374 



EFFECT OF IRRITATION OF A POLARIZED NERVE. 



Time. 



Number of ex- 

 periment. 



h. m. 



1 20 

 21 

 22i 

 24" 

 40 

 47 



2 01 

 04 

 08 

 10 

 11 

 16 

 18 

 24 

 27 

 28 

 30 ' 

 31 

 34 i 

 38 I 

 41 

 42 I 

 44 

 45 

 50 . 

 52 i 



9 89 



40 

 44 

 46 



10 06 

 10 

 12 

 14 

 17 

 20 

 35 



33. 



1st iirit.itions . . 

 2(1 irritations. . . 

 3d irritations . . . 

 4tli irritatioua. . 

 5th irritations. . 

 6th irritations. . 

 7th irritations. . 

 8th iiritations. . 

 9th irritations. . 

 10th irritations, 

 nth irritations. 

 12th irritations. 

 lljth irri;ations. 

 14th irritalions 

 loth irritations. 

 lOth irritations - 

 17th irritations. 

 181h irritati(ms. 

 19th irritations. 

 20th iiritations. 

 21st irritations . 

 22d irritations. - 

 23il irritations. . 

 24th irritations . 

 25th iiTJtations 

 26th irritations - 



34. 



1st irritations . 

 2d irritations. . 

 3d irritations. - 

 4th irritations . 



Irritation without 

 polarization. 



Irritation during 

 polarization. 



1st irritations 

 2d irritations . 

 3d irritations . 

 4th irritations. 

 5th irritations 

 6th irritations 

 7th irritations. 



Remarks. 



IiTitation, 1 cell, rheo- 

 chord : 



2781 cent 3.5 



2901 cent 3. 



2901 cent 2.5 



2901 cent 2. 



2901 cent 2. 



2(>75 cent 2. 



2o75 cent 2. 



2675 cent 2. 



2675 cent 2. 



2675 cent 2. 



2675 cent 2.5 



2675 cent 2. 



2C75 cent 1. 



2075 cent 1 . 



2r82 cent 1. 



2562 cent 2. 



2502 cent 2. 



2562 cent 2. 



2562 cent 2. 



2016 cent 2. 



2010 cent 2. 



2010 cent .2. 



2127 ccn- ... 2. | 



2127 cent 2. ! 



2127 cent 1.5 I 



2127 cent 1. 



Irritation, 1 cell, rheo- 

 choid : 



3169 cent 1. 



3169 cent 0.5 



3169 cent 0.5 



3189 cent 0.5 



Irritation, 1 cell, rheo- 

 chord : 



2781 cent 1.5 



2781 cent 0.5 



2781 cent 0.5 



2781 cent 1. 



2781 cent 0.5 



2781 cent 0.5 



1526 cent 0.5 



Kana teniporaria. 



Polarization, 1 cell, 

 rhi'oehord ; 



4!) cent 4. 



t!) cent 4. 



1(1 <-c]it 4. 



1(1 cent 4. 



10 cent 3. 



10 cent 3. 



10 cent 3. 



10 cent 3. 



10 cent 2. 



10 cent 3. 



30 cent 3. 



30 cent .3. 



30 cent 3. 



30 cent 2. 



30 cent 2. 



30 cent 2. 



30 cent 2. 



30 cent 2. 



30 cent 2. 



30 cent 2. 5 



30 cent 2.5 



30 cent 2. 



30 cent 2. 5 



30 cent 2. 



30 cent 2. 



30 cent. 2. 



Polarization, 1 cell, ; Rana temporaria. 

 rheochord : 



10 cent .2. ' 



30 cent 1.5 



30 cent 0.5 < 



30 cent . 



Polarization, 1 cell : 



10 cent 2. 



10 cent 1:5 



10 cent 0.5 



10 i ent 1. 



30 cent.... 1. 



30 cent 0.5 



30 cent 1. 



Other les of List fro" 



In the i^receding experiments the muscular contractions caused by 

 the dosing of the circuit were used to measure the excitability of the 

 nerves, and are represented by the figures in columus 3 and 4. Of these 

 figures 5 represents maximal and 0.5 minimal contractions. 



Out of the thirty -five exi)eriments just given, but nine (experiments 1, 

 4, 7, 14, 17, 27, 29, 30, and 31) go to confirm the theory of Pflilger, while 

 fourteen (experiments 2, G, 8, 9, 10, 11, 13, 15, IG, 18, 21, 22, 23, and 24) 

 give results in direct opposition with it. Of the remaining twelve ex- 

 periments, in two (5 and 12) an increased excitability of the nerve was 

 produced by the polarizing current in one-half the irritations. lu ten 

 experiments (3, 19, 20, 25, 2G, 28, 32, 33, 34, and 35) Pliiiger's result was 

 usually obtained. 



From this we must conclude that Pliiiger's theory does not hold good 

 as regards the effect of a descending polarizing current on the excita- 

 bility of the nerves, as measured by means of the muscular coutractions 

 l^rodiiced by the closing of an electric circuit. 



