I.—PHÆNOGAMOUS OR FLOWERING PLANTS. (continued 4)

Chemical Composition—Angostura bark owes its peculiar odour to an essential oil which it was found by Herzog[425] to yield to the extent of ¾ per cent. It is probably a mixture of a hydrocarbon (C₁₀H₁₆) with an oxygenated oil. Its boiling point is 266° C. Oberlin and Schlagdenhauffen obtained 0·19 per cent. of the oil, and found it to be slightly dextrogyre; it assumes a fine red colour when shaken with aqueous ferric chloride, and turns yellow with concentrated sulphuric acid.

The bitter taste of the bark is attributed to a substance pointed out in 1833 by Saladin and named Cusparin. It is said to be crystalline, neutral, melting at 45° C., soluble in alcohol, sparingly in water, precipitable by tannic acid. The bark is stated to yield it to the extent of 1·3 per cent. Herzog endeavoured to prepare it but without success, nor have Oberlin and Schlagdenhauffen met with it. The latter chemists, on the other hand, isolated an alkaloid Angosturine C₁₀H₄₀NO₁₄. It is in thin prisms, melting at 85° and yielding a crystallized chlorhydrate or sulphate. Angosturine turns red when touched with concentrated sulphuric acid, or green if nitric acid or iodic acid, or other oxydizing substances, have been previously mixed with the sulphuric acid. The alcoholic solution of the alkaloid is of decidedly alkaline reaction. A cold aqueous infusion of angostura bark yields an abundant red-brown precipitate with ferric chloride. Thin slices of the bark are not coloured by solution of ferrous sulphate, so that tannin appears to be absent.

Uses—Angostura bark is a valuable tonic in dyspepsia, dysentery and chronic diarrhœa, but is falling into disuse.

Adulteration—About the year 1804, a quantity of a bark which proved to be that of Strychnos Nux Vomica reached Europe from India, and was mistaken for Cusparia. The error occasioned great alarm and some accidents, and the use of angostura was in some countries even prohibited. The means of distinguishing the two barks (which are not likely to be again confounded) are amply contained in the above-given descriptions and tests, and at length pointed out by Oberlin and Schlagdenhauffen. They also described the bark of Esenbeckia febrifuga Martius (Evodia febrifuga Saint Hilaire), a Brazilian tree belonging to the same natural order. Maisch[426] was the first to draw attention to this “new false Angostura bark.” It is at once distinguished by being devoid of aromatic properties; its taste is purely bitter.

FOLIA BUCHU.

Folia Buceo; Buchu, Bucchu, Bucha or Buka Leaves; F. Feuilles de Bucco; G. Bukublätter.

Botanical Origin—The Buchu leaves are afforded by three species of Barosma.[427] The latter are erect shrubs some feet in height, with glabrous rod-like branches, opposite leaves furnished with conspicuous oil-cells on the toothed margin as well as generally on the under surface. The younger twigs and several parts of the flower are also provided with oil-cells. The white flowers with 5-partite calyx, and the fruit formed of five erect carpels, are often found, together with small leafy twigs, in the drug of commerce.

The leaves of the three species referred to may be thus distinguished:—

1. Barosma crenulata Hook. (B. crenata Kunze).—Oblong, oval, or obovate, obtuse, narrowed towards the base into a distinct petiole; margin serrulate or crenulate; dimensions, ¾ to 1½ inches long, ³/₁₀ to ⁴/₁₀ of an inch wide.

2. B. serratifolia Willd.—Linear-lanceolate, equally narrowed towards either end, three-nerved, apex truncate always furnished with an oil-cell; margin sharply serrulate; 1-1½ inches long by about ²/₁₀ of an inch wide.

3. B. betulina Bartling.—Cuneate-obovate, apex recurved; margin sharply denticulate, teeth spreading; ½ to ¾ of an inch long by ³/₁₀ to ⁵/₁₀ wide. Substance of the leaf more harsh and rigid than in the preceding.

B. crenulata and B. betulina grow in the Divisions of Clanwilliam and Worcester, north and north-east of Cape Town, and the former even on Table Mountain close to the capital; B. serratifolia is found in the Division of Swellendam farther south.

History—The use of Buchu leaves was learnt from the Hottentots by the colonists of the Cape of Good Hope. The first importations of the drug were consigned to the house of Reece & Co., of London, who introduced it to the medical profession in 1821.[428] The species appears to have been B. crenulata.

Description—In addition to the characters already pointed out, we may observe that buchu leaves of either of the kinds mentioned are smooth and glabrous, of a dull yellowish-green hue, somewhat paler on the under side, on which oil-cells in considerable number are perceptible.

The leaves of B. crenulata vary in shape and size in different parcels, in some the leaves being larger and more elongated than in others, probably according to the luxuriance of the bushes in particular localities. Those of B. serratifolia and B. betulina present but little variation. Each kind is always imported by itself. Those of B. betulina are the least esteemed, and fetch a lower price than the others, yet appear to be quite as rich in essential oil.

Buchu leaves have a penetrating peculiar odour and a strongly aromatic taste.

Microscopic Structure—The essential oil is contained in large cells close beneath the epidermis of the under side of the leaf. The oil-cells are circular and surrounded by a thin layer of smaller cells; they consequently partake of the character of the oil-ducts in the aromatic roots of Umbelliferæ and Compositæ. The latter, however, are elongated.

The upper side of the leaf of Barosma exhibits an extremely interesting peculiarity[429]. There is a colourless layer of cells separating the epidermis from the green inner tissue (mesophyllum). If the leaves are examined under alcohol or almond oil the colourless layer is seen to be very narrow, and the thin walls of its cells shrunken and not clearly distinguishable. If the transverse sections are examined under water, these cells immediately swell up, and become strongly distended, giving off an abundance of mucilage, the latter being afforded by the solution of the very cell-walls. The mucilage of buchu leaves thus originates in the same way as in flax seed or quince seed, but in the former the epidermis is thrown off without alteration. We are not aware that other mucilaginous leaves possess a similar structure, at least not those of Althæa officinalis and of Sesamum which we examined[430].

Chemical Composition—The leaves of B. betulina afforded us by distillation 1·56 per cent, of volatile oil[431], which has the odour rather of peppermint than of buchu, and deviates the ray of polarized light considerably to the left. On exposure to cold it furnishes a camphor which, after re-solution in spirit of wine, crystallizes in needle-shaped forms. After repeated purification in this manner, the crystals of Barosma Camphor have an almost pure peppermint odour; they fuse at 85° C., and begin to sublime at 110° C. After fusion they again solidify only at 50° C. Submitted to elementary analysis, the crystals yielded us 74·08 per cent. of carbon and from 9 to 10 per cent. of hydrogen[432]. Barosma camphor is abundantly soluble in bisulphide of carbon.

The crude oil from which the camphor has been separated has a boiling point of about 200° C., quickly rising to 210° or even higher. That which distilled between these temperatures was treated with sodium, rectified in a current of common coal gas and submitted to elementary analysis, afforded us 77·86 per cent, of carbon and 10·58 of hydrogen. The formula C₁₀H₁₆O would require 78·94 of carbon and 10·53 of hydrogen.

Wayne’s experiments[433] appear to indicate that the oil also contains a substance capable of being converted into salicylic acid. An aqueous infusion of buchu leaves turns beautifully yellow if it is mixed with alkali.

On addition of perchloride of iron the infusion assumes a dingy brownish-green colour changing to red by an alkali. The infusion added to a concentrated solution of acetate of copper causes a yellow precipitate[434] which dissolves in caustic potash, affording a green solution. This may be due to the presence of a substance of the quercitrin or rutin class.

When the leaves are infused in warm water, the mucilage noticed under the microscope may easily be pressed out. It requires for precipitation a large amount of alcohol, being readily miscible with dilute alcohol. Neutral acetate of lead produces a yellow precipitate in an infusion of the leaves; the liquid affords a precipitate by a subsequent addition of basic acetate of lead. The latter precipitate is (probably) due to the mucilage, that afforded by neutral acetate partly to mucilage and partly, we suppose, to rutin or an allied substance. Yet the mucilage of buchu leaves is of the class which is not properly dissolved by water, but only swells up like tragacanth.

The leaves of B. crenulata afforded us upon incineration 4·7 per cent. of ash. Jones (1879) obtained on an average 4·54 per cent. from the same species; 5·27 from B. serratifolia; and 4·49 from B. betulina. He pointed out the presence of manganate in this ash.

The Diosmin of Landerer[435] is entirely unknown to us.

Commerce—The export of buchu from the Cape Colony in 1872 was 379,125 lb., about one-sixth of which quantity was shipped direct to the United States.[436]

Uses—Buchu is principally administered in disorders of the urino-genital organs. It is reputed diuretic and diaphoretic. In the Cape Colony the leaves are much employed as a popular stimulant and stomachic, infused in water, sherry, or brandy. They are also extensively used in the United States, both in regular medicine and by the vendors of secret remedies.

Substitutes—The leaves of Empleurum serrulatum Ait., a small shrub of the same order as Barosma and growing in the same localities, have been imported rather frequently of late and sold as Buchu. They have the same structure as regards mucilage, and nearly the same form as those of B. serratifolia, but are easily distinguished. They are still narrower, and often longer than those of B. serratifolia, devoid of lateral veins, and terminate in an acute point without an oil-duct. They have a bitterish taste and a less powerful odour than those of Barosma, even in fresh leaves as imported in London. The odour of Empleurum is moreover distinctly different from that of the leaves of Barosma. The flowers of Empleurum are still more distinct, for they are apetalous and reddish-brown. The fruit consisting of a single, compressed, oblong carpel, terminated by a flat-shaped horn, is quite unlike that of buchu.

The leaves of Barosma Eckloniana Berg (regarded by Sonder[437] as a form of B. crenulata) have to our knowledge been imported on one occasion (1873). They are nearly an inch long, oval, rounded at the base, strongly crenate, and grow from pubescent shoots.

We have seen other leaves which had been imported from South Africa and offered as buchu; but though probably derived from allied genera they were not to be mistaken for the genuine drug.

RADIX TODDALIÆ.

Botanical Origin—Toddalia aculeata Pers., a ramous prickly bush,[438] often climbing over the highest trees, common in the southern parts of the Indian peninsula as the Coromandel Coast, South Concans, and Canara, also found in Ceylon, Mauritius, the Indian Archipelago and Southern China.

History—The pungent aromatic properties which pervade the plant, but especially the fresh root-bark, are well known to the natives of India and have been utilized in their medical practice. They have also attracted the attention of Europeans, and the root of the plant is now recognized in the Pharmacopœia of India.

