RADIX RHEI.

Rhubarb; F. Rhubarbe; G. Rhabarber.

Botanical Origin—No competent observer, as far as we know, has ever ascertained as an eye-witness the species of Rheum which affords the commercial rhubarb. Rheum officinale, from which it seems, at least partly, derived is the only species yielding a rootstock which agrees with the drug.

Rheum officinale Baillon is a perennial noble plant resembling the Common Garden Rhubarb, but of larger size. It differs from the latter in several particulars: the leaves spring from a distinct crown rising some inches above the surface of the ground; they have a subcylindrical petiole, which as well as the veins of the under side of the lamina is covered with a pubescence of short erect hairs. The lamina, the outline of which is orbicular, cordate at the base, is shortly 5-to 7-lobed, with the lobes coarsely and irregularly dentate; it attains 4 to 4½ feet in length and rather more in breadth. The first leaves in spring display before expanding the peculiar metallic red hue of copper.

The plant was discovered in South-eastern Tibet, where it is said to be often cultivated for the sake of its medicinal root; but it is supposed to grow in various parts of Western and North-western China, whence the supplies of rhubarb are derived. It was obtained by the French missionaries about the year 1867 for Dabry, French Consul at Hankow, who transmitted specimens to Dr. Soubeiran of Paris. From one of these which flowered at Montmorency in 1871, a botanical description was drawn up by Baillon.[1801]

To what extent the rhubarb of commerce is derived from this plant is not known. But that the latter may be a true source of the drug is supported by the fact, that there is at least no important discrepancy between it and the accounts and figures, scanty and imperfect though they are, given by Chinese authors and the old Jesuit missionaries; and still more by the agreement in structure which exists between its root and the Asiatic rhubarb of commerce.

We have engaged in 1873 Mr. Rufus Usher at Bodicott (see below, p. 500) to cultivate Rheum officinale, which is there admirably succeeding; but it must be granted that as yet the root, notwithstanding the most careful preparation in drying it, is far from displaying the rich yellow of the commercial drug. It is most obviously marked on the other hand with the characteristic ring of stellate markings, which we have constantly observed in many roots of Rheum officinale cultivated by us at Clapham Common near London, as well as at Strassburg or, by other observers, at Paris.

Rheum palmatum L., a species known as long as 1750, has always been supposed to yield also rhubarb, and this has again been asserted by the Russian Colonel Przewalski, who observed in 1872 and 1873 that plant in the Alpine parts of Tangut round the Lake Kuku-nor, in the Chinese province of Kansu, in 36°-38° North Lat.—Rheum palmatum has been frequently cultivated in Russian Asia and in many parts of Europe since the last century, but without producing a root agreeing with Chinese rhubarb. Now, Przewalski states that from this species the drug under notice is largely collected along the river Tetung-gol (or Datung-ho), a tributary of the upper Hoang-ho, northward of the Kuku-nor. Specimens of that root were largely brought to St. Petersburg by Przewalski, but Dragendorff expressly points out in his Jahresbericht for 1877 (p. 78) that it is dissimilar to true rhubarb.

History[1802]—The Chinese appear to have been acquainted with the properties of rhubarb from a period long anterior to the Christian era, for the drug is treated of in the herbal called Pen-king, which is attributed to the Emperor Shen-nung, the father of Chinese agriculture and medicine, who reigned about 2700 b.c. The drug is named there Huang-liang, yellow, excellent, and Ta-huang, the great yellow.[1803] The latter name also occurs in the great Geography of China, where it is stated that rhubarb was a tribute of the province Si-ning-fu, eastward of Lake Kuku-nor,[1804] from about the 7th to the 10th centuries of our era.

As regards Western Asia and Europe, we find a root called ῤᾶ or ῤῆον, mentioned by Dioscorides as brought from beyond the Bosphorus. The same drug is alluded to in the fourth century by Ammianus Marcellinus,[1805] who states that it takes its name from the river Rha (the modern Volga), on whose banks it grows. Pliny describes a root termed Rhacoma, which when pounded yielded a colour like that of wine but inclining to saffron, and was brought from beyond Pontus.

