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:—

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.

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.

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.