. Electro-physiology. Electrophysiology. 268 ELECTRO-PHYSIOLOGY CHAP. effect is unmistakable to the unaided eye, or with a magnifying lens, but with the graphic method many additional details can be detected. If a sartorius (stretched in the double myograph, killed at the pelvic end, and clamped in the middle) is excited by currents of increasing strength (4-8 Dan., with rheochord), the first effect produced will be only the normal reaction of muscle injured at one end, as described already. Excitation with a descending current is followed by a pronounced make twitch (fairly symmetrical in bot
. Electro-physiology. Electrophysiology. 268 ELECTRO-PHYSIOLOGY CHAP. effect is unmistakable to the unaided eye, or with a magnifying lens, but with the graphic method many additional details can be detected. If a sartorius (stretched in the double myograph, killed at the pelvic end, and clamped in the middle) is excited by currents of increasing strength (4-8 Dan., with rheochord), the first effect produced will be only the normal reaction of muscle injured at one end, as described already. Excitation with a descending current is followed by a pronounced make twitch (fairly symmetrical in both halves of the muscle), with a subsequent persistent contraction, which appears in the kathodic half only. The closure of the ascending current is at first with- out any effect, even at such a strength of current as would in the normal muscle provoke maximal closure contractions under the same conditions. Beyond a certain limit of intensity, how- ever, the ascending (admortal) current once more begins to excite at closure, often indeed before an effective break excitation appears with the same direction of current under conditions favourable to its development, because the current is of greater density at its exit from the small end of the muscle. The make excita- tion always expresses itself at first as a pronounced twitch 011 the anodic side with- out any conspicuous persistent contrac- tion. With increased strength of current, however, this appears also, exclusively in the anodic half of the muscle; the h<tho</ic half relaxes completely after the make twitch has subsided (Fig. 94). At a certain strength of current the latter nearly always overtops the twitch at closure of the descending (" abmortal") current. "With increasing current intensity, the persistent increases rapidly at the lower end of the muscle, and in its turn soon exceeds the persistent of the descending current in magnitude and extension (Fig. 94). In addition to this, the
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