THE GENUINE RHUBARB. 295 



Kiakhta or Kan-su Rhubarb in favour of the R. palma- 

 tum 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 Maxi- 

 m.ovitch, 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. palmatinii 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 pro- 

 perty 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- 



