496 



MUSCLE-NERVE PHYSIOLOGY 



it has previously done, or fatigue ; 4, by the time since it was isolated from the 

 circulation. Perform a series of experiments varying these effects, and record 

 the results by the following outline: 



6. The Relation of the Contraction to the Strength of the Stimu- 

 lus. Minimal and Maximal Stimuli. Prepare a muscle-nerve of the 

 frog and mount in the moist chamber and arrange for stimulating the muscle 

 directly by means of the secondary current of the induction coil, with the ap- 



FIG. 352. Simple Form of Pendulum Myograph and Accessory Parts. A, Pivot upon which 

 pendulum swings; B, catch on lower end of myograph opening the key, C, in its swing; D, a spring- 

 catch which retains myograph, as indicated by dotted lines, and on pressing down the handle of 

 which the pendulum swings along the arc to D on the left of figure, and is caught by its spring. 



paratus adjusted as in figure 351. Prepare a recording cylinder for making 

 vertical records of the contractions. Adjust the writing point of the muscle 

 lever to the drum and move the drum by hand i cm. after each succeeding 

 contraction. Set the secondary coil of the induction apparatus so that it will 

 be too weak to produce a stimulus. Now attempt to stimulate the muscle, 



