IV 



ELECTROMOTIVE ACTION IN MUSCLE 



347 



Here, as in the regular muscle cylinder, the lines of intersection 

 of the isoelectric planes with the surface of the column, form 

 circles parallel with the periphery of the end-surfaces, the curves 

 of current of meridional lines. Yet a perfectly definite seat 

 of electromotive force cannot be forthwith determined, for an 

 analogous distribution of surface potential may occur in many 

 other cases, where it is at least doubtful whether electromotive 

 forces are at work within the body at only one, or at several, or 

 many places. As a matter of fact, each new seat of electro- 

 motive action implies a different system of lines of current and 

 potential, i.e. a different distribution of surface-potential ; but, as 

 Helmholtz pointed out, seeing that in a complex of electro- 

 motive forces the potential of each point on the surface of the 



+ + A 



FIG. 109. Schema of hypothetical distribution of electromotive planes in a muscle-fibre. 

 Axial longitudinal section. (Hermann.) 



body corresponds with the sum of the potentials brought into play 

 at this particular point by each electromotive force respectively, 

 we may conceive many combinations in .which the same distribu- 

 tion of surface-potential would always present itself. Turning 

 now to the case in which a cylindrical body exhibits a similar 

 electromotive action to that which occurs at both ends of a 

 muscle with parallel fibres, provided at either end with an 

 artificial transverse section, we find (amongst others) that a 

 solid copper cylinder with a zinc sheath corresponds with the 

 required conditions when immersed in any conducting fluid, 

 e.g. dilute H 2 S0 4 . This, according to schema A (Fig. 109), is 

 traversed by innumerable lines of current, which pass as a whole 

 from the electrically positive zinc sheath to the electrically nega- 

 tive end-surfaces of the copper, exhibiting a distribution of surface- 



