(UI 



As one could oppose against this important amelioration that the 

 result had been due for the greater part to the help of the eyes, I 

 repeated the test in precisely the same way, but now with eyes 

 closed. The produced gait path is found in fig. 4. Now too no sign 

 of ataxia is seen. The only deviation is, that the patient walks to 

 the right instead of walking straight on. As tliis deviation takes 

 place gradually and the gait-path remains straigjjt, the circus 

 gait must be excluded ; it seems to mo, that in this case one cannot 

 speak of a deviation to the right. It is most probable that the 

 patient did not stand straight in front of the line, but somewhat 

 in oblique direction and therefore walked in that way. 



The 4''^ fig. proves that the contact sensation through the arms 

 is yet able to abolish the ataxia, even if the [)atient misses the 

 atferent-extero-ceptive impulses from the eyes. 



One thus sees here exactly the same phenomenon as with the 

 ataxia in tabes and in vestibular affliction. 



Therefore it lies at hand to assume that cerebellar sensory 

 ataxia arises when in the cerebellum the equilibrium paths are 

 being interrupted which from the spinal cord and the nervus octavus 

 puss into it. 



This would confirm Jelgersma's^) view (pg. 217) : "The supposition 

 that the cerebellum is a central place of innervation for both these 

 organs *), is therefore probable." 



Should my view be right, then cerebellar sensory ataxia will occnr, 

 when the process of the disease arises in those parts of the cere- 

 bellum, in which the equilibrium-paths pass. 



In connection with the above a few questions arise. 



The first is whether the cerebellum exclusively dominates the 

 equilibrium. 



This question is answered in negative sense by many investigators, 

 because e.g. experiments on animals have taught that experimentally 

 obtained cerebellar ataxia can totally pass away after a certain time, 

 which proves that the afferent equilibrium impulses can arrive at 

 the cerebi'um also along other paths. 



The second question is whether the cerebellar ataxia always 

 shows the same image. 



Should I, as regards the experiments on animals, confine myself to 

 the well-known investigations of Luciani *), then he too made a 



1) Jelgersma, G. The function of the cerebellum. Psych. Neur. bl. 1915. 

 ') Meant are: tonus- and equilibrium organ and the deep sensation. 

 3j Luciani, L. Das Kleinliirn. Georg. Thieme. Leipzig 1893. 



42 

 Proceedings Royal Acad. Amsterdam. Vol. XXL 



