I.—PHÆNOGAMOUS OR FLOWERING PLANTS. (continued 7)

A fragrant balsamic resin is collected, though in but very small quantity, from Myroxylon peruiferum Linn. f., a noble tree of New Granada, Ecuador, Peru, Bolivia, and Brazil. A fine sample of this substance, accompanied by herbarium and other specimens, was presented to one of us (H.) by Mr. J. Correa de Méllo of Campinas (Brazil); it is a resin having a general resemblance to Balsam of Tolu, but of somewhat deeper and redder tint, and greater hardness. Pressed between two slips of warmed glass, it does not exhibit any crystals.

In a treatise on Brazil written by a Portuguese friar about 1570-1600,[813] mention is made of the “Cabueriba” (Cabure-iba), from which a much-esteemed balsam was obtained by making incisions in the stem, and absorbing the exudation with cotton wool, somewhat in the same way as Balsam of Peru is now collected in Salvador. This tree is Myrocarpus frondosus Allem., now called Cabriuva preta. The genus is closely allied to Myroxylon.

Another fragrant oleo-resin, which has doubtless been confounded with that of a Myroxylon, is obtained in Central America from Liquidambar styraciflua L., either by incision or by boiling the bark.

SEMEN BONDUCELLÆ.

Semen Guilandinæ; Bonduc Seeds, Grey Nicker Seeds or Nuts; F. Graines de Bonduc ou du Cniquier, Pois Quéniques, Pois Guénic.

Botanical Origin—Cæsalpinia Bonducella Roxb. (Guilandina Bonducella L.), a prickly, pubescent, climbing shrub[814] of wide distribution, occurring in Tropical Asia, Africa and America, especially near the sea. The compressed, ovate, spiny legume is 2 to 3 inches long, and contains one or two, occasionally three or four, hard, grey, globular seeds.

The plant is often confounded with C. Bonduc Roxb., a nearly allied but much rarer species, distinguished by being nearly glabrous, having leaflets very unequal at the base, no stipules, erect bracts, and yellow seeds.

History—“Pūti-Karanja” stinking Karanja, in Susruta (I.223, 1) is the plant under notice. The word Bunduk, occurring in the writings of the Arabian and Persian physicians, also in Constantinus Africanus, mostly signifies hazel-nut.[815] One of these authors, Ibn Baytar,[816] who flourished in the 13th century, further distinguished a drug called Bunduk Hindi (Indian hazel-nut), giving a description which indicates it plainly as the seed under notice. Both Bunduk and Bunduk Hindi are enumerated in the list of drugs of Noureddeen Mohammed Abdullah Shirāzy,[817] physician to the Mogul emperor Shah Jehan, a.d. 1628-1661.

The pods of C. Bonducella were figured by Clusius in 1605, under the name of Lobus echinodes, and the plant both by Rheede[818] and Rumphius. Piso and Marcgraf (1648) noticed it in Brazil and gave some account of it with a bad woodcut, under the designation of Inimbóy (now Inimboja), or in Portuguese Silva do Praya.

In recent times, Bonduc seeds have been employed on account of their tonic and antiperiodic properties by numerous European practitioners in the East, and have been included in the Pharmacopœia of India, 1868.

Description—The seeds are somewhat globular or ovoid, a little compressed, ⁴/₁₀ to ⁸/₁₀ of an inch in diameter and weighing 20 to 40 grains. They are of a bluish or greenish grey tint, smooth, yet marked by slightly elevated horizontal lines of a darker hue. The umbilicus is surrounded by a small, dark brown, semilunar blotch opposite the micropyle. The hard shell is from ¹/₂₅ to ²/₂₅ of an inch thick, and contains a white kernel; representing from 40 to 50 per cent. of the weight of the seed. It separates easily from the shell, and consists of the two cotyledons and a stout radicle. When a seed is soaked for some hours in cold water, a very thin layer can be peeled from the surface of the testa. The kernel is bitter, but with the taste that is common to most seeds of the family Leguminosæ.

Microscopic Structure—The outer layer of the testa, the epidermis above alluded to, is composed of two zones of perpendicular, closely packed cells, the outer measuring about 130 mkm., the inner 100 mkm. in length and only 5 to 7 mkm. in diameter. The walls of these cylindrical cells are thickened by secondary deposits, which in transverse section show usually four or more channels running down nearly perpendicularly through the whole cell.

The spongy parenchyme, which is covered by this very distinct outer layer, is made up of irregular, ovate, subglobular or somewhat elongated cells with large spaces between them, loaded with brown masses of tannic matter, assuming a blackish hue when touched with perchloride of iron. The thick walls of these cells frequently exhibit, chiefly in the inner layers, undulated outlines. The tissue of the cotyledons is composed of very large cells, swelling considerably in water, and containing some mucilage (as may be ascertained when thin slices are examined in oil), small starch granules, fatty oil, and a little albuminous matter.

Chemical Composition—According to the medical reports alluded to in the Pharmacopœia of India (1868), Bonduc seeds, and still more the root of the plant, act as a powerful antiperiodic and tonic.

The active principle has not yet been adequately examined. It may perhaps occur in larger proportion in the bark of the root, which is said to be more efficacious than the seeds in the treatment of intermittent fever.[819]

In order to ascertain the chemical nature of the principle of the seeds, one ounce of the kernels[820] was powdered and exhausted with slightly acidulated alcohol. The solution after the evaporation of the alcohol was made alkaline with caustic potash, which did not produce a precipitate. Ether now shaken with the liquid, completely removed the bitter matter, and yielded it in the form of an amorphous white powder, devoid of alkaline properties. It is sparingly soluble in water, but readily in alcohol, forming intensely bitter solutions; an aqueous solution is not precipitated by tannic acid. It produces a yellowish or brownish solution with concentrated sulphuric acid, which acquires subsequently a violent hue. Nitric acid is without manifest influence. From these experiments, we may infer that the active principle of the Bonduc seed is a bitter substance not possessing basic properties.

Uses—The powdered kernels either per se, or mixed with black pepper (Pulvis Bonducellæ compositus Ph. Ind.), are employed in India against intermittent fevers and as a general tonic.

The fatty oil of the seeds is sometimes extracted and used in India; it was shown at the Madras Exhibitions of 1855 and 1857.

LIGNUM HÆMATOXYLI.

Lignum Campechianum v. Campescanum; Logwood, Peachwood; F. Bois de Campèche, Bois d’Inde; G. Campecheholz, Blauholz.

Botanical Origin—Hæmatoxylon campechianum L., a spreading tree[821] of moderate size, seldom exceeding 40 feet in height, native of the bay of Campeachy, Honduras and other parts of Central America. It was introduced into Jamaica by Dr. Barham[822] in 1715, and is now completely naturalized in that and other of the West Indian Islands.

History—Hernan Cortes in his letter to the Emperor Charles V., giving an account of his expedition to Honduras in 1525,[823] refers to the Indian towns of Xiculango and Tabasco as carrying on a trade in cacao, cotton cloth, and colours for dyeing,—in which last phrase there may be an allusion to logwood. We have sought for some more definite notice of the wood in the Historia de las Indias of Oviedo,[824] the first chronicler of America, but without much success.

Yet the wood must have been introduced into England in the latter half of the 16th century, for, in 1581, an Act of Parliament[825] was passed, abolishing its use and ordering that any found should be forfeited and burned. In this Act the obnoxious dye is described as “a certain kind of ware or stuff called Logwood alias Blockwood ... of late years ... brought into this realm of England.” The object of this measure was to protect the public against the bad work of the dyers, who, it seems, were unable at that period to obtain durable colours by the use of logwood. Eighty years later the art of dyeing had so far improved that logwood was again permitted,[826] the colours produced by it being declared as lasting and serviceable as those made by any other sort of dyewood whatsoever.

The wood is mentioned by De Laet (1633) as deriving its name from the town of Campeachy, whence, says he, it is brought in great plenty to Europe.[827]

As a medicine, logwood was not employed until shortly before the year 1746, when it was introduced into the London Pharmacopœia under the name of Lignum tinctile Campechense.

Description—The tree is fit to be felled when about ten years old; the dark bark and the yellowish sapwood are chipped off, the stems cut into logs about three feet long, and the red heartwood alone exported. By exposure to air and moisture, the wood acquires externally a blackish-red colour; internally it remains brownish red. It splits well, although of a rather dense and tough texture.

The transverse section of a piece of logwood exhibits to the naked eye a series of very narrow concentric zones, formed by comparatively large pores, and of small parenchymatous circles separated by the larger and darker rings of the proper woody tissue. The numerous medullary rays are visible only by means of a lens. The wood has a pleasant odour.

For use in pharmacy, logwood is always purchased in the form of chips, which are produced by the aid of powerful machinery. The chips have a feeble, seaweed-like odour, and a slightly sweet, astringent taste, better perceived in a watery decoction than by chewing the dry wood, which however quickly imparts to the saliva its brilliant colour.

Microscopic Structure—Under a high magnifying power, the concentric zones are seen to run not quite regularly round the centre, but in a somewhat undulating manner, because they do not correspond, as in our indigenous woods, to regular periods of annual growth. The vascular bundles contain only a few vessels, and are transversely united by small lighter parenchymatous bands. The latter are made up of large, cubic, elongated or polygonal cells, each loaded with a crystal of oxalate of calcium. The large punctuated vessels having frequently 150 mkm. diameter, are surrounded by this woody parenchyme, while the prevailing tissue of the wood is composed of densely packed prosenchyme, consisting of long cylindrical cells (libriform) with thick, dark red-brown walls having small pores.

The medullary rays are of the usual structural character, running transversely in one to three straight rows; in a longitudinal section, the single rays show from 4 to 40 rows succeeding each other perpendicularly. No regular arrangement of the rays is obvious in a longitudinal section made in a tangential direction. The colouring matter is chiefly contained in the walls of the ligneous tissue and the vessels, and sometimes occurs in crystals of a greenish hue within the latter, or in clefts of the wood.

Chemical Composition—Logwood was submitted to analysis by Chevreul as early as the year 1810,[828] since which period all contributions to a knowledge of the drug refer exclusively to its colouring principle Hæmatoxylin, which Chevreul obtained in a crystallized state and called Hématine. The very interesting properties of this substance have been chiefly examined by Erdmann (1842) and by O. Hesse (1858-59).

Erdmann obtained from logwood 9 to 12 per cent. of crystallized hæmatoxylin, which he showed to have the formula C₁₆H₁₄O₆. In a pure state it is colourless, crystallizing with 1 or with 3 equivalents of water, and is readily soluble in hot water or in alcohol, but sparingly in cold water or in ether. It has a persistent sweet taste like liquorice. The crystals of hæmatoxylin acquire a red colour by the action of sunlight, as likewise their aqueous solution. They are decomposed by ozone but not by pure and dry oxygen. In presence of alkalis, hæmatoxylin exposed to the air quickly yields dark purplish violet solutions, which soon acquire a yellowish or dingy brownish colour; hence in analytical chemistry hæmatoxylin is used as a test for alkalis.

