QUANTITATIVE STIMULATION OF NERVE 467 



the stimulator at a certain distance from the responding 

 point, such as at first to cause only positive response, succes- 

 sive stimulations would then act to enhance conductivity 

 gradually, and thus give rise to the appropriate changes, 

 diphasic and negative in the response. 



The ultimate cause of these variations must therefore lie 

 in the molecular condition of the tissue. Under varying cir- 

 cumstances, this undergoes a cyclic change, the responsive 

 reaction at any given moment constituting an indication of 

 the particular molecular condition of the tissue. A more 

 complete demonstration of this, carried out by an altogether 

 different method, will be given in a subsequent chapter. My 

 principal object in this chapter has been to prove the 

 efficiency of the thermal shock as a mode of stimulation of 

 nerve. Its wider applicability, in the case of other related 

 investigations, will be treated in the two succeeding chapters. 



H II 2 



