224 SECONDARY ELECTROMOTIVE PHENOMENA IN 



Hermann has demonstrated that in the intrapolar tract a polari- 

 sation-current opposite to the polarising current must prevail (Sect. 

 15). I am curious to see to what auxiliary hypothesis he will have 

 recourse for an explanation of the actual polarisation-current which 

 is in the same direction. 



These 'directable' carriers of electromotive forces in muscles, nerves, 

 and electrical organs, referred to above as molecules, I have, as is 

 well known, called electromotive molecules ; and without in the 

 first instance saying anything about their nature, I represented 

 them diagrammatically in the simplest manner 1 . The discovery 

 of inclination-currents (Neiyungstrome) placed me later in a 

 position to state something definite about the arrangement of pre- 

 existing electromotive forces in muscles. In the place of spheres 

 of which one half was electro-positive, the other electro-negative, 

 there came electromotive discs (Fldckenelemente) 2 , while at the 

 same time I completed the representation which had remained 

 unfinished in the ' Untersuchungen,' by representing these elements 

 as foci of chemical change something like that which constitutes 

 tissue respiration. 



I know the difficulties that stand in the way of these views as 

 well as any one. Here the question is how to represent the directing 

 of the electromotive molecules by the current. In order to make it 

 clearer, I had referred to Grothuss' theory of electrolysis. Hermann 

 erroneously imputed the idea to me that the current rotated the 

 molecules electrodynamically, and he tried to deduce this rotation 

 from Ampere's fundamental law by substituting for a molecule 

 capable of being directed a current element capable of being rotated, 

 and for the total current a thread of current passing through the 

 middle of the element 3 . Later on Hermann remarked indeed that 

 he was presenting me with a theory with which I was unacquainted, 

 but notwithstanding he thinks himself justified in setting forth my 

 electrotonus hypothesis in this form (calling it simply the * electro- 

 dynamic hypothesis '), on the ground that Grothuss' view is not 

 applicable to electromotive molecules separated by interstitial fluid 4 . 



I had good grounds for avoiding any electrodynamic theory of 

 the sort. Hermann's view is quite inadequate. The problem of 



1 Loc. cit., vol. ii. part i. p. 323. 



2 Loc. cit., vol. ii. pp. 122, 291, 671, 672. 



3 Untersuchungen zur Physiologic der Muskeln und Nerven, part iii. p. 66. Berlin, 

 1866. 



* Pfluger's Archiv, 1874, vol. viii. p. 268; Handbuch der Physiologic, 1878, 

 pp. 171, 172. 



