Guaiacum, or Lignum vitae, L. is a genus of plants producing three species, the principal of which is the officinale, or Common Lignum Vita?, a native of the West Indies. - It may, in colder climates, be propagated by seeds sown in pots plunged into a hot-bed, but it is seldom cultivated in this country.

The wood of this species is of equal utility in the mechanical arts, and in medicine; being so heavy as to sink when immersed in water. It is chiefly employed in the West Indies for the wheels and cogs of sugar-mills, and is also frequently formed into mortars, bowls, and other ntensils.

The wood, gum, and bark, are all employed in medicine, though the two first are chiefly used in Europe,

Gum Guaiacum is of a friable nature, of a deep greenish colour, but sometimes of a reddish hue; and has' a pungent acrid taste.— There is another spontaneous exudation obtained from the bark of this tree, which i- called native gum ; it is imported in small irregular, semi-pellucid pieces ; and is much purer than that extracted by incision.

The general virtues of Guaiacum are those of a warm aromatic medicine : it strengthens the stomach and other viscera, and greatly promotes the discharges of urine and perspiration. Hence it is of especial service in cutaneous eruptions, and disorders arising from obstructions of the excretory glands : - in rheumatic and other pains, unattended with fever, the liberal use of gum guaiacum has often afforded considerable relief. It is likewise a good laxative, and furnishes a more active medicine than either the wood or bark of this tree.

Gum Guaiacm, when dissolved in rum, or combined with water, by means of mucilage or the yolk of an egg, or in the form of a tincture or elixir, has been found use-ful in chronic rheumatism, or even in such wandering pains of the stomach or other parts of the body, as could be attributed to the retro-cedent gout ; in which cases a small table-spoonful of the emulsion may be taken three or four times a day.