138 ARISTOTLE'S ANHOMCEOMERIA 



and the aorta. The pericardium of an ox, which was 

 probably one of the animals dissected for the heart, as 

 explained above, is very stout and covered on opposite 

 sides by a large quantity of fat, so that Aristotle's description 

 applies very well to it. 



Aristotle's statements about the presence of bones in the 

 hearts of horses and some oxen have been considered already 

 in that part of this Chapter which relates to bones and 

 cartilages. 



In his description of the position of the heart, intended 

 to apply to the human heart, he says incorrectly that the 

 heart lies above the lungs, near the bifurcation of the 

 trachea,* and that the parts of the heart near its apex lie 

 on or against the aorta. t In Man, the heart lies just below 

 the bifurcation of the trachea, and not above the lungs, 

 while the apex of the heart is some distance in front of the 

 aorta. One part of Aristotle's description of the position of 

 the human heart, however, is such that some have taken it 

 as a proof that he dissected the human body. This part of 

 his description has been discussed in Chapter viii. 



Aristotle says that the heart of a snake is small, kidney- 

 shaped, and situated near its throat, t The heart of a snake 

 cannot be considered to be small, nor is it kidney-shaped. 

 In one grass-snake, the heart, enclosed within its peri- 

 cardium, was an inch and an eighth long and half an 

 inch in diameter, the whole being almost cylindrical with 

 rounded ends. When removed from its pericardium, the 

 heart presented a much more complicated appearance, the 

 bright red ventricle, in the form of a double cone with 

 rounded ends, resting upon and between the dark red 

 auricles. The front part of the heart was about as far 

 forward as the hinder end of the long trachea. 



In the animals now called invertebrates, Aristotle did 

 not believe that a heart, properly speaking, could be found. 

 Instead of this, they had a part analogous to a heart, just 

 as they had a fluid which was not blood but analogous to it. 



The part, in cephalopods and crustaceans, which he 

 believed to represent the heart of animals with blood, was 

 the part which, he says, was called mT/tls.^ Its position, he 

 says, shows that it corresponds with the heart of animals 

 with blood, and this is proved by the sweetness of its con- 

 tained fluid, which has the characters of coagulated matter 



* H. A. i. c. 14, s. 1. f Ibid. I Ibid. ii. c. 12, s. 12. 



§ P. A. iv. c. 5, 6816 ; H. A. iv. c. 1, s. 11, iv. c. 2, s. 11 



