i8o 



HUMAN PHYSIOLOGY 



by directly stimulating the reacting mechanism. When, 

 however, removal of a part of the brain causes no loss of 

 power of movement, and }^et prevents a stimulus from 

 causing its natural response, it is justifiable to conclude that 

 that part of the brain is connected with reception. 



Km. 98. (a) Surface of the left Cerebral Hemisphere to show the situations of 

 some of the Receiving and Discharging Mechanisms (front to left) ; (b) Mesial 

 Surface of the same Hemisphere (front to right). 



2nd. In man, the chief difficulty of obtaining information 

 is in finding cases where only a limited part of the brain is 

 affected. But such cases have, in many instances, been 

 observed. Tumours of an occipital lobe, for instance, have 

 been found to be associated with loss of visual sensations 



