The collection of balsam continues until the first rain falls in April or May, when the work ceases. A vigorous tree, well treated, yields balsam for 30 years in succession, and if then allowed to rest 5 or 6 years can be used several years longer. The annual yield of balsam from 100 trees is said to be about 550 lbs.
From the very odoriferous flowers of the balsam tree or, according to others, by expressing the fruits, a _white_ Peruvian balsam is obtained, which is, however, seldom found in commerce. It is of the consistency of honey, pale-yellow, smells of vanilla and melilot, and has an aromatic bitter taste. On standing for some time it deposits crystals of myroxocarpin.
Ordinary (black) Peruvian balsam is a black-brown fluid, transparent and dark (honey-yellow in thin layers), which retains its consistency even after being kept for years and deposits no crystals. It shows a slight acid reaction, has an agreeable odor reminding one of gum benzoin and vanilla, and at first a mild, but, later on, a sharp and pungent taste.
The specific gravity of pure Peru balsam formerly varied between 1.14 and 1.16, but at present between 1.135 and 1.145, this change in the specific gravity being very likely due to a different process of purification.
Peru balsam is miscible in every proportion with absolute alcohol, while ether leaves behind undissolved a black, smeary residue, and hot oils of turpentine or almonds dissolve only about one-half. It is miscible with acetone, chloroform, amyl alcohol. By digesting the balsam with aqueous potash lye, _Peru balsam oil_, which constitutes about 60 per cent. of the balsam, separates on the surface. In an undecomposed state the oil is, according to Kachler, chiefly benzyl, cinnamate, or cinnamein. The potash solution separated from the Peru balsam oil, contains cinnamic acid, benzoic acid, and resin. The latter, according to Stotze, can be separated into two portions, one soluble, and the other insoluble, in aqueous alcohol.
Benzine and petroleum-ether dissolve from the Peru balsam only the nearly colorless cinnamein of which it contains up to 45 per cent. The behavior of Peru balsam towards bisulphide of carbon is very characteristic, 3 parts of it giving, according to Flückiger, a clear solution with 1 part of bisulphide of carbon; if, however, 8 parts more of the latter be added, up to 30 per cent. of a dark resin is separated, while the bisulphide of carbon is but slightly colored.