450 ELECTRO-PHYSIOLOGY CHAP. 



sistent excitation in the sartorius, on the strength of experiments 

 similar to the polarisation experiments. This is not the place 

 to enter further into the discussion, which may be referred to 

 Bering's recent criticism (68). 



At first sight an argument in favour of du Bois-Keymond's 

 view, and against that of the positive anodic after-current as the 

 galvanic expression of the opening excitation, might be deduced 

 from the fact that these effects of the passage of current appear 

 equally when the muscle is in deep ether narcosis, a condition 

 in which the strongest excitation fails to produce any trace 

 of visible change of form. Thus it would seem as if the local 

 capacity of reaction in the muscle were not perceptibly affected 

 by narcosis (as far as may be judged from the gal vanome trie 

 changes visible); since the capacity of the muscle to yield 

 a positive anodic after-current, when stimulated by the electrical 

 current, is not merely unimpaired by protracted treatment with 

 ether, but is even considerably augmented it subsequently 

 remains constant for some time, and only diminishes perceptibly 

 at a much later period. If the negative kathodic polarisation 

 of the etherised muscle is similarly investigated, it is also 

 found to undergo no diminution during narcosis. 



In both cases, however, the appearance of the after-current 

 is affected or totally hindered, as under normal conditions, on 

 killing the anodic or kathodic ends of fibres. In place of the 

 positive anodic polarisation, a much weaker, negative after-effect 

 may then be observed, while no trace remains of the negative 

 kathodic polarisation, even with prolonged closure. 



The idea of excitation is so closely allied in the muscle 

 with that of active change of form, or at least the possibility 

 of the same, that the hypothesis of a prolongation of excita- 

 bility when contractility has been entirely abolished, encounters 

 a priori difficulties. Secondary electromotive manifestations 

 appear indeed in a rigidly stretched muscle, but then 

 both conductivity and the negative variation are still present, 

 and the muscle would contract in toto if not mechanically 

 hindered. The ether muscle, on the other hand, has not only 

 completely lost its power of shortening on excitation, but has 

 also become wholly incapable of conducting. The great majority 

 of experiments in muscle and nerve physiology, however, justify 

 us in assuming a close relation between conductivity and excita- 



