STIMULATION OF MUSCLE AND NERVE 139 



of the nerve holder. Arrange the inductorium 

 for maximal induction currents. Lead from the 

 secondary coil to a pair of the end cups of the 

 pole-changer (without cross-wires), as in Fig. 39. 

 To the opposite cups of the pole-changer bring 

 wires from a dry cell. 

 Connect the remaining 

 cups with the non-polar- 

 izable electrodes. Turn 

 the rocker towards the in- 

 duction coil. Fasten the 

 pelvic attachment of the Fig. 39. 



curarized sartorius in 



the muscle clamp. Tie a thread to the fragment 

 of tibia, and fasten the thread to the upright pin 

 of the muscle lever, so that the horizontal muscle 

 shall record its contraction on the drum. Start 

 the drum at moderate speed. Kecord contrac- 

 tions, (1) with maximal break shocks, (2) with 

 closure of galvanic current. Compare the curves. 



The curve from galvanic stimulation will be of 

 greater height and duration, and the summit of 

 the curve will be less pointed, indicating that 

 the muscle remains longer in the stage of ex- 

 treme shortening. 



Other evidence that the duration of the stimu- 

 lus modifies the character of the contraction is 

 afforded by the following experiments : 