It is from this and other species of Toddalia, or from the allied genus Zanthoxylum,[439] that a drug is derived which under the name of Lopez Root had once some celebrity in Europe. This drug which was more precisely termed Radix Indica Lopeziana or Root of Juan Lopez Pigneiro, was first made known by the Italian physician Redi,[440] who described it in 1671 from specimens obtained by Pigneiro at the mouth of the river Zambesi in Eastern Africa,—the very locality in which in our times Toddalia lanceolata Lam. has been collected by Dr. Kirk.[441] It was actually introduced into European medicine by Gaubius[442] in 1771 as a remedy for diarrhœa, and acquired so much reputation that it was admitted to the Edinburgh Pharmacopœia of 1792. The root appears to have been sometimes imported from Goa, but its place of growth and botanical origin were entirely unknown, and it was always extremely rare andcostly.[443] It has long been obsolete in all countries except Holland, where until recently it was to be met with in the shops. The Pharmacopœia Neerlandica of 1851 says of it “Origo botanica perquam dubia—Patria Malacca?”

Description—The specimen of the root of Toddalia aculeata which we have examined was collected for us by Dr. G. Bidie of Madras whose statements regarding the stimulant and tonic action of the drug may be found in the Pharmacopœia of India, p. 442. It is a dense woody root in cylindrical, flexuous pieces, which have evidently been of considerable length and are from ½ to 1½ inches in diameter, covered with bark ⅒ to ¹/₁₂ of an inch in thickness. The bark has a soft, dull yellowish, suberous coat, wrinkled longitudinally, beneath which is a very thin layer of a bright yellow colour, and still lower and constituting two-thirds or more of the whole, is the firm, brown middle cortical layer and liber, which is the part chiefly possessing the characteristic pungency and bitterness of the drug. The yellow corky coat is however not devoid of bitterness. The wood is hard, of a pale yellow, and without taste and smell. The pores of the wood, which are rather large, are arranged in concentric order and traversed by numerous narrow medullary rays.

In a letter which Frappier[444] wrote to Guibourt from the island of Réunion where Toddalia aculeata is very common, he states that the roots of the plant are of enormous length (longueur incroyable) and rather difficult to get out of the basaltic rock into the fissures of which they penetrate. Mr. J. Horne of the Botanical Garden, Mauritius, has sent us a specimen of the root of this plant, the bark of which is of a dusky brown, with the suberous layer but little developed.

Microscopic Structure—We have examined the root for which we are indebted to Dr. Bidie, and may state that its cortical tissue is remarkable by the number of large cells filled with resin and essential oil; they are scattered through the whole tissue, the cork excepted. The parenchymatous cells are loaded with small starch granules or with crystals of oxalate of calcium. The vessels of younger roots abound in yellow resin.

Chemical Composition—None of the constituents of the Toddalia root of India have yet been satisfactorily examined. The bark contains an essential oil, which would be better extracted from fresh than from dry material. The tissue of the bark is but little coloured by salts of iron. In the aqueous infusion, tannic acid produces an abundant precipitate, probably of an indifferent bitter principle rather than of an alkaloid. We have been unable to detect the presence in the bark of berberine.

Lopez root was examined in Wittstein’s laboratory by Schnitzer[445] who found that the bark contains in addition to the usual substances a large proportion of resin,—a mixture probably of two or three different bodies. The essential oil afforded by the bark had an odour resembling cinnamon and melissa.

Uses—The drug has been introduced into the Pharmacopœia of India chiefly upon the recommendation of Dr. Bidie of Madras, who considers it of great value as a stimulating tonic. The bark rasped or shaved from the woody root is the only part that should be used.

FOLIA PILOCARPI.

Folia Jaborandi.

Botanical Origin—Pilocarpus pennatifolius[446] Lemaire, a slightly branched shrub, attaining about 10 feet in height. It is distributed through the eastern provinces of Brazil.

Pilocarpus Selloanus[447] Engler, occurring in Southern Brazil and Paraguay, appears to be not considerably different from P. pennatifolius.

History—Piso[448] recommended an infusion made with Ipecacuanha and Jaborandi. Plumier,[449] who also mentioned this, figured under the name of Jaborandi two plants of the order Piperaceæ. The introduction of the leaves of Pilocarpus pennatifolius into medical use is due to Dr. Coutinho of Pernambuco, 1874. The plant has been cultivated in European greenhouses since about the year 1847; we have repeatedly seen it flowering at Strassburg. Baillon in 1875 showed the fragments of Jaborandi as supplied by Coutinho to belong to P. pennatifolius, which had been described in 1852 by Lemaire. Holmes (1875) in examining the drug as imported from Pernambuco came to the same conclusion.

Description—The leaves of the species under examination are long-stalked, imparipennate, the opposite leaflets in 2 to 5, in cultivated plants most commonly in 2 pairs, the terminal one longer stalked, while the others are provided with a petiole attaining 1½ inch in length or remaining much shorter. The whole leaf is frequently 1½ feet long, the leaflets being often as much as 5 inches long by 2 inches wide. The latter are entire oblong, tapering or rounded at the base, tapering or obtuse or even emarginate at the apex. The leaflets are coriaceous, with a slightly revolute margin and a prominent midrib below. In transmitted light they show very numerous pellucid oil-glands.

The taste of the leaves of Pilocarpus is at first bitterish and aromatic; they subsequently produce a tingling sensation in the mouth and an abundant flow of saliva.

Microscopic Structure[450]—The oil-glands consist of large cells of the same structure as those occurring generally in the leaves of Rutaceæ, Aurantiaceæ, Myrtaceæ. In Pilocarpus they are largely distributed in the tissue covered on both sides of the leaf by the epidermis; the oil-cells are also abundantly met with in the petiole and in the bark of the stems and branches.

Chemical Composition—The active principle of Jaborandi is the alkaloid Pilocarpine, C₂₃H₃₅N₄O₄ + 4OH₂, discovered in 1875 by Hardy. It is an amorphous soft mass, but yielding crystallized salts, among which the hydrochlorate and the nitrate are now more frequently used than the drug itself. The leaves afford about ½ per cent. of the nitrate.

The occurrence of another peculiar alkaloid in Pilocarpus has been asserted, but not ultimately proved.

The leaves contain about ½ per cent. of essential oil, the prevailing constituent of it being a dextrogyrate terpene, C₁₀H₁₆, boiling at 178°, which forms a crystallized compound C₁₀H₁₆ + 2HCl melting at 49°·5 C.

Uses—Pilocarpine being a powerful diaphoretic and sialagogue, the leaves of Jaborandi are used to some extent in pharmaceutical preparations.

Other Kinds of Jaborandi—This name, as above stated, has originally been given to plants of the order Piperaceæ, some of which are still known in Brazil under the name Jaborandi. The following may be quoted as being used at least in that country: Serronia Jaborandi[451] Gaudichaud, Piper reticulatum L. (Enckea Miquel), Piper citrifolium Lamarck (Steffensia Kunth), Piper nodulosum Link, Artanthe mollicoma Miq.

Aubletia trifolia[452] Richard (Monniera L.) and Xanthoxylum elegans Engler, belonging to the same order as Pilocarpus itself, are also sometimes called Jaborandi.

We are not aware that other leaves than those of Pilocarpus are imported to some extent in Europe under the name of Jaborandi.

AURANTIACEÆ.

FRUCTUS LIMONIS.

Lemon; F. Citron, Limon; G. Citrone, Limone.

Botanical Origin—Citrus Limonum Risso (C. Medica var. β Linn.), a small tree 10 to 15 feet in height, planted here and there in gardens in many subtropical countries, but cultivated as an object of industry on the Mediterranean coast between Nice and Genoa, in Calabria, Sicily, Spain, and Portugal.

The tree which is supposed to represent the wild state of the lemon and lime, and as it seems to us after the examination of numerous specimens in the herbarium of Kew, of the citron (Citrus Medica Risso) also, is a native of the forests of Northern India, where it occurs in the valleys of Kumaon and Sikkim.

The cultivated lemon-tree is of rather irregular growth, with foliage somewhat pallid, sparse, and uneven, not forming the fine, close head of deep green that is so striking in the orange tree. The young shoots are of a dull purple; the flowers, which are produced all the year except during the winter, and are in part hermaphrodite and in part unisexual, have the corolla externally purplish; internally white, and a delicate aroma distinct from that of orange blossom. The fruit is pale yellow, ovoid, usually crowned by a nipple.

History—The name of the lemon in Sanskrit is Nimbuka; in Hindustani, Limbu, Limu, or Ninbu. It is probably originally a Cashmere word, which was transferred to the Sanskrit in comparatively modern times, not in the antiquity.[453] From these sounds the Arabians formed the word Limun, which has passed into the languages of Europe.

The lemon was unknown to the inhabitants of ancient Greece and Rome; but it is mentioned in the Book of Nabathæan Agriculture,[454] which is supposed to date from the 3rd or 4th century of our era. The introduction of the tree to Europe is due to the Arabians, yet at what precise period is somewhat doubtful. Arance and Limone are mentioned by an Arabic poet living in the 11th century, in Sicily, quoted by Falcando.[455] The geographer Edrisi,[456] who resided at the court of Roger II., king of Sicily, in the middle of the 12th century, mentions the lemon (limouna) as a very sour fruit of the size of an apple which was one of the productions of Mansouria on the Mahrân or Indus; and he speaks of it in a manner that leads one to infer it was not then known in Europe. This is the more probable from the fact that there is no mention either of lemon or orange in a letter written a.d. 1239 concerning the cultivation of the lands of the Emperor Frederick II. at Palermo,[457] a locality in which these fruits are now produced in large quantity.

On the other hand the lemon is noticed at great length by Ibn Baytar of Malaga, who flourished in the first half of the 13th century, but of its cultivation in Spain at that period there is no actual mention.[458] In 1369 at least citron trees, “arbores citronorum,” were planted in Genoa,[459] and there is evidence that also the lemon-tree was grown on the Riviera di Ponente about the middle of the 15th century, since Limones and also Citri are mentioned in the manuscript Livre d’Administration of the city of Savona, under date 1486.[460] The lemon was cultivated as early as 1494 in the Azores, whence the fruit used to be largely shipped to England; but since the year 1838 the exportation has totally ceased.[461]

Description—The fruit of Citrus Limonum as found in the shops[462] is from about 2 to 4 inches in length, egg-shaped with a nipple more or less prominent at the apex; its surface, of a pale yellow, is even or rugged, covered with a polished epidermis. The parenchyme within the latter abounds in large cells filled with fragrant essential oil. The roughness of the surface of the rind is due to the oil-cells. The peel, which varies considerably in thickness but is never so thick as that of the citron, is internally white and fibrous, and is adherent to the pale yellow pulp. The latter is divided into 10 or 12 segments each containing 2 or 3 seeds. It abounds in a pale yellow acid juice having a pleasant sour taste and a slight peculiar odour quite distinct from that of the peel. When removed from the pulp by pressure, the juice appears as a rather turbid yellowish fluid having a sp. gr. which varies from 1·040 to 1·045, and containing in each fluid ounce from 40 to 46 grains of citric acid, or about 9½ per cent.[463] In Italy all the fine and perfect fruit is exported; the windfalls and the damaged fruit are used for the production of the essential oil and the juice. About 13,000 lemons of this kind yield one pipe (108 gallons) of raw juice. Sicilian juice in November will contain about 9 ounces of citric acid per gallon, but 6 ounces when afforded by the fruit collected in April. The juice is boiled down in copper vessels, over an open fire, till its specific gravity is about 1·239.[464] Lemon juice (Succus limonis) for administration as a medicine should be pressed as wanted from the recent fruit whenever the latter is obtainable.

