PARTS OF ANIMALS, II. xiv. 



will be explained later.'* Man is the only animal 

 which has eyelashes on both lids. Why is this ? 

 The quadrupeds tend to have more hair on their 

 backs than on the underside of the body ; but in 

 man the reverse is true. The purpose of hair is to 

 give protection ; and as the quadrupeds go on all 

 fours, they need more protection on their backs ; so 

 they have no hair on their front, although the front 

 is the nobler of the two sides. Man goes upright, 

 and so there is nothing to choose as regards his need 

 of protection between front and back. Therefore 

 Nature has prescribed the protection for the nobler 

 side, the front — an example of how, out of given 

 conditions, she is ahvays the cause of that which is 

 the better. This, then, is why none of the quad- 

 rupeds has lower eyelashes (though some have a 

 few scattered hairs growing on the lower eyelid), 

 or hair in the axillae or on the pubes, as man has. 

 Instead of this, some of them have thick hair all 

 over the back part of* their body {e.g. dogs), some 

 of them have a mane {e.g. horses and such), others 

 a flowing mane, like the male lion. Again, if an 

 animal has a tail of any length, Nature decks that 

 with hair too ; long hair for tails Avith a short stem 

 (e.g. horses), short hair for tails with a long stem. 

 This, however, is not independent of the general 

 condition of the whole animal, for Nature gives 

 something to one part of the body only after she 

 has taken it from another part. So when she has 

 made an animal's body extremely hairy, we find 

 that there is not much hair about the tail. An 

 example of this is the Bears. 



» See 697 b 13 ff. 

 * Piatt deletes " the back part of," 



189 



