ARISTOTLE 



GENERATION OF ANIMALS 

 BOOK I 



With one exception we have now " spoken about I 

 all the parts * that are present in animals, both gener- {fon"'^"'^' 

 ally concerning them, and also taking them group by 

 group and dealing separately with the parts peculiar 

 to each, and have shown in what way each part exists 

 on account of the Cause which is of a corresponding 

 kind : I refer to the Cause which is " that for the 

 sake of which " a thing exists." As we know, there 

 are four basic Causes ** : (1) " that for the sake of 

 which " the thing exists, considered as its " End " ; 

 (2) the logos * of the thing's essence (really these 

 first two should be taken as being almost one and the 

 same) ; (3) the matter of the thing, and (4) that from 

 which comes the principle f of the thing's movement. 

 And with one exception I have already spoken about 

 all of these Causes, since the logos of a thing and 

 " that for the sake of which " it exists, considered as 

 its End. are the same ; and, for animals, the matter 

 of them is their parts (the non-uniform ^ parts are 

 the matter for the animal as a whole in each case ; 

 the uniform parts are the matter for the non-uniform 



3 



