Page:Popular Science Monthly Volume 75.djvu/569

Rh or arboreal beast, and lost it in the trees, the eye searches every mass of foliage silhouetted against the sky, scarcely counting on discerning the creature's outline, so much as on noting some mass of unbroken dark—dark without any sky-hole through it—sufficiently extensive to contain the animal itself. Into this mass, if one wish to kill the animal, one shoots, at a venture, and very often with success. In such cases, a single white mark on the concealed animal has a great chance of showing through the foliage, and saving the creature's life by passing for sky, making the hunter think he can see through the clump as if there were no opaque animal in it.

This wonderful universal function of top-white will only begin to have vitality in the minds of students of natural history, when they begin to take the trouble to spend hours, lying flat on the ground, studying terrestrial life from the true point of view. They will at last realize that the terms "cryptic" and "conspicuous" can refer only to the relation of objects to their background, and that a hare is as conspicuous, dark outlined against the sky, to the little mouse at his side, as the white heron looked at on the ground by man; while to the mouse, this same heron, now seen against the sky, is the perfection of procryptic coloration, just as is the hare seen from the level of a man's or hawk's eyes.

There is one more point that particularly bears on the skunk matter. There is not, through all his range, any mammal, unless one counts the porcupine (an animal to resemble which would be a protection) with which any other creature could possibly confuse him, except when he is very dimly seen, either by virtue of darkness or of interposed forms, and in either of these situations, as this article has shown, the light pattern only diminishes his recognizability. Do we not, in fact, forget the evidence that the wild animals know each other by far more subtile means than we might suppose? The dog, even after all these centuries of domestication, still keeps the power to recognize his master, not merely by his scent, but by his foot-fall, when he can not see him. And the kind of faculty implied by this is even strong in the wild races of man.

Many naturalists think that such circumstances in the life of a race as are of only occasional occurrence have no part in its evolution. History seems to demonstrate the opposite. It is the stresses that are formative, and are the weeders-out of weak elements. The men of a village, regardless, for instance, of whether all of them could swim, might go yearly all summer to their meadows, and all come home at night, till once when some sudden deluge swept their valley, only the strong swimmers would escape, and thenceforth that village would comprise only strong swimmers. How often do we hear some one tell of a small and half forgotten faculty having saved his life. This seems equally to