CHAPTER VI. 



Work of muscle ; extensibility of muscle. 



The experiments to be performed on this subject 

 are recorded upon a stationary drum which must 

 be moved onwards for about five millimetres by 

 hand after each record. 



Make a muscle preparation, preferably the sarto- 

 rius (p. 26), place it on the myograph, and arrange 

 that it shall be stimulated by induction shocks. The 

 lever should have a light scale pan suspended from 

 it near the fulcrum ; such a scale pan can readily 

 be made from the lid of a pill box. Determine : 



1. The effect upon the lift, the weight being 

 constant (say about thirty grammes), of a gradual 

 increase of the strength of the stimulus from mini- 

 mal to maximal. 



2. The amount of work which the muscle performs 

 in lifting different weights, the stimulus being con- 

 stant and maximal. Beginning with the weight 

 of the scale pan alone, weights are gradually added, 

 and the muscle being stimulated, an ordinate is 

 described for each additional weight. The work 

 of the muscle is estimated as weight X height. 



Another result is yielded in this experiment ; 

 viz., the effect of gradually increasing weights in 

 producing extension of muscle in the resting and 

 contracted conditions respectively. For it is ob- 

 vious that the lowermost point of any ordinate 

 described by a contracting muscle represents the 



