Description: Natural Order, Leguminosae. Logwood is obtained from Honduras, Campeachy, and other portions of Central America. It is a tree usually from twenty to twenty-five feet high; with a slender and rather crooked trunk, and numerous slender and crooked branches beset with spines. Leaves alternate, of three or four pairs of sessile pinnae. Flowers numerous, large, fragrant, in axillary spicate racemes, lemon-colored petals.
The sap-wood of this tree is yellowish; the center wood deep-red, compact, and of a pleasant odor. This center wood is brought to market in logs, and then cut into small chips. Its principal use is in dyeing. Imparting its color readily to water, its deep-red solution strikes corresponding precipitates with alum, muriatic, nitric, acetic, and sulphuric acids, sulphate of copper, and acetate of lead; and a deep bluish-black precipitate with sulphate of iron. With the prussiate of potash, it forms a nearly black precipitate.
Properties and Uses: This wood is a mild and slightly aromatic astringent. It is seldom employed in medicine at the present time; but may be used in the laxity of the bowels following the summer complaints of children. A serviceable ink may be made from it, by observing the following exact proportions: Dissolve four ounces of logwood extract in a gallon of rain water, in a porcelain vessel; bring it to the boil, and skim well. Then add fifteen grains of the prussiate of potassa, and ninety grains of the bi-chromate of potassa, previously dissolved in half a pint of hot water; stir for a few minutes, and then strain. Limestone water will not answer in forming this ink, and vinegar or other acid will fade it.
The Physiomedical Dispensatory, 1869, was written by William Cook, M.D.
It was scanned by Paul Bergner at http://medherb.com