Fat oil, Canada balsam, copaiba balsam, gurjun balsam, and volatile oil may be recognized by the following tests: If pure Peru balsam in a porcelain saucer is thoroughly mixed with an equal volume of pure concentrated sulphuric acid, the mixture thereby becomes heated, vapors of a pungent odor being emitted, and if then set aside to cool, it congeals. In the presence of fat or volatile oils, copaiba balsam, gurjun balsam, or Canada balsam, it remains, however, more or less thickly fluid or more or less soft-smeary. If the balsam be pure, the cold mixture, after washing with water, should yield a hardish or soft-friable mass, which, when kneaded with the fingers, should not prove smeary or sticky.
Fat oils are also very readily recognized by the use of warm petroleum-ether. The extract is evaporated, saponified with potash lye, extracted with alcohol, evaporated and decomposed with hydrochloric acid. A mixture of cinnamic acid and any of the fatty acids present in the Peru balsam is thereby obtained, which, after treatment with water, remains in the residue.
Of copaiba balsam, Peru balsam can take up as much as 25 per cent. From such adulterated balsam benzine dissolves the copaiba balsam, together with cinnamein, and the adulteration can then be recognized by the odor. Cinnamein treated with sulphuric acid acquires a cherry-red color, while in the presence of copaiba balsam or gurjun balsam, a yellow-brown coloration appears. The detection of an adulteration of Peru balsam with storax is, according to Denner, effected as follows: Shake in a test-tube 5 parts of the balsam to be examined with 5 parts of a 15 per cent. soda solution (soda lye of 1.60 specific gravity) and 10 parts of water. Then shake with 15 parts of ether, and after settling pour off the ether as much as possible. Repeat the shaking with 15 parts of fresh ether. Now heat the aqueous residue to boiling, acidulate with hydrochloric acid, add cold water, remove the resin separated thereby from the fluids, dissolve it in about 3 parts of soda lye of the above-mentioned strength, dilute with 20 parts of water, heat to boiling, and precipitate with barium chloride solution. Bring the precipitate upon the filter, and, after allowing it to drain off, dry it in the water-bath. Then extract it with alcohol, evaporate the alcoholic extract, take it up with concentrated sulphuric acid, add chloroform, and shake. In the presence of gum benzoin or storax, the chloroform acquires a violet to blue color. This method is a sure test for the recognition of even very small admixtures.
A content of asphaltum is readily detected by mixing the Peru balsam with ether compounded with about ⅛ alcohol. Any asphaltum present remains undissolved, and may be collected upon a filter.
In perfumery Peru balsam is chiefly used for pomades and fumigating pastilles, but also for cosmetics and soaps.
Tolu balsam is the produce of Myroxylon toluiferum, Humb., Bonpl. et Kunth, Toluifera balsamum, L., a tree of the natural order Papilionaceæ, growing in Northwestern South America. It exudes during the heat of the day, and is collected in gourds. It soon hardens, by which it is distinguished from Peru balsam. In commerce two varieties of Tolu balsam are found, one of the consistency of turpentine and the other solid. The first variety, Brazilian balsam, forms a semi-fluid, turpentine-like, sticky mass, of the color of copaiba balsam. By long storage it becomes hard and brownish. The solid variety, Tolu, or Carthagena balsam, is a brittle, more or less translucent yellow-brown or red-brown resin of a granular or crystalline appearance. It softens at about 86° F., and melts between 140° and 149° F. Viewed under the microscope, it appears rich in crystals of separated ciannamic and benzoic acids. Its specific gravity varies between 1 and 2. Both varieties of Tolu balsam have an aromatic, slightly pungent and sourish taste, resembling somewhat that of Peru balsam. They are readily soluble in ordinary spirit of wine, alcohol, acetone, chloroform, and potash lye, but insoluble in petroleum-ether and bisulphide of carbon. In Tolu balsam have been found toluene, cinnamic and benzoic acids, and several resins not yet sufficiently examined. According to Scharling, toluene constitutes about 1 per cent. of the Tolu balsam. It forms a colorless, limp oil, boils, according to Deville, at 338° F., and according to E. Kopp, at between 309° and 320° F., and has a specific gravity of 0.858. It has a sharp, pungent, pepper-like taste, and an odor resembling that of elemi. In the air, it is gradually converted by oxidation into a soft resin, without, however, becoming colored.
On boiling Tolu balsam with water, cinnamic and benzoic acids are separated from the solution. When treated with potash lye the resinous acids are fixed, and the toluene floats upon the fluid.
Commercial Tolu balsam is frequently more or less mixed with vegetable remains, which, however, can be readily detected with the microscope, especially after the solution of the resinous constituents. It is frequently adulterated with turpentine or pine resin. Such adulterations may be detected by bisulphide of carbon, which completely dissolves these substances, but not the Tolu balsam. When pure Tolu balsam is triturated with concentrated sulphuric acid, a cherry-red fluid is, according to Ulex, obtained, which does not evolve sulphurous acid, as is the case in the presence of turpentine-resins.
Tolu balsam is chiefly used for fumigating pastilles. The tincture prepared from it is also frequently used with advantage to give durability to the scent of handkerchief perfumes.
According to Holmes and Nalor, a Tolu balsam differing in its chemical behavior is found in the English wholesale trade. In thick layers it is yellow-brown, but perfectly transparent and gold-yellow in thin layers and extraordinarily sticky. By storage it hardens but slightly, and does not become brittle even if exposed for several days to a temperature of 212° F. Its odor reminds one somewhat of glue, and it develops a pungent, sharp taste only after chewing it for a few seconds. Its melting point lies at 136.4° F., being lower than that of ordinary Tolu balsam, from which it also differs in that it completely dissolves in ether as well as in benzine, while it is only partially dissolved by potash lye. The balsam contains no toluene, nor a hydrocarbon, boiling at 320° F. Further investigations have shown it actually to be a natural product, the derivation of which, however, could not be ascertained.