302 



THE SO-CALLED SECONDARY ELECTROMOTIVE 



As in the last-mentioned experiments on muscle, the two pairs of 

 electrodes were now identified, and the one united pair was placed 

 upon a destroyed spot, the other upon a living portion of a nerve- 

 preparation. 



In this case also, with a few exceptions in which very strong- 

 currents were used, the + after-effect appeared only with polarising- 

 currents directed from living to dead tissue, and on account of the 

 favourable leading-off it revealed itself after a weak current such as 

 that of one zinc carbon cell. 



Example. Two sciatic nerves placed together as before and 

 crushed at one end (dark line in schema) united leading-in and 

 leading-off electrodes at CC'. 



