EFFECT OF IREITATION OF A POLARIZED NERVE. 

 - EXPERIMENT 187— Continued. 



403 



Irritation alone. 



Irritation plus polarization. 



Strength of tlic irritation. 



cent. 

 Kheochoril 789 



Kheochord 691 



Khpochord 48S 



Kheochord 223 



Kheochord 188 



2 Daniels 



1 Daniel 



Height of 

 the con- 

 tractions. 



mm. 

 3.2 

 2 6 

 5.5 

 4. 



5.1 

 5. 



5.8 

 2. 

 10.1 

 0. 

 0. 

 4. 



3.6 

 3.6 

 7.2 

 4.5 

 4.8 

 4. 



8.7 

 9.5 

 3.2 

 3.2 

 10.1 

 13.3 

 7.2 

 3.1 

 3. 

 3. 



2.5 

 2.1 

 2. 



Strength of the constant 

 current. 



1 Dan-1 



Klieochord 53 



Kheochord 48 



Kheochord .50 



Height of 

 the con- 

 tractions. 



mm.. 

 8.9 

 10 3 

 11,8 

 13.1 

 8.3 

 19.6 

 11.2 

 4.5 

 11.6 

 4. 



3.5 

 4. 



3.4 

 3.4 

 4. 

 4. 

 4. 

 4. 



3.8 

 7.9 

 3.2 

 3.2 

 3.4 

 3. 



3.1 

 7.4 

 7.1 

 7.2 

 7. 



7.2 

 12. 



Eemarks. 



In this experiment a descending polarizing current of a given strength 

 (1 Daniel cell, "rheochord 38"), and an irritating current from 1 Daniel, 

 "rbeochord 091," producexl an increased excitability of the nerve to 

 the side of the kathode (Pfliiger's result.) But when the irritating 

 current was reduced in strength to 1 Daniel, "rheochord 1308," the 

 influence of the polarizing current on the excitability of the nerve was 

 annihilated, and we had the same contraction resulting from the irrita- 

 tion alone as from the irritation and polarization in conjunction. With 

 the irritating current somewhat stronger (1 Daniel, "rheochord 1214," 

 and "rheochord 1000"), the polarizing current absolutely paralyzed the 

 effect of the irritating current. Increasing this latter current still more, 

 the polarization had a varying influence on the effect of the irritation. 

 When, however, the polarizing current was now decreased in strength 

 (to 1 Daniel, "rheochord 5G"),the polarizing current again caused the 

 nerve to become more excitable. The same effect was attained with the 

 former polai'ization current ("rheochord 38") by using an irritating cur- 

 rent of 1 Daniel, "rheochord 789 " or "rheochord 691." With a stronger 

 irritating current the polarized nerve was less excitable than the non- 

 polarized nerve. This corresponds to the result obtainedby J^obili, Mat- 

 teucci, Valentin, and Eckhard, who always employed comparatively 

 strong currents. Using a polarizing current of 1 Daniel, "rheochord 

 48," or " rheochord 50" strength, with the irritation of 1 or 2 Daniel cells, 

 the former always increased the excitability of the nerve. 



