EVOLUTION OF THE HUMAN SPECIES 165 



that chimpanzees can be taught to wear clotliing and 

 to use a cup and spoon and bowl hke a human child. 

 Indeed, in mental respects, the chimpanzee surpasses 

 all of the other mammalia, with the sole exception of 

 man. An eminent psychologist has stated that it is 

 about the equal, in mental ability, of a nine months' 

 old human infant. 



The last form among the apes, the gorilla, is one that 

 brings us to a realization of our own human physical 

 degeneracy. The animal lives in West Equatorial 

 Africa, and it is a veritable giant in bulk, though its 

 height may not exceed five feet six inches. The heavy 

 ridges over the eyes, the upturned nostrils and triangular 

 nose, place it near to the orang-outang, but it is superior 

 to that form in its relatively greater brain-box, and in 

 the fact that its heavy lower jaws do not protrude so 

 greatly. It, too, is semi-erect, so that the line of the 

 vertebral axis makes an angle with the plane of the 

 ground of about seventy degrees. Its anterior limbs, 

 or arms, are again very long and bulky ; and like the 

 chimpanzee, it rests its knuckles upon the ground in 

 walking. 



It is a short step further to the human organism, 

 whose brain has become larger and more complex, with 

 a corresponding advance in the functional powers of 

 reason and the like that owe their existence to the im- 

 proved structural basis. After what has l)een said 

 earlier regarding the relation between the erect attitude 

 in walking and the increased size of the cranial part of 

 the skull as compared with the face, it will not bo difli- 

 cult to see how inevitably the former is the result of 

 the latter. Should we get upon the ground ui)ou our 



