Method of drying the Roots of the R. Rhaponticum.
For the same roots, which in this instance were of such little efficacy, when dried with proper precaution, have been found to yield a very excellent rhubarb. The process observed for this purpose, by the ingenious Mr. Pallas, was as follows: The roots, immediately after being drawn out, were suspended over a stove, where being gradually dried, they were cleansed from the earth: by these means, although they were actually taken up in autumn, they so nearly resembled the best Tartarian rhubarb in colour, texture, and purgative qualities, that they answered, in every respect, the same medicinal purposes.
A German apothecary, named Zuchert, made similar trials with the same success, both on the Rheum Rhabarbarum and R. Rhaponticum, which grow in great perfection on the mountains in the neighbourhood of Nershinsk. |Plantation of Rhubarb in Siberia.| He formed plantations of these herbs on the declivity of a rock[187], covered with one foot of good mould, mixed with an equal quantity of sand and gravel. If the summer proved dry, the plants were left in the ground; but if the season was rainy, after drawing out the roots he left them for some days in the shade to dry, and then replanted them. By this method of cultivation he produced in seven or eight years very large and sound roots, which the rock had prevented from penetrating too deep; and when they were properly dried, one scruple was as efficacious as half a drachm of Tartarian rhubarb.
The Roots of the R. Rhaponticum and R. Rhubarbarum, equal in their Effects to the Tartarian Rhubarb.
From the foregoing observations it follows, that there are other plants, besides the Rheum Palmatum, the roots whereof have been found to be similar both in their appearance and effects, to what is called the best rhubarb. And indeed, upon enquiries made at Kiachta concerning the form and leaves of the plant which produces that drug, it seems not to be the R. Palmatum, but a species with roundish scolloped leaves, and most probably the R. Rhaponticum: for Mr. Pallas, when he was at Kiachta, applied for information to a Bucharian merchant of Selin-Chotton, who now supplies the crown with rhubarb; and his description of that plant answered to the figure of the Rheum Rhaponticum. The truth of this description was still further confirmed by some Mongol travellers who had been in the neighbourhood of the Koko-Nor and Thibet; and had observed the rhubarb growing wild upon those mountains.
The true Rhubarb probably procured from different Species of Rheum.
The experiments also made by Zuchert and others, upon the roots of the R. Rhabarbarum and R. Rhaponticum, sufficiently prove, that this valuable drug was procured from those roots in great perfection. the seeds of the Rheum Palmatum were received from the father of the above-mentioned Bucharian merchant as taken from the plant which furnishes the true rhubarb, we have reason to conjecture, that these three species, viz. R. Palmatum, R. Rhaponticum, and R. Rhabarbarum, when found in a dryer and milder alpine climate, and in proper situations, are indiscriminately drawn up; whenever the size of the plant seems to promise a fine root. And perhaps the remarkable difference of the rhubarb, imported to Kiachta, is occasioned by this indiscriminate method of collecting them. Most certain it is, that these plants grow wild upon the mountains, without the least cultivation; and those are esteemed the best which are found near the Koko-Nor, and about the sources of the river Koango.
Formerly the exportation of rhubarb was confined to the crown of Russia; and no persons but those employed by government were allowed the permission of sending it to foreign countries; this monopoly however has been taken off by the present empress, and the free exportation of it from St. Petersburg granted to all persons upon paying the duty. It is sold in the first instance by the College of Commerce for the profit of the Sovereign; and is preserved in their magazines at St. Petersburg. The current price is settled every year by the College of Commerce.
Price of Rhubarb in Russia.