KATHODIC POLARISATION OF MUSCLE. 361 



tinuity of the muscle within the interpolar tract observed as results 

 of electrical excitation, so that it may be regarded as a firmly 

 established fact, that the polarisation phenomena discussed are of 

 exclusively polar origin. This is noteworthy, because otherwise it 

 would be natural to consider the experiments on positive kathodic 

 polarisation of striated muscles as supporting the views maintained 

 by du Bois-E/eymond as to the existence of an internal positive 

 polarisability of muscle. 



If, as I believe, we may maintain that we have in the main 

 succeeded in referring to the same cause, the positive after-currents 

 which are observed on the electrical excitation of locally veratrinised 

 muscle on the one hand, and those in a muscle of which the 

 kathodic fibre-ends have been killed on the other, there still 

 remains the question to be answered, how positive kathodic polar- 

 isation of currentless muscles, which have been injured as little 

 as possible is to be understood. 



This ought not to be compared with the corresponding phenomenon 

 in the uninjured muscle of Anodonta without further ground ; for 

 this latter is in a state of persistent excitation in all its parts, 

 whilst normal striated muscle may be assumed to be in repose. 

 If in the former case we are dealing only with the phenomena 

 resulting from inhibition of tonic excitation appearing at definite 

 spots, and a relative positivity of those spots caused thereby, then 

 in the latter case it is necessary to assume a local change in the 

 muscle substance in repose, which displays itself by its becoming 

 positive in regard to other unchanged parts of the fibre. As is 

 at once obvious, such a change at the kathode, under the existing 

 circumstances, can be regarded only as a phenomenon consequent 

 upon the preceding closing excitation, by which the same points 

 of the fibre become without doubt first of all strongly negative, 

 so that the idea immediately forces itself upon us, that we are 

 dealing here, so to speak, with a reaction of the living substance 

 against the preceding excitation. 



It is not without interest for the study of the changes of muscle 

 substance at the kathode, of which we are speaking, that we have 

 it in our power in every muscle, by treating any portion of it with 

 certain chemical substances, not only, as I formerly showed, to make 

 it negative 1 , but also positive as compared with other parts ; and 



1 ' Uber die Abhangigkeit des Muskelstromes von localen chemischen Verander- 

 ungen der Muskelsubstanz,' Sitzungsber. vol. Ixxxi. p. 74. 



