THE NERVOUS SYSTEM 



125 



ments ; that is, it makes the 

 muscles act at the right 

 time and with due force in 

 complex acts, such as stand- 

 ing, walking, talking. A 

 man could strike just as 

 hard without the action of 

 the cerebellum, but he would 

 not be likely to hit what he 

 aimed at. A drunken 

 man staggers and fails to 

 control the muscles in walk- 

 ing because the alcohol has 

 caused the blood to collect 

 and congest around the 

 cerebellum and press upon 

 it. One whose cerebellum 

 has been injured by accident 



Cerebri 



Fig. 114. --The Lobes of the Right 

 Side of Brain and their functions. 

 (Jegi.) 



The speech center is true only for left-handed 

 persons. Medulla is marked " Bulb." 



staggers like a drunken man. 

 Coverings of 

 the Brain. — Lin- 

 ing the skull and 

 covering the cere- 

 brum are found 

 two membranes 

 which inclose a 

 lymph-like fluid. 

 Thus a kind of 

 water bed'\% made 

 which surrounds 

 the soft and deli- 

 cate cerebrum 

 Fig. 115. — Motor and Sensory Areas of Left 



Hemisphere. Speech- center marked " Lips." anc ^ protects It 



In what region are the motor centers? The sensory centers? I TO Ul J a T S. i\ 



