STIMULATION OF MUSCLE AND NERVE 103 



method, until conduction between auricle and ven- 

 tricle is partially or wholly interrupted. The clamp 



Fig. 26. The Gaskell clamp ; about one-third the actual size. 1 



is also used to press upon the sartorius until the con- 

 duction wave is blocked while the excitation wave 

 still passes. 



The contraction takes place now only at 

 the anode, and the contraction wave spreads 

 from that point over the muscle (as making 

 the current is a less effective stimulus than 

 breaking it may be necessary to increase the 

 strength of the current, or to keep it closed a 

 considerable time, in order to secure making 

 contraction). 



4. Intestine. Place the non-polarizable anode 

 on the intestine of a freshly killed rabbit or frog, 

 the cathode on some indifferent point, for example 

 the liver. Close the key. 



The intestine will constrict in the anodal re- 

 gion and remain constricted during the passage 

 of the current, provided it be not so long as to 



1 This form was first described in the Catalogue of the Harvard 

 Apparatus Company, May, 1905. 



