230 RESEARCHES ON SECONDARY ELECTROMOTIVE 



In contradiction to this, I have arrived at the conclusion that 

 the polarisation-currents in a muscle consequent on breaking- the 

 primary or stimulating- current, result solely from alterations which 

 the latter undergoes at any point of the contractile substance of 

 the muscle -fibres at which it enters or leaves that substance ; in 

 short, at the anodes and kathodes. So long as the current flows in 

 a direction which is mathematically parallel with the muscle-fibres, 

 in all probability it does not polarise them at all ; at least there is 

 not a single recorded observation which would lead one to such a 

 conclusion. If polarisation of the muscle -substance occurred in the 

 intrapolar tract (in the strict sense of the term), in any case it 

 would be so trifling- that it might be provisionally quite neglected 

 in comparison with the polarisation-currents which accompany 

 changes at the anode and kathode. Without prejudging in any 

 way the essential nature of these changes, they may be regarded 

 as a polarisation which has ajn analogy with external polarisation, 

 but certainly not with internal. 



This holds at least for negative polarisation, whilst positive, 

 resting as it does on excitation of the living substance, does not 

 admit of comparison with physical polarisation. 



The changes which occur at the anodes of the contractile sub- 

 stance in consequence of stimulation, I call anodic polarisation, 

 those which occur at the kathodes, kathodic polarisation of those 

 spots. In a muscle-fibre through which a current is passing in a 

 longitudinal direction, only a portion where there are no anodes nor 

 kathodes is to be understood as an intrapolar tract. But, whereas 

 in a 'monomerous' muscle, the fibres of which are parallel and 

 through which a current is passing, the anodic or kathodic spots 

 are for the most part aggregated in the region where the current 

 enters or leaves the whole muscle, the tract between these two 

 spots can with approximate accuracy be termed the intrapolar 

 tract. 



At the same time it must not be forgotten that in point of fact, 

 on grounds which I have already discussed, there are always in- 

 dividual anodic and kathodic spots within this tract even when no 

 muscle-fibre terminates in it. Finally, it must not be forgotten 

 that there are other tissues in a muscle besides the muscle-fibres, 

 which possibly might be appreciably polarised. 



According to my interpretation, the positive polarisation-current 

 consequent on changes at anodic spots of the contractile substance 

 is a so-called action-current, and is generated by a break-excitation 



