Guaiacum officinale. Guaiacum.
Nat. Ord. — Zygophyllaceae. Sex. Syst. — Decandria Monogynia.
The Wood and Resin.
Description. — This is a tree of very slow growth, attaining the night of from fifty to sixty feet, with a trunk from three to six feet in circumference. The stem is generally crooked, with numerous, divaricate, knotty, short-jointed, flexuose branches ; its bark is smooth, but furrowed, of a dark-gray color, variegated with greenish or purplish spots ; that of the branches is ash-colored and striated. The wood is hard and ponderous, with a dark olive-brown center, but whitish toward the bark, and has a peculiar odor. The leaves are opposite, abruptly-pinnate, consisting of two, three, and sometimes four pairs of elliptical, entire, veined, smooth, rigid, shining, dark-green, and sub-sessile leaflets, which are from an inch to an inch and a half in length ; the common petiole is terete, and channeled above. The flowers are pale-blue, on long, simple, axillary, filiform, minutely downy peduncles, about an inch in length. The calyx consists of five ovate, obtuse, concave, hoary, deciduous sepals, the two outer of which are somewhat broader than the others. The petals are five, light-blue, roundish, obovate, thrice the length of the sepals, internally downy, with short linear claws inserted into the receptacle. The stamens are ten, awl-shaped, erect, shorter than the petals, grooved on the back, with oblong, curved anthers, bifid at the base. The ovary is two-celled, compressed, with numerous suspended ovules, and a short awl-shaped style. The capsule is obovate, succulent, glabrous, yellow, with from two to five rounded angles, and as many cells opening at these angles ; two or three of these cells are often abortive. The seeds are solitary, compressed, convex on one side, angular on the other, pendulous, with a cartilaginous albumen, and a straight, green embryo.
History. — This is a tree growing in the West Indies, particularly in Hayti and Jamaica. All parts of it are possessed of medicinal properties, but the wood and the concrete juice only are officinal. The bark is said to be the most efficient part of the tree, but it is not met with in commerce. The wood of this tree had been used as a medicine by the natives previous to the discovery of the country, and who made it known to the Europeans ; by these it was introduced into Europe in the sixteenth century, and employed with much advantage in syphilitic affections. Guaiacum wood, commonly called lignum vitae, from a supposition that it possessed superior medicinal virtues, is largely imported into this country from the West India Islands, for the purpose of making block-sheaves, and various other instruments, for which its density and extreme hardness render it especially adapted. It comes in billets about a foot in diameter, covered with a thick gray bark, which presents on its inner surface as well as on its fractured edges, numerous shining, crystalline points ; more generally, however, the bark is absent. The wood, as used in medicine, consists of turnings from the workshop of the turner, and is a uniform mixture of the alburnum and duramen.
The alburnum or sap-wood is of a yellow color, that of the duramen or heart-wood, greenish-brown, and which are mixed in about equal proportion in the shavings. Guaiacum wood is inodorous, unless rubbed or heated, when it becomes odorous; giving an agreeable scent when burned. It has an acrid, bitterish, and aromatic taste, attended with a singular pricking in the throat, and which is excited most strongly by the alburnum. It is very dense, hard and tough, of sp. gr. 1333, sinking in water. When rasped, it emits a peculiar fragrance and excites sneezing. In a state of minute division, exposure to the air turns it green ; nitric acid turns it bluish-green, as does also a solution of corrosive sublimate; this last should be applied to the shavings, and slightly heated. These tests may be employed to determine the genuineness of the wood. Boiling water and alcohol take up its active parts — the alcohol dissolving 21 per cent., the water 14. It has not been satisfactorily analyzed, but contains a bitter, pungent extractive, resin, and benzoic acid. One pound of the wood afforded to Geiger two ounces of extract. This extract treated with ether, the ethereal tincture evaporated and the residue carefully sublimed, affords a volatilizable acid, which condenses in small, brilliant needles, called guaiacic acid ; if the heat be pushed too far, an oil is produced which colors the crystals. Jahn considers this substance to be benzoic acid, with volatile oil and resin. It is stated that the guaiacum wood is also obtained from other species, especially the G. Sanctum, and G. Arboreum. The former is semi-transparent, paleryellow, and less heavy and hard, but probably, as fit for medical use as the officinal wood.
Properties and Uses. — Guaiacum wood is stimulant, diaphoretic, alterative, and diuretic. 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 diseases. As water cannot take up much of the active principle in the wood, it is probable that its reputed efficacy 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 an ounce in a pint and a half of water down to a pint, the dose of which is from two to four fluidounces every three or four hours.
Off. Prep. — Decoctum Guaiaci ; Syrupus Sarsaparillae Compositus.