Vaughan states, as well as Von Wrede, that the tree is found in Hadramaut and on the east coast of Africa. Species of Dracana occur in these regions, but of the botany of Socotra itself, nothing is known.

The Drop Dragon's Blood, of which small parcels imported from Bombay or Zanzibar, occasionally appear in the London market, is however this drug. It is in small tears and fragments, seldom exceeding an inch in length, has a clean, glassy fracture, and in thin pieces is transparent and of a splendid ruby colour. From Sumatran dragon's blood, it may be distinguished by not containing the little shell-like scales, constantly present in that drug, and by not evolving when heated on the point of a knife, the irritating fumes of benzoic acid.

Dragon's Blood of the Canary Islands-This substance is afforded by Dracana Draco L., a liliaceous tree 1 resembling a Yucca, of which the famous specimen at Orotava in Teneriffe has often been described on account of its gigantic dimensions and venerable age.2

On the exploration of Madeira and Porto Santo in the 15th century, dragon's blood was one of the valued productions collected by the voyagers, and is named as such by Alvise da ca da Mosto in 1454. It is also mentioned by the German physician, Hieronymus Münzer, who visited Lisbon about 1494.4

The tree yields the resin after incisions are made in its stem; but so far as we know, the exudation has never formed a regular and ordinary article of commerce with Europe. It has been found in the sepulchral caves of the aboriginal inhabitants.

The name Dragon's Blood has also been applied to an exudation obtained from the West Indian Pterocarpus Draco L., and to that of Croton Draco Schlecht.; but the latter according to Henkel is of the nature of kino, and neither substance is met with in European commerce.

Radix Calami aromatici, Radix Acori; Sweet Flag Root; F. Acore odorant ou vrai, Roseau aromatique; G. Kalmus.

Botanical Origin-Acorus Calamus L., an aromatic, flag-like plant, growing on the margins of streams, swamps and lakes, from the coasts of the Black Sea, through Southern Siberia, Central Asia and India, as far as Amurland, Northern China and Japan; indigenous also to North America. It is now established as a wild plant in the greater part of Europe, reaching as far north as Scotland, Scandinavia and Northern Russia; and is cultivated to a small extent in Burma and Ceylon.

1 Histological observations on the structure of the stem, accompanied by excellent figures, will be found in a memoir by Rauwenhoff (Bijdrage tot de kennis van Dracaena Draco pp. 55. tabb. 5) in the Verhand d. Kon. Acad. v. Wetensch., afd. Natuurk. x. 1863.

2 It was destroyed in 1867 by a hurricane. 3 Ramusio, Raccolta delle Navigationi et Viaggi, Venet. i. 97.

4 Kunstmann, Abhandlungen der Baierischen Akademie der Wissenschaften, vii. (1855) 342. et seq.

Regarding the introduction of Acorus Calamus into Western Europe, Clusius relates that he first received a living plant in 1574, sent from the lake Apollonia near Brussa in Asia Minor. Camerarius,2 writing in 1588, speaks of it as introduced some years previously, and then plentiful in Germany, which seems to show a rapid propagation. Gerarde at the close of the century, looked upon Acorus as an Eastern plant, which he says, is grown in many English gardens, and might hence be fitly called the "Sweet Garden Flag." Berlu 3 in 1724, observes of the root, that— "it is brought in quantities from Germany:" hence we may infer that it was not then collected in England, as we know it was at a later period.*

History-Sweet Flag root has been from the earliest times a favourite medicine of the natives of India, in which country it is sold in every bazaar. Ainslie 5 asserts that it is reckoned so valuable in the bowel complaints of children, that there is a penalty incurred by any druggist who will not open his door in the middle of the night to sell it, if demanded!

The descriptions of Acoron, a plant of Colchis, Galatia, Pontus and Crete, given by Dioscorides and Pliny, certainly refer to this drug. We think that the Káλaμos ȧρwμatikos of Dioscorides, which he states to grow in India, is the same, though Royle regards it as an Andropogon. The Káλapos of Theophrastus, and the Calamus of the English Bible are considered by some authors to refer to the Sweet Flag.

Celsus in the first century, mentioned Calamus Alexandrinus, the drug being probably then brought from India by way of the Red Sea. We know by the testimony of Amatus Lusitanus that in the 16th century, it used to be so imported into Venice. Rheede moreover described and figured Acorus Calamus as an Indian plant under the name Vacha, which it still bears on the Malabar Coast.

9

Murray states expressly that in his time (1790), Asiatic calamus was still met with in the pharmacies of Continental Europe, but that it had mostly been replaced by the home-grown drug. At the present time, the Calamus aromaticus of commerce is European; in all essential characters it agrees with that of India, a package of which is now and then offered in the London drug sales.

Collection-The London market is supplied from Germany, whither the drug is brought we believe, from Southern Russia. It is no longer collected in England,—at least in quantity, though it used to be gathered some years ago in Norfolk.

