356 INHIBITION BY EXCITATION AND 



to be indicated only by slight hesitation of the negative deflection. 

 (See below, Table 8.) 



Though kathodic polarisation in fresh uninjured muscles varies 

 in some details as to its mode of manifesting itself, still under all 

 circumstances, it is always easy to determine the fact that the 

 intensity of the led-off positive after-current is directly dependent 

 upon the time of closure of the polarising current, in such a way 

 that it always decreases rapidly as the latter increases. Beyond a 

 certain duration of closing time, a purely negative kathodic polar- 

 isation is observed without exception ; and in less excitable pre- 

 parations this is the case from the first. Positive kathodic polarisa- 

 tion also shows itself dependent upon the strength of the exciting 

 current as well as upon the closing time. Very feeble currents, if 

 they have any effect at all, produce always only feeble negative 

 after-currents ; and the same thing is true, on the other hand, of 

 very strong ones, by which the muscle substance at the kathode 

 is evidently subject to profound changes, even when the duration of 

 closing is shorter. 



Other facts which will be communicated later, support the idea 

 that a certain relation exists between the positive kathodic polar- 

 isation current and the electromotive behaviour of the muscle in 

 repose, of such a nature, that the current is more easily and more 

 strongly developed if a normal current of repose is present from 

 the very first ; e. g. when, as in our case, the lower tendinous end is 

 negative to the middle of the muscle. Although, however, on the 

 ground of results which remain to be discussed, such a relation is 

 not to be denied, yet it can by no means be held as a universal law ; 

 and therefore I desire to lay special stress on the fact that I have 

 observed positive kathodic polarisation, not only in preparations 

 which from the first showed normal differences of tension in the 

 sense of an ascending demarcation current, but also in muscles 

 wholly without current, as well as in those which were electro- 

 motive in the opposite direction. 



If we look through a long series of polarisation experiments on 

 fresh sartorius preparations of R. temporaria, as uninjured as possible, 

 we cannot fail to see, that even if positive kathodic after-currents 

 are observed in the majority of cases at the first excitations, 

 yet as a rule these are essentially of inferior strength to the 

 other secondary electromotive phenomena and particularly to 

 the positive anodic after-currents. Cases like that mentioned 

 in Table 3, of which I have observed several, are nevertheless 



