Page:Popular Science Monthly Volume 13.djvu/584

566, equilibrated influences which constitute its real wealth, its source of power, its store of potential energy, whence all its performances emanate.

In the execution of vital motion matter is to some extent "consumed." During expansion it is consumed—taken up by the expanding substance at the cost of the medium. During contraction it is consumed—taken up by the medium at the cost of the contracting substance.

Now, in conformity with the prevailing one-sided view of motility, which attributes the entire phenomenon to so-called contractility, it is generally supposed that the force displayed during living motion is derived exclusively from the consumption of matter on the part of the medium; and it is also generally supposed that this consumption consists in a process of oxidation. Oxidation, it is said, generates a certain amount of heat; this heat is the real motor power in the case.

It does not much affect the bearings of this view whether the oxidizing material be derived, as some maintain, from the contracting substance itself, or whether, as others think, it be derived from food ingredients. The combustion of matter, with accompanying evolution of heat, is deemed to be the true source of power; and the contracting substance—the muscular fibres in higher animals—are stated to be playing merely the part of machinery.

Thus viewed, the problem of life may be considered altogether hopeless. The organism then represents nothing but a force-directing engine, in which the combustion of compounds previously put together in vegetables constitutes the actual driving force. Vital manifestations, accordingly, can be only due to the action of the force liberated from vegetable compounds and applied to the organic machinery. Poor Science, of all-powerful vitality, thou art very young yet, and amazingly unconscious withal!

The moving substance, the protoplasm, plays just so much or just so little the part of machinery as the steam does in the steam-engine. The substance H2O in a calorific medium from about 32° to 212° Fahr., under ordinary atmospheric pressure, occupies a certain space. In a calorific medium above 212°, under the same pressure, it occupies an enormously larger space. This specific property of filling such different spaces, under these different thermal conditions, is the very source of its power—of that motor power which sets the engine going. Whoever wishes to become fully convinced of the fact that it is not the heat of combustion, but the specific expansibility and contractility of H2O, by which the engine is driven, may just throw, instead of so much H2O, a proportionate weight of Au into the boiler.

If this remark should happen to appear far too commonplace for the purposes of scientific illustration, I can merely state in defense of it that, perhaps, in pondering over its meaning, the reader will find himself initiated into a deeper view of force than is usually accepted.