The presence and the unchanging regularity of these great hot and cold currents in the ocean is indicated very clearly by the living inhabitants of the deep. These, as certainly as the creatures of the land, are under the influence of climate; so much so, that many of them never quit their native region in the sea. All the beautiful and delicate marine creatures and productions which dwell in the warm waters of the south are utterly absent from those shores which are laved by the cold currents that descend from the north; while, owing to the influence of the Gulf Stream, we find many of those lovely and singular creatures upon our comparatively northern shores. Of late years, as every one knows, we have all over the land been gathering these marine gems, and studying their peculiar habits with deep interest in that miniature ocean the aquarium. In the same parallel on the other side of the Atlantic none of these little lovers of heat are to be found. On the other hand, the whale, delighting as it does to lave its huge warm-blooded body in iced water, is never found to enter the Gulf Stream. Thus these fish, to some extent, define its position. Other fish there are which seem to resemble man in their ability to change their climate at will but, like him also, they are apt in so doing to lose their health, or, at least, to get somewhat out of condition. Some kinds of fish, when caught in the waters off Virginia and the Carolinas, are excellent for the table; but the same species, when taken off the warm coral banks of the Bahamas, are scarcely worth eating. In fact, we see no reason for doubting that when these fish find their health giving way in the warm regions of the south, they seek to reinvigorate themselves by change of water; and, quitting for a time the beauteous coral groves, spend a few of the sunnier months of each year in gambolling in the cool regions of the north, or, what is much the same thing, in those cool currents that flow from the north in clearly defined channels.