Os Sepiae. Cuttle Fish Bone.
Synonym.—Cuttle Fish Shell.
Cuttle fish bone, so-called, is the internal shell of the cuttle, Sepia officinalis (Class Cephalopoda), a large mollusc, common round the coasts of Great Britain, abundant in the Mediterranean and Adriatic seas. The animal consists of a head and body, the latter being ovoid and flattened with a lateral extension on each side; around the mouth are ten long tentacles, and in the centre two large, powerful, horny beaks. The body consists of a muscular mantle, in the dorsal portion of which the shell is contained. This shell may be removed by slitting up the mantle. Amongst the organs of the body the ink gland, which conveys the secretion through a duct opening close to the anus, may be noticed. The ink, or sepia, is ejected with water when the mantle is contracted, and serves to conceal the animal. From the ink gland the pigment sepia is obtained by drying the secretion, dissolving it in caustic alkali, and, reprecipitating it by an acid. The shell is found on the shores of the Mediterranean and Adriatic, but may also be obtained when the ink secretion is collected. It consists of a long, ovate mass of chitin, with a calcareous portion on its inner surface thickened posteriorly. It occurs in commerce in white, oval-oblong, flattened masses, from 10 to 25 centimetres long and from 4 to 7.5 centimetres broad. The masses consist of a hard, outer, concave chitinous coat, upon the inner surface of which friable, calcareous layers have been deposited. It has a faint odour, and a saline, earthy taste.
Constituents.—The chief constituent of cuttle fish bone is 80 to 85 per cent. of calcium carbonate, together with a little sodium chloride, traces of calcium phosphate, and about 10 to 15 per cent of organic matter.
Uses.—Cuttle fish bone is used as an ingredient of tooth powders. It is sometimes given internally for tropical sprue and dysentery, in doses of a teaspoonful, and is sold for this purpose under the names "Sys. Specific" and "Pulvis Bataviae Compositus." Powdered oyster shells are used similarly.