118 GENERAL PROPERTIES OF LIVING TISSUES 



join the remaining non-polarizable electrode. If 

 the positive pole of the secondary coil is not 

 known, determine it by the electrolytic method 

 (page 158). Arrange the primary coil of the 



inductorium for single 

 submaximal induction 

 currents. Make and 

 break the induction 



C"' u =#\ current, and record 



-^ ^ / the contractions on 



the drum. Now pass 

 a weak polarizing cur- 

 rent through the nerve and stimulate again with 

 the induction current. 



It will be found that the stimulating effect of 

 the induction current is increased when the 

 direction of the induction current coincides with 

 that of the polarizing current, i.e. when the 

 cathode (which is the sole source of the induc- 

 tion stimulus, as pointed out on page 160) coin- 

 cides with the cathode of the polarizing current. 

 When the cathode of the induction circuit falls 

 in the anodal region of the polarizing circuit, the 

 stimulating effect is diminished. Very strong 

 polarizing currents produce such alterations in 

 irritability that the additional alteration caused 

 by the brief induction current is not great enough 

 to be a stimulus. 



