A curious account of the collecting of Liquid Storax from the tree Zygia, and from another tree called Stourika, is given in the travels through Asia Minor to Palestine of the Russian abbot of Tver in a.d. 1113-1115.[1042]
The wide exportation and ancient use of Liquid Storax are very remarkable: even in the first century, as appears by the author of the Periplus of the Erythrean Sea, Storax, by which term there can be but little doubt Liquid Storax was intended, was exported by the Red Sea to India. Whether the Storax and Storax Isaurica offered to the Church of Rome under St. Silvester, a.d. 314-335, by the emperor Constantine,[1043] was Liquid Storax or the more precious resin of Styrax officinalis L., is a point we cannot determine. That the Chinese used the drug was a fact known to Garcia de Orta (1535-63): Bretschneider[1044] has shown from Chinese sources that, together with olibanum and myrrh, it was imported by the Arabs into China during the Ming dynasty, a.d. 1368-1628. This trade is still carried on: the drug is conveyed by way of the Red Sea to Bombay, and thence shipped to China. Official returns show that the quantity thus exported from Bombay in the year 1856-57 was 13,328 lb. In the time of Kämpfer (1690-92), Liquid Storax was one of the most profitable articles of shipment to Japan.[1045]
Liquid Storax is known in the East, at least in the price-currents and trade statistics of Europeans, by the strange-sounding name of Rose Malloes (Rosa Mallas, Rosum Alloes, Rosmal), a designation for it in use in the time of Garcia de Orta. Clusius[1046] considered it to be Arabic, which, however, the scholars whom we have consulted do not allow. Others identify it with Rasamala, the Malay name for Altingia excelsa. (See further on.)
The botanical origin of Liquid Storax was long a perplexing question to pharmacologists. It was correctly determined by Krinos, but his information on the subject published in a Greek newspaper in 1841, and repeated by Kosté in 1855,[1047] attracted no attention in Western Europe. The question was also investigated by one of the authors of the present work, whose observations, together with a figure of Liquidambar orientalis Miller, were published in 1857.[1048]
Method of Extraction—The extraction of Liquid Storax is carried on in the forests of the south-west of Asia Minor, chiefly by a tribe of wandering Turcomans called Yuruks. The process has been described on the authority of Maltass and McCraith of Smyrna, and of Campbell, British Consul at Rhodes.[1049] The outer bark is said to be first removed from the trunk of the tree and rejected; the inner is then scraped off with a peculiar iron knife or scraper, and thrown into pits until a sufficient quantity has been collected. It is then boiled with water in a large copper, by which process the resin is separated, so that it can be skimmed off. This seems to be performed with sea water; some chloride of sodium can therefore be extracted from the drug. The boiled bark is put into hair bags and squeezed under a rude lever, hot water being added to assist in the separation of the resin, or as it is termed yagh, i.e. oil. Maltass states that the bark is pressed in the first instance per se, and afterwards treated with hot water. In either case the products obtained are the opaque, grey, semi-fluid resin known as Liquid Storax, and the fragrant cakes of foliaceous, brown bark, once common[1050] but now rare in European pharmacy, called Cortex Thymiamatis.
We are indebted to M. Felix Sahut of Montpellier for a specimen of the bark of Liquidambar orientalis, cut from the trunk of a fine tree on his property at the neighbouring village of Lattes. The bark which is covered with a very thick corky layer and soaked in its own fragrant resin, shows no tendency to exfoliate. The investigations of Unger[1051] in Cyprus are consequently to us inexplicable; he asserts that the bark scales off, like that of the plane, by continued exfoliation, which is not the case with that of M. Sahut’s tree.
Description—Liquid Storax is a soft viscid resin, usually of the consistence of honey, heavier than water, opaque and greyish brown. It always contains water, which by long standing rises to the surface. In one sample that had been kept more than 20 years, the resin at the bottom of the bottle formed a transparent layer of a pale golden brown. When liquid storax is heated, it becomes by the loss of water dark brown and transparent, the solid impurities settling to the bottom. Spread out in a very thin layer, it partially dries, but does not wholly lose its stickiness. When free from water (which reddens litmus) it dissolves in alcohol, spirit of wine, chloroform, ether, glacial acetic acid, bisulphide of carbon, and most of the essential oils, but not in the most volatile part of petroleum (“petroleum ether”). It has a pleasant balsamic smell, especially after it has been long kept; when recent, it is contaminated with an odour of bitumen or naphthalene that is far from agreeable. Its taste is sharply pungent, burning and aromatic.
When the opaque resin is subjected to microscopic examination, small brownish granules are observed in a viscid, colourless, transparent liquid, besides which large drops of a mobile watery liquid may be distinguished. In polarized light, numerous minute crystalline fragments with a few larger tabular crystals are obvious. But when thin layers of the resin are left on the object glass in a warm place, feathery or spicular crystals (styracin) shoot out on the edge of the clear liquid, while in the large, sharply-defined drops above mentioned, rectangular tables and short prisms (cinnamic acid) make their appearance. On applying more warmth after the water is evaporated, all the substances unite into a transparent, dark brown, thick liquid, which exhibits no crystalline structure on cooling, or only after a very long time. Among the fragments of the bark occurring in the crude resin, liber-fibres are frequently observable.
Chemical Composition—The most abundant constituent of Styrax is probably the Storesin, C₃₆H₅₅(OH)₃, discovered in 1877 by W. von Miller, or rather cinnamic ethers of it and of an isomeric substance. Storesin is an amorphous substance melting at 168° C., readily soluble in petroleum ether. Several other compound ethers have also been observed in the drug, as for instance cinnamic ether of phenylpropyl, cinnamic ether of ethyl, cinnamic ether of benzyl, and especially cinnamate of cinnamyl, C₉H₇O₂·C₉H₉, the so-called Styracin. This substance, discovered by Bonastre in 1827, can be removed by ether, benzol or alcohol, after the separation from the resin of the cinnamic acid; it is insoluble in water, and volatile only in super-heated steam. It crystallizes in tufts of long rectangular prisms, which melt at 38° C., but it frequently does not solidify in a crystalline form, or only after a long time, or remains as an oily liquid. In its pure state it is inodorous and tasteless. By concentrated solution of potash, it is resolved into a cinnamate, and cinnamic alcohol (Styrone) C₉H₁₀O, which latter is not present in Liquid Storax. The cinnamic acid may be extracted to a small extent by boiling water, more completely by means of a boiling solution of carbonate of sodium, as it is present in the drug partly in the free state. Its compound ethers may be decomposed by caustic lye. The yield of cinnamic acid accordingly varies from 6 to 12 per cent.—or even, according to Löwe, as much as 23 per cent. of crystallized cinnamic acid can be obtained. The acid dissolves abundantly in ether, alcohol, or hot water, slightly in cold water; it is inodorous, but has an acrid taste. It fuses at 133° C., and boils at 290° C.; at a dull red heat it is resolved into carbonic acid and styrol, which latter is therefore related to it in the same manner as benzol (benzene) to benzoic acid. Liquid styrax is in fact the best source of cinnamic acid.
Another constituent of styrax is a fragrant substance, perhaps ethylvanillin, occurring in but small quantity.