38 



PHYSIOLOGY OF MUSCLES AND NERVES. 



key so as to allow the inductive currents to have access 

 to the muscle. The latter at once shortens, and its 

 height of elevation is indicated by a vertical stroke on 

 the smoked glass plate. On instituting a series of 

 experiments with the same muscle but with various 

 weights, it will be found that the muscle is not able 

 to raise all weights to the same height. When the 

 weight is small the height to which it is raised is great. 

 As a rule, as the weight increases, the height to which 

 it is raised becomes less, and finally, when a certain 

 weight is reached, it becomes unnoticeable. Fig. 15 







50 



100 



150 



200 



250 



Fig. 15. Height of elevation consequent on the application of 



varying weights. 



shows the result of a series of experiments of this sort. 

 The figures under each of the vertical strokes represent 

 in grammes the amount of the weight raised ; the height 

 of the strokes is double the real height of elevation, 

 the apparatus employed in the experiment representing 

 them twice their natural size. Between each two of 

 the experiments the glass plate was pushed on a little 

 further in order that the separate experiments might 

 be indicated side by side. In finding the first of 

 these heights of elevation, under which stands an 0, no 

 weight was applied, and even the weight of the indi- 

 cating lever was neutralised by an equivalent weight. 

 It appears, therefore, that the heiglit of elevation is 



