Logwood

(log'wŭd.) (Dyeing.) A very valuable dyestuff, consisting of the cuttings or ras pings of the wood of the Hæmatoxylon campechianum, a tree growing in Mexico and the neighboring countries. It is extensively employed for dyeing black with alum; but acids change the color to red immediately. Its dyeing properties are due to its containing a crystalline matter called hæmatoxylon, which is straw-yellow in its pure state, but a umes a brilliant red under the influence of oxygen and alkalies. [s. 553]