90 



PEACTICAL PHYSIOLOGY 



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

 " current of injury " is completed or broken. 



CHAPTER XXIV. (Advanced). 



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. 86. 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. 



The Galvanometer employed in these experiments is Kelvin's 

 reflecting galvanometer. It consists of a suspended system of magnets 

 so arranged as to make the system nearly " astatic " ; the magnets are 



