ON THE SKELETON. 6 



of food and size of the animal ; but those that are mediate, or concern 

 external matter, which are to be our guides, such as eyes, ears, nose, 

 &c, bear not the same proportion, but relate to the way of life that each 

 animal is adapted to. Some small animals, for example, have large 

 ears, and vice versa : the same of the eyes. But the ears seem to vary 

 most both in internal and external structure as well as size, more than 

 any of the other organs of sense. 



Parts of many animals differ greatly in size from one another when 

 compared with the size of their bodies. The head and legs of a Hon are 

 too large for the size of its body, if an ox, for instance, were our standard 

 of proportion. The size of parts often becomes a peculiar characteristic 

 of the perfection of a species in a genus : a lion has the largest head and 

 the largest feet of the whole genus, which points him out as the most 

 perfect of that genus. A white man has the largest head and hand and 

 foot of any of the human genus, which points him out as the most 

 perfect of that genus. We see that this is so far a perfection, that, as 

 the hand becomes perfect in use it increases in size, [use and size] bear- 

 ing a kind of proportion to one another : the same of the foot. The negro 

 from Africa has both a small head, and very small hands and feet. 



Fishes have the largest head in proportion to size of body, of any 

 animal. This is owing in a great measure to the gills being placed on 

 the sides of the head in many of them ; but it is a general rule which 

 extends even to those that have no gills [Cetacea] ; for in them Nature 

 seems to have added fat to give shape. This increase of head is most 

 likely for the purpose of swimming, to adapt the shape of the whole 

 body for cutting the water : their want of neck, and the whole body 

 being one uniform piece, is to answer the same purpose. 



Quadrupeds are the next in [regard to the] size of the head. Their 

 head seems to be only adapted for the purpose of life, independent of 

 the motion of the animal ; and as the head is very little resisted by the 

 air in progressive motion, Nature has given it a freer motion upon 

 the body than in fish. 



The head of a quadruped is the seat of the brain, of the senses, and [of 

 the organs] for mastication. The sense of smell in these animals being 

 the informer of proper food, &c, and therefore more acute, the nose 

 makes a large part of the head. Mastication being carried on in the head 

 in these more than in any other animal, room for teeth and muscles 

 is another cause for the size of head in quadrupeds. These two causes 

 for increase of size of head in quadrupeds is more than can be said for 

 that of the fish. 



Fowls have the smallest head in proportion to the body, of any 

 [vertebrate] animal. They have not the above reasons for size of head, 



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