RHEUM PALMATUM. 
123 
after they are cleaned, by which meansr they are deprived of a 
quantity of gummy matter; without this precaution, he says, 
even when apparently perfectly dry, they cannot be reduced to 
powder, but become pasty under the pestle until they are two years 
old, and even then the powder is apt to concrete into lumps. 
Twenty-five pounds of the recent root give only about 8 lbs. of the 
dry. The leaf stalks of rhubarb are the part of the plant used for 
culinary purposes; they contain a pleasant acid, and when made 
.into tarts, are not unlike quinces in their flavour. 
Sensible AND Chemical Properties, Analysis, &c. The 
best rhubarb, known by the name of Turkey, comes to us id small 
pieces, each perforated with a hole in the middle, by which it has'been 
strung fordrving; it should have a clear yellow colour, be dry, 
solid, compact, and moderately heavy; brittle, and when recently 
broken, appearing marked with yellow or reddish veins mixed with 
white ; easily pulverizable, and forming a powder of a fine bright 
-yellow, having a peculiar, nauseous, aromatic sinell, and a bitterish, 
somewhat astringent taste, feeling gritty under the teeth, and 
colouring the saliva; the larger pieces should be broken, in the 
choosing of rhubarb, to ascertain that they are not decayed within. 
The rhubarb brought from Canton is heavier, harder, and more 
compact, seldom perforated with holes, and either in long pieces, or 
with two flat sides ; it is less aromatic, and appears to have been 
prepared with less care. 
According to the analysis of Messrs. Brande, Henry, Schrauder, 
and others, rhubarb contains more or less of the following con- 
stituents ; gum, starch, extractive, resin, albumen, lignum, oxalate Of 
lime, phosphate of lime, malate of lime, and water. - 
The principal constituent of rhubarb is extractive matter, soluble 
in alcohol and water ; it also contains a volatile odorous matter, on 
* which its peculiar smell, and activity as a purge diepend ; for whi^n 
dissipated by age, or by any preparation to which it has been 
subjected, the powers of the medicine are destroyed; it likewise 
contains some tannin, which resides entirely in the dark coloured 
veins, and to which we may ascribe the astringent property of 
rhubarb already noticed. 
Medical Properties and Uses. Rhubarb is a mild and safe 
aperient, operating without violence, and peculiarly useful for preg- 
nant women, or children ; in some people however it occasions 
griping, and very generally, after its purgative effects have ceased, 
renders the habit costive; its great bulk isi a further objection to its 
use as an aperient remedy, the usual dose for an adult being half a 