By the combined action of ammonia and oxygen, dark violet crystalline scales of Hæmateïn, C₁₆H₁₄O₆ + 3 OH₂, are produced.[829] They show a fine green hue, which is also very commonly observable on the surface of the logwood chips of commerce. Hæmateïn may again be transformed into hæmatoxylin by means of hydrogen or of sulphurous acid.

Hæmatoxylin separates protoxide of copper from an alkaline solution of the tartrate, and deviates the ray of polarized light to the right hand. It is not decomposed by concentrated hydrochloric acid; by melting hæmatoxylin with potash, pyrogallol (pyrogallic acid, C₆H₆O₃) is obtained. Alum and the salts of lead throw down precipitates from solutions of hæmatoxylin, the latter being of a bluish-black colour. Logwood affords upon incineration 3·3 per cent. of ash.

The colouring matter being abundantly soluble in boiling water, an Extract of Logwood is also prepared on a large scale. It occurs in commerce in the form of a blackish brittle mass, taking the form of the wooden chest into which it is put while soft. The extract shares the chemical properties of hæmatoxylin and hæmateïn: whether it also contains gum requires investigation.

Production and Commerce—The felling and shipping of logwood in Central America have been described by Morelet,[830] who states that in the woods of Tabasco and Yucatan the trade is carried on in the most irrational and reckless manner. By advancing money to the natives, or by furnishing them with spirits, arms, or tools, the proprietors of the woods engage them to fell a number of trees in proportion to their debts. This is done in the dry season, the rainy period being taken for the shipment of the logs, which are conveyed chiefly to the island of Carmen in the Laguna de Terminos in South-western Yucatan, and to Frontera on the mouths of the Tabasco river, at which places European ships receive cargoes of the wood.

In 1877 the export of Laguna de Terminos amounted to 528,605 quintals (one quintal = 46 kilogrammes), that from Port-au-Prince, Hayti, in 1872, nearly to 90,000 tons.

Four sorts of logwood are found in the London market, namely Campeachy, quoted[831] at £8 10s. to £9 10s. per ton; Honduras, £6 10s. to £6 15s.; St. Domingo, £5 15s. to £6; Jamaica, £5 2s. 6d. to £5 10s. The imports into the United Kingdom were valued in 1872 at £233,035. The quantities imported during that and the previous three years were as follows:—

1869 1870 1871 1872

50,458 tons. 62,187 tons. 39,346 tons. 46,039 tons.

In 1876 the import was 64,215 tons, valued at £415,857. The largest quantity is supplied by the British West India Islands. Hamburg also imports annually about 20,000 tons of logwood.

Uses—Logwood in the form of decoction is occasionally administered in chronic diarrhœa, and especially in the diarrhœa of children. Cases have occurred in which its use has been followed by phlebitis. Its employment in the art of dyeing is far more important.

Adulteration—The woods of several species of Cæsalpinia imported under the name of Brazil Wood and used for dyeing red, bear an external resemblance to logwood, with which it is said they are sometimes mixed in the form of chips. They contain a crystallizable colouring principle called Brasilin, C₂₂H₂₀O₇, or, according to Liebermann and Burg (1876), C₁₆H₁₄O₅, which affords with alkalis red and not bluish or purplish solutions, and yields trinitrophenol, C₆H₂(NO₂) 3OH (picric acid), when boiled with nitric acid, while hæmatoxylin yields oxalic acid only. The best source for brasilin is the wood of Cæsalpinia Sappan L., a tree of the East Indies, well known as Bakam, Brazil Wood, Lignum Brasile, Verzino of the Italians, an important object of commerce during the middle ages.[832]

FOLIA SENNÆ.

Senna Leaves; F. Feuilles de Séné; G. Sennesblätter.

Botanical Origin—The Senna Leaves of commerce are afforded by two species of Cassia[833] belonging to that section of the genus which is distinguished by having leaves without glands, axillary racemes elongating as inflorescence advances, membranaceous bracts which in the young raceme conceal the flower buds but drop off during flowering, and a short, broad, flat legume.

The senna plants are low perennial bushy shrubs, 2 to 4 feet high, having pari-pinnate leaves with leaflets unequal at the base, and yellow flowers. The pods contain 6 or more seeds in each, suspended on alternate valves by long capillary funicles. These run towards the pointed end of the seed, but are curved at their attachment to the hilum just below. The seeds are compressed and of an obovate-cuneate or oblong form, beaked at the narrower end.[834]

The species in question are the following:—

1. Cassia acutifolia Delile[835]—a shrub about 2 feet high, with pale subterate or obtusely angled, erect or ascending branches, occasionally slightly zigzag above, glabrous at least below. Leaves usually 4-5-jugate; leaflets oval or lanceolate, acute, mucronate, usually more or less distinctly puberulous or at length glabrous, pale or subglaucous at least beneath, subsessile. Stipules subulate, spreading or reflexed, 1-2 lines long. Racemes axilliary, erect, rather laxly many-flowered, usually considerably exceeding the subtending leaf. Bracts membranous, ovate or obovate, caducous. Pedicels at length 2-3 lines. Sepals obtuse, membranous. Two of the anterior anthers much exceeding the rest of the fertile stamens. Legume flat, very broadly oblong, but slightly curved upwards, obliquely stipitate, broadly rounded at the extremity with a minute or obsolete mucro indicating the position of the style on the upper edge; 1½-2¼ inches long, ¾-1 inch broad; valves chartaceous, obsoletely or thinly puberulous, faintly transverse-veined, unappendaged. Seeds obovate-cuneate, compressed; cotyledons plane, extending the large diameter of the seed in transverse section.[836]

The plant is a native of many districts of Nubia (as Sukkot, Mahas, Dongola, Berber), Kordofan and Sennaar; grows also in Timbuktu and Sokoto, and is the source of Alexandrian Senna.

2. C. angustifolia Vahl[837]—This species is closely related to the preceding, the general description of which is applicable to it with the following exceptions. In the present plant the leaflets, which are usually 5-8-jugate, are narrower, being oval-lanceolate, tapering from the middle towards the apex; they are larger, being from one to nearly 2 inches long, and are either quite glabrous or furnished with a very scanty pubescence. The legume is narrower (7-8 lines broad), with the base of the style distinctly prominent on its upper edge.

The plant abounds in Yemen and Hadramaut in Southern Arabia; it is also found on the Somali coast, in Sind and the Punjab. In some parts of India it is now cultivated for medicinal use.

The uncultivated plant of Arabia supplies the so-called Bombay Senna of commerce, the true Senna Mekki of the East. The cultivated and more luxuriant plant, raised originally from Arabian seeds, furnishes the Tinnevelly Senna of the drug market.

History—According to the elaborate researches of Carl Martius,[838] a knowledge of senna cannot be traced back earlier than the time of the Elder Serapion, who flourished in the 9th or 1Oth century; and it is in fact to the Arabian physicians that the introduction of the drug to Western Europe is due. Isaac Judæus,[839] who wrote probably about a.d. 850-900 and who was a native of Egypt, mentions senna, the best kind of which he says is that brought from Mecca.

Senna (as Ssinen or Ssenen) is enumerated among the commodities liable to duty at Acre in Palestine at the close of the 12th century.[840] In France in 1542, a pound of senna was valued in an official tariff[841] at 15 sols, the same price as pepper or ginger.

The Arabian and the mediæval physicians of Europe used both the pods and leaves, preferring however the former. The pods (Folliculi Sennæ) are still employed in some countries.

Cassia obovata Coll.[842] was the species first known to botanists, and it was even cultivated in Italy for medicinal use during the first half of the 16th century. Hence the term Italian Senna used by Gerarde and others. In the records of the “Cinque savii alla mercanzia” at Venice we found an order bearing date 1526 to the effect that Senna leaves of Tuscany were inadmissible; the same was applied in 1676 to the drug from Tripoli in Barbaria, that from Cairo being exclusively permitted.

Production—According to Nectoux,[843] whose observations relate to Nubia at the close of the last century, the peasants make two senna harvests annually, the first and more abundant being at the termination of the rains,—that is in September; while the other, which in dry seasons is almost nil, takes place in April.

The gathering consists in simply cutting down the shrubs, and exposing them on the rocks to the burning sun till completely dry. The drug is then packed in bags made of palm leaves holding about a quintal each, and conveyed by camels to Es-souan and Darao, whence it is transported by water to Cairo. By many travellers it is stated that Senna jebeli, i.e. mountain senna (C. acutifolia), finds its way to the ports of Massowhah and Suakin, and thence to Cairo and Alexandria.

Cassia obovata, which is called by the Arabs Senna baladi, i.e. indigenous or wild senna, grows in the fields of durra (Sorghum) at Karnak and Luxor, and in the time of Nectoux was held in such small esteem that it fetched but a quarter the price of the Senna jebeli brought by the caravans of Nubia and the Bisharrin Arabs. It is not now collected.

Description—Three kinds of senna are distinguished in English commerce:—

1. Alexandrian Senna—This is furnished by Cassia acutifolia and is imported in large bales. It used formerly always to arrive in a very mixed and dirty state, containing, in addition to leaflets of senna, a variable proportion of leafstalks and broken twigs, pods and flowers; besides which there was almost invariably an accompaniment of the leaves, flowers and fruits of Solenostemma Argel Hayne (p. 220), not to mention seeds, stones, dust and heterogeneous rubbish. Such a drug required sifting, fanning and picking, by which most of these impurities could be separated, leaving only the senna contaminated with leaves of argel. But Alexandrian Senna has of late been shipped of much better quality. Some we have recently seen (1872) was, as taken from the original package, wholly composed of leaflets of C. acutifolia in a well-preserved condition; and even the lower qualities of senna are never now contaminated with argel to the extent that was usual a few years ago.

The leaflets, the general form of which has already been described (p. 216), are ¾ to 1¼ inches long, rather stiff and brittle, generally a little incurled at the edges, conspicuously veined, the midrib being often brown. They are covered with a very short and fine pubescence which is most dense on the midrib. The leaves have a peculiar opaque, light yellowish green hue, a somewhat agreeable tea-like odour, and a mucilaginous, not very marked taste, which however is sickly and nauseous in a watery infusion.

2. Arabian Moka, Bombay or East Indian Senna—This drug is derived from Cassia angustifolia, and is produced in Southern Arabia. It is shipped from Moka, Aden and other Red Sea ports to Bombay, and thence reaches Europe.

