Abstract
SOME Physiologists abound in statements touching the correlation of forces in living things, and are very fond of repeating the old parallel between a muscle and a steam-engine. We have no desire to deny the aptness of the illustration, but it is as well to bear in mind that, in actual point of fact, the exact correlation of heat and mechanical force has not, as far as muscle is concerned, yet been made fully out. The point of failure is this—suppose we have two muscles: let one muscle when it contracts have to pull against a weight and so produce a decided mechanical effect; let the other muscle have no such weight to pull against, and so in contracting produce no mechanical effect (the trifling weight of the muscle itself we may disregard). According to the doctrine of the correlation of forces, the heat given out in the first case ought to be less than that given out in the second, by reason of the total force produced by the combustion of the muscle going out partly as mechanical force instead of wholly as heat. We suppose of course that exactly same amount of contraction takes place in both cases, and indeed that the muscles are perfectly identical in circumstances, except so far as their load is concerned. Heidenhain some few years ago, however, found out that there was, strange to say, more heat given out in the first case. He also discovered the reason of it, which is that when a muscle is put on the stretch, as, for instance, when a muscle has in contracting to pull against a weight, all the chemical changes in the muscle are augmented, and that roughly in proportion to the amount of strain.
Article PDF
Rights and permissions
About this article
Cite this article
A Point in Muscular Physics . Nature 1, 159–160 (1869). https://doi.org/10.1038/001159a0
Issue Date:
DOI: https://doi.org/10.1038/001159a0