1895.] Hemisection of the Spinal Cord in the Cat. 475 



cent, of its final value if dissipation of energy had taken place only 

 in the outside circuit. 



Thus, while the condenser here experimented upon exhibits marked 

 viscous effects, yet we can detect no hysteresis. 



The foregoing experiments were conducted in the Physical 

 Laboratory of University College, London, and our thanks are due 

 in many respects to Professor Gr. Carey Foster in connectiou with 

 them. 



VI. " On the Changes in Movement and Sensation produced by 

 Hemisection of the Spinal Cord in the Cat." By CHARLES 

 DEVEREUX MARSHALL, F.R.C.S. Communicated by Pro- 

 fessor V. HORSLEr, F.R.S. Received January 31, 1895. 



(Abstract) . 



The present research was undertaken in order to determine more 

 exactly the nature and origin of epileptiform convulsions and the 

 paths in the spinal cord by which both afferent and efferent impulses 

 are transmitted. 



The method employed was as follows : 



Hemisection of the spinal cord was performed in the lower dorsa 

 region on the right side, the animals being anaesthetized with ether 

 and strict antiseptic precautions being observed. 



The animals were kept alive for different periods of time after the 

 operation, and the effects produced on the voluntary movements, 

 sensibility, and the reflexes were carefully noted. 



After death the spinal cords were at once removed, and after 

 hardening and staining, by Marchi's method, both the lesion and the 

 tracts of degeneration were investigated by microscopic examination. 

 There were 16 experiments performed. 



The following results are briefly what were obtained. 



(a.) Motion. After hemisection of the cord there is immediate 

 paralysis of the limb below, and on the same side as the section, this 

 remains for a time, and then gradual recovery takes place to a greater 

 or less extent ; sometimes the recovery is so complete that it is with 

 difficulty that one can determine which was the paralyzed limb. At 

 other times more or less permanent weakness is left so as to cause a 

 limp when walking, foot-drop is not infrequently seen and the 

 animal does not appear to appreciate correctly the position that the 

 leg occupies. 



(6.) The Reflexes are, as a rule, greatly exaggerated below and on 

 the same side as the lesion, and sometimes continue so for a long 

 period ; in many cases they get less as time goes on ; occasionally 

 they are not so well marked as on the opposite or uninjured side. 



