Benzoïnum; Benzoin, Gum Benjamin; F. Benjoin; G. Benzoëharz.[1474]
Botanical Origin—Styrax Benzoin Dryander, a tree of moderate height, with stem as thick as a man’s body and beautiful crown of foliage, indigenous to Sumatra and Java, in the first of which islands benzoin is produced.
The tree yielding the superior benzoin of Siam, though commonly referred to this species, has never been examined botanically, and is actually unknown. The French expedition for the exploration of the Mekong and Cochin China (1866-68), reported the drug to be produced in the cassia-yielding forests on the eastern bank of the river in question in about N. lat. 19°. Whether any benzoin is obtained from S. Finlaysoniana Wall, as conjectured by Royle, we know not.
History—There is no evidence that the Greeks and Romans,[1475] or even the earlier Arabian physicians, had any acquaintance with benzoin; nor is the drug to be recognized among the commodities which were conveyed to China by the Arab and Persian traders between the 10th and 13th centuries, though the camphor of Sumatra is expressly named.
The first mention of benzoin known to us (disregarding the word kalanusari, which in the St. Petersburg Dictionary is given as the old Sanskrit name of benzoin) occurs in the travels of Ibn Batuta,[1476] who having visited Sumatra during his journey through the East, a.d. 1325-49, notes that the island produces Java Frankincense and camphor. The word Java was at that period a designation of Sumatra, or was even used by the Arabs to signify the islands and productions of the Archipelago generally.[1477] Hence came the Arabic name Lubán Jáwí, i.e. Java Frankincense, corrupted into Banjawi, Benjui, Benzui, Benzoë and Benzoïn, and into the still more vulgar English Benjamin.
We have no further information about the drug until the latter half of the following century, when we find a record that in 1461 the sultan of Egypt, Melech Elmaydi, sent to Pasquale Malipiero, doge of Venice, a present of 30 rotoli of Benzoi, 20 rotoli of Aloes Wood, two pairs of Carpets, a small flask of balsam (of Mecca), 15 little boxes of Theriaka, 42 loaves of Sugar, 5 boxes of Sugar Candy, a horn of Civet, and 20 pieces of Porcelain.[1478] Agostino Barbarigo, another doge of Venice, was presented in a similar manner in 1490 by the sultan of Egypt with 35 rotoli of Aloes Wood, the same quantity of Benzui and 100 loaves of Sugar.[1479]
Among the precious spices sent from Egypt in 1476 to Caterina Cornaro, queen of Cyprus, were 10 lb. of Aloes Wood and 15 lb. of Benzui.[1480] These notices indicate the high value set upon the drug when first brought to Europe.
The occurrence of benzoin in Siam is noticed in the journal of the voyage of Vasco da Gama,[1481] where, in enumerating the kingdoms of India, it is stated that Xarnauz (Siam[1482]) yields much benzoin worth 3 cruzados, and aloes worth 25 cruzados per farazola. According to the same record, the price of benzoin (beijoim) in Alexandria was 1 cruzado per arratel, half the value of aloes wood.
The Portuguese traveller Barbosa[1483] visited in 1511 Calicut on the Malabar Coast, and found Benzui to be one of the more valuable items of export, one farazola (22 lb. 6 oz.) costing 65 to 70 fanoes; camphor fetched nearly the same price, and mace only 25 to 30 fanoes. From other sources we gather that benzoin was an article of Venetian trade in the beginning of the 16th century.
Garcia de Orta, writing at Goa (1563), was the first to give a lucid and intelligent account of benzoin, detailing the method of collection, and distinguishing the drug of Siam and Martaban from that produced in Java and Sumatra.
It began then to be regularly imported into Europe,[1484] being frequently called Asa dulcis. The chemists of that time submitted it, like many other substances, to dry distillation. Benzoic acid occasionally separating from the oily products (“oleum Benzoës”) was noticed already by Nostredame,[1485] Rosello,[1486] Liebaut,[1487] Blaise de Vigenère,[1488] and others. It was a common pharmaceutical preparation, under the name of Flores Benzoës, since the 17th century.[1489]
In the early part of the 17th century, there was direct commercial intercourse between England and both Siam and Sumatra, an English factory existing at Ayuthia (Siam) until 1623; and benzoin was doubtless one of the commodities imported. The import duties levied upon it in England in 1635 amounted to 10s. per lb.[1490]
Production—Benzoin is collected in Northern and Eastern Sumatra, especially in the Batta country, lying southward of the state of Achin.[1491] The tree grows in plenty also in the highlands of Palembang in the south and its resin is collected. It is chiefly on the coast regions that considerable plantations are found. Teysmann saw the cultivation in the tracts of the river Batang Leko, the trees being planted about 15 feet apart. The benzoin from the interior is mostly from wild trees, which occur at the foot of the mountains at an elevation of 300 to 1000 feet.
