. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. FREE ENERGY IN MUSCLE 143 throughout the whole mass of the muscle, and the whole contractile matter made to go over into and remain in the contracted state. Poisons like caffeine, quinine, monojodo-acetic acid or chloroform, known to produce contracture, were found un- satisfactory because the tensions developed are very small, showing that only a small fraction of the contractile suhstance is at any time in the contracted state. A satisfactory method of abolishing inhibitions is freezing with subsequent thaw- ing, which met
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. FREE ENERGY IN MUSCLE 143 throughout the whole mass of the muscle, and the whole contractile matter made to go over into and remain in the contracted state. Poisons like caffeine, quinine, monojodo-acetic acid or chloroform, known to produce contracture, were found un- satisfactory because the tensions developed are very small, showing that only a small fraction of the contractile suhstance is at any time in the contracted state. A satisfactory method of abolishing inhibitions is freezing with subsequent thaw- ing, which method also has the advantage that the muscle can be kept in the frozen state, packed in dry ice, for days with undiminished MIN FIGURE 2. Isometric contraction of the frozen sartorius of the frog on thawing. The frozen muscle was immersed into Ringer of 20° C. at 0 min. The experimental procedure was the following: The rabbit was killed by de- capitation, quickly skinned, eviscerated, and the front and the sidewalls of the belly cut off. This exposed the psoas which was liberated from its surroundings. The muscle was decomposed into smaller bundles by punching it through with a small forceps with closed tips and moving the forceps up and down while the index finger of the other hand kept the muscle somewhat lifted. If necessary, ligatures were put on the two ends of the muscle strip. Owing to the poverty of connective tis- sue, the muscle is rather soft and is easily cut through by ligatures. For this reason, relatively soft and thick threads were applied in dry condition (pearl cotton No. 5). If frozen strips were desired, fibre bundles of 2-3 mm. diameter were secured, placed on a celluloid ruler (to which the muscle does not stick), stretched to their rest length, the ligature being fixed by artery clamps. Then the strips were covered with freshly powdered dry ice. The strips used were mostly of the thickness of an average frog sartorius, weighing about 40 mg.
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
