THE ELECTKOMOTIVE PHENOMENA 309 



the current is diphasic. In the first phase, the 

 current is directed away from the nerve, in 

 the second phase, towards it. In extirpated 

 muscle, the second phase is much weaker than 

 the first. In normal muscle in situ (human 

 muscle), this difference or decrement does not 

 appear. 



The direction of the current obtained with 

 the electrometer from the whole muscle is de- 

 termined by the position of the electrodes with 

 reference to the nerve equator, namely, a trans- 

 verse line drawn at the mean distance from the 

 entrance of all the nerve fibres.- Points nearer 

 the equator are negative to points further away. 



Action Current of Human Muscle. Cover 

 the brass electrodes with cotton saturated with 

 saline solution, and connect them with an 

 inductorium arranged for tetanizing currents. 

 Close the short-circuiting key of the second- 1 

 ary coil. Tie about each of the non-polarizable 

 electrodes a piece of well washed candle-wick a 

 foot long. Saturate the wick with sodium 

 chloride solution. Place one of these elec- 

 trodes around the forearm near the elbow, the 

 other around the wrist. (The nerve equator lies 

 about the upper third of the forearm.) Connect 

 the electrodes through a short-circuiting key 

 with the capillary electrometer. Place the brass 