The peel (Cortex limonis) cut in somewhat thin ribbons from the fresh fruit is used in pharmacy, and is far preferable to that sold in a dried state.

Microscopic Structure of the Peel.—The epidermis exhibits numerous stomata; the parenchyme of the pericarp encloses large oil-cells, surrounded by small tabular cells. The inner spongy tissue is built up of very remarkable branched cells, separated by large intercellular spaces. A solution of iodine in iodide of potassium imparts to the cell-walls a transient blue coloration. The outer layers of the parenchymatous tissue contain numerous yellowish lumps of a substance which assumes a brownish hue by iodine, and yields a yellow solution if potash be added. Alkaline tartrate of copper is reduced by this substance, which probably consists of hesperidin. There also occur large crystals of oxalate of calcium, belonging to the monoclinic system. The interior tissue is irregularly traversed by small vascular bundles.

Chemical Composition—The peel of the lemon abounds in essential oil, which is a distinct article of commerce, and will be described hereafter.

Lemons, as well as other fruits of the genus Citrus, contain a bitter principle, Hesperidin, of which E. Hoffmann[465] obtained 5 to 8 per cent. from unripe bitter oranges. He extracted them with dilute alcohol, after they had previously been exhausted by cold water. The alcohol should contain about 1 per cent. of caustic potash; the liquid on cooling is acidulated with hydrochloric acid, when it yields a yellowish crystalline deposit of hesperidin, which may be obtained colourless and tasteless by recrystallization from boiling alcohol. By dilute sulphuric acid (1 per cent.) hesperidin is broken up as follows:—

C₂₂H₂₆O₁₂ = C₁₆H₁₄O₆ + C₆H₁₂O₆.

Hesperidin. Hesperetin. Glucose.

Hesperidin is very little soluble even in boiling water or in ether, but dissolves readily in hot acetic acid, also in alkaline solutions, the latter then turning soon yellow and reddish. Pure hesperidin, as presented to one of us by Hoffmann, darkens when it is shaken with alcoholic perchloride of iron, and turns dingy blackish brown when gently warmed with the latter.

Hesperetin forms crystals melting at 223° C., soluble both in alcohol or ether, not in water; they taste sweet. They are split up by potash in Phloroglucin and Hesperetic acid, C₁₀H₁₀O₄.

On addition of ferric chloride, thin slices of the peel are darkened, owing probably to some derivative of hesperidin, or to hesperidin itself.

The name hesperidin had also been applied to yellow crystals extracted from the shaddock, Citrus decumana L., the dried flowers of which afford about 2 per cent. of that substance. It is, as shown in 1879 by E. Hoffmann, quite different from hesperidin as described above; he calls it Naringin and assigns to it the formula C₂₃H₂₆O₁₂+4OH₂. Naringin is readily soluble in hot water or in alcohol, not in ether or chloroform. Its solutions turn brown-red on addition of ferric chloride.

Lemon juice, some of the characters of which have been already noticed, is an important article in a dietetic point of view, being largely consumed on shipboard for the prevention of scurvy. In addition to citric acid it contains 3 to 4 per cent. of gum and sugar, and 2·28 per cent. of inorganic salts, of which according to Stoddart only a minute proportion is potash. Cossa[466] on the other hand, who has recently studied the products of the lemon tree with much care, has found that the ash of dried lemon juice contains 54 per cent. of potash, besides 15 per cent. of phosphoric acid.

Stoddart has pointed out the remarkable tendency of citric acid to undergo decomposition,[467] and has proved that in lemons kept from February to July this acid generally decreases in quantity, at first slowly, but afterwards rapidly, until at the end of the period it entirely ceases to exist, having been all split up into glucose and carbonic acid. At the same time the sp. gr. of the juice was found to have undergone but slight diminution:—thus it was 1·044 in February, 1·041 in May, and 1·027 in July, and the fruit had hardly altered in appearance. Lemon juice may with some precautions be kept unimpaired for months or even years. Yet it is capable of undergoing fermentation by reason of the sugar, gum, and albuminoid matters which it contains.

Commerce—Lemons are chiefly imported from Sicily, to a smaller extent from the Riviera of Genoa and from Spain. From the published statistics of trade, in which lemons are classed together with oranges under one head, it appears that these fruits are being imported in increasing quantities. The value of the shipments to the United Kingdom in 1872 (largely exceeding those of any previous year) was £1,154,270. Of this sum, £986,796 represents the value of the oranges and lemons imported from Spain, Portugal, the Canary Islands and Azores; £155,330 the shipments of the same fruit from Italy; and £3,825 those from Malta.

Of concentrated lemon juice there were exported in 1877 from Messina 1,631,332 kilogrammes, valued at 2,446,996 lire. The value of concentrated lime juice exported in 1874 from Montserrat was £3,390. From Dominica, 11,285 gallons, value £1,825, were shipped in 1875.

Uses—Lemon peel is used in medicine solely as a flavouring ingredient. Freshly prepared lemon juice is often administered with an alkaline bicarbonate in the form of an effervescing draught, or in a free state.

Concentrated lemon juice is imported for the purpose of making citric acid; it is derived not only from the lemon, but also, to a smaller extent, from the lime and bergamot. Lime juice of the West Indies is chiefly used as a beverage; small quantities of it are also exported for the manufacture of citric acid. The culture of Citrus Limetta Risso, the lime, was introduced in Montserrat in 1852.

OLEUM LIMONIS.

Oleum Limonum; Essential Oil or Essence of Lemon; F. Essence de Citron; G. Citronenöl.

Botanical Origin—Citrus Limonum Risso (see p. 114).

History—The chemists of the 16th century were well acquainted with the method of extracting essential oils by distillation. Besson in his work L’art et moyen parfaict de tirer huyles et eaux de tous medicaments simples et oleogineux, published at Paris in 1571, mentions lemon-(citron) and orange-peel among the substances subjected to this process. Giovanni Battista Porta,[468] a learned Neapolitan writer, describes the method of preparing Oleum ex corticibus Citri to consist in removing the peel of the fruit with a rasp and distilling it so comminuted with water; and adds that the oils of lemon and orange may be obtained in the same manner. Essence of lemon of two kinds, namely expressed and distilled, was sold in Paris in the time of Pomet, 1692.

Production—Essential oil of lemon is manufactured in Sicily, at Reggio in Calabria, and at Mentone and Nice in France.

The lemons are used while still rather green and unripe, as being richer in oil than when quite mature. Only the small and irregular fruit, such as is not worth exporting, is employed for affording the essence.

The process followed in Sicily and Calabria may be thus described;[469] it is performed in the months of November and December.

The workman first cuts off the peel in three thick longitudinal slices, leaving the central pulp of a three-cornered shape with a little peel at either end. This central pulp he cuts transversely in the middle, throwing it on one side and the pieces of peel on the other. The latter are allowed to remain till the next day and are then treated thus: the workman seated holds in the palm of his left hand a flattish piece of sponge, wrapping it round his forefinger. With the other he places on the sponge one of the slices of peel, the outer surface downwards, and then presses the zest-side (which is uppermost) so as to give it for the moment a convex instead of a concave form. The vesicles are thus ruptured, and the oil which issues from them is received in the sponge with which they are in contact. Four or five squeezes are all the workman gives to each slice of peel, which done he throws it aside. Though each bit of peel has attached to it a small portion of pulp, the workman contrives to avoid pressing the latter. As the sponge gets saturated the workman wrings it forcibly, receiving its contents in a coarse earthen bowl provided with a spout; in this rude vessel, which is capable of holding at least three pints, the oil separates from the watery liquid which accompanies it and is then decanted.

The yield is stated to be very variable, 400 fruits affording 9 to 14 ounces of essence. The prisms of pulp and the exhausted pieces of peel are submitted to pressure in order to extract from them lemon juice, and are said to be also subjected to distillation. The foregoing is termed the sponge-process; it is also applied to the orange. It appears rude and wasteful, but when honestly performed it yields an excellent product.

Essence of lemon is prepared at Mentone and Nice by a different method. The object being to set free and to collect the oil contained in the vesicles of the peel, an apparatus is employed, which may be thus described:—a stout saucer or shallow basin of pewter, about 8½ inches in diameter with a lip on one side for convenience of pouring. Fixed in the bottom of this saucer are a number of stout, sharp, brass pins, standing up about half an inch; the centre of the bottom is deepened into a tube about an inch in diameter and five inches in length, closed at its lower end. This vessel, which is called an écuelle à piquer, has therefore some resemblance to a shallow, dish-shaped funnel, the tube of which is closed below.

The workman takes a lemon in the hand, and rubs it over the sharp pins, turning it round so that the oil-vessels of the entire surface may be punctured. The essential oil which is thus liberated is received in the saucer whence it flows down into the tube; and as this latter becomes filled, it is poured into another vessel that it may separate from the turbid aqueous liquid that accompanies it. It is finally filtered and is then known as Essence de Citron au zeste. A small additional produce is sometimes obtained by immersing the scarified lemons in warm water and separating the oil which floats off.

A second kind of essence termed Essence de Citron distillée is obtained by rubbing the surface of fresh lemons, or of those which have been submitted to the process just described, on a coarse grater of tinned iron, by which the portion of peel richest in essential oil is removed. This grated peel is subjected to distillation with water, and yields a colourless essence of very inferior fragrance, which is sold at a low price.

Description[470]—The oil obtained by the sponge-process and that of the écuelle à piquer are mobile liquids of a faint yellow colour, of exquisite fragrance and bitterish aromatic taste.

The different specimens which we have examined are readily miscible with bisulphide of carbon, but dissolve sparingly in spirit of wine (0·830). An equal weight of the oil and of spirit of wine forms a turbid mixture. No peculiar coloration is produced by mixture with perchloride of iron.