The drug thus described is usually regarded as rhubarb, or at least as the root of some species of Rheum, but whether produced in the regions of the Euxine (Pontus), or merely received thence from remoter countries, is a question that cannot be solved.

It is however certain that the name Radix pontica or Rha ponticum, used by Scribonius Largus[1806] and Celsus,[1807] was applied in allusion to the region whence the drug was received. Lassen has shown that trading caravans from Shensi in Northern China arrived at Bokhara as early as the year 114 b.c. Goods thus transported might reach Europe either by way of the Black Sea, or by conveyance down the Indus to the ancient port of Barbarike. Vincent suggests[1808] that the rha imported by the first route would naturally be termed rha-ponticum, while that brought by the second might be called rha-barbarum.

We are not prepared to accept this plausible hypothesis. It receives no support from the author of the Periplus of the Erythrean Sea (circa a.d. 64), whose list of the exports of Barbarike[1809] does not include rhubarb; nor is rhubarb named among the articles on which duty was levied at the Roman custom-house of Alexandria (a.d. 176-180).[1810]

The terms Rheum barbarum vel barbaricum or Reu barbarum occur in the writings of Alexander Trallianus[1811] about the middle of the 6th century, and in those of Benedictus Crispus,[1812] archbishop of Milan, and Isidore[1813] of Seville, who both flourished in the 7th century. Among the Arabian writers on medicine, the younger Mesue, in the early part of the 11th century, mentions the rhubarb of China as superior to the Barbaric or Turkish.[1814] Constantinus Africanus[1815] about the same period speaks of Indian and Pontic Rheum, the former of which he declares to be preferable. In 1154 the celebrated Arabian geographer Edrisi[1816] mentions rhubarb as a product of China, growing in the mountains of Buthink—probably the environs of north-eastern Tibet near Lake Tengri Nor (or Bathang in Western Szechuen?).

Rhubarb in the 12th century was probably imported from India, as we may infer from the tariff of duties levied at the port of Acon in Syria, in which document[1817] it is enumerated along with many Indian drugs. A similar list of a.d. 1271, relating to Barcelona, mentions Ruibarbo.[1818] In a statute of the city of Pisa called the Breve Fundacariorum, dating 1305, rhubarb (ribarbari) is classified with commodities of the Levant and India.[1819]

The first and almost the only European who has visited the rhubarb-yielding countries of China is the famous Venetian traveller, Marco Polo,[1820] who speaking of the province of Tangut says—“ ... et par toutes les montagnes de ces provinces se treuve le reobarbe en grant habondance. Et illec l’achatent les marchans et le portent par le monde.”

A sketch of the history of rhubarb would be incomplete without some reference to the various routes by which the drug has been conveyed to Europe from the western provinces of the Chinese Empire, and which have given rise to the familiar designations of Russian, Turkey and China Rhubarb.[1821]

The first route is that over the barren steppes of Central Asia by Yarkand, Kashgar, Turkestan, and the Caspian to Russia; the second by the Indus or the Persian Gulf to the Red Sea and Alexandria, or by Persia to Syria and Asia Minor; and the third by way of Canton, the only port of the Chinese Empire which, previous to the year 1842, held direct communication with Europe.

In 1653 China first permitted Russia to trade on her actual frontiers. The traffic in Chinese goods was thereupon diverted from the line of the Caspian and Black Sea further north, taking its way from Tangut across the steppes of the high Gobi, and through Siberia by Tobolsk to Moscow. Thus it is mentioned in 1719 that Urga on the north edge of the Gobi desert was the principal depôt for rhubarb. From the earliest times, Bucharian merchants appear to have been agents on this traffic, the producers of the drug never concerning themselves about its export.

