Page:Encyclopædia Britannica, Ninth Edition, v. 20.djvu/550

Rh 530 R H Y R H Y be counteracted by giving it with alkaline preparations. It is especially valuable in the treatment of duodenal catarrh or catarrh of the biliary ducts with jaundice ; and in certain skin diseases it has proved to be a valuable medicine, the results obtained being probably due to the chrysophan contained in it. The botanical source of Chinese rhubarb cannot be said to have been as yet definitely cleared up by actual identification of plants observed to be used for the purpose. Rheum palmatum, R. officinale, R. palmatum (var. tanguticum), R. colinianum, and Jl. Franzenbachii have been variously stated to be the source of it, but the roots produced by these species tinder cultivation in Europe do not present the characteristic network of white veins exhibited by the best specimens of the Chinese drug (see Goebel and Kunze, pt. ii., pi. i. figs. 2fc, 36). Chemistry. The chief chemical constituents of Cliinese rhubarb are chrysophan (C 15 H 10 4 ), rheotannic acid (C H 2(! U ), einodin (C 15 H 10 S ), a neutral colourless crystalline substance having the formula C^H^O^, a white and a dark brown crystalline resin; it also contains mucilage in the proportion of 11 to 17 per cent., and a considerable quantity of oxalate of lime. An albuminoid principle containing nitrogen and sulphur is also found in the root, which, in the presence of water, as recently shown by Kubli, 1 decomposes the chrysophan into chrysophanic acid and glucose, and apparently exerts a similar action on rheotannic acid, giving rise to the formation of rheumic acid (C 20 H 16 9 ) and a fermentable sugar. Rheumic acid is a reddish-brown powder, sparingly soluble iu cold water. The albuminoid principle is in- soluble in rectified spirit of wine ; consequently a preparation of the root made with that menstruum contains the active principles of the drug in the natural state, whilst an aqueous extract contains them in an altered condition. Production and Commerce, Rhubarb is produced in the four northern provinces of China proper (Chih-li, Shan-se, Shen-se, and Ho-uan), in the north-west provinces of Kan-suh formerly included in Shen-se, but now extending across the desert of Gobi to the frontier of Tibet, in the Mongolian province of Tsing-hai, including the salt lake Koko-nor, and the districts of Tangut, Sifan, and Turfan, and in the mountains of the western provinces of Sze-chuen. According to Richthofen the best rhubarb is collected exclusively from wild plants in the high mountains of western Sze-chuen between the sources of the Hoang-ho and the rivers Ya-lung Keang and Min-keang, and conies into trade under the name of Shen-se rhubarb. 2 Two of the most important centres of the trade are Sining-fu in the province of Kan-suh and Kwan- hien in Sze-chuen. From Shen-se, Kan-suh, and Sze-chuen the rhubarb is.forwarded to Hankow, and thence carried to Shanghai, whence it is shipped to Europe. Lesser quantities are shipped from Tien-tsin, and occasionally the drug is exported from Canton, Amoy, Fuli-chow, and Ning-po. Very little is known concerning the mode of preparing the drug for the market. According to Mr Bell, who on a journey from St Petersburg to Peking had the opportunity of observing the plant in a growing state, the root is not considered to be mature until it is six years old. It is then dug up, usually in the autumn, and deprived of its cortical portion and smaller branches, and the larger pieces are divided in half longitudinally ; these pieces are bored with holes and strung up on cords to dry, in some cases being previously subjected to a preliminary drying on stone slabs heated by fire underneath. In Bhutan the root is said to be hung up in a kind of drying room, in which a moderate heat is regularly maintained. The effect produced by the two drying processes is very different ; when dried by artificial heat, the exterior of the pieces becomes hardened before the interior has entirely lost its moisture, and consequently the pieces decay in the centre, although the surface may show no change. These two varieties are technically known as kiln-dried and sun-dried ; and it was on account of this difference in quality that the Russian officer at Kiachta had every piece examined by boring a hole to its centre. The best rhubarb occurs in pieces of a yellowish colour externally, more or less marked with a network of whitish veins, the surface being convex and smooth. Internally it presents no signs of decay, but is compact, marbled with reddish-brown and white, mixed sometimes with iron grey. The smaller cylindrical sections of the root which have not been divided longitudinally are technically known as "rounds," and have usually a hole with a piece of string left in it ; the flat pieces are more rarely pierced. Inferior qualities are 1 Jour. Pharm. Soc., [3], vi. p. 65. 