GUM (Gummi) is a concrete vegetable juice, of no particular smell or taste, but which becomes viscous and tenacious when moistened with water; totally dissolves in water into a liquid, more or less glutinous in proportion to the quantity of the gum; is not affected by vinous spirits or oils; burns in the fire to a black coal, without melting or catching flame; and suffers no dissipation 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.