"A balsam obtained from Toluifera Balsamum, Linné" (U. S. P.) (Myroxylon Toluifera, Kunth; Myrospermum Toluiferum, Richard; Toluifera Balsamum, Miller).
COMMON NAMES: (Balsam) Balsam of Tolu, Tolu balsam; (tree) Tolu balsam tree.
ILLUSTRATIONS: Köhler, Med. Pflanzen, Bentley and Trimen, Med. Plants, p. 84.
Botanical Source.—This tree very closely resembles that yielding balsam of Peru. The trunk is tall and bare, and at about 40 to 60 feet from the ground throws out its branches, producing a rounded crown of foliage. The younger the tree the larger the foliage of obovate leaflets, older trees suffering from the drainage of balsam. The flowers are borne in dense, axillary racemes, 3 to 43 inches long, and the calyx tube is rather tubular. The fruit is an oblong, linear legume, scarcely narrowed at its base. The tree, which is an evergreen, rises to a height of 70 or 80 feet.
History.—As with the preceding article, so with the present, it has been involved in considerable obscurity, it formerly being uncertain whether the same trees which yield balsam of Peru furnished likewise that of Tolu. Some, notably Baillon, consider that the two balsams are derived from the same species, and that the method of gathering, etc., causes their dissimilarity. It is, we believe, now quite definitely settled that entirely distinct species furnish the two balsams. The Toluifera Balsamum, which is undoubtedly the one species from which tolu is obtained, is found in many parts of South America, especially on the elevated plains and mountains near Carthagena, Tolu, and in the Magdalena province of Columbia. The balsam is said to be obtained by incisions made into the tree, from which it flows into wax (formerly) vessels placed for the purpose, and in which it solidifies. For the mode of procuring balsam of Tolu, see a paper by Mr. John Weir (Lond. Pharm. Jour., 1864, and Amer. Jour. Pharm., 1864, p. 449), summarized as follows by the authors of the Pharmacographia: "The balsam tree has an average height of 70 feet, with a straight trunk, generally rising to a height of 40 feet before it branches. The balsam is collected by cutting in the bark two deep, sloping notches, meeting at their lower ends in a sharp angle. Below this V-shaped cut the bark and wood is a little hollowed out, and a calabash of the size and shape of a deep tea-cup is fixed. This arrangement is repeated, so that as many as 20 calabashes may be seen on various parts of the same trunk. When the lower part has been too much wounded to give space for any fresh incisions, a rude scaffold is sometimes erected, and a new series of notches made higher up. The balsam-gatherer goes from time to time round the trees with a pair of bags of hide, slung over the back of a donkey, and empties into them the contents of the calabashes. In these bags the balsam is sent down to the ports, where it is transferred to the cylindrical tins in which it reaches Europe. The bleeding of the trees goes on for at least 8 months of the year, causing them ultimately to become much exhausted and thin in foliage" (Pharmacographia, 2d ed., p. 203).
Description and Tests.—Balsam of Tolu is imported from Carthagena in tin, earthen, and other vessels. When first received in this country it is soft and adhesive. As described by the U. S. P., it is "a yellowish-brown, semifluid or nearly solid mass, becoming more brittle when exposed to cold, transparent in thin layers, having an agreeable odor recalling that of vanilla, but distinct from it, and a mild, aromatic taste. Readily and completely soluble in alcohol, the solution showing an acid reaction with litmus paper. Also completely soluble in chloroform and in solutions of the fixed alkalies; almost completely soluble in ether, but nearly insoluble in water, benzin, or carbon disulphide"—(U. S. P.). It softens when chewed, melts when heated, and when burned evolves a fragrant odor.
