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 | Rhubarb Other Names: Garden Rhubarb. Bastard Rhubarb. Sweet Round-leaved Dock
Botanical Name: Rheum rhaponticum
Family: N.O Polygonaceeae |
Description: |
Rhubarb is the root of different species of Rheum, growing in the mountains of the Western and North-western provinces of China and in the adjoining Thibetan terrtory.
Rhubarb occurs in commerce under various names: Russian, Turkey, East Indian and Chinese; but the geographical source of all species is the same, the commercial names of the drug indicating only the route by which it formerly reached the European market. Previous to 1842, Canton being the only port of the Chinese Empire holding direct communication with Europe, Rhubarb mostly came by overland routes: the Russian Rhubarb used to be brought by the Chinese to the Russian frontier town of Kiachta; the Turkey Rhubarb received its name because it came to us by way of Asiatic Turkey, through the Levant; East Indian came by way of Singapore and other East Indian ports, and Chinese Rhubarb was shipped from Canton. At the present day practically all is conveyed to Europe via Shanghai.
According to Lindley's Treasury of Botany, the technical name of the genus is said to be derived from Rha, the ancient name of the Volga, on whose banks the plants grow; other authorities derive the name from the Greek rheo ('to flow'), in allusion to the purgative properties of the root. |
History: |
English Rhubarb is similar in action to Turkey or Chinese Rhubarb, though milder. It is derived from Rheum rhaponticum, the ordinary Garden Rhubarb, and from R. officinale.
It has blunt, smooth leaves; large, thick roots, running deep into the ground, reddishbrown outside and yellow within, and stems 2 to 3 feet high, jointed and purplish. The flowers are white.
About 1777, Hayward, an apothecary, of Banbury, in Oxfordshire, commenced the cultivation of Rhubarb with plants of R. Rhaponticum, raised from seeds sent from Russia in 1762, and produced a drug of excellent quality, which used to be sold as the genuine Rhubarb, by men dressed up as Turks. The Society for the encouragement of Arts, Manufactures and Commerce exerted itself for many years in promoting the cultivation of Rhubarb, granting medals not only to this original pioneer, but also, some years later, to growers of Rhubarb in Somersetshire, Yorkshire and Middlesex, some of whom, it appears, attempted also to cultivate R. palmatum. When Hayward died, he left his Rhubarb plantations to the ancestor of the present cultivators of the Rhubarb fields at Banbury, where R. officinale is also now cultivated, from specimens first introduced into this country in 1873. Both R. Rhaponticum and R. officinale are at the present time grown, not only in Oxfordshire but also in Bedfordshire. Although specimens of R. palmatum were raised from seed as early as 1764, in the Botanical Gardens in Edinburgh, it is not grown now in this country for medicinal purposes, experiments having shown that it is the least easily cultivated of the rhubarbs, the main root in this climate being liable to rot. R. officinale and R. Emodi have to some extent been grown also as an ornamental plant, being also quite hardy and readily propagated. |
Cultivation: |
Rhubarb may be raised from seed, but it is better and more usual to obtain established roots. Seeds may be sown, however, in drills a foot or more apart, in the open, from March to April, and the young plants thinned out to 10 inches, transplanting them in the autumn, allowing about 4 feet every way to each plant.
Rhubarb roots may be planted at any time of the year, although mild weather in autumn or early spring is best; it should be planted on a clear, open spot, on good soil, which should be well trenched 3 feet deep, and before planting, a good substance of rotten manure should be worked into the soil.
When the plants are to be increased, it is merely necessary to take up large roots and divide them with a spade: every piece that has a crown to it will grow. Fresh plantations are generally made in February or March, but Rhubarb may still be divided early in May.
To ensure fine rhubarb for table use, a large dressing of well-rotted manure should be dug in about the roots as soon as the last of the leaves have been pulled. It is not right to wait until the winter, before the plants are dressed.
