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Spermaceti (from Latin ''sperma'' meaning "semen", and ''ceti'' meaning "whale"〔(【引用サイトリンク】publisher=The Online Etymology Dictionary )〕) is a waxy substance found in the head cavities of the sperm whale (and, in smaller quantites, 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 confirm 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 the change in density is too small to be meaningful until the organ grows to huge size. 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.〔 Spermaceti wax is extracted from sperm oil by crystallisation at , 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 == Raw spermaceti is liquid within the head of the sperm whale, and is said to have a smell similar to raw milk.〔(William M Davis (1874). ''Nimrod of the Sea''. Chapter 6 )〕 It is composed mostly of wax esters (chiefly cetyl palmitate) and a smaller proportion of triglycerides.〔http://www.wdcs.org/submissions_bin/trade_report_201006.pdf〕 Unlike other toothed whales, most of the carbon chains in the wax esters are relatively long (C10–C22).〔(William F. Perrin, Bernd Würsig, J. G. M. Thewissen (2002). ''Encyclopedia of Marine Mammals''. pg 1164 )〕 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.〔 When it cools to 30 °C or below, the waxes begin to solidify.〔(Malcolm R. Clarke (1978). ''Physical Properties of Spermaceti Oil in the Sperm Whale.'' Journal of the Marine Biological Association of the United Kingdom )〕 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.〔(Kenneth S. Norris, George W. Harvey (1972). ''A Theory for the Function of the Spermaceti Organ of the Sperm Whale'' )〕 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. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「spermaceti」の詳細全文を読む スポンサード リンク
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