282 THE SO-CALLED SECONDARY ELECTROMOTIVE 



with the current led through, the former more transitory, the latter 

 more persistent, and, above all, observable only after short closures 

 of very strong- currents. He concludes, without any justification, 

 that both effects are also present during closure. Now, as 

 two simultaneous ordinary polarisations, a true (' negative ') and a 

 reversed (' positive ') , are not conceivable, he assumes that the first 

 only is due to true internal electrolytic polarisation, and that the 

 second is due to the 'set' of the electromotive molecules in the 

 direction of the current. He ' does not believe that any one schooled 

 in physics will come to any other conclusion ' (du Bois-Reymond, 

 p. 222). And this and no other is the ' positive polarisation cur- 

 rent which actually prevails,' in contrast with which I had opposed 

 a negative ; it was this which was to bring me to despair I 



As to the question how this rotation of molecules is to be effected 

 by the current, unfortunately nothing is learnt even from the new 

 treatise. With respect to this process, which belongs to the 

 physics of the future, du Bois-Reymond is still unable to set up any 

 theory. He is therefore obliged to have recourse to pulling the 

 strings of the model of rotating molecules for the satisfaction of his 

 credulous auditory. My request, expressed years ago, that the pro- 

 pounders of the molecular theory would once for all set forth an 

 exact theory of their molecules, remains therefore unfulfilled A . It 

 is characteristic that the moment an attempt is made to apply the 

 ordinary physical modes of thought to the subject of molecules, one 

 is repelled on the ground that the physics of the future have first to 

 teach the necessary mode of thought 2 . My objection to the credi- 

 bility of du Bois' original view according to Grothuss' theory, du 

 Bois-Reymond appears to have acknowledged as not unfounded, 

 but he disposes of the subject with half-intelligible evasions and 

 with a facility which is not reassuring. He is not willing to 

 admit electrodynamical explanations, and rightly so, as I believe. 

 But in that case what becomes of the theory ? 



I can only repeat what I said ten years ago, of which I am not 

 able to retract a word 3 . ' If the molecular schema is used for the 

 purpose of referring the electromotive activity of the nerve 

 cylinder to that of small particles, and definite physical actions 

 are treated of as affecting these particles, we are compelled to de- 

 mand that they should receive a more definite form which allows 



1 Pfliiger's ' Archiv,' vol. viii. p. 267 ; vol. xx. p. 393. 



2 Loc. cit. vol. viii. p. 267. 



3 Loc. cit. vol. viii. p. 267. 