Old roots ought to be divided and replanted every fourth or fifth year, when the plants are grown for the use of the stems.
If Rhubarb be forced on the ground where it grows, nothing more is required than to cover with large pots, half casks, or boxes, round and over which should be placed plenty of stable manure. Roots forced in greenhouse or in frames do not need to have the light excluded from them. Such roots, however, require dividing and replanting in the spring out of doors. > |
Constituents: |
Root. The constituents of R. officinale are similar to those of Chinese Rhubarb.
Rhapontic or Garden Rhubarb contains no emodine, rhein or rhabarberine, but has in it a crystalline body, rhaponticin.
Stem and Leaves of R. Rhaponticum. Potassium oxalate is present in quantity in Rhubarb leaf-stems, and certain persons who are constitutionally susceptible to salts of oxalic acid, show symptoms of irritant poisoning after eating rhubarb stewed in the ordinary manner. Many people of a gouty tendency do well to avoid it, and those subject to urinary irritation should take it very sparingly or not at all.
Rhubarb stems did not come into general use as a substitute for fruit till about 100 years ago. We hear of a pioneer grower, Joseph Myatt, of Deptford, sending, in 1810, five bunches of Rhubarb to the Borough Market and only being able to dispose of three. But he persevered in his efforts to make a market for Rhubarb, raised improved varieties, and a few years after, Rhubarb had become established in public favour as a culinary plant.
It was, however, soon realized that the use of Rhubarb as food was sometimes attended with some risk to health. Lindley, in his Vegetable Kingdom, 1846, remarks that oxalic acid exists in both Docks and Rhubarb, and that the latter contains also an abundance of nitric and malic acid, and goes on to say that whilst these give an agreeable taste to the Rhubarb when cooked, he considers them illsuited to the digestion of some persons. The Penny Cyclopaedia, 1841, warned persons subject to calculous complaints against eating Rhubarb stalks, owing to the presence of oxalic acid, stating that 'the formation of oxalate of lime, or mulberry calculus, may be the consequence of indulgence.'
The chemical constituents of Rhubarb leaves were till recently not fully ascertained, but the analysis has lately been undertaken under orders from the Home Office, in consequence of fatal and injurious effects having resulted from eating the leaves cooked as spinach. The report of the official analyist states that the leaves contain some 0.3 per cent oxalates of potassium and calcium oxalates. It is possible that the recent cases of poisoning occurred in subjects specially susceptible to oxalic poisoning, as there are also many cases reported of no harm ensuing from a use of Rhubarb leaves as a vegetable.
In Maunders' Treasury of Botany Rhubarb leaves are mentioned as a pot-herb. Green (Universal Herbal, 1832) says: 'The leaves are also used by the French in their soups, to which they impart an agreeable acidity, like that of Sorrel.' Reference has recently been made in the press to a letter which appeared in the Gardeners' Chronicle for 1846, in which the gardener of the Earl of Shrewsbury at Alton Towers, Staffordshire, told how rhubarb leaves had been used there for many years as a vegetable. He also mentioned that the flower of the plant (before the leaves expanded) could be used like broccoli. A subsequent note by him makes it clear, however, that the leaf-stems were meant, for he then says:
'I have no experience in the eating of the leaves and think them nauseous to the taste and unpleasant to the smell.... I tasted them boiled and they did not appear to me to have one redeeming feature....'
The flower of the plant, when in bud form, has been eaten as a pleasant substitute for broccoli; when cooked au gratin, with white sauce over it, the cheese quite obviates any bitterness of taste.
Further reference to the Gardeners' Chronicle, of 1847, shows records of the varying results of eating the young inflorescence, producing no ill-effects in some cases and serious illness in others, and a case is recorded of severe sickness attacking a whole family after partaking of the leaves boiled as a vegetable. In 1853 we find the question again raised. In 1872 we hear of deaths from eating the leaves in America, and in 1899 we find a revival of interest in Rhubarb leaves as a vegetable, quite opposite opinions being expressed in a correspondence in the gardening papers. In 1901 we hear of a man dying after eating stewed Rhubarb leaves, the verdict at the inquest being: 'Accidental death, caused by eating rhubarb-leaves.' It was stated then that the leaves were used as a vegetable in parts of Hampshire. The British Medical Journal in December, 1910, mentions several cases of rhubarb poisoning.
