VIII 



THE HIND-BKAIN 



441 



functional compensation, that is, the instinctive and voluntary 

 acts above described, by which the animal tries to repair the 

 effects of loss of cerebellar function. As soon as the so-called 

 motor zone of the cerebrum is destroyed on one or both sides the 

 animal with a half cerebellum loses for a long time, or for ever, 

 the newly acquired capability of holding itself upright, and 

 walking without falling towards the affected side. 



When the motor region of the left cerebral hemisphere was 

 removed from the bitch with the half cerebellum which, fourteen 

 months later, gave the tracings in Fig. 233, she once more lost 



FIG. 234. Brain of the bitch from which the preceding tracings were taken. (Luciani.) A, upper 

 surface, showing absence of right half of cerebellum and of left sigmoid gyrus. B, lower surface, 

 shows diminution of right half of pons and of left pyramid. 



the power of standing upright and walking, because the limbs of 

 the right side could not support the weight of the body. Twenty 

 days after the cerebral operation she succeeded, by leaning her 

 right side against a tree, in raising herself on her four legs. But 

 as soon as she tried to leave this support she fell. She was, how- 

 ever, able to swim well to the right, and even in a straight line, 

 notwithstanding the curvature of the vertebral column to the 

 right, because the strokes of the left limbs on the water were 

 much stronger than the right. About six months after the last 

 operation she could once more walk without support, but still 

 fell not infrequently to the right. In walking she held the 

 axis of her body very obliquely to the direction she was going in, 

 and even more curved to the right than at the time when tracing 

 b was taken. When blindfolded she did not attempt to walk, 



