EFFECT OF IRRITATION OF A POLARIZED NERVE. 383 



Fifth irritations.— Salt solntiou alonc = 1.5. Witli polarization, 0.5. 

 Sixth irritations. — Salt solution alone = 1.5. With iiolarization, 0.5. 



Experiment 83. — Sciatic nerve and gastrocnemius muscle of a Eana 

 tem])oraria. 



Polarizing current from 4 Daniel ceJh. 



First irritations. — Salt solution alone=:2, "With polarization, "3. 

 Second irritations. — Salt solntion aloue = 2. With polarization, 2. 

 Third irritations. — Salt solntion alone := 2. With polarization, 2. 

 Duration of experiment 13 minutes. 



Experiment 84. — Sciatic nerve and gastrocnemius muscle of a Eana 



temporaria. 



Polarizing current from 4 Daniel cells. 



First irritations. — Salt solution alone=0.5. With polarization, 0.5. 

 Second irritations. — Salt solution aloue=0.5. AVith polarization, 0.8. 

 Third irritations. — Salt solution alone = 0.5. With polarization, 1. 

 Fourth irritations. — Salt solution alone=0.5. With polarization, 0.5. 

 Fifth irriratious. — Salt solution alone = 0.5. With polarization, 1. 

 Sixth irritations . — Salt solution alone =0.5. With iiolarization, 0. 



ExPEEiJiENT 85. — Sciatic nerve and gastrocnemius muscle of a Eana 

 temporaria. 



Polarizing current from 4 Daniel cells. 



First iiritatious. — Salt solution alone ^3. With polarization, 4. 

 Second irritations. — Salt solntion alone -= 3. With polarization, 4. 

 Third irritations. — Salt solution alone = 3. With polarization, 4. 

 Fourth irritations.— Salt solntion alone=3. With polarization, 3.5. . 

 Fifth irritations. — Salt solution alone = 3. With polarization, 3.5. 

 Sixth irritations. — Salt solntion alone ^3. With x>olarization, 3.5. 

 Seventh irritations. — Salt solution alone=3. With polarization, 3. 

 Eighth irritations. — Salt solution alone=0. With polarization, 2. 

 Ninth irritations. — Salt solution aloue=:0. With polarization, 2.5. 

 T(Mith irritations. — Salt solution alone=:0. With polarization, 2. 

 Eleventh irritations. — Salt solntion alone ==0. With polarization, 2. 



This series of experiments made with chemical irritants certainly give 

 us no more reason to believe in the infallibility of Pflligers "laws" than 

 the preceding series. 



In finishing these series of experiments the following conclusion seems 

 to be demanded hy the facts observed : When a descending polarizing 

 current is applied to a nerve above a descending irritating current.^ the effect 

 of the latter in exciting the nerve to produce muscular contractions is not 

 necessarihj increased during the passage of the former. On the contrary, 

 it often appears to be less instating during the passage of the descending 

 I)olarizing current through the nerve. 



The ascending polarizing current applied to a nerve above a descending 



irrita t ing currcn t. 



N.. 



I. c. p. c. 



