The upper part, known as the Case, may be regarded as the great Heidelburgh Tun of the Sperm Whale. And as that famous great tierce is mystically carved in front, so the whale's vast plaited forehead forms innumerable strange devices for the emblematical adornment of his wondrous tun. Moreover, as that of Heidelburgh was always replenished with the most excellent of the wines of the Rhenish valleys, so the tun of the whale contains by far the most precious of all his oily vintages; namely, the highly-prized spermaceti, in its absolutely pure, limpid, and odoriferous state. Nor is this precious substance found unalloyed in any other part of the creature. Though in life it remains perfectly fluid, yet, upon exposure to the air, after death, it soon begins to concrete; sending forth beautiful crystalline shoots, as when the first thin delicate ice is just forming in water. A large whale's case generally yields about five hundred gallons of sperm, though from unavoidable circumstances, considerable of it is spilled, leaks, and dribbles away, or is otherwise irrevocably lost in the ticklish business of securing what you can.