liquor is strong and black. At this period the liquor is thrown through a strainer into a deep vat, narrow at bottom, to cool, and to deposit its fæculent parts. Next day the clear liquor is drawn off by a cock, and again committed to the large iron vessel. At first it is boiled briskly, but towards the end the evaporation is slow, and requires constantly stirring, to prevent burning. When it becomes of the consistence of honey, it is poured into gourds or calabashes for sale. The succotrine aloes may be prepared as above." The aloe socotorina or succotrine aloes, is so named from being formerly brought from the island Socotria or Zocrotria, at the mouth of the Red Sea it comes wrapt up in skins, and is of a bright surface, and in some degree pellucid; in the lump of a yellowish red colour with a purplish cast; when reduced into powder, of a golden colour. It is hard and friable in the winter, somewhat pliable in the summer, and softens between the fingers. Its bitter taste is accompanied with an aromatic flavour, but not sufficient to prevent its being disagreeable: the smell is not very unpleasant, and somewhat resembles that of myrrh. The aloe hepatica and barbadensis, the Hepatic, Barbadoes, or common aloes, is chiefly brought from Barbadoes; the best sort in large gourd shells, an inferior kind in pots, and a still worse in casks; is darker coloured than the foregoing, and not so clear or bright. It is generally drier and more compact, though sometimes, especially the cask sort, quite soft and clammy. Its smell is much stronger and more disagreeable: the taste intensely bitter and nauseous, with little or nothing of the aromatic flavour of the succotrine. Another kind of aloes is obtained from the aloe guineensis caballina, which is also kept in the shops, and called aloe caballina, or horse aloes. This is easily distinguished from both the foregoing, by its strong rank smell: in other respects it agrees pretty much with the hepatic, and is now not unfrequently sold in its place. Sometimes it is prepared so pure and bright as scarcely to be distinguishable by the eye, even from the succotrine, but its offensive smell readily betrays it; and if this also should be dissipated by art, its wanting the aromatic flavour of the finer aloes will be a sufficient criterion. This aloe is not admitted into the Materia Medica, and is employed chiefly by farriers. All the kinds of aloes consist of a resin united to a gummy mat ter, and dissolve in pure spirit, proof spirit, and proof spirit diluted with half its weight of water; the impurities only being left. They dissolve also by the assistance of heat in water alone; but as the liquor grows cold, the resinous parts subside. The hepatic aloes is found to contain more resin and less gum than the succotrine, and this than the caballine. The resins of all the sorts, purified by spirits of wine, have little smell: that obtained from the succotrine has scarce any perceptible taste; that of the hepatic, a slight bitterish relish; and the resin of the caballine, a little more of the aloetic flavour. The gummy extracts of all the sorts are less disagreeable than the crude aloes: the extract of succotrine aloes has very little smell, and is in taste not unpleasant: that of the hepatic has a somewhat stronger smell, but is rather more agreeable in taste than the extract of the succotrine: the gum of the caballine retains a considerable share of the peculiar rank smell of this sort of aloes, but its taste is not much more unpleasant than that of the extracts made from the two other sorts. Aloes is neither noticed by Hyppocrates nor Theophrastus, but Dioscorides mentions two kinds; and Avicenna tells us, that of the different kinds the succotrine is the best. Celsus, however, who frequently employed aloes, does not mention any peculiar sort. Aloes is a well known purgative; a property which it possesses not only when taken internally, but also by external application. This cathartic quality of aloes does not, like most of the others of this class, reside in the resinous part of the drug, but in the gum, for the pure resin has little or no purgative power. Boerhaave declares aloes to be an effectual and safe cathartic, but though we may have little to fear from its hypercathartic effects, yet in large doses it often produces much heat and irritation, particularly about the rectum, from which it sometimes occasions a bloody discharge: therefore, to those who are subject to piles, or of an hemorrhagic diathesis, or even in a state of pregnancy, its exhibition has been productive of considerable mischief: but on the contrary, by those of a phlegmatic constitution, or suffering by uterine obstructions and in some cases of dyspepsey, palsy, gout, and worms, aloes may be employed as a laxative with peculiar advantage. Its purgative effects are not always in proportion to the quantity taken, and as its principal use is rather to obviate costiveness than to operate strong 196 ly, this ought to be no objection to its use. Respecting the choice of the different kinds of aloes, it may be observed that the succotrine, as already mentioned, contains more gummy matter than the hepatic, and hence is found to purge with more certainty and greater irritation; therefore is most proper where a stimulus is required, or for promoting the uterine discharge; while the hepatic is better calculated for the purpose of a common purgative; and also by containing more resin, answers better for external application, considered as a vulnerary. A full description of this plant is given in Dr. Edward Smith's edition of Sibthorp's superb Flora Græca. Sibthorp asserts, that the aloe vulgaris, or common Barbadoes aloes, is the true Axon of Dioscorides, and in every respect resembles the Barbadoes aloes as described by Sloane in his History of Jamaica. [Dioscor. Sloane. Woodv. Powell. SECTION XXI. Rhubarb. Rheum Palmatum.