The trees, which are of quick growth, are raised from seeds grown on the [edges of?] rice-fields; they require no particular attention beyond being kept clear of other plants, until about 6 or 7 years old, when they have trunks 6 to 8 inches in diameter, and are capable of yielding the resin. Incisions are then made in their stems, from which there exudes a thick, whitish, resinous juice, which soon hardens by exposure to the air, and is carefully scraped off with a knife.
The trees continue to yield at the rate of about three pounds per annum for 10 or 12 years, after which period they are cut down. The resin which exudes during the first three years is said to be fuller of white tears, and therefore of finer quality, than that which issues subsequently, and is termed by the Malays Head Benzoin. That which flows during the next 7 or 8 years, is browner in colour and less valuable, and is known as Belly Benzoin; while a third sort, called Foot, is obtained by splitting the tree and scraping the wood; this last is mixed with much bark and refuse.[1492]
Benzoin is brought for sale to the ports of Sumatra in large cakes called Tampangs, wrapped in matting. These have to be broken, and softened either by the heat of the sun or by that of boiling water, and then packed into square cases which the resin is made to fill.
The only account of the collection of Siam Benzoin is that given by Sir R. H. Schomburgk, for some years British Consul at Bangkok.[1493] He represents that the bark is gashed all over, and that the resin which exudes, collects and hardens between it and the wood, the former of which is then stripped off. This account is confirmed by the aspect of some of the Siam benzoin of commerce as well as by that of pieces of bark in our possession; but it is also evident that all the Siam drug is not thus obtained. Schomburgk adds, that the resin is much injured and broken during its conveyance in small baskets on bullocks’ backs to the navigable parts of the Menam, whence it is brought down to Bangkok.[1494]
Whether benzoin owes its original fluidity to a volatile oil holding the resin in solution, and its solidification to the volatilization of this oil, or whether the resin itself hardens by oxidation,—what occasions the remarkable diversity of aspect between the opaque and milk-like, and the completely transparent resin, are questions to be investigated by some future observer.
Description—Benzoin (always termed in English commerce Gum Benjamin) is distinguished as of two kinds, Siam and Sumatra. Each sort occurs in various degrees of purity, and under considerable differences of appearance.
1. Siam Benzoin—The most esteemed sort is that which consists entirely of flattened tears or drops, an inch or two long, of an opaque, milk-like, white resin, loosely agglutinated into a mass. More frequently the mass is quite compact, consisting of a certain proportion of white tears of the size of an almond downwards, imbedded in a deep, rich amber-brown, translucent resin. Occasionally the translucent resin preponderates, and the white tears are almost wanting. In some packages, the tears of white resin are very small, and the whole mass has the aspect of a reddish-brown granite. There is always a certain admixture of bits of wood, bark, and other accidental impurities.
The white tears when broken, display a stratified structure with layers of greater or less translucency. By keeping, the white milky resin becomes brown and transparent on the surface.
Siam benzoin is very brittle, the opaque tears showing a slightly waxy, the transparent a glassy fracture. It easily softens in the mouth and may be kneaded with the teeth like mastich. It has a delicate balsamic, vanilla-like, fragrance, but very little taste. When heated it evolves a more powerful fragrance, together with the irritating fumes of benzoic acid; its fusing point is 75° C. The presence of benzoic acid may be shown by the microscopical examination of splinters of the resin under oil of turpentine.
Siam benzoin is imported in cubic blocks, which takes their form from the wooden cases in which they are packed while the resin is still soft.
2. Sumatra Benzoin—Prior to the renewal of direct commercial intercourse with Siam in 1853, this was the sort of benzoin most commonly found in commerce.
It is imported in cubic blocks exactly like the preceding, from which it differs in its generally greyer tint. The mass however, when the drug is of good quality, contains numerous opaque tears, set in a translucent, greyish-brown resin, mixed with bits of wood and bark. When less good, the white tears are wanting, and the proportion of impurities is greater. We have even seen samples consisting almost wholly of bark. In odour, Sumatra benzoin is both weaker and less agreeable than the Siam drug, and generally falls short of it in purity[1495] and handsome appearance, and hence commands a much lower price. The greyish-brown portion melts at 95°, the tears at 85° C.
A variety of Sumatra benzoin is distinguished by the London drug-brokers as Penang Benjamin or Storax-smelling Benjamin. We have seen it of very fine quality, full of white tears (some of them two inches long), the intervening resin being greyish.[1496] The odour is very agreeable, and perceptibly different from that of Siam benzoin, or the usual Sumatra sort. Whether this drug is produced in Sumatra and by Styrax Benzoin we know not; but it is worthy of note that S. subdenticulata Miq., occurring in Western Sumatra, has the same native name (Kajoe Kĕminjan) as S. Benzoin, and that Miquel remarks of it—“An etiam benzoiferum?”[1497]
Chemical Composition—Benzoin consists mainly of amorphous resins perfectly soluble in alcohol and in potash, having slightly acid properties, and differing in their behaviour to solvents. If two parts of the drug are boiled with one part of caustic lime and 20 parts of water, benzoic acid is removed. From the residue the excess of lime is dissolved by hydrochloric acid, and the remaining resins washed and dried. About one-third of them will be found readily soluble in ether, the prevailing portion dissolves in alcohol, and a small amount remains undissolved.