Description - The rootstock of sweet flag occurs in somewhat tortuous, subcylindrical or flattened pieces, a few inches long, and from to 1 inch in greatest diameter. Each piece is obscurely marked on

the upper surface with the scars, often hairy, of leaves, and on the under with a zigzag line of little, elevated, dot-like rings,-the scars of roots. The rootstock is usually rough and shrunken, varying in colour from dark brown to orange-brown, breaking easily with a short corky fracture, and exhibiting a pale brown spongy interior. The odour is aromatic and agreeable; the taste, bitterish and pungent.

The fresh rootstock is brownish-red or greenish, white or reddish within, and of a spongy texture. Its transverse section is tolerably uniform; a fine line (medullary sheath) separates the outer tissue from the lighter central part, the diameter of which is twice or three times the width of the former.

Microscopic Structure-The outermost layer is made up of extended epiblema-cells or of a brown corky tissue, the latter occurring in the parts free from leaf-scars. The prevailing tissue, both of the outer and the central part, consists of uniform nearly globular cells, traversed by numerous vascular bundles, especially at the boundary line (medullary sheath). Besides them, the rootstock like that of many fresh-water plants, exhibits a large number of intercellular holes. These air-holes, or more correctly water-holes, are somewhat longitudinally extended, so as to form a kind of net-work1 imparting a spongy consistence to the fresh rootstock. At certain places, where the series of cells cross one another, especially in the outer part, there are single cells, filled with essential oil, which may be made very conspicuous by adding to sections dilute potash or perchloride of iron. The other cells are loaded with small starch granules; a little mucilage and tannic matter is met with in the exterior coat.

Chemical Composition-The dried rhizome yielded us 1.3 per cent. of a yellowish neutral essential oil of agreeable odour, which in a column of 50 mm. long, deviates the ray of polarized light 13.8° to the right. According to Kurbatow (1873) this oil contains a hydrocarbon, C10H16, boiling at 159°C., and forming a crystalline compound with HCl, and another hydrocarbon boiling at 255-258° C., affording no crystallizable hydrochloric compound. The crude oil acquires a dark brownish colour on addition of perchloride of iron, but is not at all soluble in concentrated potash solution; it mixes with spirit of wine, and with 4 to 5 volumes of bisulphide of carbon, yet not so as to form with the latter a clear solution.

The bitter principle, Acorin, was isolated by Faust in 1867, as a semifluid, brownish glucoside, containing nitrogen, soluble both in ether and in alcohol, but neither in benzol nor in water. In order to obtain this substance, we precipitated the decoction of 10 Hb. of the drug by means of tannic acid, and followed the method commonly practised in the preparation of bitter principles. By finally exhausting the residue with chloroform, we succeeded in obtaining a very bitter, perfectly crystalline body, but in so minute a quantity, that we were unable to investigate its nature.

1 This moniliform or stellate arrangement of cells was observed by Albertus Magnus (A.D. 1193-1280), who says:-(Calamus aromaticus)-nascitur in India et Ethiopia sub cancro, et habet interius ex parte concava "pellem subtilem, sicut telæ sunt ara

nearum."-De Vegetabilibus, Jessen's ed. 1867. 376.

Hence the practice of peeling the rhizome which prevails in some parts of the Continent ought to be abandoned.

Uses-Sweet Flag is an aromatic stimulant and tonic, now rarely used in regular medicine. It is sold by the herbalists for flavouring beer, and for masticating to clear the voice. It is said to be also used by snuff manufacturers.

Adulteration-The rhizome of the Yellow Flag, Iris Pseudacorus L, is occasionally mixed with that of the Sweet Flag, from which it may be distinguished by its want of aroma, astringent taste, dark colour, and dissimilar structure.

LILIACEÆ.
ALOË.

Aloes; F. Aloès ou Suc d'Aloès; G. Aloë.

Botanical Origin-Several species of Aloë1 furnish a bitter juice which when inspissated, forms this drug. These plants are for the most part natives of arid, sunny places in Southern and Eastern Africa, whence a few species have been introduced into Northern Africa, Spain, and the East and West Indies.

The aloes are succulent plants of liliaceous habit, with persistent fleshy leaves, usually prickly at the margin, and erect spikes of yellow or red flowers. Many are stemless; others produce stems some feet in height, which are woody and branching. In the remote districts of Namaqua Land and Damara Land in Western South Africa, and in the Transkei Territory and Northern Natal to the eastward, aloes have been discovered which attain 30 to 60 feet in height, with stems as much as 30 feet in circumference. The following species may be named with more or less of certainty as yielding the drug :—

Aloë Socotrina Lam. (4. vera Miller), native of the southern shores of the Red Sea and Indian Ocean, Socotra, and Zanzibar (?). It is the source of the Socotrine and Moka Aloes. A. officinalis Forsk. and A. rubescens DC. are considered to be varieties of this plant. A. Abyssinica Lam. may probably contribute to the aloes shipped from the Red Sea.

