Page:Popular Science Monthly Volume 76.djvu/534

530 gaining control over the powers of nature through redirection of the vital energy of the plants along more useful lines directed toward ends of human welfare. The control is collective no less than individual: Native plants vary, and the fitter survive; Darwin noted the increasing variation of plants under domestication, and thereby detected a natural law of increasing plasticity of types; and now under the law variability is accelerated and the fitter forms are selected and multiplied, so that the efficiency of crops is increased. Under natural conditions, plants spread slowly and with the tediousness of unlimited time adjusted themselves to particular soils and climates; with settlement, pioneers introduced new plants which were often found fitter than those of native growth; now the plains and mountains of the world are scoured to find types adapted to less productive districts, and thereby the efficiency of entire floras is increasing. And the end is not yet. Agriculture began with the accidental dropping of seeds in accidentally fertilized spots; in time the middens were expanded into gardens and these into fields; and now plain common sense and reasonable foresight look to the extension of planting and cultivating and cropping over all the humid country and so far into the arid lands as complete utilization of the scant waters will permit. Our 3,000,000 square miles or 2,000,000,000 acres, now sustain about 90,000,000 inhabitants, or 30 per square mile, and our exports of food-stuffs are falling off; within 65 years the population will doubtless double, and by the end of the century it will treble—yet the 250,000,000 mouths must not only be fully fed, but a margin of food-stuffs for export must be left over if prosperity is to persist. To attain this end, plant efficiency must be increased; not only must two heads of wheat be made to grow where a blade of grass grew before, but each square rod must be made to yield a bushel instead of a peck of grain, and more nutritious grains must be invented and created and kept employed in converting the crude ore of lower nature into the coin of individual and national welfare. It is no longer enough to know the plants and vital processes of nature; it is becoming necessary so to redirect nature as to produce more efficient plants by improving the vital processes—and this is a current duty of the Bureau of Plant Industry.

Even more plastic than plants are the faunal forms, both wild and domesticated; and before history began, kine and swine and sheep and fowls were so far artificialized by selection and breeding that the ancestral forms were obscured. It is the business of the Biological Survey and Bureau of Entomology to investigate the native fauna and classify the forms, technically into orders and genera and species and practically into useful and injurious—and then to perpetuate the good and reform or extirpate the evil, operating largely through the vital forces of the organisms themselves; and the world is scoured for