1 86 HUMAN PHYSIOLOGY 



without there being any impairment in the power of moving 

 the muscles. This was long ago observed by Broca, and hence 

 this part of the brain is often called Broca's convolution. 

 Similarly, in the hand area, while crude lesions are required 

 to cause loss of power of moving the hand, very slight inter- 

 ferences with nutrition may cause loss of power of expressing 

 language in writing. 



