Under the name American storax, white Peru balsam, white Indian balsam or liquid ambar is found in commerce a product similar to storax, which is derived from Liquidambar styraciflua, L., a tree indigenous to Mexico and Louisiana. This balsam forms a clear, transparent, brownish-yellow, semi-fluid mass. It has a storax-like odor, and a sharp and pungent taste. It is only partially soluble in alcohol, specifically lighter than water, and shows an acid reaction. It is said to consist of 24 per cent. styracin, 1 per cent. benzoic acid, volatile oil, etc. It is sometimes used for fumigating purposes, but chiefly serves for the adulteration of Tolu balsam.
Myrrh (Gummi-resina myrrha, Gummi myrrha) is a gum resin, the produce of Balsamodendron Ehrenbergianum, Berg, and, perhaps, also of Balsamodendron Myrrha, Nees. The first-named tree is found in the countries bordering on the Red Sea, and extends into Africa to the Somali Coast, where the principal supply of myrrh is collected. The gum-resin exudes naturally as a white oil-like mass, which, after hardening, whereby it becomes considerably darker, is collected by the natives and brought chiefly to Berbera, a small seaport opposite Aden, to be exchanged for English and Indian goods. From there, by way of Aden and Bombay, it reaches the European market. In Bombay the first sorting takes place, which is, however, superficial, and hence has to be repeated in Europe (London). According to Parker, ten different resins are admixed with myrrh, especially bdellium resins.
In commerce Myrrha electa and Myrrha vulgaris or in sortis are distinguished. Myrrha electa, the best quality, occurs in pieces of irregular form and variable sizes, consisting of tears—either distinct or agglomerated—usually covered with a fine powder or dust. The surface is seldom smooth, but generally rough or granular. The color varies, being pale reddish-yellow, red, or reddish-brown. The fracture is conchoidal, seldom smooth, but rather granular, rough, of a fatty lustre, and sometimes shows whitish striæ or veins, or opalesces like flint. The fractured edges are more or less translucent; thin disks or splinters are translucent or transparent. The specific gravity is, according to Hager, 1.195 to 1.205, and according to Ruickholdt, 1.12 to 1.18. A Myrrha electa is the better, the more fragile, friable, and paler in color it is, and the more rapidly it ignites and burns with a yellow, sooty flame. Poorer qualities may be recognized by the dark-brown color and dirty appearance. Myrrh is with difficulty rubbed to a fine powder, this being possible only after drying, which must, however, be done at a very moderate heat in order to prevent loss of volatile oil.
According to Hager, myrrh consists in 100 parts of about 2.5 parts volatile oil (myrrhol), 25 to 35 parts resin (myrrhin), 55 to 65 parts gum soluble in water, 3 to 8 parts salts, impurities, and water. Water forms with myrrh an emulsion, and dissolves the gum. The resinous constituents are dissolved by spirit of wine.
The gum, which forms the portion of the myrrh soluble in water, but insoluble in alcohol, and amounts to from 57 to 59 per cent., is, according to Oscar Koehler, a hydrocarbon of the formula C6H10O5. The portion soluble in alcohol is, according to the same chemist, a mixture of various resins, an indifferent soft resin of the formula C26H34O5, soluble in alcohol and ether, forming the greater portion of it. There are further present two resin acids, one of which has to be considered a bibasic acid of composition C12H16O8, and the other as a monobasic acid of the formula C26H32O9. The principal constituent of the volatile oil of which, according to Koehler, 7 to 8 per cent. is present, while Ruickholdt formerly found only 2.18 per cent. corresponds to the formula C10H14O. The volatile oil is laevorotatory, and when diluted with bisulphide of carbon becomes, according to Flückiger, violet by the action of bromine. An extract of myrrh, prepared with bisulphide of carbon, gives the same reaction with bromine vapor. Hydrochloric or nitric acid also colors myrrh violet, which also applies to the volatile oil.
Petroleum-ether should, at the utmost, take up 6 per cent. of the myrrh, and the extract must be colorless.
Myrrh is frequently contaminated with bark, which forms either a film of cork as thick as paper or a crust of a fibrous and, at the same time, brittle nature. Sand or small pebbles are also frequently mixed with the myrrh. Other varieties of gum or gum-resin, which considerably decrease the value of the product, are often found in the commercial article, the inferior qualities especially being adulterated and mixed with dark pieces of Suakim gum, gum of the plum or cherry tree, bdellium, and similar substances, which are partially moistened with myrrh tincture, and scattered over with myrrh powder. Adulteration with gum-arabic, gum of the plum or cherry tree, which are coated with alcoholic myrrh solution, is recognized by the paler lustre, greater transparency, and mucilaginous taste. Pieces of resin melt on heating, while myrrh only swells up. Bdellium is detected by the dark or black-brown color, toughness, less bitter taste, and by crackling and spitting when held in the flame of a candle, as well as by the reaction of myrrh with nitric acid discovered by Bonastre. By mixing 5 cubic centimeters of alcoholic myrrh tincture with 5 to 10 drops of fuming nitric acid, a rose-color coloration passing into red results. Parker gives the following method for testing myrrh: Prepare a tincture of 1 part myrrh and 6 parts spirit of wine. Saturate with this tincture white filtering paper, allow it to drain off, and then wrap it around a glass rod moistened with nitric acid of 1.42 specific gravity. With genuine myrrh the paper immediately becomes deep yellow-brown and then black, while the edges of the paper strip appear dark purple-red. When a few drops of the tincture of myrrh are allowed to dry in, a transparent residue remains behind. The tinctures of spurious articles (with the exception of bissabol) give turbid residues.
Myrrh was already in Moses's time an article used in the sacrifices of the Israelites. It seems to have been made use of by Democrates. Dioscorides enumerates eight varieties of it, and Pliny seven, which he obtained from Abyssinia. Herodotus and Diodorus Siculus mention Arabia as the home of the myrrh tree.
In perfumery, myrrh is chiefly used for dentifrices and fumigating pastilles and essences.