29б NOTES. 



tion, for it supplies the plant with the lime requisite for the 

 formation of crystals. Perhaps, it was entirely owing to the 

 absence of these requisite conditions, that the root of the 

 R. palmatiim, as formerly cultivated in Europe, did not 

 grate between the teeth, and was less powerful in operation 

 than the Chinese Rhubarb of commerce, which it resembled 

 in every other respect. 



Another important circumstance is, that the principal 

 root becomes so rotten under cultivation, that the less 

 valuable lateral branches are alone retained for use ; whereas, 

 the pieces cut from the main root are by far the most 

 prized. Rain-water accumulates in the cavities formed by 

 the breaking off and decaying of the flower stalks, from 

 Avhich it is prevented from running off by the numerous old 

 leaf sheaths which remain round the Jiilum, or eye, and in 

 this way causes an ever-deepening and spreading decay. 

 How this can best be prevented must be left to further 

 experiments to determine ; the remedies which appear to 

 be most practical are : cutting away the old leaf sheaths 

 and withered stalks before they have had time to decay at 

 the root, and covering or stopping the eye of the stalk. 

 Perhaps, it would be best not to allow the plants, in general, 

 to bloom. Nearly all our larger kinds of Rhubarb, not 

 excepting the R, palmatiim, show in almost every joint of 

 their root-leaves and of the old stipules numerous embryo 

 buds, of which only the smallest come to maturity, because 

 the plants must develop their flower-stalks. But, whilst old 

 plants hardly ever throw out more than three flower-stalks, 

 and their principal roots have seldom more than four or 

 five root-heads, each of which has a corresponding stalk, or 

 would have, were it not for the obstructing formation of the 

 stem, which causes them to throw out numerous buds, 

 these not only add more quickly to the size of the root but 

 also form a number of shoots. Now it is j'ust this which 

 causes the marbled appearance with the irregular stellated 

 spots in the parencJiyma, and the more this is encouraged, so 

 much the more will that valued structure thrive, which, as 

 is well known, quite does away with the side branches of 