The oils are dextrogyre, but differ in their rotatory power, as may be illustrated by the following results, which we obtained by examining them in a column 50 millimetres long in the polaristrobometer of Wild. The oil of Signori Panuccio, due to the sponge-process (p. 118, note 2), deviated 20·9°, that of Monsieur Médecin (Essence de Citron au zeste) obtained by the éculle à piquer deviated 33·4° and his distilled oil 28·3°.

Chemical Composition—The prevailing portion of most essential oils of the Aurantiaceæ agrees with the formula C₁₀H₁₆; the differences which they exhibit chiefly concern their optical properties, odour, and colour. The boiling point mostly varies from about 170° to 180° C., the sp. gr. between 0·83 and 0·88. These oils are a mixture of isomeric hydrocarbons, and also contain a small amount of cymene, C₁₀H₁₄, and of oxygenated oils, not yet well known; of these we may infer the presence either from analytical results or simply from the fact that the crude oils are altered by metallic sodium. If they are purified by repeated rectification over that metal, they are finally no longer altered by it. Oils thus purified cease to possess their original fragrance, and often resemble oil of turpentine, with which they agree in composition and general chemical behaviour.

As to essential oil of lemons, its chief constituent is the terpene, C₁₀H₁₆, which, like oil of turpentine, easily yields crystals of terpin, C₁₀H₁₆ 3OH₂. There is further present, according to Tilden (1879) another hydrocarbon, C₁₀H₁₆, which already boils at 160° C., whereas the foregoing boils at 176° C. Lastly a small amount of cymene and of a compound acetic ether, C₂H₃O(C₁₀H₁₇O), would appear to occur also in oil of lemons. The crude oil of lemons already yields the crystalline compound C₁₀H₁₆ + 2HCl, when saturated with anhydrous hydrochloric gas, whereas by the same treatment oil of turpentine affords the solid compound C₁₀H₁₆ + HCl.

Essential oil of lemons (not the distilled) when long kept deposits a greasy mass, from which we have obtained small crystals apparently of Bergaptene (p. 123).

Commerce—Essence of lemons is shipped chiefly from Messina and Palermo, packed in copper bottles called in Italian ramiere and by English druggists “jars” holding 25 to 50 kilo. or more; sometimes in tin bottles of smaller size. The quantity of essences of lemon, orange and bergamot exported from Sicily in 1871 was 368,800 lb., valued at £144,520, of which about two-thirds were shipped to England.[471] In 1877 the export of these essential oils from Messina amounted to 306,948 kilogrammes, valued at 6,130,960 lire.

Uses—Essence of lemon is used in perfumery, and as a flavouring ingredient; and though much sold by druggists is scarcely employed in medicine.

Adulteration—Few drugs are more rarely to be found in a state of purity than essence of lemon. In fact it is stated that almost all that comes into the market is more or less diluted with oil of turpentine or with the cheaper distilled oil of lemons. Manufacturers of the essence complain that the demand for a cheap article forces them to this falsification of their product.

OLEUM BERGAMOTTÆ.

Oleum Bergamii; Essence or Essential Oil of Bergamot; F. Essence de Bergamotte; G. Bergamottöl.

Botanical Origin—Citrus Bergamia var. vulgaris Risso et Poiteau,[472] a small tree closely resembling in flowers and foliage the Bitter Orange. Its fruit is 2½ to 3 inches in diameter, nearly spherical, or slightly pear-shaped, frequently crowned by the persistent style; it is of a pale golden yellow like a lemon,[473] with the peel smooth and thin, abounding in essential oil of a peculiar fragrance; the pulp is pale yellowish green, of a bitterish taste, and far less acid than that of the lemon.

The tree is cultivated at Reggio in Calabria, and is unknown in a wild state.

History—The bergamot is one of the cultivated forms which abound in the genus Citrus, and which constitute the innumerable varieties of the orange, lemon and citron. Whether it is most nearly related to the lemon or to the orange is a point discussed as early as the beginning of the last century. Gallesio[474] remarks that it so evidently combines the characters of the two that it should be regarded as a hybrid between them. The bergamot first appeared in the latter part of the 17th century. It is not mentioned in the grand work on orange trees of Ferrari,[475] published at Rome in 1646, nor in the treatise of Commelyn[476] (1676), nor in the writings of Lanzoni (1690),[477] or La Quintinie (1692).[478] So far as we know, it is first noticed in a little book called Le Parfumeur François, printed at Lyons in 1693. The author who calls himself Le Sieur Barbe, parfumeur, says that the Essence de Cedra ou Bergamotte is obtained from the fruits of a lemon-tree which has been grafted on the stem of a bergamot pear; he adds that it is got by squeezing small bits of the peel with the fingers in a bottle or globe large enough to allow the hand to enter.

Volkamer of Nuremberg, who produced a fine work on the Citron tribe in 1708, has a chapter on the Limon Bergamotta, which he describes as gloria limonum et fructus inter omnes nobilissimus. He states that the Italians prepare from it the finest essences, which are sold at a high price.[479]

But, as shown by one of us,[480] the essential oil of bergamot had already, in 1688, a place among the stores of an apothecary of the German town of Giessen.

The name Bergamotta was originally applied to a large kind of pear, called in Turkish “beg-ârmûdî,” i.e. prince’s pear.[481]

Production—The bergamot is cultivated at Reggio, on low ground near the sea, and in the adjacent villages. The trees are often intermixed with lemon and orange trees, and the soil is well irrigated and cropped with vegetables.

The essential oil (Oleum Bergamottæ) is obtained from the full-grown but still unripe and more or less green fruits, gathered in the months of November and December. They are richer in oil than any one of the allied fruits. It was formerly made like that of lemon by the sponge-process, but during the last 20 years this method has been generally superseded by the introduction of a special machine for the extraction of the essential oil. In this machine the fruits are placed in a strong, saucer-like, metallic dish, about 10 inches in diameter, having in the centre a raised opening which with the outer edge forms a broad groove or channel; the dish is fitted with a cover of similar form. The inner surface both of the dish and cover is rendered rough by a series of narrow, radiating metal ridges of blades which are about ¼ of an inch high and resemble the backs of knifes. The dish is also furnished with some small openings to allow of the outflow of essential oil; and both dish and cover are arranged in a metallic cylinder, placed over a vessel to receive the oil. By a simple arrangement of cog-wheels moved by a handle, the cover, which is very heavy, is made to revolve rapidly over the dish, and the fruit lying in the groove between the two is carried round, and at the same time is subjected to the action of the sharp ridges, which, rupturing the oil-vessels, cause the essence to escape, and set it free to flow out by the small openings in the bottom of the dish. The fruits are placed in the machine, 6, 8, or more at a time, according to their size, and subjected to the rotatory action above described for about half a minute, when the machine is stopped, they are removed, and fresh ones substituted. About 7,000 fruits can thus be worked in one of these machines in a day. The yield of oil is said to be similar to that of lemon, namely 2½ to 3 ounces from 100 fruits.

Essence of bergamot made by the machine is of a greener tint than that obtained by the old sponge-process. During some weeks after extraction it gradually deposits a quantity of white greasy matter (bergaptene), which, after having been exhausted as much as possible by pressure, is finally subjected to distillation with water in order to separate the essential oil it still contains.

The fruits from which the essence has been extracted are submitted to pressure, and the juice, which is much inferior in acidity to lemon juice, is concentrated and sold for the manufacture of citric acid. Finally, the residue from which both essence and juice have been removed, is consumed as food by oxen.

Description[482]—Essential oil of bergamot is a thin and mobile fluid of peculiar and very fragrant odour, bitterish taste, and slightly acid reaction. It has a pale greenish yellow tint, due to traces of chlorophyll, as may be shown by the spectroscope. Its sp. gr. is 0·86 to 0·88; its boiling point varies from 183° to 195° C.

The oil is miscible with spirit of wine (0·83 sp. gr.), absolute alcohol, as well as with crystallizable acetic acid. Four parts dissolve clearly one part of bisulphide of carbon, but the solution becomes turbid if a larger proportion of the latter is added. Bisulphide of carbon itself is incapable of dissolving clearly any appreciable quantity of the oil. A mixture of 10 drops of the oil, 50 drops of bisulphide of carbon and one of strong sulphuric acid has an intense yellow hue. Perchloride of iron imparts to bergamot oil dissolved in alcohol a dingy brown colour.

Panuccio’s oil of bergamot examined in the same way as that of lemon (p. 120) deviates 7° to the right, and has therefore a dextrogyre power very inferior to that of other oils of the same class.[483] But it probably varies in this respect, for commercial specimens which we judged to be of good quality deviated from 6·8° to 10·4° to the right.

Chemical Composition—If essential oil of bergamot is submitted to rectification, the portions that successively distill over do not accord in rotatory power or in boiling point, a fact which proves it to be a mixture of several oils, as is further confirmed by analysis. It appears to consist of hydrocarbons, C₁₀H₁₆, and their hydrates, neither of which have as yet been satisfactorily isolated. Oil of bergamot, like that of turpentine, yields crystals of the composition C₁₀H₁₆ + 3H₂O, if 8 parts are allowed to stand some weeks with 1 part of spirit of wine, 2 of nitric acid (sp. gr. 1·2) and 10 of water, the mixture being frequently shaken. No solid compound is produced by saturating the oil with anhydrous hydrochloric gas.

The greasy matter that is deposited from oil of bergamot soon after its extraction, and in small quantity is often noticeable in that of commerce, is called Bergaptene or Bergamot Camphor. We have obtained it in fine, white, acicular crystals, neutral and inodorous, by repeated solution in spirit of wine. Its composition according to the analysis of Mulder (1837) and of Ohme (1839) answers to the formula C₉H₆O₃, which in our opinion requires further investigation. Crystallized bergaptene is abundantly soluble in chloroform, ether, or bisulphide of carbon; the alcoholic solution is not altered by ferric salts.

Commerce—Essence of bergamot, as it is always termed in trade, is chiefly shipped from Messina and Palermo in the same kind of bottles as are used for essence of lemon.

Uses—Much employed in perfumery, but in medicine only occasionally for the sake of imparting an agreeable odour to ointments.

Adulteration—Essence of bergamot, like that of lemon, is extensively and systematically adulterated, and very little is sent into the market entirely pure. It is often mixed with oil of turpentine, but a finer adulteration is to dilute it with essential oil of the leaves or with that obtained by distillation of the peel or of the residual fruits. Some has of late been adulterated with petroleum.

The optical properties, as already mentioned, may afford some assistance in detecting fraudulent admixtures, though as regards oil of turpentine it must be borne in mind that there are levogyre as well as dextrogyre varieties. This latter oil and likewise that of lemon is less soluble in spirit of wine than that of bergamot.

CORTEX AURANTII.

Bitter Orange Peel; F. Ecorce ou Zestes d’Oranges amères; G. Pomeranzenschale.