Consequent on the rectification of frontier in 1728, a line of custom-houses was established by treaty between Russia and China, whereby the commerce, previously unrestricted, was limited to the government caravans which passed the frontier only at Kiachta and at Zuruchaitu, south of Nerchinsk. The latter place always remained unimportant, while Kiachta and the opposite Chinese town of Maimatchin became the staple depôts of rhubarb.

The root was subjected to special control as early as 1687-1697 by the Russian Government, who finally monopolized the trade about 1704. Caravans fitted out by the Crown alone brought the drug to Moscow, until 1762, when the caravan-trade was for a while thrown open. It was not until this period that the export of rhubarb became considerable, although the stringent regulations, established in 1736, were still maintained. The surveillance of rhubarb was exercised at Kiachta in a special court or office called the Brake,[1822] under instructions from the Russian Minister of War, by an apothecary appointed for six years, the object being to remove from the rhubarb brought for inspection all inferior or spurious pieces, and to improve the selected drug by trimming, paring and boring. It was then carefully dried, and packed in chests, which were sown up in linen, and rendered impervious to wet by being pitched and then covered with hide. The drug was dispatched, but only in quantities of 1000 puds (40,000 lb.), once a year by way of Lake Baikal and Irkutsk to Moscow, whence it was transmitted to St. Petersburg, to be there delivered to the Crown apothecaries and in part to be sold to druggists.

We are indebted for these accounts chiefly to Calau,[1823] an apothecary appointed to supervise the examination of rhubarb, and who resided a long time at Kiachta. An exact account of the remarkable policy of the Russian Government in relation to that drug was also given by Von Schröders[1824] in 1864.

So long as China kept all her ports closed to foreign commerce except Canton in the extreme south, a large supply of fine rhubarb found its way to Europe by way of Russia. But the unpleasant accompaniments of the Russian supervision, which was exercised with unsparing severity,[1825] and the extreme tediousness of the land-transport, made the Chinese very ready to accept an easier outlet for their goods. Accordingly we find that the opening of a number of ports in the north of China exerted a very depressing influence on the trade of Kiachta, which was augmented by the rebellion that raged in the interior of China for some years from 1852.

On these accounts Russia in 1855 removed certain restrictions on the trade, though without abandoning the Rhubarb Office. She withdrew in 1860 the custom-house to Irkutsk, and declared Kiachta a free port, while by the treaty with China of November 1860, she insisted on that country abandoning all restrictions on trade.

But the overland rhubarb trade had already been destroyed: the Chinese, tempted by the increased demand occasioned by the new trading-ports, became less careful in the collection and curing of the root, while the Russians insisted with the greatest strictness on the drug being of the accustomed quality. Hence it happened that from 1860 hardly any rhubarb was delivered at Kiachta, either for the government use or to private traders; and in 1863 the Rhubarb Office was abolished.

Thus the so-called Russian or Muscovitic or Crown Rhubarb, familiarly known in England as Turkey Rhubarb, a drug which for its uniformly good quality long enjoyed the highest reputation, has become a thing of the past, which can only now be found in museum collections. It began to appear in English commerce at the commencement of the last century. Alston,[1826] who lectured on botany and materia medica at Edinburgh in 1720, speaks of rhubarb as brought from Turkey and the East Indies,—“and of late, likewise from Muscovy.”

It has been shown (p. 494) that rhubarb was shipped from Syria in the 12th century. Vasco da Gama[1827] mentions it in 1497 among the exports of Alexandria. In fact, the drug was carried from the far east to Persia, whence it was brought by caravans to Aleppo, Tripoli, Alexandria, and even to Smyrna. From these Levant ports it reached Europe, and was distributed as Turkey Rhubarb; while that which was shipped direct from China, or by way of India, became known as China, Canton, or East India Rhubarb. The latter was already the more common sort in England as early as 1640.[1828]

As the rhubarb of the Levant disappeared from trade, that of Russia took not only its place but likewise its name, until the term “Turkey Rhubarb” came to be the accepted designation of the drug imported from Russia. This strange confusion of terms was not however prevalent on the Continent, but was chiefly limited to British trade.

