378 EFFECT OF IRRITATION OF A POLARIZED NERVE. 



Time, 



h. m. 



2 49 

 52 

 53 

 54 

 55 

 58 



3 00 

 01 

 02 

 16 

 18 



2 19 

 21 

 24 

 34 

 40 



Number of ex- 

 peiiment. 



13th irritations. 

 14tli initations. 

 loth irr}»»t»oTis. 

 IGth iiTitatiinis. 

 17th iriit ill ions. 

 18th iiTitatiiins. 

 19th iiritatinus. 

 20th initatiuiis. 

 21st irritatious. 

 22d iriitatious. . 

 23d irritations . . 



59. 



1st ii-ritations. 

 2d irritations . 

 3d irritaticjns. . 

 4tli irritations. 

 5th irritations. 



Irritation without 

 polarization. 



3003 cent 0. 



3003 cent 0. 



3003 cent 0. 



3003 cent 0. 



3003 cent 0. 



2955 cent 0. 



691 cent 0. 



691 cent 0. 



2781 cent 0. 



2075 cent 1. 



2675 cent 1. 



Irritation, 1 cell, rheo- 

 chord: 



3197 cent 0.5. 



3197 cent 0. 5 



3179 cent 0. 



3179 cent 0. 



3179 cent 0. 



Irritation duriaj 

 polarization. 



4 cells 0. 



4cells 0. 



Icell 3. 



Icell 1. 



4 cells 0. 



Icell 2. 



4 cells 0. 



Icell 1. 



Icell 0. 



4cells 0. 



Icell 0. 



Polarization, 4 cells, 

 rheochord : 



3 cent 5. 



3 cent 5. 



cent 3. 



5 cent 3. 



2 cent 3. 



Eemarks. 



liana temporaria. 



In the last twenty-four experiments it will be seen that an augmented 

 excitation of the nerve for the breaking of an irritating current to the 

 side of the kathode of a constant current was produced, as a rule, in 

 but ten experiments (38, 42, 48, 53, 55, 56, 57, 58, and 59). A diminished 

 excitability of the nerve occurred under these circumstances in fourteen 

 experiments (30, 37, 39, 40, 41, 43, 45, 40, 47, 49, 50, 51, 52, and 54). 



The results obtained in these fifty-nine experiments cannot be ex- 

 plained by the theory which demands an increased excitability of the 

 nerve to the side of the kathode of the constant or polarizing current. 



In searching for an explanation of these varying results, it occurred to 

 me that the nerves and muscles on ^Yhich these experiments (as also those 

 of Pliliger) were made could hardly be considered as being in a normal 

 state, in spite of the precautions used. The differences in the results 

 could then be explained by referring them to the changes taking place 

 in a dying nerve or muscle, which changes have been so little studied. 

 To determine whether or not this was the exi)lanation, a series of ex- 

 periments were made on the uninjured nerve in its normal position. 

 Copper electrodes were covered with wax, except at the point where 

 they touch the nerve and passed underneath this structure, which was 

 then experimented upon. The making of the circuit was observed in the 

 following experiments : 



