(Indian). Guaiacon, hagioxylon, lignum benedictum, vita lignum, palus and palma sancta, euonymo adfinis occidentalis, ibirace, etc. The darker kind the Americans call hiacan, or huiacan; the yellowish they call hoaxecan; guaiacum officinale Lin. Sp. Pl. 546. Common guaiacum, or pockwood.

This wood was introduced into Europe early in the sixteenth century from Jamaica, Mexico, and the Antilles. It is brought over in large pieces, each weighing from four to five hundred weight, hard, compact, and so heavy as to sink in water, of a pale yellowish colour without, but black, of a deep brown, or marbled, within. It hath little or no smell, except when heated, and then its odour is slightly aromatic. When chewed it is slightly pungent, a quality which resides in its resin, and which it yields, in some degree, to water by boiling, but wholly to spirits.

Of the bark there are two kinds, one smooth, the other unequal on the surface: both are weaker than the wood. In the choice of this medicine, the freshest, most ponderous, of the darkest colour, and the largest pieces are preferred; and, as the finer parts are apt to exhale, they should be rasped only when used.

The wood was first introduced into Europe as a remedy for the venereal disease; and, as it warms and stimulates, promotes perspiration and urine, proving occasionally a gentle purgative, it assists the operation of mercury. When the excretory glands are obstructed, the vessels flaccid, the habit cachectic, in many cutaneous and catarrhal complaints, female weaknesses, in gouty and rheumatic disorders, it is often useful. The hectic fever, which sometimes follows a salivation, yields to a decoction of the woods. Guaiacum seems to stimulate the exhalent vessels more than the heart and great arteries; and is consequently safer than those which act more powerfully on the sanguiferous system. It is of course esteemed more effectual than other sudorifics in the lues venerea, in all cases of rheumatism, perhaps in gout.

A long use of this medicine hath been supposed to produce a yellowness of the skin. In thin emaciated habits; in an acrimonious state of the fluids; in hot bilious habits, and where the fibres are very tense, it is suspected to be injurious.

Three ounces of the wood, or four ounces of the bark, may be boiled in lb iv. of water to lb ij. and if a little liquorice is added to the latter end of the boiling, it will abate the disagreeable pungency of this medicine, which affects the throat in swallowing. Of this decoction at least half a pint should be taken in a day.

If the thin shavings of guaiacum are distilled in a retort, at first an almost purely watery fluid arises; on increasing the fire, an acid, reddish, empyreumatic liquor passes over, with a little fluid reddish oil, and much air is separated: the residuum is a coal. A pound of guaiacum wood, distilled on an open fire, gave Guaiacum 3973 iii. ss. of acid, and i. ss. of empyreumatic oil.

The extract of guaiacum, soft and hard, is prepared by boiling lb i. of guaiacum shavings in a gallon of water until half the liquor is wasted, repeating the operation by adding the same quantity of fresh water to the same shavings four or five times. The several decoctions passed through a strainer, are to be mixed and inspissated; adding, when the aqueous parts are almost exhaled, a little spiritus vini rectificatus, that the whole may be reduced into an uniform tenacious mass. This extract is called soft when of the consistence of a mass for pills, and hard when it can be powdered. The spirit is added at the conclusion of the boiling, that the resinous part may be perfectly mixed with the gummy. The harder extract is an excellent errhine.

The resin of guaiacum is prepared in the same manner as the resin of jalap, q. v. and is the only active part of this wood: it is obtained pure by means of rectified spirit of wine, both from the wood and the gum, and is procured by wounding the bark in different parts of the body of the tree, from whence it .exudes copiously. This natural resin, which is exported, is never pure; and about Guaiacum 3975 xii. of pure resin is obtained from xvi. of what is styled gum. This is partly accounted lor by its being sometimes procured by boring billets of the wood longitudinally, and then burning them at one end, while the resin exudes from the other. It is also occasionally obtained by boiling the chips in water and common salt.

This gum is of a brown colour, partly reddish, often greenish, brittle, having a glossy surface when broken, of a pungent taste, affecting the tongue and palate in the same manner as the wood. It is chiefly brought in irregular masses, of a dusky green colour: that in the form of drops is the best, but rarely met with.

In choosing the gum, those pieces which have slips of the bark adhering to them, and that easily separated from them by percussion, is the best. When held against the light it is transparent, breaks with a smooth uniform shining fracture, of a bluish green colour. It is fusible in a moderate heat, but not softened by the heat of the fingers; insoluble in water, but soluble in alcohol; without smell or taste, but on hot coals diffusing an agreeable odour. When the powder is swallowed, it occasions a very painful burning and pricking in the throat.

Neumann assures us, that a composition of colophony and balsam of sulphur is imposed on the unwary for the true gum; but the cheat is easily detected, by exposing each to a due degree of heat, by which the odour of the false is perceived to be different from that of the true.

The wood and resin only are in general use as medicines; and as the efficacy of the former is supposed to be derived merely from the quantity of resinous matter which it contains, they may be considered indiscriminately as the same medicine. Of the gum, or extracts, the dose may be from gr. v. to Э i. but in the latter dose it is often actively cathartic. It should be combined with a fluid by means of an egg, or some mucilage, as it is otherwise uneasy in the stomach. Indeed, if given in the form of an electuary or bolus, a similar medium is necessary.

Bolsam of guaiacum consists of gum. guaica. lb i. bal-samum Peruv. 3 iij sp. vini rect. lb i. ss. It was formerly called polychrestum; and from one to three drachms were given every night and morning in milk, or any convenient vehicle.

Tincture of gum guaiacum, commonly called the volatile tincture, is a solution of four ounces of the gum in a pint and a half of the compound spirit of ammonia. Pharm. Lond. 1788.

The dose is from a small tea spoonful to a large table spoonful two or three times a day, and it is very conveniently given in milk, though a proportion of the tinctura opii should be added, to prevent the larger dose from purging. Dr. Dawson frequently directs the latter close with great advantage in rheumatic and arthritic complaints, in which cases, and against palsies from lead, he considers it almost as a specific. It should not, however, be given while any inflammatory diathesis remains.

See Raii Historia Plantarum; Lewis's Materia Me-dica; Neumann's Chemical Works; Cullen's Materia Medica.