in ELECTRICAL EXCITATION OF MUSCLE 269 



A.C.C. with repeated excitation is very noticeable. There is 

 little doubt as could easily be verified experimentally by time- 

 measurements that the closing twitch in a parallel-fibred muscle 

 killed at one end is discharged with a sufficiently strong ad- 

 mortal current in the anodic half of the muscle, from whence it is 

 propagated outwards. This appears, inter alia, from the fact that 

 under these conditions the curve of the twitch on the anodic side 

 is considerably larger than that at the kathode, while in all cases 

 where excitation starts from the kathode alone, the corresponding 

 half of the muscle is most strongly contracted. 



Direct observation of the anodic end of the muscle, preferably 

 with the magnifying lens after previous banding with sepia, shows 

 that the persistent anodic contraction which appears with closure 

 of strong currents, extends, unlike the well-marked persistent 

 K.C.C., over a fairly large area, never, however, producing, as in 

 that case, a swelling at the exterior ends of the fibres, which are, 

 indeed, rather extended visibly, i.e. are unexcited. The two or 

 three most internal bands of sepia, as well as the uncoloured 

 spaces between them, do not perceptibly decrease or approximate 

 (as is characteristic at the kathodic end), whereas, on the contrary, 

 the more central bands do decrease and draw together, curving 

 conversely towards the anode. This leads to a contraction swell- 

 ing, starting from the continuity of the muscle, but close to the 

 anodic end, and gradually dying out towards the middle. If one 

 electrode (kathode) is applied to one of the two bone stumps of 

 the sartorius, while the finely-pointed anode is in contact with 

 any point of the surface of the moderately extended muscle, it is 

 apparent, even with weak currents (23 Dan.), that there is no 

 trace of contraction at the actual point of entrance, and with sepia 

 marking it is easy to see that at such a point there is a not 

 inconsiderable extension of fibres, as appears plainly in a corre- 

 sponding expansion of the cross -band in contact with the 

 electrode, as well as in the adjacent segment of fibres. This 

 passive extension at the entrance of the current is caused by a 

 more or less pronounced contraction, which originates at both 

 sides of the anode at closure, and persists during the passage of 

 the current. By this method of experiment it is possible to 

 observe the local anodic inhibition (relaxation) of the veratrin 

 muscle more easily and plainly than with the above-described 

 graphic method. It is only necessary to close the circuit twice 



