The heart-wood of Guaiacum officinale, Linné, and of Guaiacum sanctum, Linné "—(U. S. P.).
SYNONYMS: Lignum vitae, Lignum sanctum, Lignum benedictum, Palus Sanctus.
ILLUSTRATION: Bentley and Trimen, Med. Plants, 41.
Botanical Source.—Guaiacum officinale. This tree grows very slowly, varying in height from 15 to 50 feet. The trunk is usually crooked, with crowded, knobby, short-jointed, flexuose, spreading branches, about 4 feet in diameter; the bark is furrowed, spotted, and grayish. The leaves are opposite, bijugate or trijugate; the leaflets sessile, more or less obovate, rounded at the apex, nerved, and glabrous; the common petiole is terete and channeled above. The flowers are light-blue, on axillary peduncles, which are an inch long, 1-flowered, filiform, minutely downy, and several together. The calyx of sepals have the 2 exterior, somewhat broader than the others; all are obtuse and hoary with down. Petals 5, thrice the length of the sepals, oblong, bluntish, unguiculate, and internally downy. Stamens 10, without scales; filaments twice the length of the sepals, grooved on the back; anthers bifid at the base and curved. Ovary 2-celled, with numerous suspended ovules, and compressed; style short, acute and subulate; stigma simple; capsule obcordate, succulent, glabrous, yellow, 2 to 5-celled; on short stalks, somewhat fleshy, angular; the seeds are solitary, compressed, roundish, smooth, and pendulous (L.).
Guaiacum sanctum differs from the preceding in its leaflets, 6 or 8 of which compose the leaf, having an oblique-obovate, or rhomboid-ovate outline; in having a fruit with 6 cells; and in having smaller wood, which is less compact and lighter in color. It grows in Cuba, Bahama, and other West India Isles.
History, Description, and Chemical Composition.—The tree (Guaiacum officinale, Linné) inhabits the West Indian Islands, especially Jamaica, St. Thomas and St. Domingo. The wood and resin, or solidified juice, are the parts used in medicine, though the whole tree possesses medicinal virtues. The bark is said to be the most active part of it, but it is seldom met with in commerce. The wood of this tree was used as a medicine by the natives long previous to the discovery of the country, and they made it known to the Europeans; by these it was introduced into Europe in the sixteenth century, and employed to much advantage in syphilitic affections. Guaiacum wood, also known as Lignum vitae, a name given to it from a belief that its medicinal virtues were of a superior kind, is largely imported into this country from the West Indies for making block-sheaves, wooden pestles, and many other objects, for which it is peculiarly fitted by its extraordinary hardness and toughness. It is imported in billets, about a foot in diameter, and generally without the bark. The bark is hard, flat, a few lines thick, of a greenish-black color, with yellowish and grayish spots, inodorous, but very acrid. The wood, used for medicinal purposes, consists of turnings from the workshop of the turner, and is a uniform mixture of the alburnum and duramen, but that used in medicine should consist only of the latter.
The alburnum or sap-wood is of a yellow color, that of the duramen or heartwood, greenish-brown. Guaiacum wood is only odorous when burned or rasped, the odor being aromatic; its taste is acrid, aromatic, and amarous, succeeded by a pricking in the throat. It is very dense and tough, and has a specific gravity of 1.333. It is officially described as follows: "Heavier than water, hard, brown or greenish-brown, resinous, marked with irregular, concentric circles, surrounded by a yellowish alburnum, splitting irregularly; when heated, emitting a balsamic odor; taste slightly acrid. Guaiacum wood is generally used in the form of raspings or turnings, which should be greenish-brown, containing few particles of a whitish color, and should acquire a dark bluish-green color on the addition of nitric acid"—(U.S. P.). When a very fine powder of guaiacum wood is acted upon by the atmosphere, its color is converted into green. Nitric acid turns it bluish-green, and a solution of ferric chloride turns it blue. Solution of chlorinated lime effects no change in other woods, but causes the guaiacum to assume a green color in a few seconds. These tests may be employed to determine the authenticity of the wood. Alcohol takes up its active parts (see Guaiaci Resina), dissolving about 21 per cent. Flückiger (Pharmacognosie, 1891), by extracting with ether, obtained 22.12 per cent of resin from the duramen, and only 2.85 per cent from the alburnum. The same authority found a trace of essential oil by distilling the wood with water. Frémy and Urbain found vasculose (the incrustating substance in wood) to exist in guaiac wood to the extent of 36 per cent (see Jour. Pharm. Chim., 1882, p. 325). Several other trees of this family are stated to furnish the guaiacum wood, as the G. sanctum (now official), which has a translucent, paler-yellow, and less heavy and hard wood, and also the G. arboreum.
Action, Medical Uses, and Dosage.—Taken internally, guaiacum, both the wood and resin, commonly excites a sense of warmth in the stomach, and a dryness of the mouth, with thirst. They act upon the economy like stimulants, increasing the heat of the body, and accelerating the circulation. If the body be kept warm while using the decoction, which is the form generally preferred, it will prove diaphoretic; if cool, diuretic. As a diaphoretic and alterative, it has been administered (but usually in compound decoction or syrup), in chronic rheumatism, chronic cutaneous diseases, scrofula, and syphilitic disease. As water can not take up much of the active principle in the wood, it is probable that its reputed efficiency was owing principally to the active agents associated with the syrup or decoction. The resin of guaiacum is the active principle (which see). The decoction of guaiacum shavings may be made by boiling 2 ounces of the shavings in 3 pints of water down to 2 pints, the dose of which is from 2 to 4 fluid ounces every 3 or 4 hours (see Guaiaci Resina).
Related Species.—Guaiacum angustifolium, Engelmann (Porliera angustifolia, Gray). Mexico and south Texas. The wood of this tree is employed like that of guaiac. It is a yellow-brown, heavy and hard wood, splitting irregularly.
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BALSAM WOOD. Palo balsamo.—A South American tree of unknown botanical origin, the wood of which is thought to contain guaiacin. Upon distillation of the wood, about 6 parts of a thick, sticky, fragrant oil are obtained. This oil contains a crystalline solid, fusing at 91° C. (195.8° F.), and answering closely to the composition C14H24O (Schimmel & Co., Reports, 1892).