BALSAMUM DIPTEROCARPI.

Balsamun Gurjunæ; Gurjun Balsam, Wood Oil.

Botanical Origin—This drug is yielded by several trees of the genus Dipterocarpus, namely—

D. turbinatus Gärtn. f. (D. lævis Ham., D. indicus Bedd), a native of Eastern Bengal, Chittagong and Pegu to Singapore, and French Cochin China.

D. incanus Roxb., a tree of Chittagong and Pegu.

D. alatus Roxb., growing in Chittagong, Burma, Tenasserim, the Andaman Islands, Siam, and French Cochin China.

D. zeylanicus Thw. and D. hispidus Thw., indigenous to Ceylon.

D. crispalatus ... abounding, together with D. turbinatus and D. alatus, in French Cochin China.

D. trinervis Bl., a native of Java and the Philippines, and D. gracilis Bl., D. littoralis Bl., D. retusus Bl. (D. Spanoghei Bl.), trees of Java supply a similar useful product which as yet appears to be of less commercial importance.[360]

The Gurjun trees are said by Hooker[361] to be among the most magnificent of the forests of Chittagong. They are conspicuous for their gigantic size, and for the straightness and graceful form of their tall unbranched trunk, and small symmetrical crown of broad glossy leaves. Many individuals are upwards of 200 feet high and 15 feet in girth.

History—Gurjun balsam was enumerated as one of the productions of Ava by Francklin[362] in 1811, and in 1813 it was briefly noticed by Ainslie.[363] Its botanical origin was first made known by Roxburgh, who also described the method by which it is extracted.

The medicinal properties of Gurjun balsam were pointed out by O’Shaughnessy[364] as entirely analogous to those of copaiba; and his observations were confirmed by many practitioners in India. This has obtained for the drug a place in the Pharmacopœia of India (1868).

Extraction—A recent account of the production of this drug is found in the Reports of the Jury of the Madras Exhibition of 1855. It is there stated that Wood Oil, as the balsam is commonly called, is obtained for the most part from the coast of Burma and the Straits, and is procured by tapping the trees about the end of the dry season. Several deep incisions are made with an axe into the trunk of the tree and a good-sized cavity scooped out. In this, fire is placed, and kept burning until the wood is somewhat scorched, when the balsam begins to exude, and is then led away into a vessel of bamboo. It is afterwards allowed to settle, when a clear liquid separates from a thick portion called the “guad.” The oil is extracted year after year, and sometimes there are two or three holes in the same tree. It is produced in extraordinary abundance; from 30 to 40 gallons according to Roxburgh may sometimes be obtained from a single tree in the course of a season, during which it is necessary to remove from time to time the old charred surface of the wood and burn afresh.

If a growing tree is felled and cut into piece, the oleo-resin exudes and concretes on the wood, very much, it is said, resembling camphor (?) and having an aromatic smell.

Description—As Gurjun balsam is the produce of different trees as well as of different countries, it is not surprising to find that it varies considerably in its properties.

The following observations refer to a balsam of which 400 lb. were recently imported from Moulmein for a London drug firm. It is a thick and viscid fluid, exhibiting a remarkable fluorescence, so that when seen by reflected light it appears opaque and of dingy greenish grey; yet when placed between the observer and strong daylight it is seen to be perfectly transparent and of a dark reddish-brown.[365] It has a weak aromatic copaiba-like odour and a bitterish aromatic taste without the persistent acridity of copaiba. Its sp. gr. at 16·9° C. is 0·964.

With the following liquids Gurjun affords perfectly clear solutions which are more or less fluorescent, namely pure benzol (from benzoate of calcium), cumol, chloroform, sulphide of carbon, essential oils. On the other hand, it is not entirely soluble in methylic, ethylic, or amylic alcohol; in ether, acetic ether, glacial acetic acid, acetone, phenol (carbolic acid), or in caustic potash dissolved in absolute alcohol. Many samples of commercial benzin also are not capable of dissolving the oleo-resin perfectly, but we have not ascertained on what constituent of such benzin this depends. We have further noticed that that portion of petroleum which is known as Petroleum Ether, containing the most volatile hydrocarbons, does not wholly dissolve the oleo-resin. One hundred parts of the balsam warmed and shaken with 1000 parts of absolute alcohol yielded on cooling a precipitate of resin amounting when dried to 18·5 parts. All concentrated solutions of the balsam are precipitated by amylic alcohol.

