Quadrupeds again, are even more restricted in wandering over the earth; natural obstacles are continually presenting so many bars to progress in advance: the dry and thirsty desert where no water is; inaccessible snow-capped mountain ridges; the impenetrable screen of forest-trees; the broad lake; the unfordable and rapid river; the impassable line of a sea-girt shore; any of these impediments are enough to keep beasts within an area of no very great range. Thus it fares with all creatures, denizens of either earth or air; but none of these obstacles impede the activity of fish. They may swim anywhere, and everywhere, through the boundless expanse of waters; and, in defiance of trade-winds and storms, traverse the open seas at every season, unchecked; surrounded on all sides with suitable food, and finding at different depths a temperature alike congenial to health and comfort, whether in the torrid or the frozen zone. Some of the scaly tribe, to whom fresh water is not less palatable than salt or brackish, may even go far inland; visit without “Guide” lakes hitherto undescribed by tourists, or follow, à la Bruce, the meanderings of some mighty river from the mouth up to its sources. Supported in a fluid of nearly the same specific gravity as themselves, the upper portion of the body throws no weight upon the lower, and weariness is impossible. Where there is no fatigue repose becomes unnecessary, and accordingly we find these denizens of the deep—like their “mobile mother,” the sea, “who rolls, and rolls, and rolls, and still goes rolling on”—are never perfectly at rest. When all the day has been passed in swimming, and the evening paddled out in sport, away float these everlasting voyagers in a luxurious hydrostatic bed, and are borne through the night wherever the current chances to carry them; and, with only an occasional instinctive gulping for a mouthful of air to replenish the exhausted swim-bladder, on they go till early dawn—bursting upon a pair of unprotected eye-balls, gives the owners thereof timely notice to descend deeper, and to strike out fins and tail in whatever direction waking thoughts may suggest. To such tourists Madame de Stael’s definition of travel—_Le voyage, un triste plaisir_—cannot, of course, apply. Their whole journey through life is indeed singularly placid, conducing to health, and extreme longevity; for though it be not absolutely true as affirmed by Aristotle, that fish have no diseases or “plagues,” it nevertheless is certain that large fish—adequately supplied with little ones for food, well armed, and capable of defending themselves against greater enemies—will live several centuries—a Nestorian age, to which immunity from sudden changes of temperature, as well as a secured sufficiency of wholesome diet, together with their well-known habit of taking things coolly, no doubt materially contribute. So long a period allowed for growth, and such a fine field too for development as the open sea affords, readily