The most convincing proof of the reality of protective coloration is in the change of plumage or fur of some of the wild creatures to suit the season. In the far north, the grouse or ptarmigan, as they are called, do not keep feathers of the same colour the year round, as does our ruffed grouse; but change their dress no fewer than three times. When rocks and moss are buried deep beneath the snow, and a keen-eyed hawk appears, the white-feathered ptarmigan crouches and becomes an inanimate mound. Later in the year, with the increasing warmth, patches of gray and brown earth appear, and simultaneously, as if its feathers were really snowflakes, splashes of brown replace the pure white of the bird's plumage, and equally baffle the eye. Seeing one of these birds by itself, we could readily tell, from the colour of its plumage, the time of year and general aspect of the country from which it came. Its plumage is like a mirror which reflects the snow, the moss, or the lichens in turn. It is, indeed, a feathered chameleon, but with changes of colour taking place more slowly than is the case in the reptile. We may discover changes somewhat similar, but furry instead of feathery, in the woods about our home. The fiercest of all the animals of our continent still evades the exterminating inroads of man; indeed it often puts his traps to shame, and wages destructive warfare in his very midst. I speak of the weasel,--the least of all his family, and yet, for his size, the most bloodthirsty and widely dreaded little demon of all the countryside. His is a name to conjure with among all the lesser wood-folk; the scent of his passing brings an almost helpless paralysis. And yet in some way he must be handicapped, for his slightly larger cousin, the mink, finds good hunting the year round, clad in a suit of rich brown; while the weasel, at the approach of winter, sheds his summer dress of chocolate hue and dons a pure white fur, a change which would seem to put the poor mice and rabbits at a hopeless disadvantage. Nevertheless the ermine, as he is now called (although wrongly so), seems just able to hold his own, with all his evil slinking motions and bloodthirsty desires; for foxes, owls, and hawks take, in their turn, heavy toll. Nature is ever a repetition of the "House that Jack built";--this is the owl that ate the weasel that killed the mouse, and so on.