_The usual height of this tree is between thirty and forty feet. The leaves consist of two, three, and sometimes four pairs of leaflets, which are somewhat oval, and of shining dark green colour. The flowers spring, in clusters, from the division of the smaller branches; the petals are of a rich blue colour, and the stamens are crowned with yellowish anthers._ The _wood_, resin, bark, and even the flowers of this tree, are all of use either in the mechanical arts or in medicine. The former, which is yellow towards the outside, of deep blackish brown colour in the centre, and so compact and heavy as to sink, when immersed in water, is chiefly employed in the West Indies for the wheels and cogs of sugar mills. It is also formed into mortars, bowls, and domestic utensils of various kinds, for which, on account of its hardness, and not being liable to warp, it is peculiarly valuable. Lignum vitae is chiefly imported into this country from Jamaica, in logs or pieces of four or five hundred pounds' weight each, and is in great request for school-boys' rulers, and numerous articles of turnery ware. A decoction of the wood, when rasped, is occasionally administered as a medicine in rheumatic and gouty affections. The _resin_ of this tree is sometimes obtained by wounding the bark in different parts. It exudes through the wounds; and, when sufficiently hardened by exposure to the sun, is taken off, and packed in small kegs for exportation. Sometimes it is obtained by sawing the wood into billets, each about three feet in length, which are then bored with an augur longitudinally, and laid upon a fire, in such position that the melted resin, which flows through the hole as the wood burns, may be received into a vessel placed for the purpose of containing it. This resin, which is frequently called _gum guiacum_, is of a greenish colour, but has sometimes a reddish hue. Its taste is pungent and acrid. From the bark of the tree there is frequently a spontaneous exudation: this has the name of _native gum_, and is imported in small, irregular, bright pieces, which are much more pure than the gum obtained in any other way. Guiacum is used as a strengthening medicine, and a warm aromatic; it is employed as a remedy against rheumatic and other pains, and as an ingredient in many officinal preparations. On its first introduction, which was soon after the discovery of America, it was in such repute as to have been sold for seven crowns a pound. In the West Indies, the _bark_, _flowers_, and _fruit_, are each employed in medicine; and of these the former is frequently used instead of soap for washing, in which process it gives a good lather. 139. _BALSAM OF TOLU is a reddish yellow, thick, and pellucid substance, of fragrant odour, which is obtained from a tree_ (Toluifera balsamum) _which grows in South America._