3 According to Mr F. Newcombe, Mea. Press and Circ., August 2, 1882, the Chinese esteem the Shen-se rhubarb as the best, that coming from Kanchow being the most prized of all; Sze-chuen rhubarb has a rougher surface and little flavour, and brings only about half the price ; Chung-chi rhubarb also is greatly valued, while the Chi- chuang, Tai-huang, and Shan-huang varieties are considered worthless. shrunken and shrivelled on the surface, and externally of a brownish tint, showing traces of the darker bark, and when broken open are frequently decayed in the centre. European Rhubarb. As early as 1608 Prosper Alpiuus of Padua cultivated as the true rhubarb a plant which is now known as Rheum Rhaponticum, L., a native of southern Siberia and the basin of the Volga. This plant was introduced into England through Sir Matthew Lister, physician to Charles I., who gave seed obtained by him in Italy to the botanist Parkinson. The culture of this rhubarb for the sake of the root was commenced in 1777 at Banlmry in Oxfordshire, by an apothecary named Hayward, the plants being raised from seed sent from Russia in 1762, and with such success that the Society of Arts awarded him a silver medal in 1789 and a gold one in 1794. The cultivation subsequently ex- tended to Somersetshire, Yorkshire, and Middlesex, but is now chielly carried on at Banbury. English rhubarb root is sold at a cheaper rate than the Chinese rhubarb, and forms a con- siderable article of export to America, and is said to be used in Britain in the form of powder which is of a finer yellow colour than that of Chinese rhubarb. The Banbury rhubarb appears to be a hybrid between R. RJiaponticum and R. undulatum, the root, according to E. Colin, not presenting the typical microscopic structure of the former. During the last few years very good rhubarb has been grown at Banbury from Rheum officinale, but these two varieties are not equal in medicinal strength to the Chinese article, yielding less extract, Chinese rhubarb affording, according to H. Seier, 58 per cent., English rhubarb 21 per cent, and R. officinale 17 per cent. In France the cultivation of rhubarb was commenced in the latter half of the last century, R. com- pactum, R. palmatum, R. Rhaponticum, and R. undulatum, L., being the species grown. The cultivation has, however, now nearly ceased, small quantities only being prepared at Avignon and a few other localities. The culture of Rheum compactum was begun in Moravia in the beginning of the present century by Prikyl, an apothecary in Austerlitz, and until twenty-five or thirty years ago the root was largely exported to Lyons and Milan, where it was used for dyeing silk. As a medicine 5 parts are stated to be equal to 4 of Chinese rhubarb. Rhubarb root is also grown at Auspitz in Moravia and at Ilmitz, Kremnitz, and Frauenkircheu in Hungary; R. Emodi is said to be cultivated for the same purpose in Silesia. The cultivation of Rheum palmatum, var. tanguticum, has been begun within the last few years in the United States. Rhubarb is also prepared for use in medicine from wild species in the Himalayas and Java. 2. The rhubarb used as a vegetable consists of the leaf stalks of several hybrids between the species R. rhaponticum, R. undulatum, R. palmatum. The petioles of R. officinale have also been proved to be edible ; but that plant is grown more frequently on account of its ornamental foliage (see HORTICULTURE, vol. xii. p. 287). (E. M. H.) RHYL, a watering-place of North Wales, in the county of Flint, is situated near the mouth of the Clwyd, 30 miles north-west of Chester and 10 north-north-west of Denbigh, a railway line to which here joins that from Chester to Holyhead. Only recently it was a small fishing village. Its chief advantages as a watering-place are the pure air and extensive firm sands. Although the situation of the town was formerly bare and cheerless, much has been done to improve it. There are many handsome houses, and the neighbouring country is interesting both from its scenery and from its castles and other ancient buildings. The town possesses a town-hall, extensive winter gardens, racquet courts, lawn-tennis grounds, and other attractions. The east and west parades face the sea, and the pier, con- structed of iron, is 700 feet in length. There is daily communication by steamer with Liverpool, Llandudno, Bangor, &c. The population of the urban sanitary district (area 600 acres) in 1871 was 4500, and in 1881 it was 6029. RHYMER, THOMAS THE. See THOMAS OF ERCELDOUNE. RHYMNEY, an urban sanitary district of Monmouth- shire, on the borders of Glamorganshire, is situated in the valley of the Rumney river, 20 miles west of Abergavenny, and 22 north of Cardiff. It owes its importance to the neighbouring coal mines and to its iron and steel works, which employ nearly the whole population. The works of the Rhymney Iron Company, including blast furnaces and