453 ELECTRO-PHYSIOLOGY CHAP. 



the kathodic ends of fibre in normal striated and smooth muscle in 

 the other, we still believe our original interpretation to be the most 

 probable, i.e. that here as there we are in face of a condition 

 antagonistic to excitation, developed on breaking the exciting 

 current at the physiological kathode, and a consequent relative 

 positivity of the points at which current leaves the muscle to all 

 other points in its continuity. 



The local contraction often shows macroscopically, in all cases 

 easily with the microscope, that after killing the ends of fibres at 

 one end of a normal, regularly constructed muscle, the immediately 

 adjacent excitable sections of the same are in a condition of more 

 or less pronounced continuous excitation. 



From this point of view, however, there is nothing remarkable 

 in the appearance of positive kathodic after-currents ; they are 

 much rather the immediate and necessary consequence of every 

 such injury, on the presumption of a kathodic opening inhibition. 

 Such a preparation exhibits no essential difference in its reaction 

 from that of a muscle treated locally with veratrin immediately 

 after a momentary stimulus. 



The last question to be discussed is how we are to conceive 

 of positive kathodic polarisation in the normally uninjured, current- 

 less muscle. Locke's theory (I.e.'), which refers it to a surplus of 

 excitation near the centre of muscles treated with NaCl, has 

 already been considered. We regard it as answered by identical 

 experiments on perfectly fresh, non-moistened preparations. 



The positive kathodic after-current which then appears under 

 certain conditions, cannot be forthwith compared with the cor- 

 responding effect in the uninjured molluscan muscle ; for in the 

 last case we have a tissue which is in every part in a state of con- 

 tinuous (tonic) excitation, while in normal striated muscle this is 

 not so. If in the first we find only the consequences of a 

 quelling of the tonic excitation, appearing at definite points, 

 and a consequent relative positivity of those points, in the second 

 we are forced to take into account a local alteration of the 

 " resting " muscle-substance, as exhibited in the given instance by 

 a positivity of the same towards other unaltered points of fibres. 

 As we see at once, such a change at the kathode can, under the 

 obtaining conditions, be regarded only as the consequence of the 

 previous make excitation, through which the same points of fibres 

 undoubtedly become strongly negative ; so that we are forced into 



