172 THE NERVOUS SYSTEM. 



lutely proven, that the anterior masses, like the anterior 

 roots of the spinal nerves and the anterior columns of 

 the cord, are concerned in the production of motion; in 

 fact, that they are the central organs of that function. 

 The posterior gray masses are, on the contrary, supposed 

 to be the seat of sensation. 



51. The Function of the Cerebellum. The func- 

 tion of the cerebellum, or "little brain/' is the direction 

 of the movements of the voluntary muscles. When this 

 organ is the seat of disease or injury, it is usually observed 

 that the person is unable to execute orderly and regular 

 acts, but moves in a confused manner as if in a state of 

 intoxication. Like the larger brain, or cerebrum, it 

 appears to be devoid of feeling; but it takes no part in 

 the operations of the mind. 



52. The Function of the Cerebrum. The cere- 

 brum, or brain proper, is the seat of the mind; or, speak- 

 ing more exactly, it is the material instrument by which 

 the mind acts; and, as it occupies the highest position in 

 the body, so it fulfils the loftiest uses. All the other 

 organs are subordinate to it:* the senses are its messengers, 

 which bring it information from the outer world, and the 

 organs of motion are its servants, which execute its com- 

 mands. Here, as in the nervous apparatus of lower grade 

 already considered, the gray matter is the element of 

 power; and, in proportion as this substance increases in 

 extent, and in proportion to the number of convolutions 

 in the hemispheres, do the mental faculties expand. 



53. There have been a few, but only a few, men of dis- 

 tinguished ability whose brains have been comparatively 

 small in size ; the rule being that great men possess large 

 brains. The relative weight of the brain of man, as com- 



5 1 . Function of the cerebellum ? When it is diseased ? 



52. Where is the seat of the mind? The subordination of the other organs? 

 The gray matter ? 



53. What is stated of men in connection with the size of their brain ? With 

 the brains of other animals ? 