The leaves are sometimes made use of in the fabrication of fictitious cigars and tobacco. The shape of the hairs, however, as seen under a microscope, can enable the observer to detect the presence or absence of tobacco, but it is not so easy to determine the source of the fraudulent admixtures.
It is possible that the chemical composition of Rhubarb varies to some extent according to the variety and the soil on which it is grown. It has been stated that the amount of water present is less when the plants are grown on poor soil, while the acid principle is more abundant.
As regards the method of cooking, the British Medical Journal points out that hard water would precipitate the oxalate, while a soft water might leave it in the form of soluble oxalate, more readily assimilated into the systems of those susceptible to this kind of poisoning. In a recent case that terminated fatally, the leaves were well washed, drained, cut up and put into boiling water, in an iron saucepan, for 20 minutes. A little salt and kitchen soda were added, but nothing else. Being acid, the leaves should, of course, not be cooked in a copper vessel. |
Medicinal Usage: |
Though the English Rhubarb root is milder as a purgative, it is more astringent, and has been considered a better stomachic than the foreign.
It is specially useful in infantile stomach troubles and looseness of the bowels.
In fairly large doses it acts as a laxative.
Dose of powdered root, 5 to 60 grains. The dose is entirely individual, 12 grains acting on some persons, as much as 20 on others of the same age. It has been held that 20 grains of the seed are equal to 30 of the root, as regards purgative power. The properties of the seeds are similar to those of the root.
A decoction of the seeds is supposed not only to ease pains in the stomach, but to strengthen it by increasing the appetite.
A strong decoction of the root has been employed as a good w ash for scrofulous sores.
If a portion of the root be infused in water, and when strained a few grains of salt of tartar be added, a very beautiful red tincture results, which might prove valuable for the purposes of a dye.
Culpepper says of Rhubarb:
'If your body be anything strong, you may take 2 drams of it at a time being sliced thin and steeped all night in white wine, in the morning strain it out and drink the white wine; it purges but gently, it leaves a binding quality behind it, therefore dried a little by the fire and beaten into powder, it is usually given in Fluxes.' |
Ancient Lore: |
RHUBARIB RHEUM PALMATUM
In bloody flux, and those loosenesses occasioned by acrid matter remaining in the intestines, this root is very useful.
This has a long thick root, brownish on the outside and full of reddish veins inside. It is similar to Garden Rhubarb.
Where to find it: This is the Rhubarb grown in China and other parts of central and eastern Asia.
Flowering time: Early to midsummer.
Astrology: Under the dominion of Mars.
Medicinal virtues: It is a mild purgative and a mild astringent. It is given more as a strengthener of the intestines than as a purgative. It generally leaves the belly costive and is therefore preferable to other purgatives in obstinate purgings and bloody flux.
Roots which are light in texture, moist, fragrant and sound are chosen being milder in action and more grateful to the stomach. They are more likely to answer the purpose of an astringent, a diuretic or an alterative. In acute fevers where it is dangerous to take purgatives, Rhubarb may be safely given.Two or three teaspoonfuls of the tincture strengthens the intestines, whereas two or three ounces (56 or 85 g) is frequently necessary as a purgative.
Modern uses: Rhubarb is widely used in pharmaceutical preparations obtainable over the counter in chemists and health food shops. In small doses the powdered root is astringent and checks diarrhoea, but in large doses it irritates the colon causing the bowels to evacuate. The dosage of the powdered root is 3-30 grains (o.2-2 g). Tinctures and fluid extracts are available from herbalists. |
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