The two whale heads hanging from the Pequod provide an opportunity for Ishmael to give a lesson on “practical cetology.” The sperm whale has a great well of sperm, ivory teeth, a long lower jaw, and one external spout hole. Ishmael describes the sperm whale as having “more character” than the right whale, as well as a “pervading dignity” based on the “mathematical symmetry” of its head. He wonders at the whale’s small eyes, which are placed on opposite sides of its head, affording the whale a strange visual perspective. He notes also that the external portion of the whale’s ear is tiny, comprised of only a small pinhole.
The right whale, on the other hand, Ishmael explains, has bones in its mouth shaped like Venetian blinds, a huge lower lip, a tongue, and two external spout holes. He likens the right whale to a Stoic and the sperm whale to a “Platonian.”
Ishmael then points out that the blunt, large, wall-like part of the sperm whale’s head seems to be just a “wad.” In actuality, inside the thin, sturdy casing is a “mass of tremendous life.” Ishmael notes that the whale’s head, like many other things in nature, derives its strength from its flexibility and ability to be compressed and change shape.
Ishmael continues his survey by noting that the upper part of a whale’s head has two subdivisions: the case and the junk. He compares the case to the “Great Heidelburgh Tun,” a famous German wine vessel of enormous capacity. The case—which contains a reservoir of highly prized spermaceti, a valuable waxlike substance found in the oil—is carefully tapped once the whale’s head has been suspended out of the water. The junk also contains oil, but this oil is trapped in a honeycomb of tough fibers.
Ishmael describes Tashtego’s tapping of the case. The sperm that it contains is lifted from the whale’s head, which still dangles alongside the ship, to the deck by a relay of buckets. In tapping this whale, Tashtego accidentally falls into the case, which is at least twenty feet deep. In a panic, Daggoo clears the tangled lines and tries to get a line inside the head to Tashtego, but the tackle holding the head aloft breaks, and the great mass falls into the ocean. Queequeg dives in and manages to save Tashtego by cutting into the slowly sinking head and “delivering” Tashtego as a doctor would a baby.
Ishmael applies the nineteenth-century arts of physiognomy (the art of judging human character from facial features) and phrenology (the study of the shape of the skull, based on the belief that it reveals character and mental capacity) to the whale. He considers the whale’s features and, by means of physiognomic and phrenological analysis, concludes that the sperm whale’s large, clear brow gives it the dignity of a god and that its “pyramidical silence” demonstrates its genius. But Ishmael then abandons this line of analysis, saying that he isn’t a professional, and dares the reader to decipher the “hieroglyphics” of the sperm whale’s brow.