FUNCTIONS OF THE CEREBELL UM. 909 



of this or that piece of musculature, but of the musculature of the 

 body as a whole. The earlier observers, Flourens, Bouilland, etc., stated 

 this when they spoke of the cerebellum as an organ of " equilibration." 



In Rolando's " saggio " the cerebellum was likened to Volta's then 

 newly invented electric pile, and was argued to augment the power of 

 movements initiated by the cerebrum. Its removal was shown to leave 

 the innervation of certain parts weakened. This view, apart from the 

 crude simile, is to - day accepted in great part ; witness Luciani's 

 parasthenia. The rolling about the long axis of the body and other 

 phenomena of similar kind are generally explained by weakened in- 

 nervation on one side, leading to upset of balance in assumption of 

 attitudes which demand bilaterally symmetrical innervation ; the sound 

 side pushes over the weak side. Some l have, however, urged that the 

 phenomenon is rather due to abnormal over-action on the part of the 

 stronger side ; there is plenty of analogy for this latter view, although 

 specific proof is wanting. Such analogy is found in the fact that 

 severance of afferent spinal roots and that semisection of the spinal 

 cord heighten the spinal reflexes, long and short, in one-half of the 

 cord. 2 As to the exact nature of the depression of action on the 

 one side, and of the questionable increase of action on the other, 

 there seem as yet insufficient data to discuss these profitably 

 here. 



Flourens analysed differently from Eolando. He had, by reason of 

 Legallois's and his own researches on the bulbar nosud vital, been faced 

 by the existence of real foci in the nervous system, capable of marshalling 

 a complexus of muscles for orderly accomplishment of a single end. 

 Indeed, Legallois and he had discovered what Bell, having guessed at, 

 had actually groped for by dissection, but, neglecting more delicate and 

 potent means, had failed to reach, namely, the focal centre guiding 

 and co-ordinating the movements of respiration. Flourens translated 

 the disturbances ensuing on destruction of the cerebellum to mean 

 loss of a part possessing ability to co-ordinate the innervations which 

 guide and execute complex movements. By his doing so, the idea of 

 nervous co-ordination was, it seems to me, formally introduced into 

 physiology. 



Lussana and Carpenter were the earliest to literally express what 

 Flourens' inco-ordination and the vast afferent connections of the organ 

 conspire to suggest, that we have here in the cerebellum a part of the 

 machinery for, in the widest acceptation of that term, the muscular 

 sense. Impressions originating in the sensifacient organs of muscles, 

 tendons, joints, and ligaments, and those arising in the apparatus of the 

 labyrinth, appear to be transmitted directly or indirectly to the cere- 

 bellum. Therein is elaborated reflexly an adjustment of the bodily 

 " me " to the existent and constantly varying spatial relations between 

 that " me " and its environment. The connection of the cerebellum 

 with the vestibular nerve, and so with the labyrinth, is as marked as 

 is the connection between each of these structures and the tonus of 

 the muscles of the homonymous half of the body. Destruction of each 

 lowers the muscular tonus ; and I would suggest that reflex muscular 

 tonus bears to these structures the same relation as the reflex move- 

 ment bringing a luminous image into more central vision bears to the 

 eye and nervous visual centres. 



1 E.g., Brown-Sequard, loc. cit. ; Vulpian, loc. cit. 2 See above, p. 865. 