Arabian senna is usually collected and dried without care, and is mostly an inferior commodity, fetching in London sometimes as low a price as ½d. to ¼d. per lb. Yet so far as we have observed, it is never adulterated, but consists wholly of senna leaflets, often brown and decayed, mixed with flowers, pods, and stalks. The leaflets have the form already described (p. 217); short adpressed hairs are often visible on their under surface.

3. Tinnevelly Senna—Derived from the same species as the last, but from the plant cultivated in India, and in a state of far greater luxuriance than it exhibits in the drier regions of Arabia where it grows wild. It is a very superior and carefully collected drug, consisting wholly of the leaflets. These are lanceolate, 1 to 2 inches in length, of a yellowish green on the upper side, of a duller tint on the under, glabrous or thinly pubescent on the under side with short adpressed hairs. The leaflets are less rigid in texture than those of Alexandrian senna, and have a tea-like, rather fragrant smell, with but little taste.

Tinnevelly senna has of late fallen off in size, and some importations in 1873 were not distinguishable from Arabian senna, except from having been more carefully prepared. The drug is generally shipped from Tuticorin in the extreme south of India.

Chemical Composition—The analysis of senna with a view to the isolation of its active principle has engaged the attention of numerous chemists, but as yet the results of their labours are not quite satisfactory.

Ludwig (1864) treated an alcoholic extract of senna with charcoal, and obtained from the latter by means of boiling alcohol two bitter principles, Sennacrol, soluble in ether, and Sennapicrin, not dissolved by ether.

Dragendorff and Kubly (1866) have shown the active substance of senna to be a colloid body, easily soluble in water but not in strong alcohol. When a syrupy aqueous extract of senna is mixed with an equal volume of alcohol, and the mucilage thus thrown down has been removed, the addition of a further quantity of alcohol occasions the fall of a dark brown, almost tasteless, easily alterable substance, which is indued with purgative properties. It was further shown that this precipitate was a mixture of calcium and magnesium salts of phosphoric acid and a peculiar acid. The last named, separated by hydrochloric acid, has been called Cathartic Acid; it is a black substance which in the mouth is at first insipid, but afterwards tastes acid and somewhat astringent. In water or strong alcohol it is almost insoluble, and entirely so in ether or chloroform; but it dissolves in warm dilute alcohol. From this solution it is precipitable by many acids, but not by tannic.

Groves[844] in 1868, unaware of the researches of Dragendorff and Kubly, arrived at similar results as these chemists, and proved conclusively that a cathartate of ammonia possesses in a concentrated form the purgative activity of the original drug.

The exactness of the chief facts relative to the solubility in weak alcohol of the active principle of senna set forth by the said chemists, was also remarkably supported by the long practical experience of T. and H. Smith of Edinburgh.[845]

When cathartic acid is boiled with alcohol and hydrochloric acid, it is resolved into sugar and Cathartogenic Acid.

The alcoholic solution from which the cathartates have been separated contains a yellow colouring matter which was called Chrysoretin by Bley and Diesel (1849), but identified as Chrysophan[846] by Martius, Batka and others. Dragendorff and Kubly regard the identity of the two substances as doubtful.

The same alcoholic solution which contains the yellow colouring matter just described, also holds dissolved a sugar which has been named Catharto-mannite. It forms warty crystals, is not susceptible of alcoholic fermentation, and does not reduce alkaline cupric tartrate. The formula assigned to it is C₄₂H₄₄O₃₈.

Senna contains tartaric and oxalic acids with traces of malic acid. The large amount of ash, 9 to 12 per cent., consisting of earthy and alkaline carbonates, also indicates the presence of a considerable quantity of organic acids.

Commerce—Alexandrian Senna, the produce of Nubia and the regions further south, was formerly a monopoly of the Egyptian Government, the enjoyment of which was granted to individuals in return for a stipulated payment: hence it was known in continental trade as Séné de la palte, while the depots were termed paltes and those who farmed the monopoly paltiers.[847] All this has long been abolished, and the trade is now free, the drug being shipped from Alexandria.

Arabian senna is brought into commerce by way of Bombay. The quantity of senna imported thither from the Red Sea and Aden in the year 1871-72 was 4,195 cwt., and the quantity exported during the same period, 2,180 cwt.[848]

Uses—Senna leaves are extensively employed in medicine as a purgative.

Adulteration—The principal contamination to which senna is at present liable arises from the presence of the leaves of Solenostemma Argel Hayne, a plant of the order Asclepiadeæ, 2 to 3 feet high, growing in the arid valleys of Nubia. Whether these leaves are used for the direct purpose of adulteration, or under the notion of improving the drug, or in virtue of some custom or prejudice, is not very evident. It is certain however that druggists have been found who preferred senna that contained a good percentage of argel.

Nectoux, to whom we owe the first exact account of the argel or hárgel plant,[849] describes it as never gathered with the senna by accident or carelessness, but always separately. In fact he saw, both at Esneh and Phile, the original bales of argel as well as those of senna: and at Boulak near Cairo, at the beginning of the present century, the argel used to be regularly mixed with senna in the proportion of one to four.

The leaves of argel after a little practice are very easily recognized; but their complete separation from senna by hand-picking is a tedious operation. They are lanceolate, equal at the base, of the same size as senna leaflets but often larger, of a pallid, opaque, greyish-green, rigid, thick, rather crumpled, wrinkled and pubescent, not distinctly veined. They have an unmistakeably bitter taste. The small, white, star-like flowers, or more often the flower buds, in dense corymbs are found in plenty in the bales of Alexandrian senna. The slender, pear-shaped follicles, when mature 1½ inches long, with comose seeds are less frequent. It has been shown by Christison[850] that argel leaves administered per se have but a feeble purgative action, though they occasion griping. It is plain therefore that their admixture with senna should be deprecated.

The leaves or leaflets of several other plants were formerly mixed occasionally with senna, as those of the poisonous Coriaria myrtifolia L., a Mediterranean shrub, of Colutea arborescens L., a native of Central and Southern Europe, and of the Egyptian Tephrosia Apollinea Delile. We have never met with any of them.[851]

FRUCTUS CASSIÆ FISTULÆ.

Cassia Fistula; Purging Cassia; F. Casse Canefice, Fruit du Caneficer; G. Röhrencassie.

Botanical Origin—Cassia Fistula L. (Cathartocarpus Fistula Pers., Bactyrilobium Fistula Willd.) a tree indigenous to India, ascending to 4000 feet in the outer Himalaya, but now cultivated or subspontaneous in Egypt, Tropical Africa,[852] the West Indies and Brazil. It is from 20 to 30 feet high (in Jamaica even 50 feet) and bears long pendulous racemes of beautiful fragrant, yellow flowers. Some botanists have established for this tree and its near allies a separate genus, on account of its elongated, cylindrical indehiscent legume, but by most it is retained in the genus Cassia.

History—The name Casia or Cassia was originally applied exclusively to a bark related to cinnamon which, when rolled into a tube or pipe, was distinguished in Greek by the word σῦριγζ, and in Latin by that of fistula. Thus Scribonius Largus,[853] a physician of Rome during the reigns of Tiberius and Claudius, with the latter of whom he is said to have visited Britain, a.d. 43, uses the expression “Casiæ rufæ fistularum” in the receipt for a collyrium. Galen[854] describing the different varieties of cassia, mentions that called Gizi[855] (γίζεις) as being quite like cinnamon or even better; and also names a well-known cheaper sort, having a strong taste and odour which is called fistula, because it is rolled up like a tube.

Oribasius, physician to the Emperor Julian in the latter half of the 4th and beginning of the 5th century, describes Cassia fistula as a bark of which there are several varieties, having pungent and astringent properties (“omnes cassiæ fistulæ vires habent acriter exalfacientes et stringentes”), and sometimes used in the place of cinnamon.[856]

It is doubtless the same drug which is spoken of by Alexander Trallianus[857] as Κασίας σῦριγζ (casia fistula) in connexion with costus, pepper and other aromatics; and named by other Greek writers as Κασία συριγγώδης (casia fistularis). Alexander still more distinctly calls it also Κασία αἰγυπτία.[858]

The tree under examination and its fruit were exactly described in the beginning of the 13th century by Abul Abbâs Annâbatî of Sevilla;[859] the fruit, the Cassia Fistula of modern medicine, is noticed by Joannes Actuarius, who flourished at Constantinople towards the close of the 13th century; and as he describes it with particular minuteness,[860] it is evident that he did not consider it well known. The drug is also mentioned by several writers of the school of Salernum. The tree would appear to have found at an early period its way to America, if we are correct in referring to it the Cassia Fistula enumerated by Petrus Martyr among the valuable products of the New World.[861] The drug was a familiar remedy in England in the time of Turner, 1568.[862]

The tree was figured in 1553 by the celebrated traveller Belon who met with it in the gardens of Cairo, and in 1592 by Prosper Alpinus who also saw it in Egypt.

Description—The ovary of the flower is one-celled with numerous ovules, which as they advance towards maturity become separated by the growth of intervening septa. The ripe legume is cylindrical, dark chocolate-brown, 1½ to 2 feet long by ¾ to 1 inch in diameter, with a strong short woody stalk, and a blunt end suddenly contracted into a point. The fibro-vascular column of the stalk is divided into two broad parallel seams, the dorsal and ventral sutures, running down the whole length of the pod, The sutures are smooth, or slightly striated longitudinally; one of them is formed of two ligneous bundles coalescing by a narrow line. If the legume is curved, the ventral suture commonly occupies its inner or concave side. The valves of the pods are marked by slight transverse depressions (more evident in small specimens) corresponding to the internal divisions, and also by inconspicuous transverse veins.

Each of the 25 to 100 seeds which a legume contains, is lodged in a cell formed by very thin woody dissepiments. The oval, flattish seed from ³/₁₀ to ⁴/₁₀ of an inch long, of a reddish-brown colour, contains a large embryo whose yellowish veined cotyledons cross diagonally, as seen on transverse section, the horny white albumen. One side is marked by a dark line (the raphe). A very slender funicle attaches the seed to the ventral suture.

In addition to the seeds, the cells contain a soft saccharine pulp which in the recent state fills them up, but in the imported pods appears only as a thin layer, spread over the septum, of a dark viscid substance of mawkish sweet taste. It is this pulp which is made use of in pharmacy.

Microscopic Structure—The bands above described running along the whole pod, are made up of strong fibro-vascular bundles mixed with sclerenchymatous tissue. The valves consist of parenchymatous cells, and the whole pod is coated with an epidermis exhibiting small tabular cells, which are filled with dark granules of tannic matter. A few stomata are also met with. The thin brittle septa of the pod are composed of long ligneous cells, enclosing here and there crystals of oxalate of calcium.

