CEREBRUM 



183 



From the various fibres, collaterals come off which connect 

 different parts of the cortex of the same side, and which also 

 connect the cortex of one side with that of the other, and 

 with the basal ganglia (fig. 93). 



FIG. 94. (a) Surface of the left Cerebral Hemisphere of a Monkey to show the 

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

 Surface of the same Hemisphere (front to right). 



Physiology 



1. General Considerations. The functions of the cerebrum 

 may be best understood by first contrasting the condition of 

 animals with, and of animals without, this part of the brain. 



(1) In the frog the cerebral lobes may easily be removed. 

 The animal sits in its characteristic attitude. When touched 

 it jumps, when thrown into water it swims. It is a perfect 

 reflex machine, with the power of balancing itself unimpaired. 

 But it differs from a normal frog in moving only when 



