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SELECTED ARTICLES. 
tected in larger proportions than 3 or 4 per cent. To these 
let us add, the necessity which exists of a perfect comprehen- 
sion of what is meant by the terms, resin, yellow matter, 
bitter of rhubarb, rheine, rhabarbarin, rhabarbarine and 
caphopicrite, &c, by which the different products are desig- 
nated. 
1st. The yellow matter, the rhabarbarin and rheine ap- 
pear to be the same substance, in a greater or less degree of 
purity. 
2d. The bitter resin, the bitter of rhubarb, the rhabarba- 
rine, and the caphopicrite may easily be confounded, especi- 
ally, as Caventou observes, if this bitter matter is nothing else 
than a mixture of the preceding yellow resinous substance and 
a bitter principle, soluble in water; a compound, which from its 
properties is no longer similar to the yellow resin, but pos- 
sesses particular characters. 
3d. Furthermore, many experiments detect gum, or a sub- 
stance which resembles it in character so much, as to lead to 
the belief, that it is more or less pure, according to the che- 
mists who have obtained it. 
4th. Finally — it is lignin, and not pectin, which has been 
supposed to exist in the insoluble part, and which Hornemann 
has isolated under the name of matter extracted by potassa. 
These propositions established, I can now pass to the chemi- 
cal analysis which I have made of the roots of the Rheum 
australe, cultivated near Paris. 
Examination of the roots of indigenous Hheum australe. 
Physical Characters. The recent roots of this vegetable 
were all extremely healthy, but of a size which evinced that 
they had not received, either from the age of the vegetable, 
or from the soil or climate in which they had grown, all the 
developement manifested by the rhubarb roots met with in 
commerce. They were only as large as the two fingers, — 
and of an elongated cylindrical form; of a brown colour ex- 
ternally, and marbled orange-yellow internally; they were 
surrounded by a thin cortical portion, easily separated; they 
