332 INHIBITION BY EXCITATION AND 



conception in regard to the cause of the negative anodic and posi- 

 tive kathodic after-currents, especially as both phenomena, as will be 

 shown, appear distinctly in striated muscle, only under certain 

 conditions. It seems that here, certain subsequent phenomena 

 of electrical excitation of tonically contracted muscles must be 

 taken into consideration in the first place ; these do not constitute 

 excitation phenomena in the ordinary sense, i. e. phenomena of 

 contraction, but much rather their opposite, that is, as relaxation 

 of previously contracted parts, caused by an inhibition of ex- 

 citation. 



In this connexion I will only call to mind the phenomena of 

 inhibition which result on electrical excitation of the muscle of the 

 heart in systolic contraction, and which are so easily demonstrable 

 and at the same time so remarkable. In studying these, one is 

 necessarily led to the assumption of two processes antagonistic to 

 the polar phenomena of excitation which I have denoted as ' inhibi- 

 tion of closing and opening,' or ' anodic and kathodic inhibition,' 

 because the former has its origin at the point of entrance of the 

 current, and the latter at its point of exit *. 



I further called attention to the fact, that if we assume a per- 

 sistent tonic condition of excitation, then the result of the electrical 

 excitation of such a muscle in respect to the secondary electromotive 

 phenomena, must necessarily manifest itself under the circumstances, 

 as a positive kathodic after-current, that is to say as a negative 

 anodic one. Thus the strong positive kathodic polarisation, which 

 under fitting circumstances is observed uniformly on electrical 

 excitation of the adductor muscle of Anodonta, in consideration of 

 its very marked 'tonus,' would be also easily explained by the 

 hypothesis of a kathodic opening inhibition. The legitimacy of this 

 conception, with which moreover other facts stated in the work men- 

 tioned are in complete accordance, was nevertheless necessarily left 

 doubtful, since I had not succeeded in demonstrating the existence 

 of polar phenomena of relaxation in so unequivocal a manner in 

 the object named, as I had done in the muscle of the heart. Still 

 this circumstance could hardly be maintained as a fundamental 

 objection, because the tonus of this preparation is as a rule so 

 strong, that a local and not very marked relaxation might easily 

 escape demonstration by means of graphical methods, and all the 

 more as the changes of form follow only languidly and slowly. 



My effort has since been directed to gain certain and infallible 

 * ' tibpr das Herz von Helix pomatia,' Sitzungsber, vol. Ixxxix. p. 19. 