Botanical Origin—Citrus vulgaris Risso (C. Aurantium var. a amara Linn., C. Bigaradia Duhamel).

The Bitter or Seville or Bigarade Orange, Bigaradier[484] of the French, is a small tree extensively cultivated in the warmer parts of the Mediterranean region, especially in Spain, and existing under many varieties.

Northern India is the native country of the orange tree. In Gurhwal, Sikkim, and Khasia there occurs a wild orange which is the supposed parent of the cultivated orange, whether Sweet or Bitter.

The Bitter Orange reproduces itself from seed, and is regarded, at least by cultivators, as quite distinct from the Sweet Orange, from which however it cannot be distinguished by any important botanical characters. Generally speaking, it differs from the latter in having the fruit rugged on the surface, of a more deep or reddish-orange hue, with the pulp very sour and bitter. The peel, as well as the flowers and leaves, are more aromatic than the corresponding parts of the Sweet Orange, and the petiole is more broadly winged.

History—The orange was unknown to the ancient Greeks and Romans; and its introduction to Europe is due to the Arabs, who, according to Gallesio,[485] appear to have established the tree first in Eastern Africa, Arabia, and Syria, whence it was gradually conveyed to Italy, Sicily, and Spain. In the opinion of the writer just quoted, the bitter orange was certainly known at the commencement of the 10th century to the Arabian physicians, one of whom, Avicenna,[486] employed its juice in medicine.

There is strong evidence to show that the orange first cultivated in Europe was the Bitter Orange or Bigarade. The orange tree at Rome, said to have been planted by St. Dominic about a.d. 1200, and which still exists at the monastery of St. Sabina, bears a bitter fruit; and the ancient trees standing in the garden of the Alcazar at Seville are also of this variety. Finally, the oranges of Syria (ab indigenis Orenges nuncupati) described by Jacques de Vitri, Bishop of Acon (ob. a.d. 1214) were acidi seu pontici saporis.[487]

The Sweet Orange began to be cultivated about the middle of the 15th century, having been introduced from the East by the Portuguese. It has probably long existed in Southern China, and may have been taken thence to India. In the latter country there are but few districts in which its cultivation is successful, and the Bitter Orange is hardly known at all. The name it has long borne of China[488] or Portugal Orange indicates what has been the usual opinion as to its origin. It probably alludes more exactly to a superior variety brought about 1630 from China to Portugal.[489]

One of the first importations of oranges into England occurred in a.d. 1290, in which year a Spanish ship came to Portsmouth, of the cargo of which the queen of Edward I. bought one frail of Seville figs, one of raisins or grapes, one bale of dates, 230 pomegranates, 15 citrons, and 7 oranges (“poma de orenge”).[490]

Description—The Bitter Orange known in London as the Seville Orange is a globular fruit, resembling in size, form, and structure the common Sweet Orange, but having the peel much rougher, and when mature of a somewhat deeper hue. The pulp of the fruit is filled with an acid bitter juice. The ripe fruit is imported into London; the peel is removed from it with a sharp knife in one long spiral strip, and quickly dried, or it is sold in the fresh state. It is the more esteemed when cut thin, so as to include as little as possible of the white inner layer.

Well-dried orange peel should be externally of a bright tint and white on its inner surface; it should have a grateful aromatic smell and bitter taste. The peel is also largely imported into London ready dried, especially from Malta. We have observed it from this latter place of three qualities, namely in elliptic pieces or quarters, in broad curled strips, and lastly a very superior kind, almost wholly free from white zest, in strips less than ⅛ of an inch in width, cut apparently by a machine. Such needless subdivision as this last has undergone must greatly favour an alteration and waste of the essential oil. Foreign-dried orange peel fetches a lower price than that dried in England.

Microscopic Structure—There is no difference between the tissues of this drug and those of lemon peel.

Chemical Composition—The essential oil to which the peel of the orange owes its fragrant odour, is a distinct article of commerce, and will be noticed hereafter under a separate head. The other constituents of the peel probably agree with those of lemon peel. The substance mentioned under the name of Hesperidin (p. 116) particularly abounds in unripe bitter oranges.

Uses—Bitter orange peel is much used in medicine as an aromatic tonic.

OLEUM NEROLI.

Oleum Aurantii florum; Oil or Essence of Neroli; F. Essence de Néroli; G. Neroliöl.

Botanical Origin—Citrus vulgaris Risso. (See page 124.)

History—Porta, the Italian philosopher of the 16th century referred to (p. 118), was acquainted with the volatile oil of the flowers of the citron tribe (“Oleum ex citriorum floribus”), which he obtained by the usual process of distillation, and describes as possessing the most exquisite fragrance. That distilled from orange flowers acquired a century later (1675-1685) the name of Essence of Neroli from Anne-Marie de la Trémoille-Noirmoutier, second wife of Flavio Orsini, duke of Bracciano and prince of Nerola or Neroli. This lady employed it for the perfuming of gloves, hence called in Italy Guanti di Neroli.[491] It was known in Paris to Pomet, who says[492] the perfumers have given it the name of Neroli, and that it is made in Rome and in Provence.

Production—Oil of Neroli is prepared from the fresh flowers of the Bigarade or Bitter Orange by the ordinary process of distillation with water, conducted in small copper stills. The flowers of all the allied plants are far less aromatic. The water which distills over with the oil constitutes, after the removal of the latter from its surface, the Orange Flower Water (Aqua aurantii florum vel Aqua Naphæ)[493] of commerce. The manufacture is carried on chiefly in the south of France at Grasse, Cannes, and Nice. The yield is about 0·6 to 0·7 per cent. of oil from fresh flowers, as stated by Poiteau et Risso.[494] The flowers of the sweet orange afford but half that amount of oil.

Description and Chemical Composition—Oil of Neroli as found in commerce is seldom pure, for it generally contains an admixture of the essential oil of orange-leaf called Essence of Petit Grain.

By the kind assistance of Mr. F. G. Warrick of Nice, we have obtained a sample of Bigarade Neroli of guaranteed purity, to which the following observations relate. It is of a brownish hue, most fragrant odour, bitterish aromatic taste, and is neutral to test-paper. Its sp. gr. at 11° C. is 0·889. When mixed with alcohol, it displays a bright violet fluorescence, quite distinct from the blue fluorescence of a solution of quinine. In oil of Neroli the phenomenon may be shown most distinctly by pouring a little spirit of wine on to the surface of the essential oil, and causing the liquid to gently undulate. The oil is but turbidly miscible with bisulphide of carbon. It assumes a very pure, intense, and permanent crimson hue if shaken with a saturated solution of bisulphide of sodium. Examined in a column of 100 mm. we observed the oil to deviate the ray of polarized light 6° to the right.

Subjected to distillation, the larger part of the oil passes over at 185°-195° C.; we found this portion to be colourless, yet to display in a marked manner the violet fluorescence and also to retain the odour of the original oil. The portion remaining in the retort was mixed with about the same volume of alcohol (90 per cent.) and some drops of water added, yet not sufficient to occasion turbidity. A very small amount of the crystalline Neroli Camphor then made its appearance, floating on the surface of the liquid; by re-solution in boiling alcohol it was obtained in crystals of rather indistinct form. The redistilled oil gave no camphor whatever.

Neroli Camphor was first noticed by Boullay in 1828. According to our observations it is a neutral, inodorous, tasteless substance, fusible at 55° C., and forming on cooling a crystalline mass. The crystallization should be effected by cooling the hot alcoholic solution, no good crystals being obtainable by slow evaporation or by sublimation. The produce was extremely small, about 60 grammes of oil having yielded not more than 0·1 gramme. Perhaps this scantiness of produce was due to the oil being a year and a half old, for according to Plisson[495] the camphor diminishes the longer the oil is kept.[496] We were unable to obtain any similar substance from the oils of bergamot, petit grain, or orange peel.

Orange Flower Water is a considerable article of manufacture among the distillers of essential oils in the south of Europe, and is imported thence for use in pharmacy. According to Boullay[497] it is frequently acid to litmus when first made,—is better if distilled in small than in large quantities, and if made from the petals per se, rather than from the entire flowers. He also states that only 2 lb. of water should be drawn from 1 lb. of flowers, or 3 lb. if petals alone are placed in the still. As met with in commerce, orange flower water is colourless or of a faintly greenish yellow tinge, almost perfectly transparent, with a delicious odour and a bitter taste. Acidulated with nitric acid, it acquires a pinkish hue more or less intense, which disappears on saturation by an alkali.

Uses—Oil of Neroli is consumed almost exclusively in perfumery. Orange flower water is frequently used in medicine to give a pleasant odour to mixtures and lotions.

Adulteration—The large variation in value of oil of Neroli as shown by price-currents[498] indicates a great diversity of quality. Besides being very commonly mixed, as already stated, with the distilled oil of the leaves (Essence de Petit Grain)[499], it is sometimes reduced by addition of the less fragrant oil obtained from the flowers of the Portugal or Sweet Orange. In some of these adulterations we must conclude that orange flower water participate: metallic contamination of the latter is not unknown.

Other Products of the genus Citrus.

Essence or Essential Oil of Petit Grain—was originally obtained by subjecting little immature oranges to distillation (Pomet—1692); but it is now produced, and to a large extent, by distillation of the leaves and shoots either of the Bigarade or Bitter Orange, or of the Portugal or Sweet Orange. The essence of the former is by far the more fragrant, and commands double the price. Poiteau and Risso[500] state that the leaves of the Brigaradier with bitter fruit are by far the richest in essential oil among all the allied leaves; they are obtained in the lemon-growing districts of the Mediterranean where the essence is manufactured. Lemon-trees being mostly grafted on orange-stocks, the latter during the summer put forth shoots, which are allowed to grow till they are often some feet in length. The cultivator then cuts them off, binds them in bundles, and conveys them to the distiller of Petit Grain. The strongest shoots are frequently reserved for walking-sticks. The leaves of the two sorts of orange are easily distinguished by their smell when crushed. Essence of Petit Grain, which in odour has a certain resemblance to Neroli, is used in perfumery and especially in the manufacture of Eau de Cologne.

According to Gladstone (1864) it consists mainly of a hydrocarbon probably identical with that from oil of Neroli.

Essential Oil of Orange Peel—is largely made at Messina and also in the south of France. It is extracted by the sponge-, or by the écuelle-process, and partly from the Bigarade and partly from the Sweet or Portugal Orange, the scarcely ripe fruit being in either case employed. The oil made from the former is much more valuable than that obtained from the latter, and the two are distinguished in price-currents as Essence de Bigarade and Essence de Portugal.

These essences are but little consumed in England, in liqueur-making and in perfumery. For what is known of their chemical nature, the reader can consult the works named at foot[501].

