"Such a structure as this, being firm and elastic in the highest degree, operates like so much india rubber, possessing a density and power of resistance which increases with the pressure. But this thick coating of fat subserves other important uses. An inhabitant of seas where the cold is most intense, yet warm blooded, and dependent for existence on keeping up the animal heat, the whale is furnished in this thick wrapper with a substance which resists the abstraction of heat from the body as fast as it is generated, and thus is kept comfortably warm in the fiercest polar winters. Again, the oil contained in the cells of the skin, being superficially lighter than water, adds to the buoyancy of the animal, and thus saves much muscular exertion in swimming horizontally and in rising to the surface; the bones, being of a porous or spongy texture, have a similar influence." [Illustration: ENEMIES OF THE WHALE.] ENEMIES OF THE WHALE. "The whales, gigantic as they are, and little disposed to injure creatures less in bulk and power than themselves, find, however, to their cost, in common with nobler creatures, that harmlessness is often no defence against violence. Several species of the voracious sharks make the whale the object of their peculiar attacks; the arctic shark is said, with its serrated teeth, to scoop out hemispherical pieces of flesh from the whale's body as big as a man's head, and to proceed without any mercy until its appetite is satiated. "Another shark, called the thrasher, which is upwards of twelve feet long, is said to use its muscular tail, which is nearly half its own length, to inflict terrible slaps on the whale; though one would be apt to imagine that if this whipping were all, the huge creature would be more frightened than hurt." A sperm whale was killed off the coast of Peru several years since, whose sides were found to be greatly bruised, and portions of the blubber were reduced nearly to a fluid state. Two thrashers probably attacked the whale, one on one side of it, and the other on the other, and beat him in the manner above described. This fact shows that thrashers are not only able to injure the whale, but most likely by repeated attacks even to kill it. "The sword fish, in the long and bony spear that projects from its snout, seems to be furnished with a weapon which may reasonably alarm even the leviathan of the deep, especially as the _will_ to use his sword, if we may believe eye witnesses, is in no wise deficient." Thus sharks, thrashers, and sword fish, in pursuit of the whale, and meeting him at every turn, and in all directions, must be powerful antagonists, even with the monster of the deep; and it is not at all unlikely but that, in the conflicts with him, they finally conquer and destroy him.