IV. 10. 123 



operations, as indeed of necessity they must be. There are, how- 

 ever, differences in the male organ corresponding to. differences 

 in the body generally. For it is not of an equally sinewy 

 character in all animals. This organ, again, is the only one that, 

 independently of any .morbid change, admits of augmentation 

 and of diminution of bulk. The former change is of service in 

 copulation, while the other is required for the advantage of the 

 body at large. For, were the organ constantly in a state of 

 erection, it would be an incumbrance. The organ therefore has- 

 been formed of such constituents, as will admit of either condition. 

 For it is partly sinewy, partly cartilaginous,^* and thus is enabled 

 either to contract or to become extended, and is capable of 

 admitting air.^* 



All female quadrupeds void their urine backwards, because 

 the position of the parts which this implies is useful to them 

 in the act of copulation. This is the case with very few males, 

 though there are some exceptions, as the lynx, the lion, the 

 camel, and the hare.^^ No quadruped with a solid hoof is 

 retromingent. 



The posterior portion of the body and the parts about the 

 legs are different in man from what they are in quadrupeds. 

 Nearly all these latter have a tail, and this whether they are 

 viviparous or oviparous. For, even if the tail be of no great 

 size, yet they have a kind of scut; as at any rate a small repre- 

 sentative of it. But man is tail-less. He has however buttocks, 

 which exist in none of the quadrupeds. His legs also, calves 

 and thighs alike, are fleshy ; while in all other animals that 

 have legs, viviparous or not, they are fleshless, being made of 

 sinew and bone and a substance resembling fish-spine.^^ For 

 all these differences there is, so to say, one common explanation, 

 and this is that of all animals man alone stands erect. It was 

 to facilitate the maintenance of this position that nature made 

 his upper parts light, taking away some of their corporeal 

 substance, and using it to increase the weight of the parts 

 below, so that the buttocks, the thighs, and the calves of the 

 legs, all became fleshy. The character which she thus gave 

 to the buttocks renders them at the same time useful in resting 

 the body. For standing causes no fatigue to quadrupeds, and 

 even the long continuance of this posture produces in them no 

 weariness ; for they are supported the whole time by four props, 

 689b. 