-WILDEN. THE rheum or rhubarb genus has eight species, as follows, all of which are actively or slightly aperient. 1. R. rhaponticum. Common rhubarb, a native of Thrace. 2. R. palmatum. 3. R. undulatum. 4. R. compactum. of Tartary. 5. R. ribes. Palmate-leaved, or true Chinese rhubarb. Thick leaved or compact rhubarb, a native Wasted-leaved Persian rhubarb. 6. R. Tartaricum. Tartarian or heart-leaved rhubarb. 7. R. hybridum. Hybrid rhubarb, a native of Asia. 8. R. leucorrhizum. A native of Siberia. The officinal rhubarb is the species named in the second of these. The root is perennial, thick, of an oval shape, and sends off long tapering branches; externally it is brown, and internally of a deep yellow colour: the stalk is erect, round, hollow, jointed, sheathed, slightly scored, branched towards the top, and rises to the height of six or eight feet the radical leaves are numerous, large, rough, of a roundish figure, and deeply cut into lobes, and irregularly pointed segments, and stand upon long smooth round footstalks: the leaves which proceed from the stalk are placed at the joints, which they supply with membraneous sheaths, and are successively smaller towards the upper part of the stem : the flowers terminate the branches, which they surround in numerous clusters, forming a kind of spike, and appear in April and May: the corolla divides into six obtuse segments, which are of a greenish white colour, and alternately smaller the calyx is wanting: the filaments are nine, slender, about the length of the corolla, and furnished with oblong double antheræ : the style is very short, and terminated by three reflected stigmata: the germen becomes a triangular seed, with membraneous margins of a reddish colour. It is a native of Tartary in Asia. It was not until the year 1732 that naturalists became acquainted with any plant which seemed to afford the rhabarbarum officinale*, when some plants, received from Russia by Jussieu at Paris, and Rand at Chelsea+, were said to supply this important desideratum, and as such were adopted by Linnæus, in his first edition of the Species Plantarum, under the name of Rheum Rhabarbarum. This however was not very generally received as the genuine rhubarb plant; and with a view to ascertain this matter more completely, Kauw Boerhaave procured from a Tartarian rhubarb merchant the seeds of those plants, whose roots he annually sold, and which were admitted at Petersburgh to be the true rhubarb: these seeds were soon propagated, and were discovered by De Gorter to produce two distinct species, viz. the R. rhabarbarum of Linnæus, or as it has since been called R. undulatum, and another species, a specimen of which was presented to Linnæus, who declared it to be a new one, and was first mentioned in the second edition of the Sp. Plantarum in 1762, by the name of R. palmatum. Previous to this • The rheum rhaponticum of Linnæus, or rhaponticum folio lapathi majoris glabro of C. Bauhin, is generally supposed to be the rhabarbarum of the ancients; Alpinus aliique putant esse Pa vel Pnoy veterum, cujus radicem usur (Vide Dioscorid. Mat. Med. lib. 3, cap. 2.) Ipse Alpinus sibi circa annum 1610, stirpem ex Thracia procuravit, et hæc Patavio Venetiam primo, dein inde in Angliam ad Parkinsonium (Theat. Bot. p. 157.) devenit." Murray Ap. Med. vol. iv. 354. It is well known that the ancient rhubarb had not the purgative power of the modern. + Seeds of this species were also sent to Miller from Boerhaave, at Leyden, by the title of "Rhabarbarum verum Chinense." See his Gard. Dict. time, De Gorter had repeatedly sent its seeds to Linnæus. but the young plants which they produced constantly perished: at length he obtained the fresh root, which succeeded very well at Upsal, and afterwards enabled the younger Linnæus to describe this plant†, ann. 1767. But two years antecedent to this, Dr. Hope's account of the rheum palmatum, as it grew in the botanic garden near Edinburgh, had been read before the Royal Society at London; and of the great estimation in which this plant was held by him, we have the following proof: "From the perfect similarity of this root with the best foreign rhubarb in taste, smell, colour, and purgative qualities; we cannot doubt of our being at last possessed of the plant which produces the true rhubarb, and may reasonably enter. tain the agreeable expectations of its proving a very important acquisition to Britain." But from the relation we have given, it appears that the seeds of both R. undulatum and R. palmatum, were transmitted to Petersburgh, as those of the true rhubarb : we are therefore to conclude, that the former species has an equal claim to this importance with the latter; and from further inquiries made in Russia, there is the best authority for believing that the R. compactum also affords this very useful drug. The seeds of the rheum palmatum were first introduced into Britain in 1762, by Dr. Moun sey, (who sent them from Russia) and were supposed to be a part of those already mentioned; and since their prosperous cultivation by the late professor of botany at Edinburgh, the propagation of this plant has been gradually extended to most of our English gardens, and with a degree of success which promises in time to supersede the importation of the foreign root. Two sorts of rhubarb roots are usually imported into this country for medical use, viz. The Chinese ‡, and the Turkey rhubarb §; the * See the letters between De Gorter and Linnæus, by Nozeman, in Verhandelingen van het Genootschap to Rotterdam, vol. i. p. 455, and cited by Murray. + Vide Plant. rarior. hort. Upsal, fasc. 1. Colitur hoc a Chinensibus, præcipue in provincia Xensi sub nomine Taihoang, Bergius, M. M. p. 332. § "Olim, quum commercium in orientalibus regionibus per Natoliam fieret, Rhabarbarum ex portibus Turcicis ad Europæas transferebatur, unde nomen Rhabarbari Turcici." Murray, 1. c. Mr. Bell (in his Travels from St. Petersburg to divers parts of Asia) says, that the best rhubarb grows plentifully on a |