EFFECT OF IRRITATION OF A POLARIZED NERVE. 

 EXPERIMENT No. 190— Continued. 



407 



Irritation alono. 



[ Heipht of 

 Stronsth of the irritation. the eon- 

 tractions. 



mm. 

 4.5 

 4.2 

 6. 



5.1 

 ].5 

 ]..') 

 2.4 

 4. 

 G. 1 

 3.4 

 4. 



Irritation'with polarization. 



Strength of the constant 

 current. 



3 Daniels 



Eheochord. 

 Khcoehord. 



Heisht of 

 the con- 

 tractions. 



mm,. 

 0. 

 0. 

 0. 

 0. 

 C.9 



5^8 



3.2 



0. 



0. 



0. 



Ohservations. 



In tlie preceding experiment descending irritating currents with both 

 ascending and descending pohirizing currents were used. When an as- 

 cending poUiriziug current from 1 Daniel, "rheocbord 55," and irritating 

 currents from 2 Daniels or 1 Daniel, "rheocbord ll'Gl," Mere used, the ef- 

 fect of the irritation was diminished bj^ the polarization. With the same 

 strengths of currents, but with a descending instead of an ascending po- 

 larizing current, the oi>posite effect was produced. That is, under these 

 circumstances there was diminished excitability in the anelectrotonic 

 and increased excitability of the nerve in the katelectrotonic phase — 

 riiuger's result. When, now, this irritating current was increased to 1 

 Daniel, "rheoehord 1059," both the descending and ascending polarizing 

 currents diminished the excitiibility of the nerve. After some minutes, 

 however, with the same currents, augmented excitability occurred in the 

 hatelectrotonic phase. With polarization, 1 Daniel, " rheochord •43," and 

 irritation, 1 Daniel, "rheochord 440," the ascending polarizing current 

 produced an increased excitability. Decreasing the strength of the polar- 

 izing current to 1 Daniel, "rheochord fO," the opposite effect was pro- 

 duced. With an irritating current from 1 Daniel cell, an ascending polar- 

 izing current from 1 Daniel, "rheochord 38," at first fails to affect the ex- 

 citability of the nerve, but later increases it. With the same irritation, a 

 polarizing current from 1 Daniel, "rheochord 43," produces an increased 

 excitability of the nerve. The irritation being the same, an ascending 

 polarizing current from 1 Daniel, "rheochord 4," does not in the least af- 

 fect the excitability of the nerve. With a polarizing current from 1 Dan- 

 iel and an irritating current of the same strength, the effect of the latter 

 is increased during the presence of the former. The effect of the same 

 irritating current is, however, absolutely annihilated by an ascending 

 polarizing current from 3 Daniel cells. After this it was found that the 

 effect of an irritation (I Daniel) was increased by an ascending polarizing 

 current from 1 Daniel, "rheochord 43," which earlier in the experiment 

 had the opposite effect. The very opposite result was obtained with 

 irritation, 1 Daniel, and polarization, 1 Daniel, " rheochord 38." 



