vin THE HIND-BKAIN 481 



These effects of the extirpation of lobules of the cerebellum 

 obtained by van Kynberk were continued at least in essentials 

 by the researches of Pagano (1904), Marassini (1905-6), Luna 

 (1907), Hulshoff Pol (1909), and Binnert (1908). 



The results obtained on dogs were continued by a series of 

 fresh researches by van Kynberk and Vincenzoni (1908) on the 

 sheep's cerebellum, in which the S lobule is more developed than 

 in dogs. In sheep, too, excision of the paramedian lobule causes 

 rotation round the long axis of the animal. 



Eothmann's experiments on monkeys (1910-11) harmonise well 

 with the localisations indicated by Bolk. He further found that 

 in dogs the extirpation of the lower part of the anterior lobule 

 disturbs phonation (barking), and also produces noticeable dis- 

 turbances in the movements of the tongue and jaws. These results 

 were not, however, confirmed by Grabower (1912). 



As a whole, these experimental facts to a large extent confirm 

 the inductions of Bolk, and are the first positive indication of 

 localisation in the cerebellum. There is no experimental control 

 for the less accessible parts of the cerebellum ; it has been 

 impossible to study the effects which follow on local extirpation 

 of the whole anterior lobe-- which, according to Bolk, must 

 influence the muscles of the head and of the formatio reticularis, 

 which must be in relation with the caudal and spinal muscles. 



These results agree perfectly with the general theory of the 

 function of the cerebellum as stated above, and there is no necessity 

 for reviving Flourens' old hypothesis. By his morphological 

 studies Bolk has suggested to other investigators this new develop- 

 ment of cerebellar physiology, according to which the several 

 lobules of the cerebellum have a more intimate or direct relation 

 with special groups of muscles ; on the other hand the function of 

 reinforcement is everywhere the same in the cerebellum, and 

 defect of any of the lobules can be met by organic compensation 

 in the lobules that remain. 



One of the most important results of the analysis of cerebellar 

 ataxy produced in dogs by the unilateral or bilateral ablation of 

 the cerebellum is the sharp separation of the symptoms of cere- 

 bellar deficiency from those vi functional compensation ; the latter 

 are the purposive and voluntary acts by which the animal succeeds 

 in obviating the effects of deficient or lost cerebellar innervation. 



Directly the sigmoid gyrus of one or both cerebral hemispheres, 

 which contains the greater part of the voluntary motor centres, is 

 destroyed, the animal which has lost half or the whole of its 

 cerebellum loses again for a time, or permanently, the power of 

 maintaining the erect posture and of walking (p. 440). 



In reviewing the facts which show that the compensation of 

 cerebellar ataxy is dependent on the motor zone of the cerebrum, 

 a new series of problems is at once presented to the physiologist. 



VOL. Ill 2 I 



