Dictionary.net

Gum-resin. A milky juice, obtained by making incisions into the branches, stalks and roots of certain vegetables. Gum-resins are compounds of resin, gum, often with essential oil, and different other vegetable matters. They are solid, opake, brittle, of a strong odour, acrid taste, variable colour, and are heavier than water. Water dissolves a part of them, and alcohol another; hence proof spirit is the proper menstruum. The generality of the gum-resins are powerful stimulants to the whole or to parts of the economy. The chief are asafoetida, gum ammoniac, euphorbium, galbanum, camboge, myrrh, olibanum, opoponax, scammony, aloes, &c.