188 SECONDARY ELECTROMOTIVE PHENOMENA IN 



I believe I have demonstrated in two ways that this explanation, 

 although conceivable, is not correct. I first formed an idea of the 

 magnitude which the after-effect would here attain. Instead of 

 the polarising battery, I allowed the mechanism, which regulates the 

 time of closure and of the 'transmission time' (Ubertragungszeit), 

 (Sect. 6), to close the primary current of the inductorium. I left 

 the nerve still attached to the group of muscles and laid it 

 on the platinum plates of my electrodes (stromzuftihrende Vorricli- 

 tung) 1 . By the action of this mechanism, the muscle was thus, 

 instead of being polarised, tetanised for the fraction of a second, 

 and between the end of the tetanus and closing of the multiplier 

 circuit, the same transmission time intervened as between the end 

 of the polarising current and the closing of the multiplier circuit. 

 The result of several experiments which, according to the standard 

 of that time were perfect, was that when this method of experi- 

 menting was used, only traces of after-effect were visible, and were 

 by no means sufficient to explain the observed differences of polari- 

 sation. Indeed this might have been predicted, for the after-effect 

 increases with the duration of the tetanus which here only lasted 

 a very short time. 



Secondly, I cut the muscles at the equator about half through 

 their thickness so that there was a gaping wound which behaved 

 as an artificial transverse section. The wedge-pad, which was 

 usually applied to the equator, was now applied to the wound. 

 The muscle-current now had the reverse direction in both halves, 

 and consequently the negative variation was also reversed. Yet 

 now, as formerly, the ascending positive polarisation predominated 

 in the upper half of the muscle, and the descending one in the 

 under half. 



If I consequently considered it proved that the positive polarisation 

 in both halves of the muscle is stronger in the direction from the 

 equator to the ends than in the other direction, this is equivalent 

 merely to a statement of the phenomenon actually observed, a 

 phenomenon which admits of more than one interpretation. If 

 we call the positive and negative polarisation generated by the 

 ascending current respectively Pt, II t, the corresponding polari- 

 sation from the descending current likewise PI, III, then the state 

 of matters is this, that not P\ IIT = PI III, but that in the 



1 TJntersuchungen viber thierische Elektricitat, vol. i. p. 450. It was in March, 

 1857, before ' physiological ' salt clay and unpolarisable electrodes were in use. The 

 muscle current was observed by the nerve-multiplier. 



