Page:Popular Science Monthly Volume 85.djvu/409

Rh progress in his manner of living, by following the same laws other living things have followed in their progress; or must he create out of his own compelling needs new methods of living, new principles, new laws of conduct, that are solely applicable to himself?

To these questions science has given various answers, for life, as well as nature, has many sides, and science sees them through diverse eyes.

Nature is, indeed, so vast, so intricate, that one science can see but a very small part of her; and since no science can long preserve its images undimmed, nor adequately utilize the vision of other sciences, our mental picture of nature is a mosaic patchwork of flickering images; a changing, composite caricature, that exaggerates her most conspicuous features, her most discussed and most recently discovered phases.

But yesterday, nature seemed to be the essentially unchanging product of a precipitative creative fiat; to-day, the still changing product of a slow process of growth; and to-morrow, what will the image be? Which science will throw the high lights of nature on the mind of man? Which one will cast the shadows?

The great naturalists of the preceding generation—those brilliant students of interwoven lives playing their varied parts on shifting scenes of forest, field, and shore—gave us our first vivid picture of an ever-changing nature. It was largely their testimony, and the overwhelming evidence gathered from their point of view, that won the verdict for evolution. After the great naturalists came the modern schools of biologists, exploring the streams of life to their source, and by greater refinements of methods seeking in the seclusion of the laboratory to obtain a nearer and a larger view of nature in accouchement: now scrutinizing with microscope and blazing lights the minutely woven fabric of egg, and sperm, and embryo; now seeking the first throbs of nascent life in cell and organ; now, by artful and instantaneous killing, striving to fix in their order the mincing steps of life, and to preserve them for more deliberate inspection; now striving to view the steps of life in action; and again, by mimicking the processes of life, hoping to catch their meaning, or perhaps the meaning of life itself.

The field naturalists and the modern schools of biologists survey a particular phase of life through a particular medium, or facet, and each school has evolved a set formula, or diagram, for the one thing it most clearly sees; notably the Lamarckians, who see the inheritance of acquired characters, and the moulding influence of habit and of the external environment; the Darwinians, who see little else than "natural selection" and the "survival of the fittest"; the Weismannians, who specialize in an omnipotent, but obedient, "germ plasma," and who insistently deny the inheritance of acquired characters; the