692 



AN AMERICAN TEXT-BOOK OF PHYSIOLOGY. 



FIG. 191. Lateral view of the left hemisphere of an orang-utang, showing the motor area about 

 the central fissure (Beevor and Horsley). 



by parts of the cortex from which no response can be obtained upon direct 

 stimulation (see Fig. 191). 



FIG. 192. Lateral view of a left human hemisphere, showing the motor areas in man. The schema 

 is based on the observations on the monkey, on pathological records, human, and on direct experiments 

 on man. It is to be remembered that in the human brain the excitable localities are surrounded by 

 rather extensive areas not directly excitable (Dana). 



FIG. 193. Mesial view of a human hemisphere, showing motor areas. Formed in the 

 same way as Figure 192. 



By a few direct experiments and by many pathological observations some- 

 thing is known of the motor centres in the human cerebral cortex. When 



