ARISTOTLE. 35 



Lastly, it should be remembered that though this may 

 have been but a lucky guess on Aristotle's part the 

 relative weight of brain to the entire body has been 

 shown, with few exceptions, to be greater in man than in 

 any other animal. 



In describing the heart Aristotle says : " The heart lies 

 about the centre of the body, but rather in its upper 

 than in its lower half, and also more in front than 

 behind. ... In man it inclines a little towards the left, 

 so that it may counterbalance the chilliness of that side. 

 It is hollow, to serve for the reception of the blood ; 

 while its wall is thick, that it may serve to protect the 

 source of heat. For here, and here alone, in all the 

 viscera, and in fact in all the body, there is blood without 

 blood-vessels, the blood elsewhere being always contained 

 within vessels. The heart is the first of all the parts of 

 the body to be formed, and no sooner is it formed than 

 it contains blood. . . . For no sooner is the embryo 

 formed than its heart is seen in motion like a living 

 creature, and this before any of the other parts. The 

 heart is abundantly supplied with sinews. ... In no 

 animal does the heart contain a bone, certainly in none 

 of those that we ourselves have inspected, with the 

 exception of the horse and a certain kind of ox. In 

 animals of great size the heart has three cavities ; in 

 smaller animals it has two ; and in all it has at least 



