82 iii. 9 — iii, lo. 



the safety of the kidneys, and to maintain their natural heat. 

 For placed, as these organs are, close to the surface, they require 

 a greater supply of heat than other parts. For while the 'back, 

 is thickly covered with flesh, so as to form ^ shield for the heart 

 and neighbouring viscera, the loins, in accordance with a rule 

 that applies to all joints, are destitute of flesh ;^^ and fat is 

 therefore formed as a substitute for it, so that the kidneys may 

 not be without protection. The kidneys, moreover, by being 

 fat are the better enabled to secrete and concoct their fluid ; for 

 fat is hot, and it is heat that effects concoction. 



Such then are the reasons why the kidneys are fat. But in 

 all animals the right kidney is less fat than its fellow.^''' The 

 reason for this is, that the parts on the right side are naturally 

 more solid and more suited for motion than those on the left. 

 But motion is antagonistic to . fat, for it tends to melt it. 



Animals then, as a general rule, derive advantage from their 

 kidneys being fat; and the fat is often very abundant and extends 

 over the whole of these organs. But, should the like occur in the 

 sheep, death ensues. Be its kidneys however as fat as they may, 

 they are never so fat but that some part, if not in both at any 

 rate .in the right one, is left free.'^ The reason why sheep are 

 the only animals that suffer in this manner, or suffer more than 

 others, is that their fat is harder 'and more abundant than that 

 of other animals. For the soft lard, of which the fat of some 

 animals is composed, is of fluid consistence, so that there is not 

 the same chance in their case of wind getting shut in and causing 

 mischief • But it is to such an enclosure of wind that rot ^^ is 

 due. And thus even in men, though it is beneficial to them to 

 have fat kidneys, yet should these organs become over-fat and 

 diseased, deadly pains ensue. As to those animals whose fat 

 consists of suet, their suet is not so dense as that of sheep, 

 neither is it nearly so abundant ; for of all animals there is 

 none in which the kidneys become so soon gorged with fat as 

 in the sheep.^" Rot then is produced by the m'oisture and the 

 wind getting shut up in the .kidneys, and is a malady that 

 carries off sheep with great rapidity. For the disease forthwith 

 reaches the heart, passing thither by the aorta and the great 

 vessel, the ducts which connect these with the kidneys being 

 of unbroken continuity. 



(Ch. \o.) We have now dealt with the heart and the lung, 

 672b. # 



