276 ELECTRO-PHYSIOLOGY CHAP. 



current and the fibres, and thus new excitation is occasioned. In 

 this wise the marvellous wave can be accounted for." Special 

 attention, however, must be given, on the one hand to the starting- 

 point of the wave, and on the other to the difficulty already pointed 

 out by Hermann, that the wave fails to appear just when, as it 

 seems, all the conditions are most favourable to the production 

 of secondary kathodes by curvature of the fibres, i.e. in completely, 

 relaxed muscle. If it is admitted, as Hermann states, that under 

 certain conditions of zig-zag curvature in the muscle, the physio- 

 logical effect of longitudinal passage of current may be equivalent 

 to that of purely transverse current since in the one case, as 

 in the other, the anode and kathode of the same fibre are 

 exactly opposite it must also be remarked that the wave is 

 conspicuously absent in many cases, where curvature of the fibres 

 can hardly be detected in the extended muscle. In order to 

 explain the slow propagation of the waves of contraction (in one 

 direction only), Hermann assumes that there is injury to con- 

 ductivity within the entire intrapolar area, in consequence of 

 excitation by strong currents. This, however, seems question- 

 able when we reflect that a perfectly similar wave may also be 

 observed, independently of the passage of current in quite fresh 

 muscle, if it is excited in a given way (mechanically). It was 

 shown above that the same muscle may transmit slow and fast 

 waves of contraction, without any considerable underlying altera- 

 tion in its condition. It is due far more to the quality of the 

 stimulus. 



It is very essential to the entire theory of these mani- 

 festations of excitation in the continuity of the muscle (as to which 

 there is still much to be explained) that we should know 

 whether the electrical current does not produce further change 

 within the area of muscle traversed, in addition to the polar 

 effects described, or whether as has, so far, been tacitly accepted 

 this tract is only indirectly affected by the action set up at the 

 most important physiological points of anode and kathode. Here 

 there is of course no question of the temporary effectuation of 

 secondary electrode points. Von Bezold (10), to whom we owe 

 the first thorough investigation into the electrical excitation of 

 denervated muscle, included this question in his experimental 

 inquiries, and replied to it by saying that, so long as current 

 traversed the muscle at constant strength, there were continuous 



