Page:Popular Science Monthly Volume 11.djvu/353

Rh developed the malady which were born toeless? I regret, on closing this paper, not to be able to take the psychological aspect of the question, because it is very interesting in a forensic point of view, and as bearing on the question of responsibility.



O be able to live, in any way known to us, it is indispensable to have a body. And, as living bodies come by growth and continue by nourishment, it is first necessary to have materials whereof bodies can be made—and renewed and kept in warmth and strength. Just these materials, with permission of the reader, we will try to take account of, as resources of life. Life is not maintained "by bread alone;" other needful resources being known to physical science, and still other resources greater than all being recognized by their results in life; but we have the bread alone, as enough, certainly, to be considered in the present article.

Living things are in very deed made of "the dust of the earth;" but it is by no means all of the dust of the earth that serves this purpose. We have to distinguish between substances out of which organized instruments of life can be made, and a much larger number of substances never used in the making of these instruments.

We have it in mind that matter is made up of sixty-three simples. At all events, the earth's crust and air are constituted, substantially, of these sixty-three sorts of atoms, and, as a good many of the same are already revealed in the sun and stars by the spectroscope, it is likely that they are the chief elements in the universe of matter. Of the sixty-three, certain elements, found only in very small quantities, appear to be of subordinate importance in that part of the universe under our immediate observation, Whatever purposes they may fulfill in other earths or in the centre of our own, or at other epochs. Others of the elements bear an important part in the structure of the globe or in the uses of mankind, but are not organizable materials, and they are not in our present consideration. Of the sixty-three, only fourteen or fifteen simples, about one-fourth of those known to us, are used in the construction of plants and animals. These, then, are before us, as the elemental resources of life.

It will be understood that the tissues are not built directly of these fourteen elements, but of their chemical compounds. Each one of these compounds is a definite substance in external character distinct from its constituents, as, in a familiar example, water is distinct from