Origin. - A balsamic resin obtained from Styrax Benzoin Dryander and other unidentified species of Styrax. A large tree indigenous in Sumatra and Java, and probably in Cochin-China and Siam.

Description and Properties. - Benzoin exudes from incisions in the bark, and upon exposure to the air hardens into lumps consisting of agglutinated, yellowish-brown tears, which are internally milk-white, or in the form of a reddish-brown mass, more or less mottled from whitish tears imbedded in it. It is almost wholly soluble in 5 parts of moderately warm alcohol and in solutions of the fixed alkalies. When heated it gives off fumes of benzoic acid. It has an agreeable balsamic odor and a slight aromatic taste.

Benzoin is of the nature of a balsam, containing from 20 to 24 per cent. of benzoic acid, resin, and volatile oil. Some varieties contain cinnamic acid, which is undesirable, while the benzoin from Siam contains vanillin and possesses the odor of vanilla.

Dose. - Benzoin is rarely administered in substance. [15 grains (1 Gm.), U. S. P.].

Official Preparations

Adeps Benzoinatus - Adipis Benzoinati - Benzoinated Lard (2 per cent). -For external use.

Tinctura Benzoini - Tincturae Benzoini - Tincture of Benzoin (20 per cent.). Dose, 30 minims to I fluidram (2-4 Cc.) [15 minims (1 Cc), U. S. P.].

Tinctura Benzoini Composita - Tincturae Benzoini Compositae - Compound Tincture of Benzoin. - Benzoin, 10; aloes, 2; storax, 8; tolu, 4; alcohol, q. s. parts. Dose, 1/2-2 fluidrams (2-8 Cc.) [30 minims (2 Cc), U. S. P.].

Antagonists and Incompatibles. - The tincture and compound tincture are incompatible with aqueous preparations, the benzoins and other resins and balsams being precipitated from their alcoholic solutions by water.

Physiological Action. - The action of benzoin is due to the benzoic acid which it contains, and will therefore be considered under Benzoic Acid.