STIMULATION OF MUSCLE AND NERVE 93 



IV 



THE ELECTRICAL STIMULATION OF MUSCLE 

 AND NERVE 



THE GALVANIC CURRENT 



THE study of the changes occasioned in muscle 

 and nerve by electrical stimulation may profit- 

 ably begin with the action of the galvanic 

 current. 



Non-Polarizable Electrodes. When metal 

 electrodes come in contact with an electro- 

 lyte, polarization currents develop (see page 51). 

 Electrodes of metal for this reason should be 

 avoided in the study of the effect of the galvanic 

 current on muscle and nerve. A "non-polar- 

 izable " electrode should be employed. Strictly 

 speaking, no electrode is non-polarizable, but 

 practically the polarization errors are excluded 

 by the device shown in Fig. 23. 



The boot electrodes (Fig. 23) are made of potter's 

 clay, skilfully fired, and are unglazed. The leg is 

 pierced with a hole 28 mm. deep and 8 mm. in 



