GENERATION OF ANIMALS, II. vi. 



earthenware), flesh, or its counterpart, is formed : it 

 is the cold which " sets " the flesh, and that is why 

 fire dissolves it. As the nourishment wells up, the 

 excessively earthy stuff in it, which contains but little 

 fluidity and heat, becomes cooled while the fluid is 

 evaporating together with the hot substance, and is 

 formed into parts that are hard and earthy in appear- 

 ance, e.g., nails, horns, hoofs and bills ; hence, these Nails, etc. 

 can be softened, but not one of them can be melted, 

 by fire ; though some, e.g., eggshell, can be melted 

 by fluids. 



The sinews and bones are formed, as the fluidity sinews and 

 sohdifies, by the agency of the internal heat ; hence ''<>°*^- 

 bones (like earthenware) cannot be dissolved by fire ; 

 they have been baked as it were in an oven bv the 

 heat present at their formation. This heat, however, 

 to produce fleshy or bone, does not work on some 

 casual material in some casual place at some casual 

 time ; material, place and time must be those 

 ordained by Nature : that which is potentially will not 

 be brought into being by a motive agent which lacks 

 the appropriate actuality ; so, equally, that which 

 possesses the actuality will not produce the article out 

 of any casual material. No more could a carpenter 

 produce a chest out of an\i:hing but wood ; and, 

 equally, without the carpenter no chest will be pro- 

 duced out of the wood. 



This heat resides in the seminal residue, and the 

 movement and the activity which it possesses are in 

 amount and character correctly proportioned to suit 

 each several part. If they are at all deficient or 

 excessive, to that extent they cause the forming pro- 

 duct to be inferior or deformed. The same is true 

 of things that are " set " by heat elsewhere than in 



221 



