BBS Dr. A. Waller and A. cle Watfcevflle. [Dec. 7. 



nerves of man follow a course essentially similar to those observed in 

 the motor nerves. 



Proof hy Makes and Breaks of a Galvanic Current. 



1. The effect of a make excitation is increased by the kathodie 

 inflnence of the polarising current. This effect is. as usual, more 

 marked in the polar zone (where the density is greater) than in the 

 peripolar, and increases, within physiological limits, with the strength 

 of the polarising current. 



Placing the neutral electrode on the back and the exploring elec- 

 trode over one of the cutaneous nerves at the wrist we obtained the 

 following numbers. Xo external resistance was used, but the galva- 

 nometer showed that no change of resistance in the circuit took 

 place during the experiment : — 





^ 



2 



4 



6 



s 



Strength of current necessary 

 to produce minimal sensa- 

 tion expressed in number of < 



rin polar \ 

 zone J 



9 



6 



5 



4 





ln pen- 

 jpolar zone 



jio 



8 



6 



5 



3 



"2. The effect of a break excitation in the polar zone is rapidly 

 diminished and abolished by the anodic influence of the polarising 

 current. (Owing to the strength of current required this can scarcely 

 be ascertained fur the peripolar zone.) 



Arranging our electrodes as in the experiment first described, we 

 take a current of thirty cells, which gives a distinct sensation at 

 break. TV~e then introduce a polarising current gradually increased. 

 The sensation becomes rapidly fainter, and disappears alt02"ether when 

 the polarising current has reached live or six cells. 



Proof hy Induction Currents. 



1. The effect of induction shocks is increased when the excitation 

 falls upon the kathodie zone of the polarising current. 



A. series of experiments made with the testing electrode placed 

 (according to the method above described) on various superficial 

 nerves gave the following numbers : they are derived from experiments 

 made with and without additional resistance (the numbers obtained 

 having been reduced in the latter case). For the sake of comparison 

 we also give the numbers obtained from experiments on motor 

 nerves. 



