LOGWOOD, the heart-wood of Henia toxylon campechianum, a leguminous tree which grows wild, in most places, along the eastern shores of Mexico and Central America. From its abundance in some parts near the Bay of Campeachy it is sometimes called Campeachy wood. The leaves are pinnate; the flowers small, yellowish and disposed in auxiliary racemes at the extremity of the usually spinous branches. The wood is red, tinged with orange and black, so heavy as to sink in water, and susceptible of receiving a good polish; and it yields an extract much used in dyeing. (See DYES). Though cultivated to some extent in Jamaica, the logwood of commerce is chiefly obtained from Honduras, where the cutting of it forms an extensive hut unhealthy branch of business. Haiti• and Santo Domingo also pro duce tpuch. The finest kind comes from Cam peachy, the inferior qualities from Honduras and from Jamaica, to ,which island it is not indigenous although it grows abundantly since its introduction. In the preparation of this wood for use, the trees, which are 20 to 50 feet high, are cut down, the bark and alburnum re moved and the hard centre parts cut up into three-foot logs. It is afterward hewn into
much smaller pieces, and ground or rasped to small chips. The, aqueous extract is muddy and of a reddish-brown color. By acids the red color is made paler; • by alkalis it is converted to purple. Salts of iron, aluminum and lead give precipitates of a blue, violet or purple color. Logwood is chiefly consumed .in dyeing cotton cloth, silk, wool and leather; by mor danting the fabric with iron, black is produced; with alumina, violet and lilac; with copper, blue; and with chromium, a black or green— the exact tint depending on the composition of the mordants and logwood liquors, and the mode of application. The coloring power of logwood depends chiefly on a crystalline in gredient called hamatoxylin (q.v.). In medi cine both the extract and the decoction of logwood are used to some extent. The former is prepared by exhausting the wood with boil ing water, filtering and evaporating to a thick ish syrup; the latter is the water extract of the wood along with some cinnamon. Both are used as astringents in diarrhoea and dysentery.