122 GENERAL PROPERTIES OF LIVING TISSUES 



wound (not over- wound), and the drum should 

 revolve at its most rapid speed. Write two 

 muscle curves. For the first stimulate through 

 the metal electrodes nearer the muscle ; for the 

 second through the metal electrodes farther from 

 the muscle. 



While each curve is writing, let a tuning fork 

 record its vibrations beneath the point of the 

 the muscle lever. To mark on the abscissa of 

 the muscle curve the exact moment at which the 

 muscle was stimulated, turn back the drum until 

 the writing point of the signal lies precisely in 

 the line described by it when the current was 

 broken. Now stimulate the muscle with another 

 induction shock. The curved ordinate of the 

 muscle lever will be synchronous with the ordi- 

 nate of the signal. 



The interval between the moment of stimula- 

 tion, as recorded by the signal, and the beginning 

 of contraction, is greater when the nerve is stim- 

 ulated far from the muscle. The difference is 

 the time required for the nerve impulse to tra- 

 verse the length of nerve between the electrodes, 

 provided of course that the interval between the 

 arrival of the nerve impulse in the muscle and 

 the beginning of the contraction is the same in 

 both cases, an assumption considered reasonable 

 by most physiologists. 



