Abstract
ONE of the most remarkable features of the - animal body is the fact that each organ has more substance than is necessary to do its normal amount of work. Teleologically it is easy to see that some such arrangement is necessary for successful survival, but it is more difficult to imagine the mechanism by which it is kept in working order. If a muscle is used less it grows smaller, and if it is used more it grows larger. In each case it preserves the margin of power which is known as “reserve force,” despite the definite general relation between quantity of substance and quantity of function. In a recent number of the Journal of Pathology and Bacteriology (vol. xxv. p. 414) Dr. V. R. Khanolkar makes some interesting speculations and observations which seem to throw light on the problem, and he extends them into suggestions which may clear up some obscure points in respect of the distribution of pathological lesions in organs. So long ago as 1871 Bowditch formulated the proposition that if the frog's heart responds at all to an artificial stimulus it responds with the greatest contraction of which the muscle is at the time capable. This principle of “all or nothing “has since been extended to other excitable tissues, most convincingly to muscle and nerve, and by implication to glands which receive their normal stimuli through the nervous system. On this basis, moderate activity of a skeletal muscle means maximal activity of a, moderate number of the units, in this case muscle fibres, of which it is made up and not moderate activity of all the units.
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The Unit Activity of Animal Organs. Nature 111, 304 (1923). https://doi.org/10.1038/111304a0
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DOI: https://doi.org/10.1038/111304a0