212 ELECTRO-PHYSIOLOGY 



the current ; otherwise it must be assumed that the knee-joint on 

 the kathodic side, or the remains of the pelvis on the anodic, act 

 as kathode for the thigh muscles." But as Hering showed, this 

 view is that which was long ago opposed by Engelmann, since for 

 him the anode is the place where current enters the muscle-fibres, 

 the kathode the place at which it leaves them. Hering (I.e. 

 p. 241) expresses this more exactly as follows : the real physiolo- 

 gical anode in the muscle is formed by the collective points at which 

 current enters the contractile substance ; the physiological kathode by 

 the collective points at which it leaves them. 



This proposition leads to a corollary, best expressed in Bering's 

 own words. " If we picture the entire current which traverses 

 the muscle longitudinally to be divided into single lines of cur- 

 rent, these would indeed, generally speaking, lie parallel with the 

 direction and limits of the single fibres in a parallel-fibred muscle, 

 and the collective anodic points would lie at one end, the collect- 

 ive kathodic points at the other, of the muscle ; in detail, how- 

 ever, there would be innumerable exceptions. In the first place, 

 quite apart from any tendinous intersections, we must consider 

 the case in which the single muscle-fibres end at different points 

 of the muscle, although the bulk of them may be approximately 

 as long as the muscle itself. But directly such muscle-fibres 

 occur, the points at which the current enters or leaves are no 

 longer to be sought exclusively at the ends of the muscle, and 

 besides the chief centres of polar current action, other centres 

 will be distributed in the muscle. 



" Moreover an absolute parallelism between the lines of 

 current and the muscle-fibres cannot, as a rule, be predicated, 

 particularly where the muscle is not extended, or is subjected 

 to pressure at any spot, or if its surface is not entirely freed 

 from the remains of adherent conducting matters, solid or fluid. 



" In muscles which are lying relaxed upon a slide, the fibres, 

 as we know, by no means invariably run straight, but are often 

 undulatory, especially after a preceding twitch of the muscle, 

 because they cannot elongate again on account of the friction on 

 their under -surface. A current traversing the muscle longi- 

 tudinally would then find innumerable points of entry and exit 

 along the edges of each individual muscle-fibre, and it would be 

 quite fallacious to place the physiological anode and kathode 

 exclusively at the ends of the muscle. If the muscle is clamped 