The risk and expense of the enormous land-transport over almost the whole breadth of Asia, caused rhubarb in ancient times to be one of the very costly drugs. Thus at Alexandria in 1497, it was valued at twelve times the price of benzoin. In France in 1542,[1829] it was worth ten times as much as cinnamon, or more than four times the price of saffron. At Ulm in 1596,[1830] it was more costly than opium. A German price-list of the magistrate of Schweinfurt, of 1614, shows Radix Rha Barbari to be six times as dear as fine myrrh, and more than twice the price of opium. An official English list[1831] giving the price of drugs in 1657, quotes opium as 6s. per lb., scammony 12s., and rhubarb 16s.

Production and Commerce—The districts of the Chinese Empire which produce rhubarb extend over a vast area. They are comprised in the four northern provinces of China Proper, known as Chihli, Shansi, Shensi,[1832] and Honan; the immense north-western province of Kansuh, formerly partly included in Shensi, but now extending across the desert of Gobi and to the frontiers of Tibet; the province of Tsing-hai inhabited by Mongols, which includes the great salt lake of Koko-nor and the districts of Tangut, Sifan, and Turfan; and lastly the mountains of the western province of Szechuen. The plant is found on the pasturages of the high plateaux, growing particularly well on spots that have been enriched by encampments.

What little we know regarding the production of rhubarb and its preparation for the market, from Catholic missionaries,[1833] is of a rather meagre and unsatisfactory character. The root is dug up at the beginning of autumn when the vegetation of the plant is on the decline, and the operation is probably continued for a few months, or in some districts for the whole winter. It is cleaned, its cortical part sliced off, and the root cut into pieces for drying. This is performed either by the aid of fire-heat, or by simple exposure to sun and air, or the pieces are first partially dried on a hot stone, and then strung on a cord and suspended until the desiccation is complete.

According to F. von Richthofen[1834] the best rhubarb is collected exclusively from plants growing wild in the high alps of western Szechuen, especially in the Bayankara range, between the sources of the Hoang-ho and the rivers Ya-lung-Kiang and Min-Kiang. This variety is chiefly known under the name Shensi rhubarb, although the inhabitants of the province of Szechuen pretend the superiority of the drug of their own country. The important places for the commodity are Sining-fu in the province of Kansu, and Kwan-hien in Szechuen. In the plain of Tshing-tu-fu, according to Richthofen, rhubarb is cultivated in fields, but its product is stated to be much inferior to that of the true plant which is said not to succeed under culture.

Rhubarb is now purchased for the European market chiefly at Hankow on the upper Yangtsze, whither it is brought from the provinces of Shensi, Kansu, and Szechuen. From Hankow it is sent down to Shanghai, and there shipped for Europe. The exports from Hankow are stated in official documents[1835] to have amounted to the following numbers of peculs (one pecul = 133⅓ lb. = 60·479 kilogrammes):

In 1877 there were exported by way of Hankow 2096 peculs from Shensi and 3385 peculs from Szechuen.—From all the Chinese ports, 5124 peculs of rhubarb were shipped in 1874.

Much smaller quantities (554 peculs in 1872, 1055 peculs in 1874) are shipped from Tientsin; and there are occasional exportations from Canton, Amoy, Foochow, and Ningpo. The imports of rhubarb into the United Kingdom in 1870 amounted to 343,306 lb., the estimated value of which was £62,716.[1836]

We have no information about the rhubarb which is stated by Bellew[1837] to grow on the hills near Kayn or Ghayn in eastern Persia (about 32½° N. lat.).

