ELEMENTARY EXPERIMENTAL PHYSIOLOGY 49 



FIG. 46. Effect of two successive maximal stimuli, with gradually diminishing 



intervals, upon the gastrocnemius. To be read from below upwards. 

 Time tracing, 50 per sec. In the two upper curves are shown both the contraction in response 



to the first stimulus alone and the combined contractions caused by the two successive stimuli. 



(M.S.P.) 



P.C 



FIG. 47. Diagram of the vibrating reed in circuit. 



and take a trace for about 3 or 4 seconds, then close the key, but 

 let the drum run till the lever falls to its previous level, then stop it. 



