46 CHANGES OF EXCITABILITY IN NERVES. 



completely to arrest the action of the stimulus when exercised in 

 the region of the positive pole. 



Hermann's theory, therefore, cannot explain all the phenomena 

 which attend the changes produced by a constant current in the 

 magnitude of the muscular contractions. They may, however, be 

 explained by Pfliiger's theoretical view in accordance with which 

 the cause of the changes in size of the muscular contractions is 

 to be sought in the local changes of excitability produced ly the 

 current in the nerve. Until new facts are discovered which neces- 

 sitate a modification of this view, it may be accepted. 



No such fact has presented itself in the foregoing investiga- 

 tion. 