Essence of Cedrat—The true Citron or Cedrat tree is Citrus medica Risso, and is of interest as being the only member of the Orange tribe the fruit of which was known in ancient Rome. The tree itself, which appears to have been cultivated in Palestine in the time of Josephus, was introduced into Italy in about the 3rd century. In a.d. 1003 it was much grown at Salerno near Naples, whence its fruits were sent as presents to the Norman princes[502].

At the present day, the citron appears to be nowhere cultivated extensively, the more prolific lemon tree having generally taken its place. It is however scattered along the Western Riviera, and is also grown on a small scale about Pizzo and Paola on the western coast of Calabria, in Sicily, Corsica, and Azores. Its fruits, which often weigh several pounds, are chiefly sold for being candied. For this purpose the peel, which is excessively thick, is salted and in that state shipped to England and Holland. The fruit has a very scanty pulp[503].

Essence of Cedrat which is quoted in some price-lists may be prepared from the scarcely ripe fruit by the sponge-process; but as it is more profitable to export the fruit salted, it is very rarely manufactured, and that which bears its name is for the most part fictitious.

FRUCTUS BELÆ.

Bela; Bael Fruit, Indian Bael, Bengal Quince.

Botanical Origin—Ægle Marmelos[504] Correa (Cratæva Marmelos L.), a tree found in most parts of the Indian peninsula, which is often planted in the neighbourhood of temples, being esteemed sacred by the Hindus. It is truly wild in the forests of the Coromandel Ghâts and of the Western Himalaya, ascending often to 4,000 feet and growing gregarious when wild.

It attains a height of 30-40 feet, is usually armed with strong sharp thorns and has trifid leaves, the central leaflet being petiolate and larger than the lateral. The fruit is a large berry, 2 to 4 inches in diameter, variable in shape, being spherical or somewhat flattened like an orange, ovoid, or pyriform[505], having a smooth hard shell; the interior divided into 10-15 cells each containing several woolly seeds, consists of a mucilaginous pulp, which becomes very hard in drying. In the fresh state the fruit is very aromatic, and the juicy pulp which it contains has an agreeable flavour, so that when mixed with water and sweetened, it forms a palatable refrigerant drink. The fruit is never eaten as dessert, though its pulp is sometimes made into a preserve with sugar.

The fruit of the wild tree is described as small, hard, and flavourless, remaining long on the tree. The bark of the stem and root, the flowers and the expressed juice of the leaves are used in medicine by the natives of India.

History—The tree under the name of Bilva[506] is constantly alluded to as an emblem of increase and fertility in ancient Sanskrit poems, some of which as the Yajar Veda are supposed to have been written not later than 1000 b.c.—Constantinus Africanus was acquainted with the fruit under notice.

Garcia de Orta, who resided in India as physician to the Portuguese viceroy at Goa in the 16th century, wrote an account of the fruit under the name of Marmelos de Benguala (Bengal Quince) Cirifole or Beli[507], describing its use in dysentery.

In the following century it was noticed by Bontius, in whose writings edited by Piso[508] there is a bad figure of the tree as Malum Cydonium. It was also figured by Rheede,[509] and subsequently under the designation of Bilack or Bilack tellor by Rumphius.[510] The latter states that it is indigenous to Gujarat, the eastern parts of Java, Sumbawa and Celebes, and that it has been introduced into Amboina.

But although Ægle Marmelos has thus been long known and appreciated in India, the use of its fruit as a medicine attracted no attention in Europe till about the year 1850. The dried fruit which has a place in the British Pharmacopœia is now not unfrequently imported.

Description—We have already described the form and structure of the fruit, which for medicinal use should be dried when in a half ripe state. It is found in commerce in dried slices having on the outer side a smooth greyish shell enclosing a hard, orange or red, gummy pulp in which are some of the 10 to 15 cells existing in the entire fruit. Each cell includes 6 to 10 compressed oblong seeds nearly 3 lines in length, covered with whitish woolly hairs. When broken the pulp is seen to be nearly colourless internally, the outside alone having assumed an orange tint. The dried pulp has a mucilaginous, slightly acid taste, without aroma, astringency, or sweetness.

There is also imported Bael fruit which has been collected when ripe, as shown by the well-formed seeds. Such fruits arrive broken irregularly and dried, or sawn into transverse slices and then dried, or lastly entire, in which case they retain some of their original fragrance resembling that of elemi.

Microscopic Structure—The rind of the fruit is covered with a strong cuticle, and further shows two layers, the one exhibiting not very numerous oil-cells, and the other an inner made up of sclerenchyme. The tissue of the pulp, which, treated with water, swells into an elastic mass, consists of large cells with considerable cavities between them. The seeds when moistened yield an abundance of mucilage nearly in the same way as White Mustard or Linseed. In the epidermis of the seeds certain groups of cells are excessively lengthened, and thus constitute the curious woolly hairs already noticed. They likewise afford mucilage in the same way as the seed itself.

Chemical Composition—We are unable to confirm the remarkable analyses of the drug alluded to in the Pharmacopœia of India;[511] nor can we explain by any chemical examination upon what constituent the alleged medicinal efficacy of bael depends.

The pulp moistened with cold water yields a red liquid containing chiefly mucilage, and (probably) pectin which separates if the liquid is concentrated by evaporation. The mucilage may be precipitated by neutral acetate of lead or by alcohol, but is not coloured by iodine. It may be separated by a filter into a portion truly soluble (as proved by the addition of alcohol or acetate of lead), and another, comprehending the larger bulk, which is only swollen like tragacanth, but is far more glutinous and completely transparent.

Neither a per-nor a proto-salt of iron shows the infusion to contain any appreciable quantity of tannin,[512] nor is the drug in any sense possessed of astringent properties.

Uses—Bael is held in high repute in India as a remedy for dysentery and diarrhœa; at the same time it is said to act as a laxative where constipation exists.

Adulteration—The fruit of Feronia Elephantum Correa, which has a considerable external resemblance to that of Ægle Marmelos and is called by Europeans Wood Apple, is sometimes supplied in India for bael. It may be easily distinguished: it is one-celled with a large five-lobed cavity (instead of 10 to 15 cells) filled with numerous seeds. The tree has pinnate leaves with 2 or 3 pairs of leaflets. We have seen Pomegranate Peel offered as Indian Bael.[513]

SIMARUBEÆ.

LIGNUM QUASSIÆ.

Quassia, Quassia Wood, Bitter Wood; F. Bois de Quassia de la Jamaïque, Bois amer; G. Jamaica Quassiaholz.

Botanical Origin—Picræna excelsa Lindl. (Quassia excelsa Swartz, Simaruba excelsa DC., Picrasma excelsa Planchon), a tree 50 to 60 feet in height, somewhat resembling an ash and having inconspicuous greenish flowers and black shining drupes the size of a pea. It is common on the plains and lower mountains of Jamaica, and is also found in the islands of Antigua and St. Vincent. It is called in the West Indies Bitter Wood or Bitter Ash.

History—Quassia wood was introduced into Europe about the middle of the last century. It was derived from Quassia amara L., a shrub or small tree with handsome crimson flowers, belonging to the same order, native of Panama, Venezuela, Guiana, and Northern Brazil. It was subsequently found that the Bitter Wood of Jamaica which Swartz and other botanists referred to the same genus, possessed similar properties, and as it was obtainable of much larger size, it has since the end of the last century been generally preferred. The wood of Q. amara, called Surinam Quassia, is however still used in France and Germany.[514]

The first to give a good account of Jamaica quassia was John Lindsay,[515] a medical practitioner of the island, who writing in 1791 described the tree as long known not only for its excellent timber, but also as a useful medicine in putrid fevers and fluxes. He adds that the bark is exported to England in considerable quantity—“for the purposes of the brewers of ale and porter.”

Quassia, defined as the wood, bark, and root of Q. amara L., was introduced into the London Pharmacopœia of 1788; in the edition of 1809, it was superseded by the wood of Picræna excelsa. In the stock-book of a London druggist (J. Gurney Bevan, of Plough Court, Lombard Street) we find it first noticed in 1781 (as rasuræ), when it was reckoned as having cost 4s. 2d. per lb.

Description—The quassia wood of commerce consists of pieces of the stem and larger branches, some feet in length, and often as thick as a man’s thigh. It is covered with bark externally of a dusky grey or blackish hue, white and fibrous within, which it is customary to strip off and reject. The wood, which is of a very light yellowish tint, is tough and strong, but splits easily. In transverse section it exhibits numerous fine close medullary rays, which intersect the rather obscure and irregular rings resembling those of annual growth of our indigenous woody stems. The centre is occupied by a cylinder of pith of minute size. In a longitudinal section, whether tangential or radial, the wood appears transversely striated by reason of the small vertical height of the medullary rays.

The wood often exhibits certain blackish markings due to the mycelium of a fungus; they have sometimes the aspect of delicate patterns, and at others appear as large dark patches.

Quassia has a strong, pure bitter taste, but is devoid of odour. It is always supplied to the retail druggist in the form of turnings or raspings, the former being obtained in the manufacture of the Bitter Cups, now often seen in the shops.

Microscopic Structure—The wood consists for the most part of elongated pointed cells (libriform), traversed by medullary rays, each of the latter being built up of about 15 vertical layers of cells. The single layers contain from one to three rows of cells. The ligneous rays thus enclosed by medullary parenchyme, are intersected by groups of tissue constituting the above-mentioned irregular rings. On a longitudinal section this parenchyme exhibits numerous crystals of oxalate of calcium, and sometimes deposits of yellow resin. The latter is more abundant in the large vessels of the wood. Oxalate and resin are the only solid matters perceptible in the tissues of this drug.

Chemical Composition—The bitter taste of quassia is due to Quassiin, which was first obtained, no doubt, from the wood of Quassia amara, by Winckler in 1835. It was analysed by Wiggers,[516] who assigned it the formula C₁₀H₁₂O₃, now regarded as doubtful. According to the latter, quassiin is an irresolvable, neutral substance, crystallizable from dilute alcohol or from chloroform. It requires for solution about 200 parts of water, but is not soluble in ether; it forms an insoluble compound with tannic acid. Quassia wood is said to yield about ⅒ per cent. of quassiin. A watery infusion of quassia, especially if a little caustic lime has been added to the drug, displays a slight fluorescence, due apparently to quassiin. Goldschmiedt and Weidel (1877) failed in obtaining quassiin. They isolated the yellow resin which we mentioned above, and stated that it yields protocatechuic acid when melted with potash. Quassia wood dried at 100° C. yielded us 7·8 per cent. of ash.

Commerce—The quantity of Bitter Wood shipped from Jamaica in 1871 was 56 tons.[517]

Uses—The drug is employed as a stomachic and tonic. It is poisonous to flies, and is not without narcotic properties in respect to the higher animals.