Description—China Rhubarb as imported into Europe[1838] consists of portions of a massive root which display considerable diversity of form, arising from the various operations of paring, slicing and trimming, to which they have been subjected. Thus some pieces are cylindrical or rather barrel-shaped, others conical, while a large proportion are plano-convex, and others again are of no regular shape. These forms are not all found in the same package, the drug being usually sorted into round and flat rhubarb. In dimensions we find 3 to 4 inches the commonest length, though an occasional piece 6 inches long or more may be met with. The width may be stated at 2 to 3 inches. The outer surface of the root is somewhat shrivelled, often exhibiting portions of a dark bark that have not been pared away. Many pieces are pierced with a hole, in which may be found the remains of a cord used to suspend the root while drying. The drug is dusted over with a bright brownish-yellow powder, on removal of which the outer side of the root is seen to have a rusty-brown hue, or viewed with a lens to be marked by the medullary rays, which appear as an infinity of short broken lines of deep brown, traversing a white ground.

The character which most readily distinguishes the rhubarb of China is that well-developed pieces, broken transversely, display these dark lines arranged as an internal ring of star-like spots. Although this character is by no means obvious in every piece of Chinese rhubarb, it is of some utility from the fact that in European rhubarb, such spots are generally wholly wanting, or at most occur only sparingly and in an isolated manner.

In judging of rhubarb, great stress is laid upon the appearance of the root when broken, and the circumstance of the fractured surface presenting no symptoms of decay, discoloration, or sponginess.[1839] In good rhubarb, the interior is found to be compact, and beautifully veined with reddish-brown and white, sometimes not unmixed with iron-grey. The root when chewed tastes gritty, by reason of the crystals it contains of oxalate of calcium; but it is besides bitter, astringent and nauseous. The odour is peculiar, and except by the druggist, is mostly regarded as very disagreeable.

Microscopic Structure—The tissue of rhubarb is made up of a white parenchyme, brown medullary rays and a few irregularly scattered very large fibro-vascular bundles, which are devoid of ligneous cells.

On a transverse fracture of specimens, which are not too much peeled, a narrow dark cambial zone may be distinguished. In that part of the root, only the medullary rays display the usual radial arrangement, and in the interior of the root no regular structure is met with. There is no well-marked pith, but the central portion of the tissue shows a mixture of white parenchyme and brown medullary rays running in every direction. In full-grown roots, the central part is separated from the cambial zone by the band of stellate patches[1840] already mentioned.

As to the contents of the white cells, they are loaded either with starch or tufted crystals of oxalate of calcium, the amount of the latter being especially liable to variation. Scheele, after having discovered the oxalic acid, pointed out in 1784 that the crystals under notice consist of that acid in combination with lime; he was the first to point out the true composition of those crystals which are of so wide a distribution throughout the vegetable kingdom. The medullary rays contain the substances peculiar to rhubarb, but none of them occur in a crystalline state.

Chemical Composition—The active constituent of the root has long been supposed to reside in the yellowish-red contents of the medullary rays. Schrader as early as 1807 prepared a Rhubarb-Bitter, to which he attributed the medicinal powers of the drug. Since then several substances of the same kind have been separated by various methods, and described under different names: such are the Rhabarberstoff of Trommsdorff, the Rheumin of Hornemann, the Rhabarberin of Buchner and Herberger, the Rhubarb-Yellow or Rheïn, and the Rhabarbaric Acid of Brandes.

Schlossberger and Döpping in 1844 first recognized among the above-named substances a definite chemical body named Chrysophan or Chrysophanic Acid,

which had been found in 1843 by Rochleder and Heldt in the yellow lichen, Parmelia parietina. It partly forms the yellow contents of the medullary rays of rhubarb, and when isolated crystallizes in golden yellow needles or in plates. It dissolves in ether, alcohol, or benzol; though scarcely soluble in water, it is nevertheless extracted from the root to some extent by that solvent, probably by reason of some accompanying substance. Alkalis dissolve it, forming fine dark red solutions. Chrysophan, C₁₅H₁₀O₄, is a derivative of anthracene, C₁₄H₁₀, and closely allied to alizarin, C₁₄H₈O₄.

