On Skin Currents. 



491 



mechanical excitation and electrical excitation by induction shocks in 

 either direction caused ingoing effects, occasionally preceded by out- 

 going effects. 



Waller* finds that the normal and regular response of the frog's 

 skin to any sort of disturbance — mechanical, chemical, or electrical — 

 consists in a positive (outgoing) current. 



Volt 



■03 ■ 



Erog's skin. Summation of effects of direct excitation. Compensation is established 

 at the outset of experiment, and left unaltered during its progress. The 

 first deflection is that of 1 /100th volt. The next is a trial deflection in 

 response to a single break shock, 1000 + . The subsequent effects are by 

 single break shocks, 2000 — , at 2 minute intervals. At each excitation the 

 galvanometer is short-circuited for about 2 seconds, and the deflection there- 

 fore drops. The summating series of positive (outgoing) effects approximate 

 towards a maximum of about 0*03 volt. 



* 1 Proc. Physiol. Soc.,' 1900. 



