KATHODIC POLARISATION OF MUSCLE. 363 



spots at the time, but on other, for the present unknown, conditions. 

 Otherwise, after local treatment of the kathodic end of the muscle 

 with dilute solutions of Na 2 CO 3 , by which excitability is enor- 

 mously increased, we should expect to find, with a corresponding 

 direction of current, positive kathodic after-currents in those cases 

 also, in which previously no trace of them could be demonstrated. 

 This is however never the case, the result of such a procedure being 

 always merely to favour in a remarkable manner the negative kathodic 

 and positive anodic polarisation (as expressions of the closing and 

 opening excitations respectively), whilst positive kathodic and 

 negative anodic after-currents do not appear even with the shortest 

 possible duration of closure attainable by means of the switch. 

 It still remains to be investigated, how the secondary electromotive 

 phenomena would behave under the same circumstances, on exci- 

 tation with induced currents. It must be left for further investi- 

 gations to decide whether the positive reaction of muscle substance, 

 which has been assumed here, is exclusively determined by electrical 

 excitation and only occurs at the spot directly excited (the physio- 

 logical kathode), or whether it may also be observed when other 

 excitants are employed and at a distance from the excited spot 

 namely in the continuity of the muscle, as if it followed the propa- 

 gation of the wave of excitation. 



The results at which I arrived, at the time of my investigations 

 on the consequences of electrical excitation of the muscle of the 

 heart (of the snail and of the frog) as well as of the adductor 

 muscle of Anodonta, gain in significance from the fruits of the 

 present work. For I am now in a position to generalise the 

 conclusions to which I was then led by the observation of the 

 effects of exciting the cardiac muscle when in different states of 

 contraction. 



The assumption of two processes of inhibition, antagonistic to 

 the polar processes of excitation, which seemed to be incontestable 

 for the cardiac muscle in the state of systole, now proves to be 

 that which is capable of affording the simplest explanation of the 

 phenomena following on electrical excitation of striated muscle. 



The same thing is true for results of mechanical stimulation 

 as for electromotive after-effects. The two methods of investigation, 

 viz. the examination of the changes in form of the excited muscle 

 on the one hand, and the determination of the condition of polar- 

 isation at the close of excitation on the other, mutually supplement 

 each other in the desired way, so that a satisfactory insight into 



