78 ON THE INTERNAL POLARISATION OF NERVES. 



Meanwhile Matteucci had made similar observations. In several 

 papers communicated to the Academic des Sciences of Paris from 

 1860 to 1867, he gave an account of his investigations on this 

 subject 1 . His experimental method was faulty, and could by no 

 possibility give exact results. He thus describes it, ' Lorsque 

 le passage du courant a dure un certain temps, depuis quelques 

 secondes jusqu'a 25-30 minutes, on enleve le nerf avec un support 

 forme d'une lame de gutta-percha, et on le porte en contact des 

 coussinets du galvanometre, dont 1'homogeneite a etc reconnue 

 d'avance ' 2 . Besides demonstrating polarisation, and showing that 

 it increases with the strength and duration of the current ac- 

 cording to a law which he did not investigate more closely, he 

 claims to have found that the electromotive force of polarisation 

 is much stronger in the neighbourhood of the positive than in that 

 of the negative pole. In proof of this he gives the following 

 experiment. He passed the current (8-10 Daniells) an indefinite 

 time (25-30 minutes and upwards) through a preparation con- 

 sisting of two nerves. Afterwards the nerves were cut off and 

 successively brought into the galvanometer circuit, arranged, how- 

 ever, in opposite directions. There then showed itself as difference 

 of polarisation in the two nerves a current indicating that polarisa- 

 tion at the positive pole was stronger than elsewhere 3 . That an 

 experiment so arranged proves nothing is evident without discussion. 

 In contradiction to Matteucci's conclusions, du Bois-Reymond had 

 found that, if the electrodes of the galvanometer are pushed along 

 the conductor (that is the nerve) under investigation, without alter- 

 ing their distance from each other, equal deflections are obtained at 

 all parts of the conductor 4 . 



In connection with his researches on electrotonus, Hermann 

 made new investigations on the internal polarisation of nerves. 

 To the results obtained by du Bois-Reymond he added observa- 

 tions on the duration and course of polarisation, which showed 



1 Matteucci, Comptes Rendus de I'Acad&nie des Sciences, torn. 52, pp. 231-235, 

 1861 ; torn. 56, pp. 760-764, 1863 ; torn. 65, pp. 151-156, 1867. 



2 Ibid. torn. 52, p. 232, 1861. 'When the passage of the current has lasted for a 

 certain time, from a few seconds up to 25-30 minutes, the nerve is removed on a 

 support consisting of a plate of gutta-percha, and placed in contact with the elec- 

 trodes of the galvanometer, it having been previously ascertained that they are 

 homogeneous.' 



3 Ibid. torn. 65, p. 154, 1867. 



* Du Bois-Reymond, Gesammelte Abhandlungen, i. p. 15. (The original is of the 

 year 1856.) 