A. vulgaris Lam. (A. perfoliata, var. T. vera Linn., A. Barbadensis Mill.), a plant of India and of Eastern and Northern Africa, now found also on the shores of Southern Spain, Sicily, Greece, and the Canaries; introduced into the West Indies, or as some think, possibly a true native. It affords Barbados and Curaçao Aloes. A. indica Royle,3 a plant of the North-west Provinces of India, common in Indian gardens, appears to be a slight variety of A. vulgaris Lam. A. litoralis König, said to grow in abundance at Cape Comorin, is unknown to us. Dr. Bidie suggests that

1

Apparently derived from the Syriac Alwai. It is important to bear in mind that the word Aloes or Lign Aloës, in Latin Lignum aloes, is used in the Bible and in many ancient writings, to designate a substance totally distinct from the modern Aloes, namely the resinous wood of Aquilaria Agallocha Roxb., a drug which was once generally valued for use as incense, but now esteemed only in the East.

Various species of Agave, especially 4. Americana L., are popularly called Aloe. All of them are plants of Mexico, while the true aloes are natives of the old world. Botanically the genus Agave differs from Aloë, in that the former has the ovary inferior, while in the latter it is superior.

Dyer in Gardeners' Chronicle, May 2, 1874, with figures.

3 Dr. Bidie of Madras has kindly sent us a living specimen of this plant.

it is a form of the preceding, stunted by a poor saline soil and exposure to the sea breeze. Both A. indica and A. litoralis are named in the Pharmacopoeia of India.

Aloe ferox L., and hybrids obtained by crossing it with A. Africana Mill. and A. spicata Thunb., A. perfoliata Linn. (quoad Roxb.) and A. linguæformis are reputed to yield the best Cape Aloes.

A. Africana Mill. and its varieties, and A. plicatilis Mill. afford an extract which Pappe1 says, is thought to be less powerful.

A. arborescens Mill., A. Commelini Willd. and A. purpurescens Haw. are stated to produce a portion of the Cape Aloes of commerce.2

History-Aloes was known to the Greeks as a production of the island of Socotra as early as the 4th century B.C., if we might credit a remarkable legend thus given in the writings of the Arabian geographer Edrisi. When Alexander had conquered the king of the Persians and his fleets had vanquished the islands of India, and he had killed Pour, king of the Indies, his master Aristotle recommended him to seek the island that produces Alocs. So when he had finished his conquests in India, he returned by way of the Indian Sea into that of Oman, conquered the isles therein, and arrived at last at Socotra, of which he admired the fertility and the climate. And from the advice which Aristotle gave him, he determined to remove the original inhabitants and to put Greeks in their place, enjoining the latter to preserve carefully the plant yielding aloes, on account of its utility, and because that without it, certain sovereign remedies could not be compounded. He thought also that the trade in and use of this noble drug would be a great advantage for all people. So he took away the original people of the island of Socotra, and established in their stead, a colony of Ionians, who remained under his protection and that of his successors, and acquired great riches, until the period when the religion of the Messiah appeared, which religion they embraced. Then they became Christians, and so their descendants have remained up to the present time (circa A.D. 1154).

4

This curious account, which Yule says is doubtless a fable, but invented to account for facts, is alluded to by the Mahommedan travellers of the 9th century 5 and in the 10th by Masudi," who says that in his time aloes was produced only in the island of Socotra, where its manufacture had been improved by Greeks, sent thither by Alexander the Great.

Aloes is not mentioned by Theophrastus, but appears to have been well known to Celsus, Dioscorides, Pliny and the author of the Periplus of the Erythrean Sea, as well as to the later Greek and the Arabian physicians. From the notices of it in the Anglo-Saxon leech-books, and a reference to it as one of the drugs recommended to Alfred the

1 Flora Capensis Medica Prodromus, ed. 2, 1857. 41.

In the above revision of the medicinal species of Aloë, we have made free use of M. Baillon's recent observations on the same subject, contained in the Dictionnaire des Sciences Médicales, iii. 360, also Journ. de Pharm. v. (1867) 406. We have also had the advantage of consulting W. Wilson Saunders, Esq., F.R.S., whose long famili

arity with these plants in cultivation impart great weight to his opinion.

3 Géographie d'Edrisi, traduite par P. A. Jaubert, Paris, i. (1836) 47.

4 Marco Polo, ii. 343.

5 Anciennes Relations des Indes et de la Chine de deux Voyageurs Mahometans, qui y allèrent dans le neuvième siècle, traduites de l'Arabe, Paris, 1718. 113.

Tome iii. 36.-See p. 541, note 4.,