HERMANN VON HELMHOLTZ 



current distribution in non-prismatic conductors. 

 He showed that, on the assumption of peripolar 

 molecules in the muscle substance, no weak currents 

 could occur on the surface or in transverse sections, 

 and that the difference of potential between the 

 surface and the transverse section would not increase 

 with the size of the muscle. He also showed that 

 the differences between the results of the actual 

 experiment and what was to be expected from Du 

 Bois Reymond's assumption might simply be due to 

 the weakening of the electromotive forces by contact 

 with air, with fluids such as are used in the experiment, 

 and by dying of the muscle substance. Further, he 

 argued that the electromotive forces in the muscle, and 

 certainly in the model, are modified by polarization. 

 Subsequent experiments by Du Bois Reymond him- 

 self, and especially by Hermann, support this view. 



In the address given by Donders, when he presented 

 Helmholtz with the von Graefe medal, he said that 

 the latter had denied the pre-existence of electro- 

 motive forces in muscle. This observation evidently 

 caused some annoyance to Du Bois Reymond, as, in 

 his eloge on Helmholtz, he repudiates the statement. 

 No doubt, in one of his writings, Helmholtz indicated 

 that in the uninjured muscle no current could be 

 demonstrated between the surface and the natural 

 cross section (tendon), but he explained to Du Bois 

 Reymond that this was a mistake, and that the unin- 

 jured natural cross section was either weakly negative 

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