GENERATION OF ANIMALS, III. xi. 



and the putrefied matter are a residue of that which 

 has been concocted, for no creature's formation uses 

 up the trhole of the material," any more than in the 

 case of objects fashioned by the agency of art, other- 

 wise there would be no need to make anything at all, 

 whereas what happens in actual fact is that the use- 

 less material is removed in the one case by art and 

 in the other by Nature. 



Animals and plants are formed in the earth and in 

 the water because in earth water is present, and in 

 water pneuma is present, and in all pneuma soul-heat is 

 present,* so that in a way all things are full of Soul ; 

 and that is why they quickly take shape once it has 

 been enclosed. Now it gets enclosed as the liquids 

 containing corporeal matter '^ become heated, and 

 there is formed as it were a frothy bubble. The 

 object which thus takes shape may be more valuable 

 in kind or less valuable ; and the differences herein 

 depend upon the envelope which encloses the soul- 

 principle ; and the causes which determine this are 

 the situations where the process takes place and the 

 physical substance which is enclosed. Now in the 

 sea earthy substance is plentiful, and that is why 

 the Testacea "^ are formed and constructed out of a 

 composition which is earthy in character : the earthy 

 substance hardens all round and congeals in the same 

 way that bones and horns do (since these cannot be 

 melted by fire), while within it the physical substance 

 that contains the life becomes enclosed. 



Of such creatures the only tribe which has been 

 observed to copulate is that of the snails ; but whether 



' Sea-water is such a liquid ; see above, 761 b 9 and im- 

 mediately below, 1. 27. Also App. B §§ 13-17. 



•* Lit., the nature of the Testacea ; cf. above, 7til b 24. 



357 



