The inhabitants of the water are much more numerous than those of the solid earth. "Upon a surface less varied than we find on continents," says Humboldt, "the sea contains in its bosom an exuberance of life of which no other portion of the globe could give us any idea. It expands in the north as in the south; in the east as in the west. The seas, above all, abound with it; in the bosom of the deep, creatures corresponding and harmonizing with each other sport and play. Among these especially the naturalist finds instruction, and the philosopher subjects for meditation. The changes they undergo only impress upon our minds more and more a sentiment of thankfulness to the Author of the universe." Yes, the ocean in its profoundest depths--its plains and its mountains, its valleys, its precipices, even in its ruins--is animated and embellished by innumerable organized beings. These are at first plants, solitary or social, erect or drooping, spreading into prairies, grouped in patches, or forming vast forests in the oceanic valleys. These submarine forests protect and nourish millions of animals which creep, which run, which swim, which sink into the sands, attach themselves to rocks, lodge themselves in crevices, which construct dwellings for themselves, which seek for or fly from each other, which pursue or fight, caress each other lovingly, or devour each other without pity. Charles Darwin truly remarks somewhere that our terrestrial forests do not maintain nearly so many living beings as those which swarm in the bosom of the sea. The ocean, which for man is the region of asphyxia and death, is for millions of animals the region of life and health: there is enjoyment for myriads in its waves; there is happiness on its banks; there is the blue above all. * * * * * The sea influences its numerous inhabitants, animal or vegetable, by its temperature, by its density, by its saltness, by its bitterness, by the never-ceasing agitation of its waves, and by the rapidity of its currents. We have seen in preceding chapters that the sea only freezes under intense cold, and then only at the surface, and that at the depth of five hundred fathoms the same permanent temperature exists in all latitudes. On the other hand, it is agreed that the agitations produced by the most violent storms are never felt beyond the depth of twelve or thirteen fathoms. From this it follows that animals and vegetables, by descending more or less, according to the cold or disturbing movements, can always reach a medium which agrees with their constitutions.