KATHODIC POLARISATION OF MUSCLE. 



355 



6. Sartorius of R. temporaria not curarised ; the upper end of the 

 muscle tied off, everything- else as in the previous experiments. MC 

 at the commencement 52 sc. 



An inspection of the preceding tables shows that the positive 

 kathodic polarisation of uninjured muscles may sometimes attain to 

 very considerable values ; even if such powerful effects as e. g. in 

 Table 4 are regarded as exceptional, we shall nevertheless scarcely 

 ever fail to find after-currents of the kathodic half of the muscle, 

 on excitations with battery currents of medium strength and of 

 short duration, provided that the preparations are sufficiently sensi- 

 tive. These after-currents either appear at once after closing 

 the galvanometer-circuit, or are preceded by a more or less marked 

 negative preliminary jerk, which sometimes only shows itself as a 

 delay of the positive deflection. One may say in general, that the 

 kathodic polarisation phenomena of fresh muscles depend upon 

 the closing time of the exciting current in this sense, that as a 

 rule at first only unmixed positive after-currents appear, with 

 which afterwards negative ones are associated, increasing rapidly 

 with the period of closing, so that whereas at first they present 

 themselves as preliminary jerks, they subsequently entirely suppress 

 the positive effects. Hence these latter sometimes, so to speak, look 

 like a transitory 'positive variation' of a negative polarisation- 

 current, after the expiration of which, the magnet swings again 

 almost uniformly with decreasing velocity beyond the zero point, so 

 that, finally, a more or less strong negative deflection remains 

 behind, and this disappears only quite gradually. (See Tables 

 4 and 5> and below 7 and 8.) Sometimes the positive effect seems 



A a 



