TROPHIC! FUNCTIONS OF THE CORD 395 



On the other hand, it is only during post-foetal life that the activity 

 of the skeletal muscles is determined by the motor nerves of the cord. 

 Thus they may be developed normally even in the complete absence 

 of a central nervous system. Whether we are justified in assuming the 

 existence of trophic nerves exercising an influence on the nutrition of 

 the part they supply, apart from any influence on its other functions, 

 the experimental evidence before us is not sufficient to decide ; nor 

 can we as yet give a physiological analysis of the changes in nutrition 

 which may be brought about in hysterical patients under the influence 

 of emotion. 