The pulp itself, examined under water, is seen to consist of loose cells, not forming a coherent tissue. They enclose chiefly granules of albuminoid matters and stellate crystals of oxalate of calcium. The cell-wall assumes, on addition of iodine, a blue hue if they have been previously washed by potash lye. The seeds are devoid of starch, but yield a copious amount of thick mucilage, which surrounds them like a halo if they are macerated in water.

Chemical Composition—No peculiar principle is known to exist either in the woody or the pulpy portion of cassia fistula. The pulp contains sugar in addition to the commonly occurring bodies noticed in the previous section.

Uses—The pulp separated from the woody part of the pods by crushing the latter, digesting them in hot water, and evaporating the strained liquor, is a mild laxative in common domestic use in the South of Europe,[863] but in England scarcely ever now administered except in the form of the well-known Lenitive Electuary (Confectio sennæ) of which it is an ingredient.

Commerce—Cassia fistula is shipped to England from the East and West Indies, but chiefly from the latter. The pulp per se has been occasionally imported, but it should never be employed when the legumes for preparing it can be obtained.

Substitutes—The pods of some other species of Cassia share the structure above described and have been sometimes imported.

Those of C. grandis L. f. (C. brasiliana Lamarck), a tree of Central America and Brazil, are of much larger size, showing when broken transversely an elliptic outline, whose longer diameter exceeds an inch. The valves have very prominent sutures and transverse branching veins. The pulp is bitter and astringent.

The legumes of Cassia moschata H B K.,[864] a tree 30 to 40 feet high, growing in New Granada and known there as Cañafistola de purgar, bear a close resemblance to those of Cassia Fistula L., except that they are a little smaller and rather less regularly straight. They contain a sweetish astringent pulp of a bright brown hue. When crushed and exposed to the heat of a water-bath, they emit a pleasant odour like sandal-wood. The pulp is coloured dark blackish green by perchloride of iron.

TAMARINDI PULPA.

Tamarindus, Fructus Tamarindi; Tamarinds; F. Tamarins; G. Tamarinden.

Botanical Origin—Tamarindus indica L.—The tamarind is a large handsome tree, growing to a height of 60 to 80 feet, and having abruptly pinnate leaves of 10 to 20 pairs of small oblong leaflets, constituting an abundant and umbrageous foliage. Its purplish flower buds and fragrant, red-veined, white blossoms, ultimately assuming a yellowish tinge, contribute to its beautiful aspect and cause it to be generally cultivated in tropical countries.

T. indica appears to be truly indigenous to Tropical Africa between 12° N. and 18° S. lat. It grows not only in the Upper Nile regions (Sennaar, Kordofan, Abyssinia), but also in some of the remotest districts visited by Speke, Grant, Kirk, and Stanley, and as far south as the Zambesi. According to F. von Müller,[865] it occurs in Tropical Australia.

It is found throughout India, and as it has Sanskrit names it may even be really wild in at least the southern parts of the peninsula. It grows in the Indian islands, and Crawfurd[866] has adduced reasons to show that it is probably a true native of Java. The mediæval Arabian authors describe it as growing in Yemen, India, and Nigritia.

The tamarind has been naturalized in Brazil, Ecuador and Mexico. Hernandez,[867] who resided in the latter country from 1571 to 1575, speaks of it as “nuper ... ad eas oras translata.” It abounds in the West Indies where it was also introduced together with ginger by the Spaniards at an early period. The tree found in these islands bears shorter and fewer-seeded pods than that of India, and hence was formerly regarded as a distinct species, Tamarindus occidentalis Gärtn.

History—The tamarind was unknown to the ancient Greeks and Romans; nor have we any evidence that the Egyptians were acquainted with it,[868] which is the more surprising considering that the tree appears indigenous to the Upper Nile countries, and that its fruit is held in the greatest esteem in those regions.[869]

The earliest mention of tamarind occurs in the ancient Sanskrit writings where it is spoken of under several names.[870] From the Hindus, it would seem that the fruit became known to the Arabians, who called it Tamare-hindi, i.e. Indian Date. Under this name it was mentioned by Isaac Judæus,[871] Avicenna,[872] and the Younger Mesue,[873] and also by Alhervi,[874] a Persian physician of the 10th century who describes it as black, of the flavour of a Damascene plum, and containing fibres and stones.

It was doubtless from the Arabians that a knowledge of the tamarind, as of so many other eastern drugs, passed during the middle ages into Europe through the famous school of Salernum. Oxyphœnica (Ὀζυϕοίνικα) and Dactyli acetosi are names under which we meet with it in the writings of Matthæus Platearius and Saladinus, the latter of whom, as well as other authors of the period, considered tamarinds as the fruit of a wild palm growing in India.

The abundance of tamarinds in Malabar, Coromandel, and Java was reported to Manuel, king of Portugal, in the letter of the apothecary Pyres[875] on the drugs of India, written in Cochin, January 27th, 1516. A correct description of the tree was given by Garcia de Orta about fifty years later.

Preparation—Tamarinds undergo a certain preparation before being brought into commerce.

In the West Indies, the tree matures its fruit in June, July and August, and the pods are gathered when fully ripe, which is known by the fragility of the outer shell. This latter, which easily breaks between the finger and thumb, is then removed, and the pods deprived of shelly fragments are placed in layers in a cask, and boiling syrup is poured over them till the cask is filled. When cool, the cask is closed and is then ready for sale. Sometimes layers of sugar are placed between the fruits previous to the hot syrup being added.[876]

East Indian tamarinds are also sometimes preserved with sugar, but usually they are exported without such addition, the outer shell being removed and the fruits being pressed together into a mass.

In the Upper Nile regions (Darfur, Kordofan, Sennaar) and in Arabia, the softer part of tamarinds is, for the sake of greater permanence and convenience of transport, kneaded into flattened round cakes, 4 to 8 inches in diameter and an inch or two thick, which are dried in the sun. They are of firm consistence and quite black, externally strewn with hair, sand, seeds and other impurities; they are largely consumed in Egypt and Central Africa, and sometimes find their way to the south of Europe as Egyptian Tamarinds.

Description—The fruit is an oblong, or linear-oblong, strictly compressed, curved or nearly straight, pendulous legume, of the thickness of the finger and 3 to 6 inches in length, supported by a woody stalk. It has a thin but hard and brittle outer shell or epicarp, which does not split into valves or exhibit any very evident sutures. Within the epicarp is a firm, juicy pulp, on the surface of which and starting from the stalk are strong woody ramifying nerves; one of these extends along the dorsal (or concave) edge, two others on either side of the ventral (or convex) edge, while between these two there are usually 2, 3, or 4 less regular and more slender nerves,—all running towards the apex and throwing out branching filaments. The brownish or reddish pulp has usually an acid taste, though there are also sweetish varieties.

The seeds, 4 to 12 in number, are each of them enclosed in a tough, membraneous cell (endocarp), surrounded by the pulp (sarcocarp). They are flattened and of irregular outline, being roundish, ovate, or obtusely four-sided, about ⁶/₁₀ of an inch long by ³/₁₀ thick, with the edge broadly keeled or more often slightly furrowed. The testa is of a rich brown, marked on the flat sides of the seed by a large scar or oreole, of rather duller polish than the surrounding portion which is somewhat radially striated. The seed is exalbuminous, with thick hard cotyledons, a short straight included radicle, and a plumule in which the pinnation of the leaves is easily perceptible.

Tamarinds are usually distinguished in trade as West Indian and East Indian, the former being preserved with sugar, the latter without.

1. West Indian Tamarinds, Brown or Red Tamarinds.—A bright reddish-brown, moist, saccharine mass consisting of the pulpy internal part of the fruit, usually unbroken, mixed with more or less of syrup. It has a very agreeable and refreshing taste, the natural acidity of the pulp being tempered by the sugar. It is this form of tamarinds that is usually found in the shops.

2. East Indian Tamarinds, Black Tamarinds.—These differ from the last described in that they are preserved without the use of sugar. They are found in the market in the form of a firm, clammy, black mass, consisting of the pulp mixed with the seeds, stringy fibres, and some remains of the outer shell. The pulp has a strong acid taste.

Notwithstanding the rather uninviting appearance of East Indian tamarinds, they afford a good pulp, which may be satisfactorily used in making the Confectio Sennæ of pharmacy. In fact, on the continent this sort of tamarind alone is employed for medicinal purposes.

Microscopic Structure—The soft part of tamarind consists of a tissue of thin-walled cells of considerable size, which is traversed by long fibro-vascular bundles. In the former a few very small starch granules are met with, and more numerous crystals, which are probably bitartrate of potassium.

Chemical Composition—Water extracts from unsweetened tamarinds, sugar together with acetic, tartaric and citric acids, the acids being combined for the most part with potash. The neutralized solution reduces alkaline cupric tartrate after a while without heat, and therefore probably contains grape sugar. On evaporation, cream of tartar and sugar crystallize out. The volatile acids of the fatty series, the presence of which in the pulp has been pointed out by Gorup-Besanez, have not been met with by other chemists. Tannin is absent as well as oxalic acid. We have ascertained that in East Indian tamarinds, citric acid is present in but small quantity. No peculiar principle to which the laxative action of tamarinds can be attributed is known.

The fruit-pulp diffused in water forms a thick, tremulous, somewhat glutinous and turbid liquid. It was examined as early as the year 1790 by Vauquelin under the name of “vegetable jelly,”—the first described among the pectic class of bodies.

The hard seeds have a testa which abounds in tannin, and after long boiling is easily separated, leaving the cotyledons soft. These latter have a bland mucilaginous taste, and are consumed in India as food during times of scarcity.

Commerce—Tamarinds are shipped in comparatively small quantities from several of the West Indian islands, and also from Guayaquil.

The export from the Bombay Presidency in the year 1871-72 was 6286 cwt., which quantity was shipped chiefly to the Persian Gulf, Sind, and ports of the Red Sea.[877] 128,144 centners were re-exported in 1877 from Trieste.

Uses—In medicine, tamarinds are considered to be a mild laxative; they are sometimes used to make a refrigerant drink in fever. In hot countries, especially the interior of Africa, they are regarded as of the highest value for the preparation of refreshing beverages. The Black Tamarinds are said to be used in the manufacture of tobacco.

BALSAMUM COPAIBA.

Copaiba; Balsam of Copaiba or Copaiva, Balsam Capivi; F. Baume ou Oléo-résine de Copahu; G. Copaivabalsam.

Botanical Origin—The drug under notice is produced by trees belonging to the genus Copaifera, natives of the warmer countries of South America. Some are found in moist forests, others exclusively in dry and elevated situations. They vary in height and size, some being umbrageous forest trees, while others have only the dimension of shrubs; it is from the former alone that the oleo-resin is obtained.

The following are reputed to furnish the drug, but to what extent each contributes is not fully known.

1. Copaifera officinalis L. (C. Jacquini Desf.), a large tree of the hot coast region of New Granada as far north as Panama, of Venezuela and the island of Trinidad.