Substitutes—The wood of Quassia amara L., the Bitter Wood of Surinam, bears a close resemblance, both external and structural, to the drug just noticed; but its stems never exceed four inches in diameter and are commonly still thinner. Their thin, brittle bark is of a greyish yellow, and separates easily from the wood. The latter is somewhat denser than the quassia of Jamaica, from which it may be distinguished by its medullary rays being composed of a single or less frequently of a double row of cells, whereas in the wood of Picræna excelsa, they consist of two or three rows, less frequently of only one.

Surinam Quassia Wood is exported from the Dutch colony of Surinam. The quantity shipped thence during the nine months ending 30th Sept, 1872, was 264,675 lb.[518]

The bark of Samadera indica Gärtn., a tree of the same natural order, owes its bitterness to a principle[519] which agrees perhaps with quassiin. The aqueous infusion of the bark is abundantly precipitated by tannic acid, a compound of quassiin probably being formed. A similar treatment applied to quassia would possibly easier afford quassiin than the extraction of the wood by means of alcohol, as performed by Wiggers.

BURSERACEÆ.

OLIBANUM.

Gummmi-resina Olibanum, Thus masculum[520]; Olibanum, Frankincense; F. Encens; G.Weihrauch.

Botanical Origin—Olibanum is obtained from the stem of several species of Boswellia, inhabiting the hot and arid regions of Eastern Africa, near Cape Gardafui and of the southern coast of Arabia. Notwithstanding the recent elaborate and valuable researches of Birdwood,[521] the olibanum trees are still but imperfectly known, as will be evident in the following enumeration:—

1. Boswellia Carterii Birdw.—This includes the three following forms, which may be varieties of a single species, or may belong to two or more species,—a point impossible to settle until more perfect materials shall have been obtained.

a. Boswellia No. 5, Oliver, Flora of Tropical Africa, I. (1868) 324, Mohr meddu or Mohr madow of the natives; meddu, according to Playfair and Hildebrandt, means black. The leaflets are crenate, undulate, and pubescent on both sides.

This tree is found in the Somali Country, growing a little inland in the valleys and on the lower part of the hills, never on the range close to the sea. It yields the olibanum called Lubân Bedowi or Lubân Sheheri (Playfair).

Hildebrandt describes the Mohr meddu as a tree 12 to 15 feet high, with a few branches, indigenous to the limestone range of Ahl or Serrut, in the northern part of the Somali Country, where it occurs in elevations of from 3000 to 5000 feet. To this tree belongs the figure 58 in Bentley and Trimen’s Medicinal Plants (Part 20, 1877).

b. Boswellia No. 6, Oliver, op. cit., Birdwood, Linn. Trans. xxvii., tab. 29.—Sent by Playfair among the specimens of the preceding, and with the same indications and native name. This form, the “Mohr meddu” of the Somalis, has obscurely serrulate or almost entire leaflets, velvety and paler below, glabrous above. The figure (which is not given in the reprint) is very much the same as that of the following.

c. Maghrayt d’sheehaz of the Maharas, Birdwood, l. c. tab. 30, reprinted in Cooke’s report, plate I; Carter, Journ. of Bombay Branch of R. Asiat. Soc. ii., tab. 23; B. sacra Flückiger, Lehrbuch der Pharmakognosie des Pflanzenreiches, 1867. 31.—Ras Fartak, S.E. coast of Arabia, growing in the detritus of limestone cliffs and close to the shore,[522] also near the village of Merbat (Carter, 1844-1846).

Birdwood’s figure refers to a specimen propagated in the Victoria Gardens, Bombay, from cuttings sent there from the Somali country by Playfair.

2. B. Bhau-Dajiana Birdw. l. c. tab. 31, or plate III. of the reprint.—Somali Country (Playfair); cultivated in Victoria Gardens, Bombay, where it flowered in 1868. The differences between this species and B. Carterii are not very obvious.

3. Boswellia No. 4, Oliver, op. cit.—Bunder Murayah, Somali Country (Playfair). Grows out of the rock, but sometimes in the detritus of limestone; never found on the hills close to the sea, but further inland and on the highest ground. Yields Lubân Bedowi and L. Sheheri; was received at Kew as Mohr add, a name applied by Birdwood also to B. Bhau-Dajiana.

From the informations due to Captains Miles[523] and Hunter and to Haggenmacher[524] it would appear that the Beyo or Beyu of the Somalis (Boido, Capt. Hunter) is agreeing with this tree.

4. Boswellia neglecta, S. Le M. Moore, in Journ. of Botany, xv.(1877) 67 and tab. 185. This tree has been collected by Hildebrandt in the limestone range, Ahl or Serrut, in the northern part of the Somali Country. It occurs in elevations of 1000 to 1800 metres, and attains a height of 5 to 6 metres. Its exudation, according to Hildebrandt, is collected in but small quantity and mixed with the other kinds of olibanum. Moore gives Murlo as the vernacular name of this tree, Hildebrandt calls it Mohr add.

In addition to the foregoing, from which the olibanum of commerce is collected, it may be convenient to mention also the following:—

1. Boswellia Frereana Birdw., a well-marked and very distinct species of the Somali Country, which the natives call Yegaar. It abounds in a highly fragrant resin collected and sold as Lubân Meyeti or Lubân Mati, which we regard to be the substance originally known as Elemi (see this article).

2. B. papyrifera Richard (Plösslea floribunda Endl.), the “Makar” of Sennaar and the mountainous region ascending to 4000 feet above the level of the sea on the Abyssinian rivers Takazze and Mareb. It appears not to grow in the outer parts of north-eastern Africa. Its resin is not collected, and stated by Richard[525] to be transparent; it consists no doubt merely of resin (and essential oil?) without gum.[526]

3. B. thurifera Colebr. (B. glabra et B. serrata Roxb.), the Salai tree of India, produces a soft odoriferous resin which is used in the country as incense but is not the olibanum of commerce. The tree is particularly abundant on the trap hills of the Dekhan and Satpura range. Berg, in “Offizinelle Gewächse,” xiv. c. gives a good figure of this species.

History—The use of olibanum goes back to a period of extreme antiquity, as proved by the numerous references[527] in the writings of the Bible to incense, of which it was an essential ingredient. It is moreover well known that many centuries before Christ, the drug was one of the most important objects of the traffic which the Phœnicians[528] and Egyptians carried on with Arabia.

Professor Dümichen[529] of Strassburg has discovered at the temple of Dayr el Báhri in Upper Egypt, paintings illustrating the traffic carried on between Egypt and a distant country called Punt or Pount as early as the 17th century b.c. In these paintings there are representations not only of bags of olibanum, but also of olibanum trees planted in tubs or boxes, being conveyed by ship from Arabia to Egypt. Inscriptions on the same building, deciphered by Professor D., describe with the utmost admiration the shipments of precious woods, heaps of incense, verdant incense trees,[530] ivory, gold, stimmi (sulphide of antimony), silver, apes, besides other productions not yet identified. The country Pount was first thought to be southern Arabia, but is now considered to comprehend the Somali coast, together with a portion of the opposite Arabian coast. Punt possibly refers to “Opone,” an old name for Hafoon, a place south of Cape Gardafui.

A detailed account of frankincense is given by Theophrastus[531] (b.c. 370-285) who relates that the commodity is produced in the country of the Sabæans, one of the most active trading nations of antiquity, occupying the southern shores of Arabia. It appears from Diodorus that the Sabæans sold their frankincense to the Arabs, through whose hands it passed to the Phœnicians who disseminated the use of it in the temples throughout their possessions, as well as among the nations with whom they traded. The route of the caravans from south-eastern Arabia to Gaza in Palestine, has recently (1866) been pointed out by Professor Sprenger. Plutarch relates that when Alexander the Great captured Gaza, 500 talents of olibanum and 100 talents of myrrh were taken, and sent thence to Macedonia.

The libanotophorous region of the old Sabæans is in fact the very country visited by Carter in 1844 and 1846, and lying as he states on the south coast of Arabia between long. 52° 47′ and 52° 23′ east.[532] It was also known to the ancients, at least to Strabo and Arrian, that the opposite African coast likewise produced olibanum,[533] as it is now doing almost exclusively; and the latter states that the drug is shipped partly to Egypt and partly to Barbaricon at the mouth of the Indus.

As exemplifying the great esteem in which frankincense was held by the ancients, the memorable gifts presented by the Magi to the infant Saviour will occur to every mind. A few other instances may be mentioned: Herodotus[534] relates that the Arabians paid to Darius, king of Persia, an annual tribute of 1000 talents of frankincense.

A remarkable Greek inscription, brought to light in modern times[535] on the ruins of the temple of Apollo at Miletus, records the gifts made to the shrine by Seleucus II., king of Syria (b.c. 246-227), and his brother Antiochus Hierax, king of Cilicia, which included in addition two vessels of gold and silver, ten talents of frankincense (λιβανωτοός) and one of myrrh.

The emperor Constantine made numerous offerings to the church under St. Silvester, bishop of Rome a.d. 314-335, of costly vessels and fragrant drugs and spices,[536] among which mention is made in several instances of Aromata and Aromata in incensum, terms under which olibanum is to be understood.[537]

With regard to the consumption of olibanum in other countries, it is an interesting fact that the Arabs in their intercourse with the Chinese, which is known to have existed as early as the 1Oth century, carried with them olibanum, myrrh, dragon’s blood, and liquid storax,[538] drugs which are still imported from the west into China. The first-named is called Ju-siang, i.e. milk perfume, a curious allusion to its Arabic name Lubân signifying milk. In the year 1872, Shanghai imported[539] of this drug no less than 1,360 peculs (181,333 lb.).

Collection—The fragrant gum-resin is distributed through the leaves and bark of the trees, and even exudes as a milky juice also from the flowers; its fragrance is stated to be already appreciable in a certain distance. Cruttenden,[540] who visited the Somali Country in 1843, thus describes the collecting of olibanum by the Mijjertheyn tribe, whose chief port is Bunder Murayah (lat. 11° 43′ N.)[541]:—

“During the hot season the men and boys are daily employed in collecting gums, which process is carried on as follows:—About the end of February or beginning of March, the Bedouins visit all the trees in succession and make a deep incision in each, peeling off a narrow strip of bark for about 5 inches below the wound. This is left for a month when a fresh incision is made in the same place, but deeper. A third month elapses and the operation is again repeated, after which the gum is supposed to have attained a proper degree of consistency. The mountain sides are immediately covered with parties of men and boys, who scrape off the large clear globules into a basket, whilst the inferior quality that has run down the tree is packed separately. The gum when first taken from the tree is very soft, but hardens quickly.... Every fortnight the mountains are visited in this manner, the trees producing larger quantities as the season advances, until the middle of September, when the first shower of rain puts a close to the gathering that year.”

