition. Meantime we shall recount the particulars which 

 either manifestly appear in the special history of the chick 

 from the egg, or which differ from the ideas usually enter- 

 tained, or that seem to demand further inquiry. 



EXERCISE THE FORTY-SEVENTH. 



Of the manner in which the efficient cause of the chick acts, 

 according to Aristotle. 



It is universally allowed, that the male is the primary effi- 

 cient cause in generation, on the ground that in him the 

 species or form resides; and it is further affirmed, that the 

 emission of his ' geniture' during coition, is the cause both of 

 the existence and the fertility of the egg. But none of the 

 philosophers nor physicians, ancient or modern, have suffi- 

 ciently explained in what manner the seed of the cock pro- 

 duced a chick from the egg ; nor have they solved the question 

 proposed by Aristotle. Nor, indeed, is Aristotle himself much 

 more explanatory, when he says, "that the male contributes 

 not in respect of quantity, but of quality, and is the origin of 

 action ; but that it is the female which brings the material." 

 And a little after, " It is not every male that emits seed, and 

 in those which do so, this is no part of the foetus ; just as in 

 the case of a carpenter, nothing is translated from him to the 

 substance of the wood which he uses, nor does any part of the 

 artist's skill reside in the work when completed ; but a form 

 and appearance are given by his operation to the matter j and 

 the soul, which originates the idea of forms, and the skill to 

 imitate them, moves the hands, or other limb, whatever it may 

 be, by a motion of a certain quality ; or from diversity pro- 

 ceeds difference ; or from similarity proceeds resemblance. 

 But the hands and instruments move the material. So the 

 nature of a male, which emits semen, uses that semen as an 



