Interruption of Afferent and Efferent Tracts of Cerebellum. 199 



"Phenomena resulting from Interruption of Afferent and 

 Efferent Tracts of the Cerebellum." By J. S. RISIEN 

 RUSSELL, M.D., M.R.C.P., Research Scholar to the British 

 Medical Association, Assistant Physician to the Metro- 

 politan Hospital, and Pathologist to the National Hospital 

 for the Paralysed and Epileptic, Queen's Square. Com- 

 municated by Professor VICTOR HORSLEY, F.R.S. Received 

 June 17, Read June 18, 1896, 



(From the Pathological Laboratory of University College, London.) 

 (Abstract.) 



The research was undertaken in the hope of obtaining evidence in 

 support of or against the view that the cerebellum exercises a direct 

 influence 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 otherwise left intact, and 

 the results obtained by this procedure were controlled by experiments 

 in which the lateral tracts of the medulla oblongata were divided on 

 one side without injury to the pyramid on the one hand or to the 

 posterior columns and their nuclei on the other. Further control 

 experiments consisted in dividing transversely the posterior columns 

 and their nuclei a few millimetres above the calamus scriptorins, on 

 one side, without including the lateral tracts of the medulla in the 

 lesion. 



The results obtained by these different experiments were supple- 

 mented by others in which the electrical excitability of the two cere- 

 bral hemispheres was tested and compared, immediately 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 which all the structures on one 

 side were divided, with the exception of the pyramid which was left 

 as far as possible intact. 



Other experiments consisted in observing the ways in which con- 

 vulsions, 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 medulla 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 scrip torius. 



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 



