(Gumm), is a concrete vegetable juice, of no particular smell or taste, becoming viscos and tenacious GUM

cious when moistened with water; totally dissolving in water into a liquid, more or less glutinous in proportion to the quantity of the gum; not dissolving in various spirits or in oils; burning in the fire to a black coal, without melting or catching flame; suffering no distillation in the heat of boiling water.

The true gums are gum arabic, gum tragacanth, gum senegal, the gum of cherry and plum trees, and such like. All else have more or less of resin in them.

GUM Arabic is the produce of a species of Mimosa; which see in Chemistry and Materia Medica Index.

GUM Senegal, is a gum resembling gum arabic, which is brought from the country through which the river Senegal runs, in loofe or single drops: but these are much larger than those of the gum arabic usually are; sometimes it is of the bigness of an egg, and sometimes much larger: the surface is very rough or wrinkled, and appears much less bright than the inner substance where the masses are broken. It has no smell, and fearsce any taste. It is probably produced from a tree of the same kind with the former. The virtues of it are the same with the gum arabic; but it is rarely used in medicine, unless as mixed with the gum arabic; the dyers and calico printers consume the great quantities of it that are annually imported. The negroes dissolve it in milk, and in that state make it a principal ingredient in many of their dishes, and often feed on it thus alone.

GUM Tragacanth, the gum of the tragacanth, a thorny bush growing in Crete, Asia, and Greece. See Astragalus, Botany Index.

Other substances known by the name of gums are as follows:

GUM Ammoniac. See Ammoniac. GUM Elemi. See Amyris. GUM Kino. See Kino. GUM Guaiacum. See Guaiacum. GUM Lacc. See Cocculus and Lacc.

among gardeners, a kind of gangrene incident to fruit trees of the stone kind, arising from a corruption of the sap; which, by its viscosity, not being able to make its way through the fibres of the tree, is, by the protrusion of other juice, made to extravasate and ooze out upon the bark.

When the distemper surrounds the branch, it admits of no remedy; but when only on one part of a bough, it should be taken off to the quick, and some cow-dung clapped on the wound, covered over with a linen cloth, and tied down. M. Quintinie directs to cut off the morbid branch two or three inches below the part affected.