PARTS OF ANIMALS, IV. i.-ii. 



creatures have one stomach only, as do the other 

 animals that have front teeth in both jaws. And 

 their viscera are quite small, as are those of the 

 other creatures which have no bladder. However, 

 on account of the shape of the serpents' bodies, 

 which is long and narrow, the shape of their viscera 

 too is consequently long, thus differing from those 

 of other animals. This is because the shape of them 

 is fashioned, as though in a mould, on account of the 

 space available for them. 



All blooded animals have an omentum, a mesen- 

 tery, and the whole intestinal equipment ; also a dia- 

 phragm and a heart ; and all but the fishes have a 

 lung and a windpipe too. The relative positions of 

 the windpipe and the oesophagus are the same in all 

 of them. The reasons for this have been given 

 already. ** 



II. The majority of the blooded animals have a Gaii-biadder 

 gall-bladder in addition. In some it is placed up ^^'^ ^^^®' 

 against the liver ; in others it is separate from the 

 liver and placed against the intestines, indicating 

 that equally in these its derivation is from the lower 

 gut.^ This is clearest in the fishes, all of which have 

 one, and in most of them it is placed against the 

 intestines, though in some it runs along the whole 

 length of the intestine, like a woven border, as in 

 the Amia ; a similar arrangement is found in most of 

 the serpents. Hence, those who assert that the gall- 

 bladder is present for the sake of some act of sensation 

 are wrong. They say its purpose is as follows : — 

 on the one hand (a) to irritate that part of the Soul 

 which is around the liver, and so to congeal it '^ ; and 

 on the other hand (6) by running free to make that 

 part cheerful. This cannot be true ; because some 



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