PARTS OF ANIMALS, II. vii.-viii. 



will make it set fast, thus producing various forms of 

 disease, madness, and death. Indeed, the heat that 

 is in the heart, being the source, is extremely re- 

 sponsive to any influence upon it ; and if the blood 

 which surrounds the brain undergoes any change or 

 any other affection, then this heat at once becomes 

 sensitive of it. 



We may now claim to have considered all the fluids 

 which are present in animal bodies from their very 

 earliest stages. There are others which are first 

 produced only at some latter stage, and among these 

 we must reckon the residues of the nourishment — 

 that is to say, the deposits from the bladder and 

 from the gut ; and also semen, and milk ; these 

 make their appearance according to the species and 

 sex of the animal concerned. Discussion of the resi- 

 dues of the nourishment will come in appropriately 

 during our general consideration and examination 

 of nourishment ; we shall then show in what animals 

 they occur, and why they do so. Semen, which 

 gives rise to generation, and milk, which exists on 

 account of generation, we shall deal with in the 

 treatise on Generation.'^ 



VIII. We must now go on to consider the rest of Flesh and 

 the uniform parts. Let us take first of all Flesh (and, ^^^^^* 

 where Flesh is absent, its counterpart), for this is to 

 animals both a principle and a body in itself. Its 

 primacy can also be logically shown, as follows. We 

 define an animal as something that has the powder of 

 sensation, and chiefly the primary sensation, which 

 is touch ; and the organ through which this sensation 

 is effected is the flesh (or its counterpart). And 

 flesh is either its primary organ (comparable to the 

 pupil in the case of sight), or else it is the organ and 



157 



