GALBANUM, in pharmacy, a gum issuing from the stem of an umbelliferous plant growing in Persia and many parts of Africa.
It is sometimes met with in the shops, in loose granules, called drops or tears; and sometimes in large masses, formed of a number of these blended together; but in these masses some accidental foulness is often mixed with the gum. The single drops usually approach to a roundish, oblong, pear-like form. Galbanum is soft like wax, and, when fresh drawn, white; but it afterwards becomes yellowish or reddish: it is of a strong smell, of an acrid and bitterish taste; it is inflammable in the manner of a resin, and soluble in water like a gum.
In medical virtue, and sensible qualities, it resembles the gum ammoniacum; but is less efficacious than it in asthma, though more efficacious in hysterical disorders. When assa fetida is too strong, galbanum may be tried; and, if it disagrees, give ammoniacum.
A mixture of spirit of wine two parts, with one part water, dissolves all but the impurities, which are commonly in considerable quantities.
Great part of the virtue of galbanum consists in its essential oil, and is carried up in distillation either with water or with spirit, whence great care is required in purifying it. For making of plasters, and such like inferior purposes, the best method is to expose it in winter to a sharp frost, and whilst it is brittle to powder it; thus the impurities may in some measure be separated.
Gale. rated in the fearce: for internal uses, it is best managed by including it in a bladder, and keeping it in hot water, until it is soft enough to be strained by pressure through an hempen cloth.
Besides the essential oil yielded by distillation with water, an empyreumatic oil is obtained by distilling in a retort without mixture. This empyreumatic oil is of a fine blue colour, but changes in the air to a purple.