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This gum-resin, which possesses a pleasant vanilla-like odor, comes from a tree belonging to the Order of Styracaceæ, the Styrax Benzoin, and probably another species of Styrax, indigenous to tropical Asia, especially Siam and Sumatra. The collection of benzoin is very similar to that of pine resin; the bark of the tree is cut open, the exuding juice is allowed to harden on the trunk, and is thus brought into commerce. Benzoin differs according to its origin, the age of the tree, etc., and in commerce a number of sorts (Siam, Penang, Palembang, and Sumatra) are distinguished. As a rule, benzoin comes in lumps ranging in size to that of a child’s head. They are of a light gray color and inclose white, almond-shaped pieces. The finest quality, known as Siam benzoin after its source, usually is in small pieces (Siam benzoin in tears) which are translucent, light yellow to brown externally, but milky white on fracture, and have a strong vanilla odor. Less fine but still very good is Siam benzoin in lumps, consisting of large reddish-brown pieces inclosing white particles. All other kinds mentioned above come from the island of Sumatra, in lumps the size of a fist. What was formerly known as Calcutta benzoin formed large friable pieces of a dirty reddish-gray color. Siam as well as Penang benzoin often contains, besides benzoic acid, also cinnamic acid; it is not known why it is not a regular constituent. The worst quality is sold as “benzoin sorts,” consisting of brownish pieces without white spots; they are often mixed with splinters of wood, bast fibres, and fragments of leaves, and can be used only for cheap perfumes.

Good benzoin, besides the qualities named, must have a sweetish and burning sharp taste, it should be very friable, and when heated in a porcelain capsule should emit vapors (benzoic acid) of an acrid taste and a pronounced aromatic odor; it should dissolve completely in strong alcohol. In perfumery, benzoin serves for the preparation of many odors, washes, and the manufacture of benzoic acid. The latter will be further discussed under the head of aromatic substances obtained by means of chemistry.