VI. 



THE LATENT PERIOD 



105 



excised pads that we tested by direct excitation, the " normal 

 current " was ingoing in precisely the opposite direction to 

 what might have been expected in a piece of living tissue with 

 an artificial section in one pad the effects of excitation were 

 ingoing, increments of the normal current ; in the other they 

 were outgoing, decrements of the " normal current." 



Seconds. 



FlG 43. Cat. Ingoing response of pad of foot aroused by excitation of the 

 sciatic nerve. Berne coil at 1000 units. The latent period is 3 seconds. (Galvano- 

 meter record.) 



Here are the records you saw taken a few minutes ago 

 (p. 100), showing the lost time and the course of the indirect 

 effect, on the galvanometer and on the electrometer. Compar- 



Seconds. 



FlG. 44. Electrometer-record. Indirect response (ingoing) of cat's foot-pad to 

 single break induction shock through sciatic nerve. Lost time 3 seconds. 



ing the two curves, you see that they have very similar time- 

 relations, and there does not seem to be much to choose between 

 the two instruments. This, however, is merely due to the fact 



