. Electro-physiology . FIG. 54.—Tetanus arising from, and resolving into, single twitches. The beginning and end of the tracing only are represented. In the omitted, central portion of 1'9 sec. the line traced by the muscle was horizontal. (Engelmann.) This will be recognised as very incomplete tetanus, with deep indentations, so that only in a minor degree can the muscle be said to be permanently shortened. The summits of the in- dentations lie almost horizontal. If the exciting induction currents are strengthened, or increased in frequency, the teeth become shorter and flatter, and the inden
. Electro-physiology . FIG. 54.—Tetanus arising from, and resolving into, single twitches. The beginning and end of the tracing only are represented. In the omitted, central portion of 1'9 sec. the line traced by the muscle was horizontal. (Engelmann.) This will be recognised as very incomplete tetanus, with deep indentations, so that only in a minor degree can the muscle be said to be permanently shortened. The summits of the in- dentations lie almost horizontal. If the exciting induction currents are strengthened, or increased in frequency, the teeth become shorter and flatter, and the indentations less deep; the muscle reaches a much higher degree of permanent contraction (Fig. 52). Finally, the curve rises steeply from the beginning, and the indentation becomes negligible, disappearing altogether in complete tetanus (Figs. 53, 54). According to Kohnstamm (9) the tetanus becomes more incomplete with uniform frequency, in proportion with increasing strength of stimulus, since every incre- ment of stimulation accelerates the relaxation of the single con- traction (Fig. 54). Bohr (7) finds that the tetanus curve of unfatigued muscle (frog, toad) is " an equilateral hyperbola brought to an asymp-
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