2. C. guianensis Desf., a tree of 30 to 40 feet high, very closely related to the preceding, native of Surinam, Cayenne, also of the Rio Negro between Manaos and Barcellos (Spruce). According to Bentham it seems to be the same species as the C. bijuga of Hayne.[878]

3. C. coriacea Mart. (C. cordifolia Hayne), a large tree found in the caatingas or dry woods of the Brazilian provinces of Bahia and Piauhy.

4. C. Langsdorffii Desf.[879] (C. nitida Hayne, C. Sellowii Hayne,? C. Jussieui Hayne), a polymorphous species, varying in the form and size of leaflets, and also in dimensions, being either a shrub, a small bushy tree, or a large tree of 60 feet high. Bentham admits, besides the type, three varieties:—β. glabra (C. glabra Vogel), γ. grandifolia, δ. laxa (C. laxa Hayne). The tree grows on dry campos, caatingas and other places in the provinces of S. Paulo, Minas Geraes, Goyaz, Mato Grosso, Bahia and Ceará; it is therefore distributed over a vast area. According to Gardner,[880] the Brazilian traveller, it yields an abundance of balsam.

In addition to these species, must be mentioned a tree described by Hayne and commonly cited under the name of Copaifera multijuga, as a special source of the drug shipped from Pará.[881] As its name implies, it is remarkable for the number of leaflets (6 to 10 pairs) on each leaf. But it is only known from some leaves in the herbarium of Martius which Bentham, who has examined them, informs us are unlike those of any Copaifera known to him, though certainly the leaflets are dotted with oil-vessels as in some species. In the absence of flowers and fruits, there is no sufficient evidence to prove that it belongs even to the genus Copaifera. It is not mentioned by Martius in his Systema Materiæ Medicæ Brasiliensis (1843) as a source of the drug.

History—Among the early notices of Brazil is a treatise by a Portuguese friar who had resided in that country from 1570 to 1600. The manuscript found its way to England, was translated, and was published by Purchas[882] in 1625. Its author notices many of the natural productions of the country, and among others Cupayba which he describes as a large tree from whose trunk, when wounded by a deep incision, there flows in abundance a clear oil much esteemed as a medicine.

Balsam. Copæ. yvæ is already enumerated in the 6th edition of the Pharmacopœa of Amsterdam, a.d. 1636.[883]

Father Cristoval d’Acuña,[884] who ascended the Amazon from Pará, arriving at Quito in 1638, mentions that the country affords very large Cassia fistula, excellent sarsaparilla, and the oils of Andirova (Carapa guianensis Aublet, Meliaceæ), and Copaiba, as good as balsam for curing wounds.

Piso and Marcgraf,[885] who in 1636 accompanied the Count of Nassau to the Dutch establishments in Brazil, each give an account of the Copaiba and the method of obtaining its oleo-resin. The former states that the tree grows in Pernambuco and the island of Maranhon, whence the balsam is conveyed in abundance to Europe.

The drug was formerly brought into European commerce by the Portuguese, and used to be packed in earthen pots pointed at the lower end; it often arrived in a very impure condition.[886] In the London Pharmacopœia of 1677, it was called Balsamum Capivi, which is still its most popular name.

Secretion—Karsten states that he observed resiniferous ducts, frequently more than an inch in diameter, running through the whole stem. He is of the opinion that the cell-walls of the neighbouring parenchyme are liquefied and transformed into the oleo-resin.[887] We are not able to offer any argument in favour of this opinion.

In the vessels already alluded to, the balsam sometimes collects in so large a quantity, that the trunk is unable to sustain the inward pressure, and bursts. This curious phenomenon is thus referred to in a letter addressed to one of us by Mr. Spruce:—“I have three or four times heard what the Indians assured me was the bursting of an old capivi-tree, distended with oil. It is one of the strange sounds that sometimes disturb the vast solitudes of a South American forest. It resembles the boom of a distant cannon, and is quite distinct from the crash of an old tree falling from decay which one hears not unfrequently.”

A similar phenomenon is known in Borneo. The trunks of aged trees of Dryobalanops aromatica contain large quantities of oleo-resin or Camphor Oil,[888] which appears to be sometimes secreted under such pressure that the vast trunk gives way. “There is another sound,” says Spenser St. John,[889] “only heard in the oldest forests, and that is as if a mighty tree were rent in twain. I often asked the cause, and was assured it was the camphor tree splitting asunder on account of the accumulation of camphor in some particular portion.”

Extraction—Balsam Capivi is collected by the Indians on the banks of the Orinoco and its upper affluents, and carried to Ciudad Bolivar (Angostura); some of this balsam reaches Europe by way of Trinidad. But it is obtained much more largely on the tributaries of the Caisquiari and Rio Negro (the Siapa, Içanna, Uaupés, etc.) and is sent down to Pará. Most of the northern tributaries of the Amazon, as the Trombetas and Nhamundá, likewise furnish a supply. According to Spruce, in the Amazon valley it is the tall virgin forest, Caaguaçú of the Brazilians, Monte Alto of the Venezuelans, that yields most of the oils and gum-resins, and not the low, dry caatingas, or the riparial forests. The same observant traveller tells us that in Southern Venezuela, capivi is known only as el Aceite de palo (wood-oil), the name Balsamo being that of the so-called Sassafras Oil, obtained from a species of Nectandra.

Balsam Copaiba is also largely exported from Maracaibo where, according to Engel,[890] it is produced by C. officinalis, the Canime of the natives.

The finest sort, called by the collectors white copaiba, is met with in the province of Pará, where Cross[891] saw a tree of a circumference of more than 7 feet at 3 feet from the ground. Its trunk was clear of branches to a height of at least 90 feet. The collector commenced the work by hewing out with his axe a hole or chamber in the trunk about a foot square, at a height of two feet from the ground. The base or floor of the chamber should be carefully and neatly cut with a gentle upward slope, and it should also decline to one side, so that the balsam on issuing may run in a body until it reaches the outer edge. Below the chamber a pointed piece of bark is cut and raised, which, enveloped with a leaf, serves as a spout for conveying the balsam from the tree to the tin.[892] The balsam, continues Cross, came flowing in a moderate sized cool current, full of air bubbles. At times the flow stopped for several minutes, when a singular gurgling noise was heard, after which followed a rush of balsam. When coming most abundantly a pint jug would have been filled in the space of one minute. The whole of the wood cut through by the axeman was bedewed with drops of balsam; the bark is apparently devoid of it. Trees of the largest size in good condition will sometimes yield four “potos,” equal to 84 English imperial pints.

Description—Copaiba is more or less viscid fluid, varying in tint from a pale yellow to a light golden brown, of a peculiar aromatic, not unpleasant odour, and a persistent, acrid, bitterish taste. Pará copaiba newly imported is sometimes nearly colourless and almost as fluid as water.[893] The balsam is usually quite transparent, but there are varieties which remain always opalescent. Its sp. gr. varies from 0·940 to 0·993, according as the drug contains a greater or less proportion of volatile oil. Copaiba becomes more fluid by heat; if heated in a test tube to 200° C. for some time, it does not lose its fluidity on cooling. It is sometimes slightly fluorescent, it dissolves in several times its weight of alcohol 0·830 sp. gr., and generally in all proportions in absolute alcohol,[894] acetone, or bisulphide of carbon, and is perfectly soluble in an equal volume of benzol. Glacial acetic acid readily dissolves the resin but not the essential oil.

Copaiba that is rich in resin of an acid character, unites with the oxides of baryum, calcium, or magnesium, to form a gradually hardening mass, provided a small proportion of water is present. Thus 8 to 16 parts of balsam will combine as a stiff compound when gently warmed with 1 part of moistened magnesia; and still more easily with lime or baryta.

Buignet has first shown (1861) that copaiba varies in its optical power. A sample from Trinidad examined by one of us was strongly dextrogyre, and also several samples imported in 1877 from Maturin (near Aragua, Venezuela), and Maracaibo into Hamburg, whereas we found Pará balsam to be levogyre.[895]

The Pará and Maranham balsams are regarded in wholesale trade as distinct sorts, and experienced druggists are able to distinguish them apart by odour and appearance, and especially by the greater consistence of the Maranham drug. Maracaibo balsam is reckoned as another variety, but is now rarely seen in the English market. West Indian copaiba is usually said to be of inferior quality, but except that it is generally opalescent, we know not on what precise grounds.

Chemical Composition—The balsam is a solution of resin in volatile oil; the latter constitutes about 40 to 60 per cent. of the balsam,[896] according to the age of the latter and its botanical origin. The oil has the composition C₁₅H₂₄; its boiling point is 245° C. or even higher. It smells and tastes like the balsam, and dissolves in from 8 to 30 parts of alcohol 0·830 sp. gr. The oil exhibits several modifications differing in optical as well as in other physical properties, but numerous samples of the drug, either dextrogyre or levogyre, invariably afforded us essential oils deviating to the left; their sp. gr. varies from about 0·88 to 0·91.

After the oil of copaiba has been removed by distillation, there remains a brittle amorphous resin of an acid character soluble both in benzol and amylic alcohol, and yielding only amorphous salts. Sometimes copaiba contains a small amount of crystallizable resin-acid, as first pointed out in 1829 by Schweitzer. By exposing a mixture of 9 parts of copaiba and two parts of aqueous ammonia (sp. gr. 0·95) to a temperature of-10° C., Schweitzer obtained crystals of the acid resin termed Copaivic Acid. They were analysed in 1834 by H. Rose, and exactly measured and figured by G. Rose. Hess (1839) showed that Rose’s and his own analyses assign to copaivic acid the formula C₂₀H₃₂O₂. It agrees with Maly’s abietic acid from colophony in composition, but not in any other way. Copaivic acid is readily soluble in alcohol, and especially in warmed copaiba itself; much less in ether. We have before us crystals, no doubt of copaivic acid, which have been spontaneously deposited in an authentic specimen of the oleo-resin of Copaifera officinalis from Trinidad, which we have kept for many years. The crystals may be easily dissolved by warming the balsam; on cooling the liquid, they again make their appearance after the lapse of some weeks. After recrystallization from alcohol they fuse at 116-117 C°., forming an amorphous transparent mass which quickly crystallizes if touched with alcohol.

An analogous substance, Oxycopaivic Acid, C₂₀H₂₈O₃, was examined in 1841 by H. von Fehling, who met with it as a deposit in Pará Copaiba. And lastly Strauss (1865) extracted Metacopaivic Acid, C₂₂H₃₄O₄, from the balsam imported from Maracaibo. He boiled the latter with soda-lye, which separated the oil; the heavier adjacent liquid was then mixed with chloride of ammonium, which threw down the salts of the amorphous resin-acid, leaving in solution those of the metacopaivic acid. The latter acid was separated by hydrochloric acid and recrystallization from alcohol. We succeeded in obtaining metacopaivic acid by washing the balsam with a dilute solution of carbonate of ammonium, and precipitating by hydrochloric acid. The precipitate dissolved in dilute alcohol yields the acid in small crystals, but to the amount of only about one per cent.