If the balsam is kept for a long time in a stoppered vessel at 100° C. it simply becomes a little turbid; but about 130° C. it is transformed into a jelly, and on cooling does not resume its former fluidity. Balsam of copaiba heated in a closed glass tube to 220° C. does not at all lose its fluidity, whereas Gurjun balsam becomes an almost solid mass.

Chemical Composition—Of the balsam 6·99 grammes dissolved in benzol and kept in a water bath until the residue ceased to lose weight, yielded 3·80 grammes of a dry, transparent, semi-fluid resin, corresponding to 54·44 per cent., and 45·56 of volatile matters expelled by evaporation. But another sample afforded us much less residue. By submitting larger quantities of the above balsam to the usual process of distillation with water in a large copper still, 37 per cent. of volatile oil were easily obtained. The water passing over at the same time did not redden litmus paper. A dark, viscid, liquid resin remained in the still.

The essential oil is of a pale straw-colour and less odorous than most other volatile oils. Treated with chloride of calcium and again distilled, it begins to boil at 210° C. and passes over at 255°-260° C., acquiring a somewhat empyreumatic smell and light yellowish tint. The purified oil has a sp. gr. of 0·915;[366] it is but sparingly soluble in absolute alcohol or glacial acetic acid, but mixes readily with amylic alcohol.

According to Werner (1862) this oil has the composition C₂₀H₃₂ like that of copaiba. He says it deviates the ray of polarized light to the left, but that prepared by one of us deviated strongly to the right, the residual resin dissolved in benzol being wholly inactive. The oil does not form a crystalline compound with dry hydrochloric acid, which colours it of a beautiful blue.[367] De Vry[368] states that the essential oil after this treatment deviates the ray to the right.

The resin contains, like that of copaiba, a small proportion of a crystallizable acid which may be removed by warming it with ammonia in weak alcohol. That part of the resin which is insoluble even in absolute alcohol,[369] we found to be uncrystallizable. The Gurgunic Acid, as the crystallized resinous acid is called by Werner,[370] but which it is more correct to write Gurjunic, may consequently be prepared by extracting the resin with alcohol (·838) and mixing the solution with ammonia. From the ammoniacal solution gurjunic acid is precipitated on addition of a mineral acid, and if it is again dissolved in ether and alcohol it may be procured in the form of small crystalline crusts. From the specimen under examination we were not successful in obtaining indubitable crystals.

Gurjunic acid, C₄₄H₆₈O₈ according to Werner, melts at 220° C., and concretes again at 180° C.; it begins to boil at 260° C., yet at the same time decomposition takes place. By assigning to this acid the formula C₄₄H₆₄O₅ + 3H₂O, which agrees well with Werner’s analytical results, we may regard it as a hydrate of abietinic acid, the chemical behaviour of which is perfectly analogous. Gurjunic acid is soluble in alcohol 0·838, but not in weak alcohol; it is dissolved also by ether, benzol, or sulphide of carbon (Werner).

In copaiba from Maracaibo, Strauss (1865) discovered Metacopaivic Acid which is probably identical with gurjunic; the former, however, fuses at 206° C.

The amorphous resin forming the chief bulk of the residue of the distillation of the balsam, has not yet been submitted to exact analysis. We find that after complete desiccation it is not soluble in absolute alcohol. A crystallized constituent of Gurjun, which we obtained from a balsam of unknown origin, has been shown[371] to answer to the formula C₂₈H₄₆O₂. Its crystals, belonging to the asymmetric system, melt at 126°-130°C.; they are entirely devoid of acid character. A comparative examination of the product of each of the above named species of Dipterocarpus would be highly desirable.

Commerce—Gurjun balsam is exported from Singapore, Moulmein, Akyab and the Malayan Peninsula, and is a common article of trade in Siam. It is likewise produced in Canara in Southern India. It is occasionally shipped to Europe. More than 2000 lb. were offered for sale in London under the name of East India Balsam Capivi, 4th October 1855; and in October 1858, a no less quantity than 45 casks appeared in the catalogue of a London drug-broker. It is now not unfrequent in the London drug sales.

Uses—In medicine it has hitherto been employed only as a substitute for copaiba, and chiefly in the hospitals of India.

In the East its great use is as a natural varnish, either alone or combined with pigments; and also as a substitute for tar as an application to the seams of boats, and for preserving timber from the attacks of the white ant. To the first application it is often made better appropriated[372] by boiling it, so that the essential oil is evaporated.

