EFFECT OF IRRITATION OF A POLARIZED NP^RVE. 



409 



The polarizing current used in the preceding experiment passed in an 

 ascending direction, while a descending irritating current was applied 

 to the nerve below it. When the former was of the strength of 1 Daniel, 

 '^rheochord 50," it failed to influence the efi'ect of an irritating current 

 derived from 1 Daniel cell. \Vhen, however, the strength of the former 

 current was increased to "rheochord" 53 or 48, it jiroduced a diminished 

 excitability of the nerve; but with "rheochord" 43, 38, 1*8, 18, or 8, the 

 opposite eflect was i)roduced. With "rheochord 4" a diminished excit- 

 ability was jjroduced. The same result was obtained when the polariz- 

 ing current was increased to 1, 2, 3, 4, or Daniels. A polarizing cur- 

 rent of 1 Daniel, "rheochord 18," again i)roduced an augmented excit- 

 ability' of the nerve. 



ESPERIMEIfT 192. 



In the foregoing experiment the descending irritating current was 

 kept of one strength throughout the experiment. In the beginning it 

 remained unaffected by a polarizing current from 1 Daniel, "rheochord 

 55," but the contractions which it produced were pie%-eiite(l by a polar- 

 izing current of 2 Daniels. A polarizing curreiiT of 1 Daniel, '* rheocliord 

 38," increased the excitability, while still further increasing this current 

 to "rheochord 8" almost annihilated the eflects of the irritation. 



