Involved in the Electric Change in Muscle and Nerve. 179 



proportional to the difference of potential between them. Thus the current 

 in the external circuit at any point at any given moment is directly pro- 

 portional to the slope at that point of the curve giving the E.M.F. of the 



Fig. 1. — Sciatic nerve fibre, at 6'2° 0., showing observed monophasic electric response 

 (lower curve) moving from right to left with velocity about 10 metres per second, 

 and consequent current distribution in nerve (upper curves). Black curved arrows 

 show tiow of current outside fibre : dotted curved arrows show conjectured flow 

 inside fibre. The numbers in square brackets below the fibre represent times (in 

 seconds) since the front of the wave passed the corresponding points. 



electric change, and is represented graphically by the upper curve of the 

 figure. 



This current distribution should be regarded as sweeping along the nerve 

 to the left with velocity a. It is probable that the currents observed on the 

 outside of the fibre by experimental means return on the inside of the fibre, 

 as shown by the dotted arrows of fig. 1, but, as the internal electrical 