By precipitating alcoholic solutions of extract of rhubarb with ether, Schlossberger and Döpping obtained, together with chrysophan, resinous bodies which they named Aporetin, Phæoretin and Erythroretin.

De la Rue and Müller (1857) extracted from rhubarb, in addition to chrysophan, an allied substance, Emodin, which crystallizes in orange-coloured prisms, sometimes as much as two inches long. Its constitution was subsequently found to agree with the formula

Kubly (1867) has obtained from rhubarb the following constituents:—

1. Rheo-tannic Acid, C₂₆H₂₆O₁₄, a yellowish powder abundantly present in rhubarb, soluble in water or alcohol, not in ether. Its solutions produce blackish-green precipitates with persalts of iron, and greyish ones slowly turning blue, with protosalts of the same.

2. Rheumic Acid (Rheumsäure), C₂₀H₁₆O₉, obtained as a reddish-brown powder, by boiling rheo-tannic acid with a dilute mineral acid, a fermentable sugar being developed at the same time. Rheumic acid exhibits nearly the same reactions as rheo-tannic acid, but is very sparingly soluble in cold water. It partly pre-exists in rhubarb.

3. Neutral colourless substance, sparingly soluble in hot water, and separating from the latter in prismatic crystals of the formula C₁₀H₁₂O₄; no name has yet been given to it. A “white crystalline resin” (and a dark brown crystalline resin) has been isolated in 1878 by Dragendorff.

4. Phæoretin, C₁₆H₁₆O₇, agreeing with the substance thus named by Schlossberger and Döpping. It is a brown powder, soluble in alcohol or in acetic acid, but not in ether, chloroform or water.

5. Chrysophan, described above.

According to Dragendorff (1878) mucilaginous matters occur in the different varieties of rhubarb to the amount of from 11 to 17 per cent. He states them to consist of mucilage (properly so called), arabic acid, metarabic acid and pararabin, and moreover enumerates also pectose among the constituents of the drug.

Small quantities of albuminoid substances, malic acid, fat and sugar have also been met with in rhubarb. As to its mineral constituents, their amount is exceedingly variable. Two samples of good China Rhubarb dried at 100° C. and incinerated, yielded us respectively 12·9 and 13·87 per cent. of ash. Another sample, which we had particularly selected on account of its pale tint, afforded no less than 43·27 per cent. of ash. The ash consists of carbonates of calcium and potassium. English rhubarb from Banbury (portions of a large specimen) left after incineration 10·90 per cent. of ash.

From a practical point of view the chemical history of rhubarb is far from satisfactory, for we are still ignorant to what principle the drug owes its therapeutic value, or what are the pharmaceutical preparations in which the active matter may be most appropriately exhibited. Chrysophan is said to act as a purgative, but less powerfully than rhubarb itself.

Uses—Rhubarb is one of the commonest and most valuable purgatives; it is also taken as a stomachic and tonic.

Substitutes—These are found in the roots of the various species of Rheum cultivated in Europe. In most countries, the cultivation of rhubarb for medicinal use has at some time been attempted. Yet in but few instances has it been persistently carried on; and though the drug produced has often been of good appearance, it has failed to gain the confidence of medical men, and to acquire much importance in the drug-market. The European rhubarb most interesting from our point of view is

English Rhubarb—So early as 1535, Andrew Boorde, an English Carthusian monk and practitioner of medicine, obtained seeds of rhubarb, which he sent as “a grett tresure” to Sir Thomas Cromwell, Secretary of State to Henry VIII.; but as he says they “come owtt of barbary” we must be allowed to hold their genuineness as doubtful.[1841]

In the following century, namely about the year 1608, Prosper Alpinus of Padua cultivated as the True Rhubarb a plant which is now known as Rheum Rhaponticum L., a native of Southern Siberia and the regions of the Volga.[1842] From this stock, Sir Matthew Lister, physician to Charles I., procured seeds when in Italy, and gave them to Parkinson,[1843] who raised plants from them.

