Page:Popular Science Monthly Volume 58.djvu/484

476 which exists between heat and motion." He includes both animal and vegetable vitality in his generalization.

"The life of man, or of any of the higher animals, essentially consists in the manifestation of forces of various kinds, of which the organism is the instrument."

All organic life involves the direction of nature's forces and their utilization by direction of the energies; but this striking and important distinction is observed, as Carpenter first definitely asserted: The animal employs energy derived by the disintegration of vegetable growth to its will-directed, and to its internal automatic, work; while the vegetable directs the energy of the sun's rays and of chemical action to the building up of new organic matter into its life-forms. A cycle thus transfers and transforms energy radiated to the earth from the sun, building up the vegetable, sacrificing the structure in the building of the animal organism, breaking down the animal structure again, and setting free the circling energy to continue its progress along other paths into other organic matter, or elsewhere, as directing agencies may compel.

Thus, in all nature and in all manifestations of natural law and of motion, general experience has satisfied us that matter is persistent, that it is endowed with inalienable properties which include the so-called physical forces, similarly persistent in their character and methods of action and their intensities, and that energy, a property of matter in motion, is also persistent, but not also permanently affecting any given mass; its total quantity is invariable, but it may be distributed indefinitely, transferred in any manner and transformed to any extent, irrespective of other than quantitative measures of matter affected. Matter not only permanently retains its characteristic forces, but, reciprocally, the forces permanently require and maintain matter as their residence. No exception to this constancy of union of matter and forces is yet known, and the only question now remaining to be fully answered is: How far may such relations be traced into the more intangible realms of nature and life and consciousness.

Herbert Spencer has stated the fundamental idea of science in this field most concisely, accurately and clearly. He says in 'First Principles': "We cannot go on merging derivative truths in these wider truths from which they are derived without reaching at last a wider truth which can be merged in no other or derived from no other. And whoever contemplates the relation in which it stands to the truths of science in general will see that this truth, transcending demonstration, is the Persistence of Force." Indeed, Faraday had already, years before, asserted this law to be the highest that our faculties can appreciate in physical science. In fact, as we may perhaps still more strongly put it: The Law of the Persistence of Substance, including its every attribute,