manner: the watery liquid left in the still after the distillation of 28 lb. of Manila elemi was poured off from the mass of hard resin, and having been duly concentrated, it deposited together with a dark extractiform matter, colourless acicular crystals of bryoidin. The deposit in question having been drained and allowed to dry, the bryoidin may be separated by boiling water or by cold ether. We found the latter the more convenient; it readily takes up the bryoidin contaminated only with a little resin. The ethereal solution should be allowed to evaporate and the residual crystalline mass boiled in water, when the solution (which is colourless), poured off from the resin, will deposit upon cooling brilliant tufts of acicular crystals of bryoidin. The boiling in water requires to be several times repeated before the whole of the bryoidin can be removed; the latter sometimes crystallizes as a mossy arborescent growth. Bryoidin is a neutral substance, of bitter taste, scarcely soluble in cold water, but dissolving easily in boiling water, or in alcohol or ether. When a little is placed in a watch-glass, covered with a plate of glass, and then gently heated over a lamp, it sublimes in delicate needles. To obtain it perfectly pure, it is best to sublime it in a current of dry carbonic acid. Thus purified its fusing point is 133 5 C.; after fusion it concretes as a transparent, amorphous mass, which if immersed in glycerin and raised to the temperature of 135° C., suddenly crystallizes.

We have observed that if the filtered mother-liquor of bryoidin after complete cooling and standing for a day or two is warmed, it becomes turbid and that in a few minutes there separate from it long white flocks like bits of paper or wool, which do not disappear either by warming or by cooling the liquid; under the microscope they are seen to consist partly of thread-like, partly of acicular crystals. It is possible this substance is Baup's Bréidine; we found it to fuse at 135° C., to be neutral, and to crystallize from weak alcohol exactly like bryoidin. Both it and bryoidin look very voluminous in water, but are extremely small in weight, and are present in the drug in but a very small amount. The composition of bryoidin agrees with the formula C20HO3, which might be written thus (CH)*+30H. But it contains no water of crystallization. In the vapour of dry hydrochloric gas, bryoidin assumes a fine red colour, turning violet, then blue, and lastly green. This behaviour is not at all displayed by amyrin.

The liquids from which bryoidin is obtained contain an amorphous brown substance of intensely bitter taste, at the same time somewhat aromatic. It is decomposed by dilute mineral acids, evolving a very peculiar strong odour.

Buri' isolated from Manila Elemi an extremely small amount of Elemic acid, CHO. It is in very brilliant crystals, much larger than those of the other constituents of elemi. Although we have before us some prisms of the acids several millimetres long, it has been found impossible to ascertain their crystallographic character, each of the prisms being formed of very intimately aggregated crystals. Elemic acid melts at 215 ̊C.; its alcoholic solution decidedly reddens litmus. Elemate of potassium is a crystalline salt.

1 Pharm. Journ. viii. (1878) 601.

The relations of the substances hitherto isolated from elemi may perhaps be given thus:

Uses Elemi is scarcely used in British medicine except in the form of an ointment, sometimes prescribed as a stimulating application to old wounds.

Other sorts of Elemi-1. Mexican Elemi, Vera Cruz ElemiThis drug, which used to be imported into London about thirty years ago, but which has now disappeared from commerce, is the produce of a tree named by Royle Amyris elemifera growing at Oaxaca in Mexico.1 It is a light yellow, or whitish, brittle resin occurring in semi-cylindrical scraped pieces, or in irregular fragments which are sometimes translucent but more often dull and opaque. It easily softens in the mouth so that it may be masticated, and has an agreeable terebinthinous odour. Treated with cold spirit of wine (828), it breaks down into a white magma of acicular crystals (Amyrin ?).

2. Brazilian Elemi-Was described as long ago as 1658 by the traveller Piso, as a substance completely resembling the elemi of the Old World and applicable to the same purposes. It is the produce of several trees described as species of Icica, as I. Icicariba DC.2 I. heterophylla DC., I. heptaphylla Aublet, I. guianensis Aubl., I. altissima Aubl.-In New Granada a similar exudation is furnished by I. Caranna H.B.K.

A specimen in our possession from Pernambuco is a translucent, greenish-yellow, fragrant, terebinthinous resin, which by cold spirit of wine may be separated into two portions, the one soluble, the other a mass of colourless acicular crystals. The resin spontaneously exuded and collected from the trunks, is often opaque and white, grey, or yellowish, looking not unlike fragments of old mortar. The microscope shows it to be made up of minute acicular crystals.5

3. Mauritius Elemi-Fine specimens of this substance and of Colophonia Mauritiana DC. the tree affording it, were sent to one of us (H.) in 1855 by Mr. Emile Fleurot of Mauritius. The resin accords in its general characters with Manila elemi, like which it leaves after treatment with cold spirit of wine, an abundance of crystals resembling amyrin.

