350 INHIBITION BY EXCITATION AND 



in striated muscle when excited by battery currents under suitable 

 conditions. It appears to be essential that the spots of fibre, which 

 represent the physiological kathode, shall be already in a uniform 

 state of strong excitation at the moment they are stimulated, and 

 this is obviously in complete accord with the theoretical views 

 already mentioned. 



It might be advanced as an objection, that the question in these 

 experiments is not so much that of a kathodic opening inhibition 

 comparable to the anodic closing effect, but rather that of the 

 result of a local fatigue of the muscle, due to previous excitation 

 at the points of exit of the current, the fatigue having enfeebled 

 the already existing excitation transitorily or permanently. Against 

 such a view however the fact speaks decisively, that the magnitude 

 of the positive deflections throughout does not increase in proportion 

 to the duration of closure of the polarising current, as would 

 certainly be the case if the relative positivity of the kathodic points 

 of the fibre were conditioned only by a local fatigue. 



Thus a glance at the tables before us shows that an increase 

 of the positive kathodic effects with increasing duration of closure, 

 takes place only within very narrow limits and soon changes to 

 the opposite, although the tonic excitation still exists in sufficient 

 amount, and therefore excitations of short duration are succeeded 

 afterwards as before, by positive deflections. It is often possible 

 to observe that when the duration of closure is gradually increased, 

 the deflections which were at first entirely positive, next become 

 diphasic (positive deflection with a negative preceding it) ; finally 

 the second phase gradually diminishes, until at last it gives way 

 to effects wholly negative in direction (comp. Table a). 



It is quite as much out of the question to explain the positive 

 kathodic after-current by an opening excitation propagated from 

 the anode up to the middle electrode of the galvanometer. Any 

 such assumption is seen from the first to be inadmissible, when we 

 consider the comparatively slight strength of the exciting current, 

 combined with the short time of closure, and the fact that the de- 

 scending direction of the current is unfavourable for producing strong 

 opening excitation of the sartorius. It is however easy to convince 

 oneself in every case, that on leading off in the continuity of the 

 muscle, at about the middle third, no considerable differences of 

 tension are to be found under the given conditions of experiment. 



Thus, so far as I see, the hypothesis already mentioned alone 

 remains, viz. that at the moment of opening the exciting current, an 



