"The commercial extract of the root of Glycyrrhiza glabra, Linné (Nat. Ord.—Leguminosae)"—(U. S. P.).
Source, History, and Description.—The black cylindrical sticks met with in commerce are an extract of liquorice root (Extractum Glycyrrhizae), which is prepared in some of the southern European countries; they are in the form of hard, black cylinders, which are prepared by inspissating the decoction in copper kettles, till the mass is thick enough to become firm on cooling. Water slowly dissolves from 3/5 to 11/12 of it, alcohol only about 1/8, and acquires an acrid taste, while the residuum is purely sweet, and entirely soluble in water.
The impure extract is in slightly compressed and cylindrical sticks, about 6 inches long, and from 9 to 12 lines in diameter, being enveloped in sweet bay leaves. The best kind is dark brownish-black, smooth, shining, brittle when cold, tough and flexible when warm, very sweet and soluble in water. It should be freed from impurities for internal use.
The U. S. P. describes extract of glycyrrhiza: "In flattened, cylindrical rolls, from 15 to 18 Cm. (6 to 7 inches) long, and from 15 to 30 Mm. (1/2 to 1 1/5 inch) thick; of a glossy black color. It breaks with a sharp, conchoidal, shining fracture, and has a very sweet, peculiar taste. Not less than 60 per cent of it should be soluble in cold water"—(U. S. P.). To purify liquorice, the crude extract is dissolved in water without boiling, the solution strained, and evaporated to the proper consistence. (See purified extract of liquorice.) If the water be boiled during the purification, much of the impurity may be taken up, which is not desirable. Immense amounts of extract of liquorice, in the form of mass extract, are imported into this country for the use of tobacconists, who employ it to sweeten plug chewing tobacco.
King's American Dispensatory, 1898, was written by Harvey Wickes Felter, M.D., and John Uri Lloyd, Phr. M., Ph. D.