Page:Life in Motion.djvu/169

Rh which I stimulate at regular intervals of time. You observe a little catch on the edge of the wheel, which keeps the wheel from going in the opposite way during the relaxation of the muscle. Consequently the muscle, as you see, winds up the weight. Now if we multiply the weight by the height through which the muscle has lifted it we get a measure of the work done. We speak of a foot pound, that is one pound weight lifted one foot in height, or we speak of a kilogrammetre, that is one kilogram lifted one metre in height. In like manner, in estimating the work of a muscle, we use the phrase gramme-millimetre, that is one gramme lifted one millimetre in height, or about fifteen grains lifted the one-twenty-fifth of an inch. You observe how easy it is to get a notion of what musclework means by the use of this beautiful instrument.

It has been found that the work actually obtained from a frog's muscle may be stated as follows: one gramme of muscle (that is about fifteen grains) will yield four gramme-metres of work. A gramme-metre is one gramme lifted one metre (a little over three feet). Four gramme-metres represent, then,