KATHODIC POLAKISATION OF MUSCLE. 351 



inhibition of the state of excitation already existing- at the physio- 

 logical kathode develops itself, giving- rise to relative positivity of 

 the kathodic spots of fibre, and that in the case now before us, the 

 positive kathodic after-current is conditioned by this inhibition. 



The experiments in regard to the variations of form of electrically 

 excited veratrine muscle, spoken of in the second section of this paper, 

 stand in perfect agreement with this interpretation of the observed 

 phenomena. It accords no less completely with facts which remain 

 to be described. 



As already frequently mentioned, the resulting phenomena of the 

 changes of the stimulated muscle substance, produced under the 

 influence of the anode whilst the current remains closed, resemble 

 in every respect those observed under the same circumstances at 

 the kathode on opening the current. This holds good, not only 

 with regard to the variations in form of the muscle, which may be 

 characterised in both cases as a locally limited relaxation, but also in 

 regard to the accompanying electromotive phenomena which are 

 characterised by the relative positivity of the point of entrance or of 

 the point of exit of the current, and give rise in the one case to 

 a negative anodic, in the other to a positive kathodic after- current. 



Since the method of the investigation of secondary electromotive 

 effects only permits of determining the results of electrical excitation 

 after opening the polarising current, it is clear, that as soon as the 

 conditions for producing distinct opening excitation are given 

 (especially when stronger currents and longer period of closure are 

 used) the positive anodic after-current caused thereby will come 

 into prominence, whilst the negative after-current can only some- 

 times make itself apparent as a preliminary jerk. Only in the 

 case in which the accomplishment of the opening excitation is 

 impeded in any way, or is altogether prevented, can one expect 

 to observe stronger effects in the direction of a negative anodic 

 polarisation current, as e. g. is actually the case with exhausted 

 preparations, or after the anodic ends of fibre have been killed. In 

 this connection, it is of interest to notice that under the same 

 circumstances in which on opening the current, strong kathodic 

 effects are observed in the sartorius veratrinised at one end, 

 negative anodic after-currents are also found to exist if the 

 current enters at the poisoned end of the muscle, and this happens 

 under conditions in which in normal preparations, purely positive 

 anodic polarisation of considerable strength might have been ex- 

 pected to present itself. (Comp. Tables i and 2.) 



