263. Balsamum tolutanum.—Balsam of Tolu.
BOTANICAL CHARACTERISTICS.—A lofty evergreen tree with warty branches; the wood contains a liquid balsam, which exudes when incisions are made. Leaflets 7 to 8, ovate-oblong. Legume indehiscent, with winged expansions and a winged stalk; very broad at apex.
HABITAT.—Venezuela and New Granada.
COLLECTION.—The balsam is obtained by making V-shaped incisions through the bark and collecting the exudate in small cups or calabashes. It is imported from Venezuela in tins holding from ten to twenty-five pounds. This tapping of the tree continues for eight months, causing the tree to become partially exhausted, showing itself in the lessened foliage. A spurious article has been found on the market. It has a soft consistence, is very sticky, especially when chewed, and under the microscope shows only an occasional crystal. On distilling a portion of this balsam with water, it was observed to contain more of a fragrant volatile oil and less cinnamic acid than the genuine drug.
DESCRIPTION OF DRUG.—A very viscid, yellowish-brown semi-solid, with a sweet, fragrant odor, and feebly aromatic taste. Long kept, it gradually hardens into a more or less solid mass, which is brittle in the cold. Soluble in volatile oils, alcohol, chloroform, glacial acetic acid, and solution of potassa. Readily fusible, and burns with an aromatic odor.
CONSTITUENTS.—A volatile oil (chiefly toluene, C10H16), a resin, free acids (cinnamic and benzoic), and benzylic ethers of these, principally of the former. If a thin layer of the balsam be viewed under the microscope, numerous crystals of the free cinnamic acid are seen.
ACTION AND USES.—Stimulant expectorant, similar in action but weaker than balsam of Peru. The syrup is used as an agreeable basis for cough mixtures. Dose of the balsam: 8 to 30 drops (0.5 to 2 Mils).