42 EXPERIMENTAL PHYSIOLOGY 



when contracted is extended by the same weight. If the ordinates 

 are at regular distances apart, a line joining their lowermost ends 

 gives the curve of extension of the resting muscle, and a line joining 

 the tops of the ordinates the curves of extension of the contracting 

 muscle. Further, if the weights are removed in succession and 



1 



FIG. 39. Experiment for investigating the effect of heat on the 

 extensibility of muscle. 



ordinates are again described after each such removal, curves of 

 recovery from extension i.e., of retraction can be obtained. This 

 experiment can be conveniently performed with the sartorius, large 

 shot serving as the weights. 



3. The efiect of after-loading (p. 28). Take a series of contraction 

 ordinates, using a maximal stimulus and a constant weight (say about 