The informations due to J. M. Hildebrandt, who visited the Somali in 1875, are in accordance with Cruttenden’s statements. The former says, that the latest crops are greatly injured by the rains, the drug being partly dissolved by the water.

Carter[542] describing the collection of the drug in southern Arabia, writes thus:—“The gum is procured by making longitudinal incisions through the bark in the months of May and December, when the cuticle glistens with intumescence from the distended state of the parts beneath; the operation is simple, and requires no skill on the part of the operator. On its first appearance the gum comes forth white as milk, and according to its degree of fluidity, finds its way to the ground, or concretes on the branch near the place from which it first issued, from whence it is collected by men and boys employed to look after the trees by the different families who possess the land in which they grow.” According to Captain Miles,[543] the drug is not collected by the people of the country, but by Somalis who cross in numbers from the opposite coast, paying the Arab tribes for the privilege. The Arabian Lubân, he says, is considered inferior to the African.

It would even appear that the collection of the drug has ceased in Arabia, and that the names of Lubân Maheri or Mascati or Sheehaz, referring to the coast of Arabia between Ras Fartak (52° 10′ E.) and Ras Morbas (54° 34′) are now applied to the olibanum brought there from the opposite African coast.[544] Hildebrandt informed one of us (letter dated 26th Dec., 1878) that he has ascertained at Aden, that all the frankincense imported in Aden comes from Africa.

Description—Olibanum as found in commerce varies rather considerably in quality and appearance. It may in general terms be described as a dry gum-resin, consisting of detached tears up to an inch in length, of globular, pear-shaped, clavate, or stalactitic form, mixed with more or less irregular lumps of the same size. Some of the longer tears are slightly agglutinated, but most are distinct. The predominant forms are rounded,—angular fragments being less frequent, though the tears are not seldom fissured. Small pieces of the translucent brown papery bark are often found adhering to the flat pieces. The “Lubân Fasous Bedow” as exported from the Mijjertheyn district, in the eastern part of the Somali Country, is in very fine large tears.

The colour of the drug is pale yellowish or brownish, but the finer qualities consist of tears which are nearly colourless or have a greenish hue. The smallest grains only are transparent, the rest are translucent and somewhat milky, and not transparent even after the removal of the white dust with which they are always covered. But if heated to about 94° C., they become almost transparent. When broken they exhibit a rather dull and waxy surface. Examined under the polarizing microscope no trace of crystallization is observable.

Olibanum softens in the mouth; its taste is terebinthinous and slightly bitter, but by no means disagreeable. Its odour is pleasantly aromatic, but is only fully developed when the gum-resin is exposed to an elevated temperature. At 100° C. the latter softens without actually fusing, and if the heat be further raised decomposition begins.

Chemical Composition—Cold water quickly changes olibanum into a soft whitish pulp, which when rubbed down in a mortar forms an emulsion. Immersed in spirit of wine, a tear of olibanum is not altered much in form, but it becomes of an almost pure opaque white. In the first case the water dissolves the gum, while in the second the alcohol removes the resin. We find that pure olibanum treated with spirit of wine leaves 27 to 35 of gum,[545] which forms a thick mucilage with three parts of water. Dissolved in 5 parts of water it yields a neutral solution, which is precipitated by perchloride of iron as well as by silicate of sodium, but not by neutral acetate of lead. It is consequently a gum of the same class as gum arabic, if not identical with it. Its solution contains the same amount of lime as gum arabic affords.

The resin of olibanum has been examined by Hlasiwetz (1867), according to whom it is a uniform substance having the composition C₂₀H₃₀O₃. We find that it is not soluble in alkalis, nor have we succeeded in converting it into a crystalline body by the action of dilute alcohol. It is not uniformly distributed throughout the tears; if they are broken after having been acted upon by dilute alcohol, it now and then happens that a clear stratification is perceptible, showing a concentric arrangement.

Olibanum contains an essential oil, of which Braconnot (1808) obtained 5 per cent., Stenhouse (1840) 4 per cent., and Kurbatow (1871-1874) 7 per cent. According to Stenhouse it has a sp. gr. of 0·866, a boiling point of 179·4° C., and an odour resembling that of turpentine but more agreeable. Kurbatow separated this oil into two portions, the one of which has the formula C₁₀H₁₆, boils at 158° C., and combines with HCl to form crystals; the other contains oxygen. The bitter principle of olibanum forms an amorphous brown mass.

The resin of olibanum submitted to destructive distillation affords no umbelliferone. Heated with strong nitric acid it develops no peculiar colour, but at length camphretic acid (see Camphor) is formed, which may be also obtained from many resins and essential oils if submitted to the same oxidizing agent.

Commerce—The olibanum of Arabia is shipped from several small places along the coast between Damkote and Al Kammar, but the quantity produced in this district is much below that furnished by the Somali Country in Eastern Africa. The latter is brought to Zeyla, Berbera, Bunder Murayah, and many smaller ports, whence it is shipped to Aden or direct to Bombay. The trade is chiefly in the hands of Banians, and the great emporium for the drug is Bombay. A certain portion is shipped through the straits of Bab-el-Mandeb to Jidda,—Von Kremer[546] says to the value of £12,000 annually. The quantity exported from Bombay in the year 1872-73 was 25,100 cwt., of which 17,446 cwt. were shipped to the United Kingdom, and 6,184 cwt. to China.[547]

Uses—As a medicine olibanum is nearly obsolete, at least in Britain. The great consumption of the drug is for the incense used in the Roman Catholic and Greek Churches.

MYRRHA.

Gummi-resina Myrrha; Myrrh; F. Myrrhe; G. Myrrhe.

Botanical Origin—Ehrenberg who visited Egypt, Nubia, Abyssinia, and Arabia in the years 1820-26, brought home with him specimens of the myrrh trees found at Ghizan (Gison or Dhizân), a town on the strip of coast-region called Tihâma, opposite the islands of Farsan Kebir and Farsan Seghir, and a little to the north of Lohaia, on the eastern side of the Red Sea, in latitude 16° 40′, and also on the neighbouring mountains of Djara (or Shahra) and Kara. Here the myrrh trees form the underwood of the forests of Acacia, Moringa, and Euphorbia. Nees von Esenbeck who examined these specimens, drew up from them a description of what he called Balsamodendron Myrrha, which he figured in 1828.[548]

After Ehrenberg’s herbarium had been incorporated in the Royal Herbarium of Berlin, Berg examined these specimens, and came to the conclusion that they consist of two species, namely that described and figured by Nees, and a second to which was attached (correctly we must hope) two memoranda bearing the following words:—“Ipsa Myrrhæ arbor ad Gison,—Martio,” and “Ex huic simillima arbore ad Gison ipse Myrrham effluentem legi.[549] Hæc specimina lecta sunt in montibus Djara et Kara Februario.” This plant Berg named B. Ehrenbergianum.[550] Oliver in his Flora of Tropical Africa (1868)[551] is disposed to consider Berg’s plant the same as B. Opobalsamun Kth., a tree or shrub yielding myrrh, found by Schweinfurth on the Bisharrin mountains in Abyssinia, not far from the coast between Suakin and Edineb. But Schweinfurth himself does not admit the identity of the two plants.[552] It is certain, however, that the myrrh of commerce is chiefly of African origin.

Captain F. M. Hunter, Assistant Resident of Aden, informed us[553] that the Arabian myrrh tree, the Didthin, is found not only in the southern provinces of Arabia, Yemen, and Hadramant, probably also in the southern part of Oman, but likewise on the range of hills which, on the African shore, runs parallel to the Somali coast. The Somalis who gather the myrrh in Arabia allege that the Arabian “Didthin” is identical with that of their own district. Its exudation is the true myrrh, “Mulmul” of the Somalis, the “Mur” of the Arabs, or “Heerabole”[554] of the Indians.

Another myrrh tree, according to Captain Hunter, is growing in Ogadain and the districts round Harrar, that is between the 7th and 10th parallels, N. lat., and 43° to 50° E. long. This is the “Habaghadi” of the Somalis, which is not found in Arabia, nor in the coast range of the Somali country, but only at a considerable distance from the sea-shore. Its exudation is the coarse myrrh, habaghadi of the Somalis and Arabs and “Baisabole” of the Indians.

Hildebrandt has collected the didthin, or didin as he writes, in the coast range alluded to, that is in the Ahl or Serrut Mountains, where the tree is growing on sunny slopes in elevations of 500 to 1,500 metres. He has ascertained that it is identical with Ehrenberg’s tree, Balsamodendron Myrrha Nees. It is a low tree of crippled appearance, attaining not more than 3 metres. This species must therefore be pointed out as the source of true myrrh of the European commerce.

History—(See also further on, Bissabol). Myrrh has been used from the earliest times together with olibanum as a constituent of incense,[555] perfumes, and unguents. It was an ingredient of the holy oil used in the Jewish ceremonial as laid down by Moses: and it was also one of the numerous components of the celebrated Kyphi of the Egyptians, a preparation used in fumigations, medicine, and the process of embalming, and of which there were several varieties.

In the previous article we have pointed out (p. 137) several early references to myrrh in connection with olibanum, in which it is observable that the myrrh (when weights are mentioned) is always in the smaller quantity. Of the use of the drug in mediæval Europe there are few notices, but they tend to show that the commodity was rare and precious. This myrrh is recommended in the Anglo-Saxon Leech-books[556] to be used with frankincense in the superstitious medical practice of the 11th century. In a manuscript of the Monastery of Rheinau, near Schaffhausen, Switzerland, we also find that, apparently in the 11th century, myrrh as well as olibanum were used in ordeals in the “judicium aquæ bullientis.”[557] The drug was also used by the Welsh “Physicians of Myddfai” in the 13th century. In the Wardrobe accounts of Edward I. there is an entry under date 6th January, 1299, for gold, frankincense, and myrrh, offered by the king in his chapel on that day, it being the Feast of Epiphany.[558] Myrrh again figures in the accounts of Geoffroi de Fleuri,[559] master of the wardrobe (argentier) to Philippe le Long, king of France, where record is made of the purchase of—“4 onces d’estorat calmite” (see Styrax) “et mierre (myrrh) ... encenz et laudanon,” (Ladanum, the resin of Cistus creticus L.)—for the funeral of John, posthumous son of Louis X., a.d. 1316.

Gold, silver, silk, precious stones, pearls, camphor, musk, myrrh, and spices are enumerated[560] as the presents which the Khan of Cathay sent to Pope Benedict XII. at Avignon about the year 1342. The myrrh destined for this circuitous route to Europe[561] was doubtless that of the Arabian traders, with whom the Chinese had constant intercourse during the middle ages. Myrrh in fact is still somewhat largely consumed in China.[562]