184 Mr. F. Gotchon Electrical Relations of Brain, dc. [March 7, 



(2) The anatomical plan and minute structure of the spinal cord 

 and brain were then described, and the condition of the brain in 

 diflferent mammals was depicted. Special attention was drawn to 

 the important recent additions which had been made to our knowledge 

 of the course of nerve fibres through these complex organs, by the 

 employment of histological methods which differentiated between 

 degenerated and sound nerve fibres, and between partially and com- 

 pletely developed nerve fibres. Observations made along such lines 

 had, it was pointed out, grouped together certain fibres as having 

 common centres both of nutrition and of growth. 



(3) The results of the investigations of the last ten years into 

 the j)hysiological relations of the brain and spinal cord were then 

 referred to, and the extent of our knowledge of cerebral localisation 

 determined. The indirect nature of the evidence as to the actual 

 passage of nerve impulses in either direction along the nerve fibres 

 composing the spinal cord was next alluded to — this evidence being 

 the arrival of the nerve impulses at outlying muscles. 



(4) Details were then given of the application of the method 

 previously used to determine the electrical changes in the nerves in 

 order to ascertain what changes of a similar kind were present in 

 the spinal cord. Exj)eriments made for the first time by Y. Horsley 

 and the lecturer were cited to show that such electrical effects were 

 produced when {a) the so-called motor regions of the brain, (h) the 

 columns in the spinal cord, and (c) the entering sensory spinal nerves 

 were stimulated ; and evidence was adduced to prove that the 

 electrical effects thus obtained were true indications of the passage 

 of nerve impulses along the nerve fibres in the particular region of 

 the cord investigated. 



(5) The physiological relations of the brain, spinal cord, and 

 spinal nerves as determined by the newly discovered electrical 

 relations of these organs were then touched upon ; and a series of 

 experimental investigations still in progress were referred to which 

 seemed to warrant the belief that a basis had been reached for the 

 construction of a scheme of physiological localisation in the fibres of 

 the cord for both efferent (motor), and afferent (sensory) fibres, such 

 as would be in harmony with the known anatomical relations of the 

 central nervous system. 



[F. G-l 



