BIOELECTRIC MEASUREMENTS 



125 



tween the electrodes, because the 'breakdown' of the nerve mem- 

 brane, which characterizes the action potential, causes electrode i 



FIG. 26a. — ^Action potential recorded between inside and outside of squid giant 

 axon. The vertical scale shows the potential in millivolts of one electrode 

 inside the axon, relative to a second electrode in the external medium, 

 assumed to be at zero potential (after Hodgkin & Huxley, 1945). 



FIG. 266. — The same action potential as in a, without any recovery phase. In 

 both cases, the dots below the action potentials are Tooth of a second apart. 



to be transiently connected to a 'sodium battery' (Fig. 28). In 

 Fig. 27c the action potential is between the electrodes,* which 



* The wave-length of the action potential is assumed to be short compared 

 with the inter-electrode distance. 