These resin-acids have a bitterish taste and an acid reaction; their salts of lead and silver are crystalline but insoluble; metacopaivate of sodium may be crystallized from its watery solution.

Commerce—The balsam is imported in barrels direct from Pará and Maranham, sometimes from Rio de Janeiro, and less often from Demerara, Angostura, Trinidad, Maracaibo, Savanilla, and Cartagena. It often reaches England by way of Havre and New York. In 1875 there were exported 10,150 kilogrammes from Savanilla, 99,800 lb. from Ciudad Bolivar (Angostura), and 65,243 kilos. from Pará.

Uses—Copaiba is employed in medicine on account of its stimulant action on the mucous membranes, more especially those of the urino-genital organs.

Adulteration—Copaiba is not unfrequently fraudulently tampered with before it reaches the pharmaceutist; and owing to its naturally variable composition, arising in part from its diverse botanical origin, its purity is not always easily ascertained.

The oleo-resin usually dissolves in a small proportion of absolute alcohol: should it refuse to do so, the presence of some fatty oil other than castor oil may be surmised. To detect an admixture of this latter, one part of the balsam should be heated with four of spirit of wine (sp. gr. 0·838). On cooling, the mixture separates into two portions, the upper of which will contain any castor oil present, dissolved in alcohol and the essential oil. On evaporation of this upper layer, castor oil may be recognized by its odour; but still more positively by heating it with caustic soda and lime, when œnanthol will be formed, the presence of which may be ascertained by its peculiar smell. By the latter test an admixture of even one per cent. of castor oil can be proved.

The presence of fatty oil in any considerable quantity is likewise made evident by the greasiness of the residue, when the balsam is deprived of its essential oil by prolonged boiling with water.

The admixture of some volatile oil with copaiba can mostly be detected by the odour, especially when the balsam is dropped on a piece of warmed metal. Spirit of wine may also be advantageously tried for the same purpose. It dissolves but very sparingly the volatile oil of copaiba: the resins of the latter are also not abundantly soluble in it. Hence, if shaken with the balsam, it would remove at once the larger portion of any essential oil that might have been added. For the recognition of Wood Oil if mixed with copaiba, see page 233, note 1.

Substitutes—Under this head two drugs deserve mention, namely Gurjun Balsam or Wood Oil, described at p. 88, and Oleo-resin of Hardwickia pinnata Roxb.—The tree, which is of a large size, belongs to the order Leguminosæ and is nearly related to Copaifera. According to Beddome,[897] it is very common in the dense moist forests of the South Travancore Ghats, and has also been found in South Canara. The natives extract the oleo-resin in exactly the same method as that followed by the aborigines of Brazil in the case of copaiba,—that is to say, they make a deep notch reaching to the heart of the trunk, from which after a time it flows out.

This oleo-resin, which has the smell and taste of copaiba, but a much darker colour, was first examined by one of us in 1865, having been sent from the India Museum as a sample of Wood Oil; it was subsequently forwarded to us in more ample quantity by Dr. Bidie of Madras. It is a thick, viscid fluid, which, owing to its intense tint, looks black when seen in bulk by reflected light; yet it is perfectly transparent. Viewed in a thin layer by transmitted light, it is light yellowish-green, in a thick layer vinous-red,—hence is dichromic. It is not fluorescent, nor is it gelatinized or rendered turbid by being heated to 130° C., thus differing from Wood Oil.[898] Broughton[899] obtained by prolonged distillation with water an essential oil to the extent of 25 per cent. from an old specimen, and of more than 40 per cent. from one recently collected. The oil was found to have the same composition as that of copaiba, to boil at 225° C., and to rotate the plane of polarization to the left. The resin[900] is probably of two kinds, of which one at least possesses acid properties. Broughton made many attempts, but without success, to obtain from the resin crystals of copaivic acid.

The balsam of Hardwickia has been used in India for gonorrhœa, and with as much success as copaiba.

GUMMI ACACIÆ.

Gummi Arabicum; Gum Arabic; F. Gomme Arabique; G. Arabisches Gummi, Acacien-Gummi, Kordofan-Gummi.

Botanical Origin—Among the plants abounding in mucilage, numerous Acaciæ of various countries are in the first line. The species particularly known for affording the largest quantities of the finest gum arabic is Acacia Senegal[901] Willdenow (syn. Mimosa Senegal L., A. Verek Guillemin et Perrottet), a small tree not higher than 20 feet, growing abundantly on sandy soils in Western Africa, chiefly north of the river Senegal, where it constitutes extensive forests. It is called by the negroes Verek. The same tree is likewise found in Southern Nubia, Kordofan, and in the region of the Atbara in Eastern Africa, where it is known as Hashab. It has a greyish bark, the inner layers of which are strongly fibrous, small yellowish flowers densely arranged in spikes 2 to 3 inches long, and exceeding the bipinnate leaves, and a broad legume 3 to 4 inches in length containing 5 to 6 seeds.

According to Schweinfurth,[902] it is this tree exclusively that yields the fine white gum of the countries bordering the Upper Nile, and especially of Kordofan. He states that only brownish or reddish sorts of gum are produced by the Talch, Talha or Kakul, Acacia stenocarpa Hochstetter, by the Ssoffar, A. fistula Schweinf. (A. Seyal Delile, var. Fistula), as well as by the Ssant or Sont, A. nilotica Desfont (A. arabica Willd.). These trees grow in north-eastern Africa; the last named is, moreover, widely distributed all over tropical Africa as far as Senegambia,[903] Mozambique and Natal, and also extends to Sindh, Gujarat[904] and Central India. We find even the first sort, “Karami,” of gum exported from the Somali coast,[905] to be inferior to good common Arabic gum. Hildebrandt (1875) mentions that gum is there largely collected from Acacia abyssinica Hochst. and A. glaucophylla Steudel.

History—The history of this drug carries us back to a remote antiquity. The Egyptian fleets brought gum from the gulf of Aden as early as the 17th century b.c. Thus in the treasury of king Rhampsinit (Ramses III.) at Medinet Abu, there are representations of gum-trees, together with heaps of gum. The symbol used to signify gum, is read Kami-en-punt. i.e. gum from the country of Punt. This, in all probability, includes both the Somali coast as well as that of the opposite parts of Arabia (see article Olibanum, p. 136). Thus, gum is of frequent occurrence in Egyptian inscriptions; sometimes mention is made of gum from Canaan. The word kami is the original of the Greek κόμμι, whence through the Latin our own word gum.[906]

The Egyptians used gum largely in painting; an inscription exists which states that in one particular instance a solution of Kami (gum) was used to render adherent the mineral pigment called chesteb,[907] the name applied to lapis lazuli or to a glass coloured blue by cobalt.

Turning to the Greeks, we find that Theophrastus in the 3rd and 4th century b.c. mentioned Κόμμι as a product of the Egyptian Ἂκανθα, of which tree there was a forest in the Thebaïs of Upper Egypt. Strabo also, in describing the district of Arsinöe, the modern Fayûm, says that gum is got from the forest of the Thebaïc Akanthe.

Celsus in the 1st century mentions Gummi acanthinum; Dioscorides and Pliny also describe Egyptian gum, which the latter values at 3 denarii [2s.] per lb.

In those times gum no doubt used to be shipped from north-eastern Africa to Arabia; there is no evidence showing that Arabia itself had ever furnished the chief bulk of the drug. The designation gum arabic occurs in Diodorus Siculus (2, 49) in the first century of our era, also in the list of goods of Alexandria mentioned in our article on Galbanum.

Gum was employed by the Arabian physicians and by those of the school of Salerno, yet its utility in medicine and the arts was but little appreciated in Europe until a much later period. For the latter purpose at least the gummy exudations of indigenous trees were occasionally resorted to, as distinctly pointed out about the beginning of the 12th century, by Theophilus or Rogker:[908] “gummi quot exit de arbore ceraso vel pruno.“

During the middle ages, the small supplies that reached Europe were procured through the Italian traders from Egypt and Turkey. Thus Pegolotti,[909] who wrote a work on commerce about a.d. 1340, speaks of gum arabic as one of the drugs sold at Constantinople by the pound not by the quintal. Again, in a list of drugs liable to duty at Pisa in 1305,[910] and in a similar list relating to Paris in 1349,[911] we find mention of gum arabic. It is likewise named by Pasi,[912] in 1521, as an export from Venice to London.

Gum also reached Europe from Western Africa, with which region the Portuguese had a direct trade as early as 1449.

Production—Respecting the origin of gum in the tribe Acaciæ, no observations have been made similar to those of H. von Mohl on tragacanth.[913]

It appears that gum generally exudes from the trees spontaneously, in sufficient abundance to render wounding the bark superfluous. The Somali tribes of East Africa, however, are in the habit of promoting the outflow by making long incisions in the stem and branches of the tree.[914] In Kordofan the lumps of gum are broken off with an axe, and collected in baskets.

The most valued product, called Hashabi gum, from the province of Dejara in Kordofan, is sent northward from Bara and El Obeid to Dabbeh on the Nile, and thence down the river to Egypt; or it reaches the White Nile at Mandjara.

A less valuable gum, known as Hashabi el Jesire, comes from Sennaar on the Blue Nile; and a still worse from the barren table-land of Takka, lying between the eastern tributaries of the Blue Nile and the Atbara and Mareb; and from the highlands of the Bisharrin Arabs between Khartum and the Red Sea. This gum is transported by way of Khartum or El Mekheir (Berber), or by Suakin on the Red Sea. Hence, the worst kind of gum is known in Egypt as Samagh Savakumi (Suakin Gum).

According to Munzinger,[915] a better sort of gum is produced along the Samhara coast towards Berbera, and is shipped at Massowa. Some of it reaches Egypt by way of Jidda, which town being in the district of Arabia called the Hejaz, the gum thence brought receives the name of Samagh Hejazi; it is also called Jiddah or Gedda Gum. The gums of Zeila, Berbera and the Somali country about Gardafui, are shipped to Aden, or direct to Bombay. A little gum is collected in Southern Arabia, but the quantity is said to be insignificant.[916]

In the French colony of Senegal, gum, which is one of its principal productions, is collected chiefly in the country lying north of the river, by the Moors who exchange it for European commodities. The gathering commences after the rainy season in November when the wind begins to set from the desert, and continues till the month of July. The gum is shipped for the most part to Bordeaux. The quantity annually imported into France since 1828 from Senegal is varying from between 1½ to 5 millions of kilogrammes.

