332 PEACTICAL PHYSIOLOGY 



the kaolin plugs ; thus the circuit is suddenly made and can be 

 suddenly broken by the removal of the watch-glass. If the prepar- 

 ation be very excitable, a twitch is observed at each make and 

 break of the circuit ; the nerve is stimulated when the circuit of its 

 " current of injury " is completed or broken, 



CHAPTER XIX. 



THE ELECTROMOTIVE PROPERTIES OF MUSCLE AND NERVE 

 CONTINUED. THE GALVANOMETER AND THE CAPILLARY 

 ELECTROMETER. 



DEMONSTRATIONS. The galvanometer and the capillary electro- 

 meter are delicate instruments which are easily damaged; they are 

 employed to investigate the electromotive properties of muscle and 

 nerve. The essential experiments upon that subject have already been 

 performed by means of the so-called " rheoscopic frog." In this course. 



FIG. 210. Galvanometers. 



therefore, the experiments with the galvanometer and the capillary 

 electrometer will be demonstrated to the student and only brief 

 details will here be given. 