Chemical Composition.—According to Frémy, Tolu balsam consists of cinnamein, cinnamic acid, and resin, and the balsam resinifies to a crystalline mass with greater facility than the balsam of Peru. About 8 parts of volatile oil are obtained from 4000 parts of tolu by distillation with water; this oil contains tolene (C10H16), which is thin, colorless, and volatile, and has an acrid, hot taste and a pleasant odor. Its density is 0.858. Oxygen is rapidly absorbed by this body. Benzoic acid, cinnamic acid, benzylic benzoate, and benzylic cinnamate are present in balsam of Tolu, the latter in larger proportion (Busse). Vanillin was also found in this balsam (E. Schmidt). Guibourt states that as the balsam solidifies its odor becomes more feeble, but its quantity of cinnamic acid is augmented, which is probably owing to the action of the atmosphere upon its oil effecting a chemical change. According to E. Kopp, the solid, resinous portion of the balsam consists of two resins which have the composition of hydroxides of styracin (see Balsam of Peru), one easily and the other difficultly soluble in alcohol. Deville, however, maintained that there is but one resinous body. Upon dry distillation, beside the above-mentioned acids and ethers, balsam of Tolu yields a hydrocarbon termed toluol (C7H8), styrol, and phenol. Toluol, or toluene (C7H8), is the body found among the products when wood, certain resins, and other vegetable substances are submitted to destructive distillation. It is likewise found in coal tar. Chemically it is methyl-benzene (C6H5.CH3 or C7H8). It is a powerfully refractive, oily liquid devoid of color, and has a benzol-like odor. It boils at 111° C. (231.8° F), and refuses to congeal at -20° C. (-40° F.). Its density is 0.80.
Balsam of Tolu is scarcely soluble in the essential oils (Pharmacographia), but water at 100° C. (212° F.) takes up its cinnamic acid. It yields very little volatile oil when distilled with water, and if the distillation be continued its acid sublimes. Mr. Hatchett found that when he dissolved it in the smallest possible quantity of liquor potassae, it completely lost its own odor and assumed a most fragrant smell, somewhat resembling that of the clove pink (T.). "When balsam of Tolu is pressed between two warm plates of glass, so as to obtain it in a thin, even layer, and then examined with a lens, it exhibits an abundance of crystals, of cinnamic acid" (Pharmacographia). Acetone and glacial acetic acid easily dissolve it, and it is insoluble in benzene. G. L. Ulex (Pharm. Jour. and Trans., p. 550, Vol. XII, from Archiv. der Pharmacie, Jan., 1853) gives the following mode of testing the purity of balsam of Tolu: "Pure Tolu balsam, heated in sulphuric acid, dissolves without any disengagement of sulphurous acid, yielding a cherry-red liquid; when, however, colophony, with which it is frequently adulterated, is present, the substance blackens, swells up, and disengages much sulphurous acid." The same is true of turpentine. "Carbon disulphide, aided by a gentle heat, removes from the balsam scarcely anything but some of its cinnamic and benzoic acids. On decanting and evaporating the disulphide no substance having the properties of resin should remain"—(U. S. P.). Recently efforts have been made to distinguish between the different balsams, including Tolu and Peru balsams, and to recognize admixtures of resin, etc., by determining the saturation-power of the balsams for alkalies, and by similar methods (Kremel and Dieterich).
Action, Medical Uses, and Dosage.—Balsam of Tolu, like that of Peru, is a stimulant, tonic, and expectorant, and may be used as a substitute for it in chronic catarrhs, and other pulmonary affections not actively inflammatory in their character. It is usually preferred on account of its more agreeable flavor, and for which it is often added to cough-mixtures. The balsam, dissolved in ether, and the vapor therefrom inhaled, is reputed beneficial in coughs and bronchial affections of long standing. Two parts of Tolu, 3 of almond oil, 4 of gum Arabic, and 16 of rose water, make an excellent liniment for excoriated nipples. The dose is from 10 to 30 grains, frequently repeated, and given in tincture, syrup, or similar to balsam of Peru.
Related Species.—Myroxylon punctatum, Klotzsch (Toluifera punctata, Baillon; Myrospermum balsamifera, Ruiz et Pavon). This species grows in the northern portion of South America, and is known to the Peruvians as Quino-quino. Bentley, Trimen, and Flückiger, among others, regard it as identical with Toluifera Balsamum, Miller.