Description—Gum arabic does not exhibit any very characteristic forms like those observable in gum tragacanth. The finest white gum of Kordofan, which is that most suitable for medicinal use, occurs in lumps of various sizes from that of a walnut downwards. They are mostly of ovoid or spherical form, rarely vermicular, with the surface in the unbroken masses, rounded,—in the fragments, angular. They are traversed by numerous fissures, and break easily and with a vitreous fracture. The interior is often less fissured than the outer portion. At 100° C. the cracks increase, and the gum becomes extremely friable. In moist air, it slowly absorbs about 6 per cent. of water.

The finest gum arabic is perfectly clear and colourless; inferior kinds have a brownish, reddish or yellowish tint of greater or less intensity, and are more or less contaminated with accidental impurities such as bark. The finest white gum turns black and assumes an empyreumatic taste, when it is kept for months at a temperature of about 98° C., either in an open vessel, or enclosed in a glass tube, after having been previously dried over sulphuric acid or not.

An aqueous solution of gum deviates the plane of polarization 5° to the left in a column 50 mm. long; but after being long kept, it becomes strongly acid, the gum having been partly converted into sugar, and its optical properties are altered. An alkaline solution of cupric tartrate is not reduced by solution of gum even at a boiling heat, unless it contains a somewhat considerable proportion of sugar, extractable by alcohol, or a fraudulent admixture of dextrin.

We found the sp. gr. of the purest pieces of colourless gum dried in the air at 15° C., to be 1·487; but it increases to 1·525, if the gum is dried at 100°.

The foregoing remarks apply chiefly to the fine white gum of Kordofan, the Picked Turkey Gum or White Sennaar Gum of druggists. The other sorts which are met with in the London market are the following:—

1. Senegal Gum—As stated above, this gum is an important item of the French trade with Africa, but is not much used in England. Its colour is usually yellowish or somewhat reddish, and the lumps, which are of large size, are often elongated or vermicular. Moreover Senegal gum never exhibits the numerous fissures seen in Kordofan gum, so that the masses are much firmer and less easily broken. In every other respect, whether chemical or optical, we find[917] Senegal gum and Kordofan gum to be identical; and the two, notwithstanding their different appearance, are produced by one and the same species of Acacia, namely Acacia Senegal.

2. Suakin Gum, Talca or Talha Gum, yielded by Acacia stenocarpa, and by A. Seyal var. Fistula, is remarkable for its brittleness, which occasions much of it to arrive in the market in a semi-pulverulent state. It is a mixture of nearly colourless and of brownish gum, with here and there pieces of a deep reddish-brown. Large tears have a dull opaque look, by reason of the innumerable minute fissures which penetrate the rather bubbly mass. It is imported from Alexandria.

3. Morocco, Mogador or Brown Barbary Gum—consists of tears of moderate size, often vermiform, and of a rather uniform, light, dusky brown tint. The tears which are internally glassy become cracked on the surface and brittle if kept in a warm room; they are perfectly soluble in water. The above mentioned Acacia nilotica is supposed to be the source of the gum exported from Morocco, and also from Fezzan.

Gums of various kinds, including the resin Sandrac, were exported from Morocco in the year 1872 to the extent of 5110 cwt., a quantity much below the average.[918]

4. Cape Gum—This gum, which is uniformly of an amber brown, is produced in plenty in the Cape Colony, as a spontaneous exudation of Acacia horrida Willd. (A. Karroo Hayne, A. capensis Burch.), a large tree, the Doornboom, Wittedoorn or Karródoorn of the Cape colonists, the commonest tree of the lonely deserts of South Africa. The Blue Book of the Cape Colony, published in 1873, states the export of gum in 1872 as 101,241 lb.

5. East India Gum—The best qualities consist of tears of various sizes, sometimes as large as an egg, internally transparent and vitreous, of a pale amber or pinkish hue, completely soluble in water. This gum is largely shipped from Bombay, but is almost wholly the produce of Africa; the imports into Bombay from the Red Sea ports, Aden and the African Coast in the year 1872-73, were 14,352 cwt. During the same year the shipments from Bombay to the United Kingdom amounted to 4,561 cwt.[919]

6. Australian Gum, Wattle Gum—This occurs in large hard globular tears and lumps, occasionally of a pale yellow, yet more often of an amber or of a reddish-brown hue. It is transparent and entirely soluble in water; the mucilage is strongly adhesive, and said to be less liable to crack when dry than that of some other gums. The solution, especially that of the darker and inferior kinds, contains a little tannin, evidently derived from the very astringent bark which is often attached to the gum.

A. pycnantha Benth.; A. decurrens Willd. (A. mollissima Willd., A. dealbata Link), Black or Green Wattle-tree of the colonists, and A. homalophylla A. Cunn., are the trees which furnish the gum arabic of Australia.[920]

Chemical Characters and Composition—At ordinary temperatures gum dissolves very slowly and without affecting the thermometer in an equal weight of water, forming a thick, glutinous, slightly opalescent liquid, having a mawkish taste and decidedly acid reaction. At higher temperatures the dissolution of gum is but slightly accelerated, and water does not take up a much larger quantity even at 100°. The finest gum dried at 100° C. forms with two parts of water a mucilage of sp. gr. 1·149 at 15° C.

This solution mixes with glycerine, and the mixture may be evaporated to the consistence of a jelly without any separation taking place. Solid gum in lumps, on the contrary, is but little affected by concentrated glycerine. In other liquids, gum is insoluble or only slightly soluble, unless there is a considerable quantity of water present. Thus 100 parts of spirit of wine containing 22 volumes per cent. of alcohol, dissolve 57 parts of gum; spirit containing 40 per cent. of alcohol takes up 10 parts, and spirit of 50 per cent. only 4 parts. Aqueous alcohol of 60 per cent. no longer dissolves gum, but extracts from it a small quantity (⅓ to ½ per cent. according to the variety) of resin colouring matter, glucose, calcium chloride, and other salts.

Neutral acetate of lead does not precipitate gum arabic mucilage; but the basic acetate forms, even in a very dilute solution, a precipitate of definite constitution.

Soluble silicates, borates, and ferric salts render gum solution turbid, or thicken it to a jelly. It is not a compound of gum with any of these substances which is formed, but in the cases of the first, basic silicates separate. No alteration is produced by silver salts, mercuric chloride or iodine. Ammonium oxalate throws down the lime contained in a solution of gum. Gum dissolves in an ammoniacal solution of cupric oxide. Acted upon by nitric acid, mucic acid is produced.

Small, air-dried lumps of gum lose by desiccation over concentrated sulphuric acid (or by heating them in the water-bath) 12 to 16 per cent. of water. If gum independently of its amount of lime, be presented by the formula C₁₂H₂₂O₁₁ + 3H₂O, the loss of 3 molecules of water will correspond to a decrease in weight of 13·6 per cent.; in carefully selected colourless pieces, we have found it to amount to 13·14 per cent. At a temperature of about 150° C., gum parts with another molecule of water, and partly loses its solubility and assumes a brownish hue and empyreumatic taste. Gum already by keeping it for a week at a temperature not exceeding 95° C. gradually acquires a decidedly empyreumatic taste. We have also observed, on the other hand, a fine white gum affording an imperfect solution which was glairy, like the mucilage of marshmallow, but in no other respect could we find that it differed from ordinary gum. On exposing it for some days to a temperature of 95° C., it afforded a solution of the usual character.

When gum arabic is dissolved in cold water and the solution is slightly acidulated with hydrochloric acid, alcohol produces it in a precipitate of Arabin or Arabic Acid. It may be also prepared by placing a solution of gum (1 gum + 5 water), acidulated with hydrochloric acid, on a dialyser, when the calcium salt will diffuse out, leaving behind a solution of arabin.

Solution of arabin differs from one of gum in not being precipitated by alcohol. Having been dried, it loses its solubility, merely swelling in water, but not dissolving even at a boiling heat. If an alkali is added, it forms a solution like ordinary gum. Neubauer who observed these facts (1854-57) showed that gum arabic is essentially an acid calcium salt of arabic acid.

Arabic Acid dried at 100° C. has the composition C₁₂H₂₂O₁₁, and gives up H₂O when it unites with bases. It has however a great tendency to form salts containing a large excess of acid. An acid calcium arabate of the composition (C₁₂H₂₁O₁₁)₂Ca + 3 (C₁₂H₂₂O₁₁ + 5 OH) would afford by incineration 4·95 per cent. of calcium carbonate. Nearly this amount of ash is in fact sometimes yielded by gum. The most carefully selected colourless pieces of it yield from 2·7 to 4 per cent. of ash, consisting mainly of calcium carbonate, but containing also carbonates of potassium and magnesium. Phosphoric acid appears never to occur in gums.

Natural gum may therefore be regarded as a salt of arabic acid having a large excess of acid, or perhaps as a mixture of such salts of calcium, potassium and magnesium. It is to the presence of these bases, which are doubtless derived from the cell-wall from which the gum exuded, that gum owes its solubility.

It still remains unexplained why certain gums, not unprovided with mineral constituents, merely swell up in water without dissolving, thus materially differing from gum arabic. There is also a marked difference between gum arabic and many other varieties of gum or mucilage, which immediately form a plumbic compound if treated with neutral acetate of lead. The type of the swelling, but not really soluble gums, is Tragacanth, but there are a great many other substances of the same class, some of them perfectly resembling gum arabic in external appearance. The name of Bassora gum has also been applied to the latter kinds.

Commerce—The imports of Gum Arabic into the United Kingdom have been as follows:—

1871 1872

76,136 cwt. 42,837 cwt.

value £250,088. value £123,080.

The country whence by far the largest supplies are shipped, is Egypt.

Uses—Gum is employed in medicine rather as an adjuvant than as possessing any remedial powers of its own.

Substitutes—A great number of trees are capable of affording gums more or less similar to gum arabic. There is to be mentioned for instance Prosopis glandulosa Torrey, a tree growing from 30 to 40 feet in height, occurring very abundantly in Texas, and extending as far west as the Colorado and the gulf of California. It is universally known by its Mexican name Mesquite. It belongs to the same suborder of the Mimosæ like the Acaciæ tribe of the Adenanthereæ. Mesquite gum agrees not with the fine description, but with the inferior sorts of gum arabic, and is sometimes used in America,[921] since 1854, in the manufacture of confectionery and the arts.

Feronia Gum, or Wood Apple Gum. This is the produce of Feronia Elephantum Correa, a spiny tree, 50 to 60 feet high, of the order of Aurantiaceæ, common throughout India from the hot valleys of the Himalaya to Ceylon, and also found in Java. There exudes from its bark abundance of gum, which appears not to be collected for exportation per se, but rather to be mixed indiscriminately with other gum, as that of Acacia.

