244 Dr. W. P. May. On the Segmental Representation 



"Investigations into the Segmental Representation of Move- 

 ments in the Lumbar Region of the Mammalian Spinal 

 Cord." By WILLIAM PAGE MAY, M.D., B.Sc., M.R.C.P., 

 Fellow of University College, London. Communicated by 

 Professor VICTOR HORSLEY, F.R.S. Received July 1, 1896. 



(From the Laboratory of the Physiological Institute, Berlin, and the Pathological 

 Laboratory of University College, London.) 



(Abstract.) 

 Introduction. 



The following researches were carried out in consequence of sug- 

 gestions made to me by Professor Victor Horsley, F.R.S., with the 

 view of throwing light upon the degree to which certain movements, 

 or, speaking more precisely, sensori-motor (kin aesthetic) phenomena 

 are represented in any given segment of the lumbo-sacral region of 

 the mammalian spinal cord, and further of determining what relation- 

 ship exists between the representation of one movement and that of 

 another. Of methods suggesting themselves for this investigation 

 the one selected was direct excitation of the anterior or posterior 

 roots or of the spinal cord itself. 



Historical Introduction. 



A series of laborious investigations has been carried out to deter- 

 mine the localisation of certain movements and the physiological 

 relationship of various muscles in and to definite segments of the 

 spinal cord, by Terrier and Yeo, Bert and Marcacci, Forgue, Sherring- 

 ton, and Russell, the method of which was limited (controlled by 

 exclusion experiments) to stimulation of the motor roots. I am 

 only aware of one antecedent localisation experiment (by S herring- 

 ton) carried out by stimulation of the posterior roots ; nor can I find 

 any record of the direct excitation of the surface of the cord for in- 

 vestigating the localisation of movement. 



Method of Investigation and Precautions Observed. 



(a) Species of Animal. The animals chiefly employed were the 

 dog and monkey (Macacus sinicus and rhesus). 



(b) Ancesthetic. The narcotic agents used were morphia and ether 

 or, in the monkey, ether alone. 