4. Luban Meyeti or Luban Mati.-This substance, which we claim to be the Oriental or African Elemi of the older writers, and also one of

1 Royle's very imperfect specimens of this plant are in the British Museum.

2 Now Protium Icicariba Marchand, in Flora Brasiliensis, fascicul. 65 (1874) tab. liii.

3 G. Planchon, Bulletin de la Soc. Bot. de France, xv. (1868) 16.

Given me by Mr. Manley, late of Pernambuco. I have also an authentic specimen of the resin of I. heterophylla col

lected at Santarem, Pará, by Mr. H. W. Bates in 1853.-D. H.

5 For some experiments on the resin of Icica, see Gmelin, Chemistry, xvi. (1866) 421. Also Stenhouse and Groves, in Liebig's Annalen der Chemie, 180 (1876) 253, on resin and oil of Icica heptaphylla. The former would appear to agree with the formula (C3H3)9 ÓĤ2.

Luban is the general Arabic name for

the resins anciently designated Animi, is the exudation of Boswellia Frereana Birdwood, a remarkable tree gregarious on the bare limestone hills near Bunder Murayah to the west of Cape Gardafui. The tree which is called Yegaar by the natives, is of small stature, and differs from the other species of Boswellia growing on the same coast in having glabrous, glaucous leaves with obtuse leaflets, crisped at the margin.2 The bark is smooth, papery, and translucent, and easily stripped off in thin sheets which are used for writing on. Though growing wild, the trees are said by Capt. Miles' to be carefully watched and even sometimes propagated. The resin exudes after incision in great plenty, soon hardens, and is collected by the Somali tribes who dispose of it to traders for shipment to Jidda and ports of Yemen: occasionally a package reaches London among the shipments of olibanum. It is used in the East for chewing like mastich.

In modern times Luban Mati has been mentioned by Wellsted in his "Travels in Arabia" (1838).

Luban Meyeti occurs in the form of detached droppy tears and fragments, occasionally in stalactitic masses several ounces in weight. It breaks very easily with a brilliant conchoidal fracture, showing an internal substance of a pale amber yellow and perfectly transparent. Externally it is more or less coated with a thin opaque white crust, which seen under the microscope appears non-crystalline. Many of the tears have pieces of the thin, brown, papery bark adhering to them. The resin has an agreeable odour of lemon and turpentine, and a mild terebinthinous taste.

a

Treated with alcohol (838) it is almost entirely dissolved; the very small undissolved portion is not crystalline. The former agrees with the formula C2H3O2. 20 lb. of Luban Mati yielded us 10 ounces of volatile oil (3.1 per cent.) having a fragrant odour suggestive of elemi and sp. gr. 0856 at 17° C. The oil examined in a column 50 millim. long, deviates the ray 25 to the left. By fractional distillation we found it to consist of dextrogyre hydrocarbon, CH, mixed with an oxygenated oil which we did not succeed in isolating; the latter is evidently lævogyre, and exists in proportion more than sufficient to overcome the weak dextrogyre power of the hydrocarbon.

There is no gum in this exudation; it is therefore essentially different from olibanum, the product of closely allied species of Boswellia.

olibanum: meyeti perhaps from Jebel Meyet,

a mountain of 1200 feet on the Somali Coast in long. 47° 10.

By the assistance of Professor G. Planchon we have ascertained that it is identically the same substance as described by Guibourt under the name Tacamaque jaune huileuse A.-Hist. des Drogues, iii. (1850) 483.

2

Figured in Birdwood's paper, Trans. Linn. Soc. xxvii. (1870) tab. 32; also, (reduced) in Cooke's report on the Gums, Resins, etc., of the India Museum, 1874, plate iv.

4

3 Journ. Geograph. Soc. xlii. (1872) 61. Fluckiger, on Luban Mati and Olibanum, Pharm. Journ. viii. (1878) 805, with sketch map of the Somali Coast.

MELIACEÆ.

CORTEX MARGOSÆ.

Cortex Azadirachta; Nim Bark, Margosa Bark.

Botanical Origin-Melia indica Brandis (M. Azadirachta L., Azadirachta indica Juss.), an ornamental tree, 40 to 50 feet high and attaining a considerable girth,' well known throughout India by its Hindustani name of Nim, or by its Portuguese appellation of Margosa. It is much planted in avenues, but occurs wild in the forests of Southern India, Ceylon and the Malay Archipelago, as far as Java.3

The hard and heavy wood which is so bitter that no insect will attack it, the medicinal leaves and bark, the fruit which affords an acrid bitter oil used in medicine and for burning, the gum which exudes from the stem, and finally a sort of toddy obtained from young trees, cause the Nim to be regarded as one of the most useful trees of India.

