CHAPTER LXXXIX 



MAN'S BRAIN 



513. Hand and brain. The hand of man and the brain of 

 man are the organs that make all the important differences 



Pigeon 



Dog 



Monkey Man 



Fig. 259. Brains of vertebrates 



Note the relative size of the cerebellum in the bird and mammals. In the mammals 



note the great increase of cerebrum and the increasing amount of convolution, or 



wrinkling, of the brain surface. The greater brain area in the higher animals corresponds 



to greater numbers of association neurons, and thus to greater intelligence 



between him and the other animals. And the doings possible 

 for the hand depend finally upon the powers of the brain. It 

 is this organ, therefore, that may properly be considered man's 

 supreme possession. 



497 



