. General physiology; an outline of the science of life. 466 GENERAL PHYSIOLOGY That which appears especially interesting is the fact, discovered by Yalentin ('47), and Eduard Weber ('46), that excised muscles also are capable of recovery. This, also, can best be seen by the aid of the graphic record of the muscular movement. If an isolated gastrocnemius of a frog be fatigued by being alternately tetanized for perhaps five seconds and allowed to rest for five seconds, after some time, the intensity of the stimulus remaining constant, the curve begins to fall, until, finally, the stimulation no
. General physiology; an outline of the science of life. 466 GENERAL PHYSIOLOGY That which appears especially interesting is the fact, discovered by Yalentin ('47), and Eduard Weber ('46), that excised muscles also are capable of recovery. This, also, can best be seen by the aid of the graphic record of the muscular movement. If an isolated gastrocnemius of a frog be fatigued by being alternately tetanized for perhaps five seconds and allowed to rest for five seconds, after some time, the intensity of the stimulus remaining constant, the curve begins to fall, until, finally, the stimulation no longer produces any contraction, and the muscle remains at rest in a slightly contracted condition, determined by the contraction- remainder. If, then, the stimulation be interrupted and the muscle be left to itself for a considerable time, protected from m^j^mm, ^®. ;P^/^': A ^cs:^' B Fig. 241.— of the sparrow. A, Morning ; B, evening. (After Hodge.) drying, contractions nearly equal to those before the fatigue can be induced anew with the same strength of stimulus. The muscle now becomes fatigued more rapidly than before. One factor in the recovery, which has recently been established in Richet's laboratory by J. Joteyko ('96), is of interest. This is found in the fact that excised muscle recovers only when oxygen is available; with the exclusion of oxygen after complete fatigue the muscle cannot be put again into activity. Hence oxygen is absolutely necessary for the restoration of the irritability of muscle. But the fact that after great fatigue excised muscle is able to recover in a medium containing oxygen proves that the muscle- substance, while it can perform contractions for a considerable time independentlj^ of the circulating blood, must possess in Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly re
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