Spermaceti

A spermaceti wax candle and bottle of sperm oil.

Spermaceti (from Latin sperma meaning "semen", and ceti meaning "whale"[1]) is a waxy substance found in the head cavities of the sperm whale (and, in smaller quantities, in the oils of other whales). Spermaceti is created in the spermaceti organ inside the whale's head.

Two theories for the spermaceti organ's biological function suggest it either controls buoyancy, or acts as a focusing apparatus for the whale's sense of echolocation. There has been concrete evidence to support both theories. The buoyancy theory holds that the sperm whale is capable of heating the spermaceti, lowering its density and thus allowing the whale to float; in order for the whale to sink down again, it must take water into its blowhole which cools the spermaceti into a denser solid. This claim, however, has been called into question by recent research which indicates a lack of biological structures to support this heat exchange, as well as the fact that the change in density is too small to be meaningful until the organ grows to huge size.[2]

The proportion of wax esters in the spermaceti organ increases with the age of the whale: 38–51% in calves, 58–87% in adult females, and 71–94% in adult males.[3] Spermaceti wax is extracted from sperm oil by crystallisation at 6 °C (43 °F), when treated by pressure and a chemical solution of caustic alkali. Spermaceti forms brilliant white crystals that are hard but oily to the touch, and are devoid of taste or smell, making it very useful as an ingredient in cosmetics, leatherworking, and lubricants. The substance was also used in making candles of a standard photometric value, in the dressing of fabrics, and as a pharmaceutical excipient, especially in cerates and ointments. The candlepower was a photometric unit defined in the English Metropolitan Gas Act 1860 and adopted at the International Electrotechnical Conference of 1883. It depended upon a standardised pure spermaceti candle.

Properties

Spermaceti is taken from the spermaceti organ (yellow) and junk (orange) within the sperm whale's head.

Raw spermaceti is liquid within the head of the sperm whale, and is said to have a smell similar to raw milk.[4] It is composed mostly of wax esters (chiefly cetyl palmitate) and a smaller proportion of triglycerides.[5] Unlike other toothed whales, most of the carbon chains in the wax esters are relatively long (C10–C22).[3] The proportion of wax esters in the spermaceti organ increases with the age of the whale: 38–51% in calves, 58–87% in adult females, and 71–94% in adult males. The blubber oil of the whale is about 66% wax.[3] When it cools to 30 °C or below, the waxes begin to solidify.[6] The speed of sound in spermaceti is 2,684 m/s (at 40 kHz, 36 °C), making it nearly twice as good a conductor of sounds as the oil in a dolphin's melon.[7]

Spermaceti is insoluble in water, very slightly soluble in cold alcohol, but easily dissolved in ether, chloroform, carbon disulfide, and boiling alcohol. Spermaceti consists principally of cetyl palmitate (the ester of cetyl alcohol and palmitic acid), C15H31COO-C16H33.

A botanical alternative to spermaceti is a derivative of jojoba oil, jojoba esters, C19H41COO-C20H41, a solid wax which is chemically and physically very similar to spermaceti and may be used in many of the same applications. Esters of cetyl alcohol and jojoba oil are used as a substitute for spermaceti.

Biological function

Currently there is disagreement on what biological purpose or purposes spermaceti serves. It might be used as a means of altering the whale's buoyancy, since the density of the spermaceti alters with its phase.[8] Another hypothesis has been that it is used as a cushion to protect the sperm whale's delicate snout while diving.[9][10]

The most likely primary function of the spermaceti organ is to add internal echo or resonator clicks to the sonar echo location clicks emitted by the respiratory organs. This makes it possible for the whale to sense the motion of its prey as well as its position. The changing distance to the prey affects the time interval between the returning clicks reflected by the prey (doppler effect). This would explain the low density and high compressibility of the spermaceti, which enhance the resonance by the contrast of the acoustic properties of the sea water and of the hard tissue surrounding the spermaceti.

Spermaceti processing

Further information: Sperm whaling

After killing a sperm whale, the whalers would pull the carcass alongside the ship, cut off the head and pull it on deck, whereupon they would cut a hole in it and bail out the matter inside with a bucket. The harvested matter, raw spermaceti, was stored in casks to be processed back on land. A large whale could yield as much as 500 gallons. The spermaceti was boiled and strained of impurities to prevent it from going rancid. On land, the casks were allowed to chill during the winter, causing the spermaceti to congeal into a spongy and viscous mass. The congealed matter was then loaded into wool sacks and placed in a press to squeeze out the liquid. This liquid was bottled and sold as "winter-strained sperm oil". This was the most valuable product: an oil that remained liquid in freezing winter temperatures.

Later, during the warmer seasons, the leftover solid was allowed to partially melt, and the liquid was strained off to leave a fully solid wax. This wax, brown in color, was then bleached and sold as "spermaceti wax".[11][12] Spermaceti wax is white and translucent. It melts at about 50 °C and congeals at 45 °C.[13]

Gallery

References

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