262 



THE NERVOUS SYSTEM 



damp part the conduction in the dry part beyond is in 

 no way impaired. This experiment shows that the impulse 

 depends for its conduction upon energy hberated along its 

 course, and that the nervous impulse obeys the all-or-none 

 law in that its intensity is independent of the intensity of 

 the stimulus to which it owes its origin. 



A 



B 





N 



CO 



To Muscle 



'\r^ 



II d I d' 



Fig. 39. — Adrian's experiment (from the Journal of Physiology). 



In confirmation of this view is the evidence, already 

 given, of a definite increase in the metabohsm of a nerve- 

 fibre when it is active. 



Conduction from Nerve to Muscle 



The axis cylinder pierces the sarcolemma of the muscle- 

 fibre and arborises in a mass of protoplasm known as the 



