866 



THE CENTRAL NERVOUS SYSTEM 



animal cause it to fall in that direction. A similar experiment with 

 dogs yields like results, but the operation is of course considerably more 

 difficult. In man, a destructive tumor of the cerebellum produces a con- 

 dition known as "cerebellar ataxy," in which the patient moves his 

 limbs in a very incoordinate fashion; he staggers, is uncertain in his 

 gait, and behaves in general very like a drunken man. 



Although these immediate effects of cerebellar extirpation indicate 



Fig. 222. Footprints after destruction of the cerebellum in a dog: a, before the operation; 

 b, four days after; c, five days after; d, a month after; e, two months after. (From Luciani.) 



clearly that this organ has to do with the control of muscular movements, 

 yet the results are probably not primarily dependent on the ablation, 

 but rather on the conditions of irritation which are set up as a result of 

 the operation, and which probably affect the cerebellar peduncles. At 

 least, such is the view that Luciani, one of the greatest investigators in this 

 field, has adopted because of the fact that, if the animal is kept alive for 

 sufficient time so that the symptoms of irritation disappear, they become 



