490 



APPENDIX 



will fuse. This is the mechanical condition of things in this experiment. 

 The shape of the curve, of course, depends chiefly on the time-relations 

 of the two stimulations. (See Expts. 65 and 68.) 



Expt. 47. Tetanus. (Apparatus: Same as in last experiment.) 

 Using the key, stimulate the muscle at first slowly and then more|fre- 

 quently, making a curve for each speed. Determine how many stimula- 

 tions per second are necessary in order that the muscle may not have 

 time to relax at all, thus writing a curve smooth on top, but up-hill 

 somewhat. 



This condition is practically a continuation of the last experiment. 

 Here the stimuli are so frequent that the muscle has no chance to me- 

 chanically relax to any degree, and the resulting myogram becomes 

 essentially a smooth line. The number of stimulations per second 



FIG. 274 



Apparatus as set up by students to study the superimposed fatigue-curve of muscle. 



required to occasion complete tetanus depends largely on the condition 

 of the muscle; fatigue, for example, renders slower the relaxation (as 

 well as the contraction), reducing the number of stimuli per second 

 required to produce this condition. Typical tetanus may be made 

 with induction-shocks coming at the rate of from 30 to 100 per second. 

 Muscular tetanus is of relatively small theoretical importance. 



Expt. 48. Fatigue. (Apparatus: Myograph with attachment for 

 breaking circuit at each rotation of the drum, signal, inductorium, two 

 stand-rods, two femur-clamps, and strip of spring-brass.) Put signal 

 and femur-clamp holding the brass strip and signal on one stand-rod, 

 and the myograph on the other. Arrange the inductorium for making 

 maximal signal-shocks, placing signals, key and automatic circuit- 

 maker in the primary circuit; the myograph is in the secondary circuit. 

 Keep the kymograph fully wound, or, better, turn the drum with an elec- 



