GENERATION OF ANIMALS, I. xvui. 



considerable quantities in those who through age or 

 disease are in a very bad state of health, the same is 

 not true of semen ; such persons either have none at 

 all, or if they have, it is infertile because of the useless 

 and diseased residue that gets mixed with it. 



Hence, semen is part of a useful residue ; and the 

 most useful of the residues is that which is produced 

 last, that from which each of the parts of the body is 

 directly formed. I said " last," for of course some 

 of the residues are produced earlier, some later. 

 Nourishment in its first stage yields as its residue 

 phlegma and any other such stuff." Yes, phlegma too 

 is a residue from the useful nourishment, as is shown 

 by the fact that when it is mixed with pure nourish- 

 ment it nourishes the body,^ and that the body con- 

 sumes it in cases of disease. The residue which 

 comes last, however, is very small in bulk though 

 the nourishment which pelds it is very large '^ ; but 

 we must bear in mind that it requires very Uttle 

 to supply the growth of animals and plants from 

 day to day, since the continual addition of a very 

 small amount to the same thing would make its 

 size excessive. 



Our own statement therefore must be the opposite Semen a 

 of what the early people said. They said the semen ''^^'^"®- 

 is that which was drawn from the whole of the body ; 

 we are going to say the semen is that whose nature 

 it is to be distributed to the whole of the body.** And 

 whereas they said it was a colUquescence, we see it is 

 more correct to call it a residue. After all, it is more 

 reasonable to suppose that the surplus residue of the 

 final nourishment which is distributed all over the 

 body resembles that nourishment, just as (to take a - 

 common instance) the paint left over on an artist's 



81 



