Page:Proceedings of the Royal Society of London Vol 60.djvu/219

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The research was undertaken in the hope of obtaining evidence in support of or against th e view th a t the cerebellum exercises a directinfluence on the spinal centres, as opposed to any indirect influence exerted through the agency of the cerebral cortex. The inferior peduncle of the cerebellum was accordingly divided on one side, the organ itself and its other peduncles being otherw ise left intact, and the results obtained by this procedure were controlled by experim ents in which the lateral tracts of the m edulla oblongata were divided on one side w ithout injury to the pyram id on the one hand or to the posterior columns and their nuclei on the other. F u rth er control experiments consisted in dividing transversely the posterior columns and their nuclei a few m illim etres above th e calamus scriptorius, on one side, w ithout including the lateral tracts of th e medulla in the lesion.

The results obtained by these different experim ents were supplem ented by others in which the electrical excitability of the two cerebral hemispheres was tested and compared, im mediately after division of one inferior peduncle of the cerebellum, and at some later period, such as three weeks, after the section of the peduncle ; also after partial hemisection of the medulla in w hich all the structures on one side were divided, w ith the exception of the pyram id w hich was left as far as possible intact.

Other experiments consisted in observing the way3 in which convulsions, induced by the intravenous injection of the essential oil of absinthe, were modified by division of one inferior peduncle of the cerebellum, by partial hemisection of the m edulla in which the pyramid was the only structure left intact on one side, and by transverse section of the posterior columns and their nuclei, on one side, a few millimetres above the calamus scriptorius.

Considered in conjunction with results previously obtained by the author and others after ablation of one lateral half of the cerebellum, and after intracranial section of the auditory nerve, the results now