Electro-physiology (1896-98) Electro-physiology . electrophysiolog02bied Year: 1896-98 174 ELECTRO-PHYSIOLOGY CHAR. current of low intensity (the ascending direction is, on the whole, to be recommended, because the anodic effect is there developed without interference)—there will soon be seen along with the retarded opening twitch, which is alone visible at first, a second, which commences at the moment of breaking the circuit, filling up the interval before the delayed muscle twitch begins, and thus being in some sort introductory to it (Figs. 190, 191,1). Whether this effect appears as a pe
Electro-physiology (1896-98) Electro-physiology . electrophysiolog02bied Year: 1896-98 174 ELECTRO-PHYSIOLOGY CHAR. current of low intensity (the ascending direction is, on the whole, to be recommended, because the anodic effect is there developed without interference)—there will soon be seen along with the retarded opening twitch, which is alone visible at first, a second, which commences at the moment of breaking the circuit, filling up the interval before the delayed muscle twitch begins, and thus being in some sort introductory to it (Figs. 190, 191,1). Whether this effect appears as a perfectly distinct twitch, the muscle relaxing again completely before the retarded twitch (opening twitch II) begins, or whether it fuses with the latter partially or completely, depends of course upon the time that elapses between the moment of opening and the commencement of break twitch II, and thus upon the duration of the current also. The excitability of the nerve sinks gradually as the alcohol A. Ji FIG. 193.—Bud of series, Fig. 191. Decrease of break twitch II to zero, with persistence (and sub- sequent increase) of break twitch I. treatment takes effect, the height of the closure twitch, as well as of the opening twitch II, being proportionately diminished, and it is remarkable that the first opening twitch (break twitch I) reaches its greatest height when the excitability is already much diminished. The second opening twitch fails altogether at a somewhat later period, and does not reappear even with pro- longed passage of current; break twitch I, however, persists along with the reduced closure twitch, with which it is for the most part equal, if it does not exceed it (Fig. 193). If the whole preparation is freely moistened at this time with a 0*6 °/Q solution of NaGl, it is easy to restore the normal relations of excitability in the nerve, so that a closure twitch is the only effect of excita- tion at any point, with moderately strong ascending or descending
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