Collinson obtained rhubarb plants from seeds procured in Tartary, and sent to him in 1742 by Professor Siegesbeck of St. Petersburg.[1844]

About 1777 Hayward, an apothecary of Banbury in Oxfordshire, commenced the cultivation of rhubarb with plants of Rh. Rhaponticum, raised from seeds sent from Russia in 1762. The drug he produced was so good that the Society of Arts awarded him in 1789 a silver medal, and in 1794 a gold medal.[1845] The Society also awarded medals about the same time (1789-1793) to growers of rhubarb in Somersetshire, Yorkshire, and Middlesex, some of whom, it appears, cultivated Rh. palmatum. On the death of Hayward in 1811, his rhubarb plants came into the possession of Mr. P. Usher, by whose descendants, Mr. R. Usher and sons, they are still cultivated at Bodicott, a village near Banbury.

The authors of this book had the pleasure of inspecting the rhubarb fields of Messrs. Usher on Sept. 4, 1872, and of seeing the whole process of preparing the root for the market.[1846] The land under cultivation is about 17 acres, the soil being a rich friable loam. The roots are taken from the ground during the autumn up to the month of November. It is considered advantageous that they should be 6 or 7 years old, but they are seldom allowed to attain more than 3 or 4 years. The clumps of root as removed from the field to the yard, where the trimming takes place, are of huge size, weighing with the earth attached to them as much as 60 or 70 lb. They are partially cleaned, the smaller roots are cut off, and the large central portion is rapidly trimmed into a short, cylindrical mass the size of a child’s head. This latter subsequently undergoes a still further paring, and is finally sliced longitudinally; the other and less valuable roots are also pared, trimmed, and assorted according to size. The fresh roots are fleshy, easily cut, and of a beautiful deep yellow. All are dried in buildings constructed for the purpose, and heated by flues. The drying occupies several weeks. The root after drying has a shrivelled, unsightly appearance, which may be remedied by paring and filing. The finished drug has to be stored in a warm dry place.

When well prepared, Banbury rhubarb is of excellent appearance. The finest pieces, which are semi-cylindrical, are quite equal in size to the drug of China. The colour is as good, and the fractured surface exhibits pink markings not less distinct and brilliant. Even the smaller roots, which are dried as sticks, have internally a good colour, and afford a fine powder. But the odour is somewhat different from that of Chinese rhubarb; the taste is less bitter but more mucilaginous and astringent, and the root is of a more spongy, soft, and brittle texture. The structure is the same as that of the Chinese rhubarb, except that, as already stated, the star-like spots, if present, are isolated, and not arranged in a regular zone.

The drug commands but a low price, and is chiefly sold, it is said, for exportation in the state of powder. It is not easily purchased in London.

French and German Rhubarb—The cultivation of rhubarb was commenced in France in the latter half of the last century, and has been pursued with some enthusiasm in various localities. The species grown were Rheum palmatum L., Rh. undulatum L., Rh. compactum L., and Rh. Rhaponticum L. The first was thought by Guibourt[1847] to afford a root more nearly approaching than any other the rhubarb of China; but it is that which is cultivated the least readily, the central root being liable to premature decay. Both this plant and Rh. undulatum were formerly cultivated by order of the Russian Government on a large scale at Kolywan and Krasnojarsk in Southern Siberia, but the culture has, we believe, been long abandoned.[1848]

As to France, it appears from inquiries we have lately made (1873), that except in the neighbourhood of Avignon and in a few other scattered localities, the cultivation has now ceased.

Rheum Rhaponticum is the source of the rhubarb which is produced at Austerlitz and Auspitz in Moravia, and at Ilmitz, Kremnitz and Frauenkirchen in Hungary. Some rhubarb is also produced in Silesia from Rh. Emodi Wall. (Rh. australe Don.).