120 APPENDIX I. 



circuit closed by establishing a bridge between two 

 points of it ; and a spring-key, which the person 

 holds in his hand, ready, by it, to make the circuit 

 a^ain after it has been broken by the lever-key. 

 All the rest is very simple, and easily understood 



FIG. 3. 



-3' 



C d / 



when looking at the broken line b V in Fig. 3, which 

 is the record of an experiment as written down by 

 the style 6. At c, the lever-key has been pressed 

 down in order to prepare the experiment. At d, 

 the circuit of the magnet B, and of the primary coil 

 of the induction apparatus, has been broken, and 

 the induction current passed through the skin, all 

 by again lifting the lever-key. At e, the person, 

 having perceived the shock, has made the circuit 

 again by means of the spring-key, and at / has 

 broken it once more, in order to render another 

 experiment possible. So that the distance d e here 

 would correspond to the time we have designated 

 by T, and would be found to be greater or smaller 

 according to the distance the nervous agent had to 

 travel from the stimulated place on the skin to the 

 brain. 



The velocity of the nervous agent in the nerves 

 of common sensation, in the living body of man, 

 has thus been found by Dr. Schelske to be 29-6 



