216 



OUR BODIES AND HOW WE LIVE 



been noted in men of great mental capacity, in which the 

 brain weighed sixty-four ounces. As a rule, a large brain 

 stands for a vigorous mind and superior faculties. 



The brain and head in a child are very large in propor- 

 tion to the rest of the body. The brain grows very rapidly 

 until the fifth year, then very slowly, and after twenty the 



growth is not per- 

 ceptible. 



292. The Three 

 Parts of the Brain. 

 The three princi- 

 pal masses or 

 parts which make 

 up the brain are: 



(1) the cerebrum, 

 or brain proper ; 



(2) the cerebellum, 

 or lesser brain ; 



(3) the medulla ob- 

 longata. 



293. The Cere- 

 brum. The cere- 

 brum fills the 

 whole of the up- 

 per part of the 

 skull, and is nearly 

 seven eighths of 



the entire mass. It consists of two parts, or halves, almost 

 separated from each other by a deep cleft, or fissure, from 

 front to back. Each of these halves or hemispheres, as 

 they are called consists of three portions, or lobes, so 

 that the cerebrum is made up of six distinct parts. 



FIG. 135. The Upper Surface of the Cerebrum. 



Showing its division into two hemispheres, 

 and also the convolutions. 



