Page:Mongolia, the Tangut country, and the solitudes of northern Tibet vol 2 (1876).djvu/323

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THE GENUINE RHUBARB.

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Kiakhta or Kan-su Rhubarb in favour of the R. palmatum L., he himself having gathered in Kan-su and brought a quantity of good seed to the Botanical Gardens at St. Petersburg. To the communication of Colonel Prejevalsky, (see supra, vol. ii. p. 82) I may add, says Professor Maximovitch, that the dried roots (about 36 lbs.) brought home by this traveller, after having been carefully analyzed and tested by our chemists and physicians, entirely agreed with the best Kiakhta Rhubarb both in internal structure as well as in the number of the crystals of oxalate of lime, the quantity of extract obtained from the root, and in the medicinal effect of the powder and other preparations. The only apparent difference between them was, that not having been subjected to a second cleaning and sorting process, small layers of rind still adhered to these samples, and the holes through which the string had passed by which they had been suspended to dry, were of smaller diameter than those of the Kiakhta Rhubarb, in which all the rind was carefully scraped off and the holes enlarged in order to remove all discoloured or bad pieces. The rules for the cultivation of Rhubarb (R. palmatum L.), are as follow: — Plant in light, loose black soil, in a shady situation, and not exposed to the south; leave sufficient space for each plant to develope itself (8 feet), water regularly, for it must be borne in mind that the climate of Kan-su is damp. Moreover, I think it necessary to call attention to two other conditions.

According to an analysis of the (salt) water of Koko-nor, made by Professor Schmidt of Dorpat, from samples brought by Colonel Prejevalsky, it was found to be much richer in salts of lime than other salt water; and this property Professor Schmidt attributes to the lime contained in the sweet waters which fall into the lake. But since the medicinal value of the root increases in proportion with the greater quantity of crystals of oxalate of lime contained in it, and a good root is immediately ascertained if it grate between the teeth on being chewed, it follows that hard (lime-containing) water is essential to its successful cultiva-