Log-Wood, Heematoxyhtm Campechianum, L. an exotic plant, which grows wild in the bay of

Campeachy, Honduras, and other parts of the Spanish West Indies, where it rises from 16 to 24 feet in height.—In the beginning of the I8th century, it was introduced into Jamaica, where it is employed as a fence against cattle.—If the lower branches be pruned away, while the tree is young, it will grow to a considerable size; and, when old, its wood will be of equal value to that imported from Honduras.— The trees are cut into billets, the bark and white sap of which are chipped off, while the red part, or heart only, is selected for sale.

Logwood is used in great quantities for dyeing purple, green, blue, and especially for black colours ; according to the different ingredients employed. The last mentioned dyes, however, are not durable, unless previously tinged brown, in a decoction of the dried Iceland Liverwort (see p. 117) ; which serves as the basis of fixing the colouring matter. Indeed, there are many indigenous plants that may be advantageously substituted for logwood, and other dyeing drugs: a general survey of which, the reader Will find in our General Index of Reference, to be given at the conclusion of the present work.-Hence we shall only add, on the authority of Porner, that in ail the experiments made with logwood, he found alum, without adding any cream of tartar, to produce a better effect than in a state of combination with this acid; and, for fixing or rendering the different colours more durable, blue vitriol was uniformly the most successful ingredient.

Independently of its utility as a dyeing drug, logwood has lately been found to possess considerable as-tringency as a medicine : hence a decoction, as well as an extract from it, has been given with advantage, in cases of diarrhoea.