Wood Oil of China—The oleo-resin of Dipterocarpus must not be confounded with the so-called Wood Oil of China, which is of a totally different nature. The latter is a fatty oil expressed from the seeds of Aleurites cordata Müll. Arg. (Dryandra cordata Thunb. Elaeococca Vernicia Sprgl. Prodromus xv. part 2, p. 724), the well-known Tung tree of the Chinese. It is a large tree of the order Euphorbiaceæ, found in China and Japan. The oil is an article of enormous consumption among the Chinese, who use it in the caulking and painting of junks and boats, for preserving woodwork, varnishing furniture, and also in medicine. In the commercial reports of H.M. Consuls in China (No. 5, 1875, p. 3, 26) we find that this oil is largely exported from Hankow: 199·654 peculs in 1874, and forms an article of import at Ningpo: 15·123 peculs in 1874 (pecul = 133·33 lb. avoirdupois). It is, however, not shipped to foreign countries. The oil of the Tung tree is also extremely remarkable on account of its chemical properties as shown by Cloëz (1875-1877).

MALVACEÆ.

RADIX ALTHÆÆ

Botanical Origin—Althæa officinalis L., the marshmallow, grows in moist places throughout Europe, Asia Minor, and the temperate parts of Western and Northern Asia, but is by no means universally distributed. It prefers saline localities such as in Spain the salt marshes of Saragossa, the low-lying southern coasts of France near Montpellier, Southern Russia, and the neighbourhood of salt-springs in Central Europe. In southern Siberia Althæa has been met with by Semenoff (1857) ascending as high as 3,000 feet in the Alatau mountains, south of the Balkash Lake.

In Britain it occurs in the low grounds bordering the Thames below London, and here and there in many other spots in the south of England and of Ireland.

The cultivated marshmallow thrives as far north as Throndhjem in Norway, and has been naturalized in North America (salt marshes of New England and New York) and Australia. It is largely cultivated in Bavaria and Württemberg.

History—Marshmallow had many uses in ancient medicine, and is described by Dioscorides as Άλθαία, a name derived from the Greek verb ἀλθειν, to heal.

The diffusion of the plant in Europe during the middle ages was promoted by Charlemagne who enjoined[373] its culture (a.d. 812) under the name of “Mismalvas, id est alteas quod dicitur ibischa.”

Description—The plant has a perennial root attaining about a foot in length and an inch in diameter. For medicinal use the biennial roots of the cultivated plant are chiefly employed. When fresh they are externally yellowish and wrinkled, white within and of tender fleshy texture. Previous to drying, the thin outer and a portion of the middle bark are scraped off, and the small root filaments are removed. The drug thus prepared and dried consists of simple whitish sticks 6 to 8 inches long, of the thickness of the little finger to that of a quill, deeply furrowed longitudinally and marked with brownish scars. Its central portion, which is pure white, breaks with a short fracture, but the bark is tough and fibrous. The dried root is rather flexible and easily cut. Its transverse section shows the central woody column of undulating outline separated from the thick bark by a fine dark outline shaded off outwards.

The root has a peculiar though very faint odour, and is of rather mawkish and insipid taste, and very slimy when chewed.

Microscopic Structure—The greater part of the bark consists of liber, abounding in long soft fibres, to which the toughness of the cortical tissue is due. They are branched and form bundles, each containing from 3 to 30 fibres separated by parenchymatous tissue. Of the cortical parenchyme many cells are loaded with starch granules, others contain stellate groups of oxalate of calcium, and a considerable number of somewhat larger cells are filled with mucilage. The last named on addition of alcohol is seen to consist of different layers.

The woody part is made up of pitted or scalariform vessels, accompanied by a few ligneous cells and separated by a parenchymatous tissue, agreeing with that of the bark. On addition of an alkali, sections of the root assume a bright yellow hue.

Chemical Composition—The mucilage in the dry root amounts to about 25 per cent. and the starch to as much more. The former appears from the not very accordant analysis of Schmidt and of Mulder to agree with the formula C₁₂H₂₀O₁₀, thus differing from the mucilage of gum arabic by one molecule less of water. It likewise differs in being precipitable by neutral acetate of lead. At the same time it does not show the behaviour of cellulose, as it does not turn blue by iodine when moistened with sulphuric acid, and it is not soluble in ammoniacal solution of oxide of copper.

The root also contains pectin and sugar (cane-sugar according to Wittstock), and a trace of fatty oil. Tannin is found in very small quantity in the outer bark alone.

