PARTS OF ANIMALS, III. vii. 



hares appear to have a couple of livers ; so do certain 

 fishes, especially the cartilaginous ones.* 



The spleen owes its existence to the liver being 

 placed somewhat over to the right-hand side of the 

 body : this makes the spleen a necessity in a way, 

 though not an urgent one, for all animals. 



Thus, the reason why the viscera are double in 

 their formation is, as we have said, that the body 

 is two-sided, having right and left. Each of the two 

 aims at similarity, just as the sides themselves strive 

 to have a similar nature, and to be as like as twins ; 

 and just as the sides, though dual, are conjoined 

 together into a unity, so also it is with the several 

 viscera. 



The viscera which are below the diaphragm are 

 all of them present for the sake of the blood-vessels, 

 in order that the latter may have freedom of carriage 

 and at the same time be attached to the body by 

 means of the viscera, which act as a bond. Indeed, 

 there are, as it were, anchor-lines thrown out to 

 the body through the extended parts : e.g. from the 

 Great Blood-vessel to the liver and to the spleen, for 

 these viscera act, as it were, like rivets and fasten it 

 to the body ; that is to say, the liver and the spleen 

 fasten the Great Blood-vessel to the sides of the body 

 (since blood-vessels pass to them from it alone), while 

 the kidneys fasten it to the rear parts. And to the 

 kidneys — to each of them — there is a blood-vessel 

 passing not only from the Great Blood-vessel but 

 also from the Aorta. 



These advantages, then, accrue to the animal organ- 

 ism from the lower viscera. Liver and spleen also 

 assist in the concoction of the food, since they both 



« Sharks, etc. 



263 



