HELMHOLTZ IN KONIGSBERG 



in the resting state, though on the production of 

 tetanus, caused by irritating the nerve supplying the 

 muscle, a negative variation, or current in the opposite 

 direction, was observed. If a current were obtained 

 when the muscle was at rest, it was in greatly 

 diminished amount, and might even be in a con- 

 trary direction. This was explained by supposing 

 that in the uninjured muscle, the tendonous end, 

 which is the natural transverse section, contains a 

 layer of electromotive molecules, with their poles 

 reversed, so that their positive surface is towards the 

 transverse section. This layer Du Bois Reymond 

 termed the parelectrotonic layer, and when one 

 removes it by making an artificial cross section, the 

 full muscle current is obtained. 



The laws of the dispersion of currents in irregularly 

 shaped conductors had been only partially determined 

 for conductors of two dimensions by Kirchhoff, and for 

 three by Smaasen, but the results were not sufficient 

 for the complicated conditions of a muscle. It was 

 also difficult to show, on the electromotive molecule 

 theory, why weak currents could be obtained from 

 a point say in the centre of the transverse section and 

 any other point in the transverse section near the peri- 

 phery, and also between a point in the equatorial region 

 of the muscle, on its surface, and any point nearer each 

 end. These results could not be explained by the 

 copper-zinc model. Helmholtz stepped in here, and, 

 by his analytical power, developed the theory of 

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