By distilling the resin of benzoin with ten times its weight of zinc dust, Ciamician (1878) chiefly obtained toluol, C₆H₅(CH₃).
Subjected to dry distillation, benzoin affords as chief product Benzoic Acid, C₇H₆O₂, together with empyreumatic products, among which Berthelot has proved the presence (in Siam benzoin) of Styrol (p. 274). The latter has been obtained in 1874 by Theegarten from Sumatra benzoë by distilling it with water. When the resin is fused with potash, it is partly decomposed and then, according to Hlasiwetz and Barth (1866), yields among other products, protocatechuic acid (more than 5 per cent.), C₆H₃(OH)₂COOH, para-oxybenzoic acid, C₆H₄(OH)COOH, and pyrocatechin, C₆H₄(OH)₂.
Benzoic acid exists ready-formed in the drug to the extent of 14 to 18 per cent.[1498] Although the acid dissolves in 12 parts of boiling water, the resin in which it is imbedded precludes its complete extraction by this means. It is however easily accomplished by the aid of an alkali, most advantageously by milk of lime, which does not combine with the amorphous resins.
Benzoin is not manifestly acted on by bisulphide of carbon, but if kept in contact with it for a month or two, very large colourless crystals of benzoic acid make their appearance. Brought into a warm room, the crystals quickly dissolve, but are easily reproduced by exposure to cold.
Most pharmacopœias require not the inodorous acid obtained by a wet process, but that afforded by sublimation, which contains a small amount of fragrant empyreumatic products. The resin, when repeatedly subjected to sublimation, affords as much as 14 per cent. of benzoic acid. It has long been known that the opaque white tears of benzoin are less rich in benzoic acid than the transparent brown resin in which they lie. From the latter, S. W. Brown (1833) extracted 13 per cent. of impure acid, but from the former scarcely 8½ per cent. We are by no means sure that such difference is constant.
Bitter almond oil, which by oxidation yields benzoic acid, is wanting in benzoin. Very little volatile oil is in fact to be got; half a pound of the best Penang benzoin yielded us by distillation with water only a few drops of an extremely fragrant oil (styrol?).
Ferric chloride imparts to an alcoholic solution of benzoin a dark brownish green, which is not acquired under the same circumstances by the aqueous decoction of the powdered resin. Benzoin dissolves in cold oil of vitriol, forming a solution of splendid carmine hue, from which water separates crystals of benzoic acid.
Kolbe and Lautemann in 1860 discovered in Siam and Penang benzoin together with benzoic acid, an acid of different constitution, which in 1861 they recognized as Cinnamic Acid, C₉H₉O₂. Aschoff (1861) found in a sample of Sumatra benzoin, cinnamic acid only, of which he got 11 per cent.; and in amygdaloid Siam and Penang benzoin only benzoic acid. In some samples of the latter, one of us (F.) has likewise met with cinnamic acid. On triturating this sort with peroxide of lead and boiling the mixture with water, the odour of bitter almond oil, due to the oxidation of cinnamic acid, is evolved.
The simultaneous occurrence of benzoic and cinnamic acids, or the absence of one or other of them in benzoin, is due to circumstances at present unexplained. Rump is of the opinion that the last named acid exclusively is present in the Penang (or Sumatra) benzoin and that no variety of the drug contains both those acids.
Rump (1878) treated Siam benzoic with caustic lime (see p. 407), precipitated the benzoic acid with hydrochloric acid, and agitated the liquid with ether. The latter on evaporating afforded a mixture of benzoic acid and Vanillin (see article Vanilla).
Commerce—The statistics of Singapore,[1499] the great emporium of the commerce of the Indian Archipelago, show the imports of Gum Benjamin in 1871 as 7442 cwt., of which quantity 6185 cwt. had been shipped from Sumatra and 405 cwt. from Siam. In 1877 only 1871 peculs (2227 cwts.) were exported from Singapore. Penang, which is also a mart for this drug was stated in 1871 to have received from Sumatra for trans-shipment, 4959 cwt. of Gum Benjamin.
Padang in Sumatra exported in 1870, 4303 peculs (5122 cwt.); and in 1871, 4064 peculs (4838 cwt.) of benzoin.[1500]
The imports of Gum Benjamin into Bombay in the year 1871-72 were no less than 5975 cwt., and the exports 1043 cwt.[1501]
Uses—Benzoin appears to be nearly devoid of medicinal properties, and is but little employed. It is chiefly imported for use as incense in the service of the Greek Church.