PHENOMENA OF MUSCLE AND NERVE. 281 



Reymond's molecular theory of electrotonus. It is indeed nothing- 

 more or less than the demonstratio ad oculos, that the current produces 

 corresponding rotation of the electromotive molecules in the animal 

 tissues (Sect. 21)! 



' Repeatedly,' says du Bois-Reymond (p. 223), ' and on two quite 

 distinct hypothetical bases, Hermann has demonstrated that in the 

 intrapolar tract a polarisation -current opposed in direction to the po- 

 larising current must prevail. I am curious to see by what auxiliary 

 hypotheses he will deal with the polarisation current in the same 

 direction which actually prevails.' That some of his most zealous 

 molecular adherents, e. g. Bernstein 1 and v. Fleischl 2 , have followed 

 me and have been heretical enough to confirm the fact of an effect in 

 the intrapolar region opposed to the current, in contradiction to 

 himself, is a subject upon which he is silent, and he is not curious 

 as to the auxiliary hypotheses of these authors, a circumstance 

 which I regard as most flattering- to myself. 



But what is the ' positive polarisation current actually prevailing 1 

 there ' which my theory and my auxiliary hypotheses will have to 

 satisfy ? Since when is the proof of an after-current on opening, a 

 ground for the assumption that the same current existed during 

 closure ? 3 Would physicists have ventured to deduce ordinary 

 polarisation from the polarisation after-current alone, had not the 

 steady decrease of the current led through, furnished a proof of the 

 existence of the former during closure ? And what would du Bois- 

 Reymond say if some one took it into his head to conclude from 

 the fact proved by myself and confirmed by Fick, that the anodal 

 extrapolar region of a nerve shows on opening, an after-current 

 opposed in direction to the polarising current, that electrotonus has 

 also, during closure this direction on the anodal side ? 



Du Bois-Reymond observes in the intrapolar region two conflict- 

 ing after-effects, one opposed to, the other in the same direction 



1 Loc. cit. vol. viii. p. 51. 



2 ' Sitzungaber. d. Wiener Acad. Part 3, vol. Ixxvii. 



3 This absolutely incomprehensible error of transferring, without question, condi- 

 tions which have been observed after opening, to the time of closure, plays the chief 

 part in an objection raised by du Bois-Reymond against an experiment of mine 

 (p. 200). Fifteen years ago I experimented to see if the intrapolar tract of nerve 

 showed the large increase of current which the du Bois theory requires, and I found 

 no trace of it. Du Bois-Keymond now thinks that this arose from my long time of 

 closure, in consequence of which the polarisation must have been negative; with 

 shorter times of closure positive polarisation would have given me the sought-for 

 result. In this suggestion we have an instance of the very transference which is so 

 unreliable. 