Feronia gum sometimes forms small roundish transparent, almost colourless tears, more frequently stalactitic or knobby masses, of a brownish or reddish colour, more or less deep. In an authentic sample, for which we are indebted to Dr. Thwaites of Ceylon, horn-shaped pieces about ½ an inch thick and two inches long also occur.

Dissolved in two parts of water, it affords an almost tasteless mucilage, of much greater viscosity than that of gum arabic made in the same proportions. The solution reddens litmus, and is precipitated like gum arabic by alcohol, oxalate of ammonium, alkaline silicates, perchloride of iron, but not by borax. Moreover, the solution of Feronia gum is precipitated by neutral acetate of lead or caustic baryta, but not by potash. If the solution is completely precipitated by neutral acetate of lead, the residual liquid will be found to contain a small quantity of a different gum, identical apparently with gum arabic, inasmuch as it is not thrown down by acetate of lead. If the lime is precipitated from the Feronia mucilage by oxalate of potassium, the gum partially loses its solubility and forms a turbid liquid.

From the preceding experiments, it follows that a larger portion of Feronia gum is by no means identical with gum arabic. The former, when examined in a column of 50 mm. length, deviates the rays of polarized light 0°·4 to the right,—not to the left as gum arabic. This was, we believe, the first instance of a dextrogyre gum;[922] Scheibler has afterwards shown (1873) that there are also dextrogyre varieties among the African gum from Sennar. Gum arabic may be combined with oxide of lead; the compound (arabate of lead) contains 30·6 per cent. of oxide of lead, whereas the plumbic compound of Feronia gum, dried at 110° C., yielded us only 14·76 per cent. of PbO. The formula (C₁₂H₂₁O₁₁)₂Pb + 2(C₁₂H₂₂O₁₁) supposes 14·2 per cent. of oxide of lead.

Feronia gum repeatedly treated with fuming nitric acid produces abundant crystals of mucic acid. We found our sample of the gum to yield 17 per cent. of water, when dried at 110° C. It left 3·55 per cent. of ash.

CATECHU.

Catechu nigrum; Black Catechu, Pegu Catechu, Cutch, Terra Japonica; F. Cachou, Cachou brun ou noir; G. Catechu.

Botanical Origin—The trees from which this drug is manufactured are of two species, namely:—

1. Acacia Catechu Willd. (Mimosa Catechu L. fil., M. Sundra Roxb.[923]), a tree 30 to 40 feet high, with a short, not very straight trunk4 to 6 feet in girth, straggling thorny branches, light feathery foliage, and dark grey or brown bark, reddish and fibrous internally.

It is common in most parts of India and Burma, where it is highly valued for its wood, which is used for posts and for various domestic purposes, as well as for making catechu and charcoal, while the astringent bark serves for tanning. It also grows in the hotter and drier parts of Ceylon. A. Catechu abounds in the forests of Tropical Eastern Africa; it is found in the Soudan, Sennaar, Abyssinia, the Noer country, and Mozambique, but in none of these regions is any astringent extract manufactured from its wood.

2. A. Suma Kurz[924] (Mimosa Suma Roxb.), a large tree with a red heartwood, but a white bark, nearly related to the preceding but not having so extensive a geographical range. It grows in the South of India (Mysore), Bengal and Gujerat. The bark is used in tanning, and catechu is made from the heartwood.

The extract of the wood of these two species of Acacia is Catechu in the true and original sense of the word, a substance not to be confounded with Gambier, which, though very similar in composition, is widely diverse in botanical origin, and always regarded in commerce as a distinct article.

History—Barbosa in his description of the East Indies in 1514[925] mentions a drug called Cacho as an article of export from Cambay to Malacca. This is the name for Catechu in some of the languages of Southern India.[926]

About fifty years later, Garcia de Orta gave a particular account of the same drug[927] under its Hindustani name of Kat, first describing the tree and then the method of preparing an extract from its wood. This latter substance was at that period made up with the flour of a cereal (Eleusine coracana Gärtn.) into tablets or lozenges, and apparently not sold in its simple state: compositions of this kind are still met with in India. In the time of Garcia de Orta the drug was an important article of traffic to Malacca and China, as well as to Arabia and Persia.

Notwithstanding these accounts, catechu remained unknown in Europe until the 17th century, when it began to be brought from Japan, or at least said to be exported from that country. It was known about 1641 to Johannes Schröder,[928] and is quoted at nearly the same time in several tariffs of German towns, being included in the samples of mineral origin.[929]

In 1671, catechu was noticed as a useful medicine by G. W. Wedel of Jena,[930] who also called attention to the diversity of opinion as to its mineral or vegetable nature. Schröck[931] in 1677 combated the notion of its mineral origin, and gave reasons for considering it a vegetable substance. A few years later, Cleyer,[932] who had a personal knowledge of China, pointed out the enormous consumption of catechu for mastication in the East,—that it is imported into Japan,—that the best comes from Pegu, but some also from Surat, Malabar, Bengal, and Ceylon.

Catechu was received into the London Pharmacopœia of 1721, but was even then placed among “Terræ medicamentosæ.”

The wholesale price in London in 1776 was £16 16s. per cwt.; in 1780 £20; in 1793 £14 14s., from which it is easy to infer that the consumption could only have been very small.[933]

Manufacture—Cutch, commonly called in India Kát or Kut, is an aqueous extract made from the wood of the tree. The process for preparing it varies slightly in different districts.

The tree is reckoned to be of proper age when its trunk is about a foot in diameter. It is then cut down, and the whole of the woody part, with the exception of the smaller branches and the bark, is chopped into chips. Some accounts state that only the darker heartwood is thus used. The chips are then placed with water in earthen jars, a series of which is arranged over a mud-built fireplace, usually in the open air. Here the water is made to boil, the liquor as it becomes thick and strong being decanted into another vessel, in which the evaporation is continued until the extract is sufficiently inspissated, when it is poured into moulds made of clay, or of leaves pinned together in the shape of cups, or in some districts on to a mat covered with the ashes of cow-dung, the drying in each case being completed by exposure to the sun and air. The product is a dark brown extract, which is the usual form in which cutch is known in Europe.

In Kumaon in the north of India,[934] a slight modification of the process affords a drug of very different appearance. Instead of evaporating the decoction to the condition of an extract, the inspissation is stopped at a certain point and the liquor allowed to cool, “coagulate,” and crystallize over twigs and leaves thrown into the pots for the purpose. How this drug is finished off we do not exactly know, but we are told that by this process there is obtained from each pot about 2 lb. of “Kath” or catechu, of an ashy whitish appearance, which is quite in accordance with the specimens we have received and of which we shall speak further on.

In Burma the manufacture and export of cutch form, next to the sale of timber, the most important item of forest revenue. According to a report by the Commissioner of the Prome Division, the trade returns of 1869-70 show that the quantity of cutch exported from the province during the year was 10,782 tons, valued at £193,602, of which nearly one-half was the produce of manufactories situated in the British territory. Vast quantities of the wood are consumed as fuel, especially for the steamers on the Irrawadi.[935]

Description—Cutch is imported in mats, bags, or boxes. It is a dark brown, extractiform substance, hard and brittle on the surface of the mass, but soft and tenacious within, at least when newly imported. The large leaf of Dipterocarpus tuberculatus Roxb., the Ein or Engben of the Burmese, is often placed outside the blocks of extract.

Cutch when dry breaks easily, showing a shining but bubbly and slightly granular fracture. When it is soft and is pulled out into a thin film, it is seen to be translucent, granular and of a bright orange-brown. When further moistened and examined under the microscope, it exhibits an abundance of minute acicular crystals, precisely as seen in gambier. We have observed the same in numerous samples of the dry drug when rendered pulpy by the addition of water, or moistened with glycerin and viewed by polarized light.

The pale cutch referred to as manufactured in the north of India, is in the form of irregular fragments of a cake an inch or more thick, which has a laminated structure and appears to have been deposited in a round-bottomed vessel. It is a porous, opaque, earthly-looking substance of a pale pinkish-brown, light, and easily broken. Under the microscope it is seen to be a mass of needle-shaped crystals exactly like gambier, with which in all essential points it corresponds. We have received from India the same kind of cutch made into little round cakes like lozenges, with apparently no addition. The taste of cutch is astringent, followed by a sensation of sweetness by no means disagreeable.

Chemical Composition—Extractiform cutch, such as that of Pegu, which is the only sort common in Europe, when immersed in cold water turns whitish, softens and disintegrates, a small proportion of it dissolving and forming a deep brown solution. The insoluble part is Catechin in minute acicular crystals. If a little of the thick chocolate-like liquid made by macerating cutch in water, is heated to the boiling point, it is rendered quite transparent (mechanical impurities being absent), but becomes turbid on cooling. Ferric chloride forms with this solution a dark green precipitate, immediately changing to purple if common water or a trace of free alkali be used.

Ether extracts from cutch, catechin. This substance has been investigated by many chemists, but as yet with discrepant results. It agrees, according to Etti (1877), with the formula C₁₉H₁₈O₈, when dried at 80° C. By gently heating catechin, Catechu-tannic acid, C₃₈H₃₄O₁₅, is produced:

2(C₁₉H₁₈O₈)-OH₂ = C₃₆H₃₄O₁₅.

This is an undoubted acid, readily soluble in water, of decidedly tanning properties, precipitating also the alkaloids and albumin. Catechu-tannic acid being the first anhydride of catechin, there are several more substances of that class; one of them is called Catechuretin. This blackish brown almost insoluble substance is obtained by heating catechin with concentrated hydrochloric acid at 180°:

2(C₁₉H₁₈O₈)-4 OH₂ = C₃₈H₂₈O₁₂.

Catechin, by melting it with caustic potash, affords Protocatechuic acid, C₆H₃(OH)₂COOH, and Phloroglucin, C₆H₃(OH)₃:

C₁₉H₁₈O₈ + 2 OH₂ = 4 H · C₇H₆O₄ · 2 C₆H₆O₃.

Gautier (1877) also obtained the two latter products, but he is of the opinion that they are due to a somewhat different reaction, the formula of catechin, as derived from his analyses, being C₂₁H₁₈O₈. He also asserts that the so-called catechin from Uncaria (see Gambier) is not identical with the substance under notice, nor with that found in the Mahogan wood, to which Gautier assigns the formula C₄₂H₃₄O₁₆.

Crystallized deposits of catechin are sometimes met with in fissures of the trunk of Acacia Catechu, and used medicinally in India under the name Keersal.[936]

Löwe (1873), by exhausting cutch with cold water and then agitating the solution with ether, obtained upon the evaporation of the latter a yellow crystalline substance which he ascertained to be Quercetin, C₂₇H₁₈O₁₂. Its solubility in water is probably favoured by the presence of catechin, water having but very little action upon pure quercetin. The amount of quercetin in cutch is exceedingly small.