. The physiology of the domestic animals; a text-book for veterinary and medical students and practitioners. Physiology, Comparative; Domestic animals. PHYSIOLOGY OF MOVEMENT. 713 Such a curve (as produced by the pendulum myograph, Fig. 277) is represented in Fig. 278. To study the characteristics of such a curve more fully certain additional apparatus is necessary. In the first place, it is necessary to know the rate of motion of the recording surface. This may be accomplished by means of a recording tuning-fork writing on the traveling surface. It is further necessary to indicate the instant
. The physiology of the domestic animals; a text-book for veterinary and medical students and practitioners. Physiology, Comparative; Domestic animals. PHYSIOLOGY OF MOVEMENT. 713 Such a curve (as produced by the pendulum myograph, Fig. 277) is represented in Fig. 278. To study the characteristics of such a curve more fully certain additional apparatus is necessary. In the first place, it is necessary to know the rate of motion of the recording surface. This may be accomplished by means of a recording tuning-fork writing on the traveling surface. It is further necessary to indicate the instant at which the nerve or muscle receives the stimulus. This may be done by including an electro-magnet writing on the traveling surface in the current through which the stimulus to the muscle passes. If the curve be examined, it will be noticed that the muscle does not commence to shorten instantaneously with the entrance of the stimulus into the nerve, but an appreciable interval elapses after the application of the stimulus before contraction commences. This interval is termed the latent period, and is usually about one-seventieth part of a second. The duration of thelatent period will depend upon the distance through which the stimulus a. 3. Fig. 278.—Muscle Curve Obtained by means of the Pendulum Myo- graph. (Foster.) (To be read from left to right.) a indicates the moment at which the induction shock is sent into the nerve ; &, the commencement; c, the maximum ; and d, the close of the contraction. The two smaller curves are due to oscillations of the lever. Below the muscle curve is the curve drawn by a tuning-fork, making one hundred and eighty double vibrations a second, each complete curve, therefore, representing 1-180 of a second. has to pass through the nerve before entering the muscle. If the elec- trodes be moved along the sciatic nerve farther from the muscle, the latent period will be increased. If moved down closer to the muscle, or applied directly upon th
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