As adulterants, are used: Alcohol, volatile oils, fat oil, especially castor oil; further, copaiba balsam, Canada balsam, gurjun balsam, storax, benzoin, and asphaltum. The establishment of these adulterants is connected with difficulties; but the properties of Peru balsam are so characteristic that it is quite easy to detect whether it is genuine and pure, or not, the specific gravity and proportions of solubility deserving especial attention in this respect. The test by the specific gravity is available, since most of the adulterants render the balsam specifically lighter, especially alcohol, but also copaiba balsam (specific gravity, O.95), castor oil (0.96), oil of turpentine (0.87), gurjun (0.96), etc. The customary procedure is as follows: Prepare a common salt solution of 1.25 specific gravity, by dissolving 1 part of dried sodium chloride in 5 parts of distilled water; drop the balsam into the solution; every drop of pure Peru balsam sinks in a roundish form to the bottom; but if the drop again comes to the surface and spreads out upon it, it is a sure sign of some kind of adulteration. However, the change in the specific gravity by the admixture of fat oils is but very slight, since the balsam can only be mixed with them to a conformable fluid in the proportion of from 7 to 10 to 1. Castor oil forms an exception in this respect, it being miscible also in other proportions. Petroleum-ether is an excellent testing agent. Bring into a test-tube about 2.5 grammes of Peru balsam, and 6 to 7 centimeters of petroleum-ether, close the tube with the finger and shake vigorously; a brown, thickly-fluid mass adheres in unequal layers to the sides of the tube, and before running together remains in this position 1 to 2 minutes after the petroleum-ether has been poured into a porcelain saucer. If, however, the mass is thinly-fluid, and does not, in the above-mentioned manner, adhere to the sides of the tube, but, after shaking, collects below the petroleum-ether, the balsam is adulterated. After shaking, immediately pour off the petroleum-ether; if the latter is almost colorless, or but slightly colored yellowish, the balsam is pure; if, however, it is turbid, and soon forms a sediment, or if it is yellow or brownish, or brown, the balsam is adulterated.