iv ELECTROMOTIVE ACTION IN MUSCLE 457 



there can be no doubt that it must, as in striated muscle, be 

 regarded solely as the expression of the opening excitation. This 

 is also evident from the fact that in perfectly fresh and highly 

 tonic preparations, positive anodic polarisation, like the persistent 

 opening contraction, preponderates over the negative kathodic 

 polarisation, or expression of the closing excitation (especially 

 at the first stimulation) ; the development of the positive anodic 

 after-current is also, as in striated muscle, delayed or prevented 

 by killing the anodic end of the muscle. 



This is not true of the positive kathodic after-current, which 

 both in striated and smooth muscle is not merely not weakened, 

 but even considerably augmented by killing the end of the 

 muscle. 



It is important to the theory of positive kathodic polarisation 

 that, as Hering found, there is sometimes, even in the perfectly 

 fresh sartorius of R. cscidcnta, and still more in temporaria 

 (directly after the first excitation with the battery current), a weak 

 deflection of the magnet in the direction of a positive kathodic after- 

 current, which may even attain a considerable magnitude. A 

 certain limit of closure is essential, as otherwise diphasic or 

 simple negative effects are produced. After killing the end of 

 the muscle corresponding with the physiological kathode, these 

 effects are considerably augmented, and it is then for the most 

 part, even on the less sensitive preparations, easy to produce 

 tolerably strong positive after-currents, on exciting with atterminal 

 (admortal) battery currents. They can thus be induced, as it 

 were, artificially, by killing the kathodic end of the muscle. Since 

 in this case the make excitation is entirely or partially excluded, we 

 cannot, apart from other reasons, admit the interpretation recently 

 attempted by Locke (17), who explains the positive kathodic 

 after-current as the consequence of a persistent excitation which is 

 longer sustained in the continuity (middle) of the muscle than at 

 the kathodic end. We are convinced that the same effects appear 

 when the sartorius preparation has not been previously treated 

 with physiological salt solution, which, according to Locke, pre- 

 disposes the muscle to tetanus contraction. 



After due consideration of all these facts, and more especially 

 of the striking coincidence between the conditions of the entrance 

 and mode of manifestation of positive kathodic polarisation in the 

 partially veratrinised muscle, on the one hand, and after killing 



