62 



PHYSIOLOGY OF MUSCLES AND NER\ES. 



form of a thin thread, through which the current may 

 pass. When, however, the muscle shortens the quick- 

 silver is torn away, and resumes its ordinary convex 

 sm'face ; and when, on the extension of the muscle, 



Fig. 22. Diagram of experiment for the electric measuremlni' 



OF time. 



the lever again sinks, though the point p again rests on 

 the platinum plate, yet the point q remains separated 

 from the quicksilver by an intermediate air-filled space, 

 and the current remains permanently interrupted. 



It still has to be explained how the irritation of the 

 nuiscle and the closing of the time-determining current 