In 1826 Bacon, a pharmacien of Caen, obtained from althæa root crystals of a substance at first regarded as peculiar, but subsequently identified with Asparagin, C₄H₈N₂O₃, H₂O. It had been previously prepared (1805) by Vauquelin and Robiquet from Asparagus, and is now known to be a widely diffused constituent of plants.[374] Marshmallow root does not yield more than 0·8 to 2·0 per cent. Asparagin crystallizes in large prisms or octohedra of the rhombic system; it is nearly tasteless, and appears destitute of physiological action. Its relation to succinic acid may be thus represented:—

Asparagin is quite permanent whether in the solid state or dissolved, but it is easily decomposed if the solution contains the albuminoid constituents of the root, which act as a ferment. Leguminous seeds, yeast or decayed cheese induce the same change, the final product of which is succinate of ammonium, the asparagin taking the elements of water and hydrogen set free by the fermentation, thus—

Under the influence of acids or bases, or even by the prolonged boiling of its aqueous solution, asparagin is converted into Aspartate of Ammonium, C₄H₆(NH₄)NO₄, of which the hydrated asparagin contains the elements.

These transformations, especially the former, are undergone by the asparagin in the root, if the latter has been imperfectly dried, or has been kept long, or not very dry. Under such conditions, the asparagin gradually disappears, and the root then yields a brownish decoction, sometimes having a disagreeable odour of butyric acid. There is no doubt that a protein-substance here acts as a ferment. The sections of the root when touched with ammonia or caustic lye should display a bright yellow, not a dingy brown, colour.

The peeled root dried at 100° C. and incinerated afforded us 4·88 of ash, rich in phosphates.

Uses—Althæa is taken as a demulcent; it is sometimes also applied as an emollient poultice. It is far more largely used on the continent than in England.

FRUCTUS HIBISCI ESCULENTI.

Botanical Origin—Hibiscus esculentus L. (Abelmoschus esculentus Guill. et Perr.) an herbaceous annual plant 2 to 3 or even 10 feet high, indigenous to the Old World.[376] It has been found growing abundantly wild on the White Nile by Schweinfurth, and also in 1861 by Col. Grant in Unyoro, 2° N. lat., near the lake Victoria Nyanza, where it is known to the natives as Bameea.

The plant is now largely cultivated in several varieties in all tropical countries.

History—The Spanish Moors appear to have been well acquainted with Hibiscus esculentus, which was known to them by the same name that it has in Persian at the present day—Bámiyah. Abul Abbas el-Nebáti, a native of Seville learned in plants, who visited Egypt in a.d. 1216, describes[377] in unmistakeable terms the form of the plant, its seeds and fruit, which last he remarks is eaten when young and tender with meat by the Egyptians. The plant was figured among Egyptian plants in 1592 by Prosper Alpinus,[378] who mentions its uses as an external emollient.

The powdered fruits as imported from Arabia Felix were known for some time (about the year 1848) in Europe as Nafé of the Arabs. They are noticed in the present work from the circumstance that they have a place in the Pharmacopœia of India.

Description—The fruit is a thin capsule, 4 to 6 or more inches long and about an inch in diameter, oblong, pointed, with 5 to 7 ridges corresponding to the valves and cells, each of which latter contains a single row of round seeds. It is covered with rough hairs and is green or purplish when fresh; it has a slightly sweet mucilaginous taste and a weak herbaceous odour. Like many other plants of the order, Hibiscus esculentus abounds in all its parts with insipid mucilage.

Microscopic Structure—A characteristic part for microscopic examination are the hairs of the fruit. They exhibit at the base one large cell, but their elongated and often slightly curved end is built up at a considerable number of small cells, without any solid contents. The middle and outer zone of the pericarp shows enormous holes filled up with colourless mucilage. In polarized light it is easily seen to be composed of successive layers.

Chemical Composition—It is probable that the fruits contain the same mucilage as Althæa, but we have had no opportunity of investigating the fact. Landrin[379] says it turns violet with iodine and yields no mucic acid when treated with nitric acid. Popp, who examined the green fruits in Egypt, states[380] that they abound in pectin, starch and mucilage. He found that when dried they afforded 2 to 2·4 per cent. of nitrogen, and an ash rich in salts of lime, potash and magnesia. The ripe seeds gave 2·4-2·5 per cent. of nitrogen; their ash 24 per cent. of phosphoric acid.

Uses—The fresh or dried, unripe fruits are used in tropical countries as a demulcent like marshmallow, or as an emollient poultice, for which latter purpose the leaves may also be employed. They are more important from an economic point of view, being much employed for thickening soups or eaten boiled as a vegetable. The root has been recommended as a substitute for that of Althæa.[381] The stems of the plant yield a good fibre.