Storax is the produce of Liquid ambar orientale, Mill, a plantain-like tree which reaches a height of about 32 feet. In Southern Asia Minor, especially in Cyprus, the tree forms handsome, dense forests. According to Flückiger, the balsam is extracted from the peeled-off bark, with the assistance of warm water. The mass thus melted out sinks down in the water, and is later on combined with the substance obtained by expressing the boiled bark while still warm. This mixture forms the liquid storax (Storax liquidus). The residue remaining after expression is dried in the sun and forms, under the name of Cortex thymiamatis, an article of commerce, which is used for fumigating purpose, for the preparation of ordinary storax, etc. The crude storax is brought to Smyrna, Syra, and Kos, and comes into the European market almost exclusively from Trieste.
Liquid storax is a sticky, opaque substance of the consistency of turpentine. It has a mouse-gray color, which by contact with the air becomes brown on the surface, an agreeable benzoin-like odor, and a sharp, pungent, aromatic taste. It is heavier than water, its specific gravity being 1.112 to 1.115. On losing its content of moisture (by drying out when heated) it becomes brown and clear. When exposed to the air in a thick layer it does not completely dry, and in a thin layer only after considerable time; but when pressed with the finger always shows a certain stickiness. It is partially soluble in spirits of wine, yielding with it a more or less turbid solution. It is also incompletely soluble in oil of turpentine, benzine, petroleum-ether, and chloroform. Viewed under the microscope liquid storax appears as a colorless thickish fluid, intermingled with larger and smaller drops, fragments of bark tissue, and now and then, perhaps, with crystals of styracin and cinnamic acid.
Liquid storax contains styrol (10 to 15 per cent.), styracin, and cinnamic acid (10 to 15 per cent.). Styrol or cinnamol seems to be the most important carrier of the odor and taste of liquid storax. If 20 parts of liquid storax are subjected to distillation together with 15 parts of crystallized soda and 200 parts of water, the cinnamol collects in the form of a yellowish, very mobile liquid upon the distillate. By rectification it can be obtained colorless, but is thereby partially converted into metastyrol, an isomeric, amorphous, odorless, and tasteless substance which is solid at an ordinary temperature. By exposure for some time to a heat of 608° F. it is reconverted into styrol. Styrol (C8H8) forms a clear, colorless, mobile liquid having an odor of benzine and naphthalene. Its specific gravity is 0.924 and its boiling point lies at 294.8° F. In water it is but sparingly soluble, but is miscible in all proportions with anhydrous spirit of wine, chloroform, benzine, ether, and oils. It stands in the same relation to cinnamic acid as benzol to benzoic acid, and is formed by distilling a mixture of cinnamic acid and barium oxide.
Styracin is cinnyl cinnamate. On distilling liquid storax with water, styrol passes over. If now from the residue the cinnamic acid be withdrawn by means of soda-solution, and the resin, which remains behind, be treated with cold spirit of wine, styracin is left, which crystallizes from ether, hot alcohol, or benzol. It forms colorless, odorless, and tasteless crystals which melt at 113° F. and remain for a long time fluid after melting. It is insoluble in water, but soluble in 25 parts cold, and 2 parts boiling, spirit of wine, as well as in 5 parts ether. By oxidizing substances it is converted into bitter almond oil and benzoic acid, and by the action of potassium hydroxide it is decomposed to cinnyl alcohol and cinnamic acid.
Good liquid storax should yield to 90 per cent. alcohol at least so much soluble matter that the dried residue of the filtered alcoholic solution amounts to 65 per cent. of the quantity of storax.
Ordinary liquid storax, which has not been stored too long, contains 10 to 20 per cent. of water and about the same quantity of impurities (fragments of plant tissue) which remain behind on treatment with the above-mentioned solvents.
Liquid storax is said to be adulterated with the turpentines of some species of larch and pine. Such adulteration is primarily detected, according to Hager, by the specific gravity. Take up a drop of the balsam with a knitting-needle, and by heating the needle make it fall into a cold solution of 1 part common salt and 8 parts water. On stirring, the drop must sink, otherwise adulteration with turpentine is very likely. Next bring 5 grammes of the storax into a test-tube, melt it in the water-bath, add ½ volume of absolute alcohol, and mix by shaking; then compound the mixture with several times its volume of petroleum-ether, shake vigorously, allow to settle, and decant the layer of petroleum-ether. Repeat twice this shaking with petroleum-ether; then evaporate the petroleum-ether solution in a tared flask in the water-bath. The residue remaining after evaporation is colorless, bluish opalescent, and of an agreeable odor; in the presence of turpentine it is yellowish and has the, not to be mistaken, odor of turpentine.
Storax in grains consists of round, longish grains of a brown-black color and smooth, lustrous surface, which soften by the warmth of the hand. It is nothing but liquid storax brought into a granular form and by storing freed more or less from impurities.
Ordinary storax (Styrax calamitus or St. vulgaris) is an artificial product prepared by mixing liquid storax with various comminuted vegetable substances. Formerly the above-mentioned bark of the storax tree (Cortex thymiamatis) was only used for this purpose, but at present sawdust and exhausted cinnamon are also taken. This storax forms a reddish or brown-black, humus-like mass, which is generally moist. When dried it is very friable and has a storax-like odor distinctly calling to mind that of cinnamon. Good qualities are abundantly covered with crystalline efflorescences (of cinnamic acid and styracin); poorer qualities prepared with the addition of sawdust have a musty odor. The admixed vegetable tissue can, according to Wiesner, be readily recognized by boiling the storax with alcohol, and after washing treating with dilute chromic acid, to which a small quantity of sulphuric acid has been added.
Liquid storax was already used for fumigating purposes by the ancient Greeks and Jews, and it forms to-day a constituent of fumigating pastilles, essences, etc. Storax tincture furthermore possesses the property of giving more constancy to scents resembling it. Piesse says, in regard to the odor of liquid storax, that it combines the agreeable with the disagreeable, it possessing partially an odor similar to that of the tuberose and partially one reminding of coal-tar oil. However, it possesses this disagreeable odor only in a concentrated state; when finely divided or diluted, it diffuses a very agreeable perfume.