M. indica is often confounded with M. Azedarach L., a native of China, and probably of India, now widely distributed throughout the warmer regions of the globe, and not rare even in Sicily and other parts of the south of Europe. The former has an oval fruit (by abortion) one-celled and one-seeded, and leaves simply pinnate. The latter has the fruit five-celled, and leaves bi-pinnate.

History The tree under the Sanskrit name of Nimba is mentioned in Susruta, one of the most ancient Hindu medical writings, composed perhaps about the 10th century of our era.

6

In common with many other productions of India, it attracted the notice of Garcia de Orta, physician to the Portuguese viceroy at Goa, and he published an account of it in his work on drugs in 1563.5 Christoval Acosta in 1578 supplied some further details and also a figure of the tree. The tonic properties of the bark, long recognized by the native physicians of India, were successively tested by Dr. D. White of Bombay in the beginning of the present century, and have since been generally admitted. The drug has a place in the Pharmacopoeia of India.

8

Description-The bark in our possession is in coarse fibrous pieces about of an inch thick and 2 to 3 inches wide, slightly channelled. The suberous coat is rough and cracked, and of a greyish rusty hue. The inner surface is of a bright buff and has a highly foliaceous structure. On making a transverse section three distinct layers may be observed-firstly the suberous coat exhibiting a large brown

Fig. in Bentley and Trimen, Medic. Plants, part 27.

2 From amargoso, bitter.

3 C. De Candolle, in Monogr. Phanerogamar. i. (1878) 459.

4 It is mentioned in Chinese writings dating long prior to the Christian era. Bretschneider, Chinese Botanical Works, 1870. 12.

5 Colloquios dos Simples, &c., Goa, 1563 Colloq. xl. p. 153.

6 Tractado de las Drogas y Medicinas de las Indias Orientales, Burgos, 1578, cap. 43. 7 Waring, in Pharmacopaia of India, 1868. 443.

8 We are indebted for it to Mr. Broughton of Ootacamund.

parenchyme interwoven with small bands of corky tissue, secondly a dark cellular layer, and then the foliaceous liber. The dry bark is inodorous and has a slightly astringent bitter taste.

Microscopic Structure-The suberous coat consists of numerous layers of ordinary cork-cells, which cover a layer of nearly cubic sclerenchymatous cells. This latter however is not always met with, secondary bands of cork (rhytidoma) frequently taking its place. The liber is commonly built up of strong fibre-bundles traversed by narrow medullary rays, and transversely separated by bands of parenchymatous liber tissue. Crystals of oxalate of calcium occur in the parenchyme more frequently than the small globular starch grains. The structure of the bark varies considerably according to the gradual development of the secondary cork-bands.

1

Chemical Composition-Margosa bark was chemically examined in India by Cornish (1856), who announced it as a source of a bitter alkaloid to which he gave the name of Margosine, but which he obtained only in minute quantity as a "double salt of Margosine and Soda," in long white needles.

From the bitter oil of the seeds he isolated a substance which he called Margosic Acid, and which he doubted to be capable of affording crystallizable salts. The composition neither of this acid nor of margosine is known, nor have the properties of either been investigated.

The small sample of the bark at our disposal only enables us to add that an infusion produced with perchloride of iron a blackish precipitate, and that an infusion is not altered by tannic acid or iodohydrargyrate of potassium. If the inner layers of the bark are alone exhausted with water, the liquid affords an abundant precipitate with tannic acid; but if the entire bark is boiled in water, the tannic matter which it contains will form an insoluble compound with the bitter principle, and prevent the latter being dissolved. It is thus evident that to isolate the bitter matter of the bark, it would be advisable to work on the liber or inner layers alone, which might readily be done, as they separate easily.

According to the recent researches of Broughton2 the bitter principle is an amorphous resin soluble in the usual solvents and in boiling solutions of fixed alkalis. From the latter it is precipitated by acids, yet, probably, altered. Broughton ascribed the formula C6H5O11 to this bitter resin purified by means of bisulphide of carbon, ether and absolute alcohol; it fused at 92° C. He obtained moreover

a small quantity of a crystallized principle, which he believed to be a fatty body, yet its melting point of 175° C. is not in favour of this suggestion.

Uses In India the bark is used as a tonic and antiperiodic, both by natives and Europeans. Dr. Pulney Andy of Madras has found the leaves beneficial in small-pox.

1 Indian Annals of Medical Science, Calcutta, iv. (1857) 104.

2 Madras Monthly Journ. Med. Science, quoted in Pharm. Journ. June 14, 1873, 992.