NERVE 



65 



pole, not along the nerve or muscle (fig. 24), but more or 

 less across it (fig. 25). 



The nerve, if under the cathode, is thus under the 

 influence of the cathode on the side near the pole, and 

 under the influence of the anode on the side away from the 

 pole, and, vice versa, under the anode (fig. 25). 



A 



^M ^ li fi 



' ' > ^ "■'?■'■'" f f I } ) 



fW"^ — 



. • ; ; J ". • 



; t > i"y:if:.i i- rzi 



'TP 



+ 



C» • , • • • > 



B 



znni 







=1=3 



* • 



• * 





' ' ' 



Fig. 25. — Electrical Stimulation of human muscle or nerve to show the 

 passage of the current across the structure, and the consequent 

 combination of effects under each pole. 



Hence there will be a stimulation both at making 

 and at breaking (p. 63) under both cathode and 

 anode. 



The cathodal closing contraction is the stronger because 

 of its dependence upon the more effective pole, the cathode, 

 as it is a closing contraction, and also because the excitation 

 begins at A, which is near the stimulating pole. The 

 cathodal opening contraction has the less effective pole — the 

 anode as its origin, since it is an opening contraction, and 

 the excitation is at the less effective position B, which is 

 separated from the stimulating pole — the anode by a 

 5 



