ON SIBERIAN AND BUCHARIAN RHUBARB. 125 
Chemistry of Rhubarb. — Grassman, to whose paper I 
have already several times referred, sent to Buchner, from 
St. Petersburg, four sorts of rhubarb, which were chemi- 
cally examined by Dr. J. E. Herberger, some of whose re- 
sults I here subjoin. I may premise, however, that the 
rhubarb which he calls Chinese, is doubtless the sort known 
in England as Russian. The white rhubarb is the kind to 
which I have referred in my Elements of Materia Medica, 
vol ii. p. 1179, 2d edition. 
Dr. Herberger subjected the rhubarbs to the successive 
action of ether, alcohol, and water, so that the residue 
which was unacted on by ether, was subjected to the action 
of alcohol, and the residue from which alcohol extracted 
nothing more, was then submitted to the action of water. 
The residue which was thus undissolved by ether, alco- 
hol, and water, was then incinerated. The lime contained 
in the obtained ashes was afterwards converted into oxalate 
of lime by means of neutral oxalate of potash. In this way 
was obtained the amount of oxalate of lime mentioned in 
the subjoined table : 
Decigrammes [2=3.0808 grs. Troy] of the following 
Rhubarbs. 
Buchanan 
Chinese. 
[Russian/ 
White. 
Siberian. 
Rhapontic 
Dry Ethereal Extract . . 
" Alcoholic do . . . 
u Aqueous do . . 
Oxalate Lime . . . . 
Other constituents of the > 
Ashes — Woody Fibre. j 
Grammes. 
0-0005 
0030 
0-0095 
0035 
Grammes. 
0-0005 
0-0020 
0-0100 
0-0040 
Grammes 
0-0005 
0-0020 
00110 
0-0043 
Grammes. 
0010 
0-0030 
00120 
0-0015 
0-0165 
0-0035 
0-0170 
0030 
■ 0-0178 
0.0022 
0-0175 
00025 
0-2000 
0-2000 
0-2000 
0-2000| 
The white rhubarb, it will be perceived, contains more 
oxalate of lime than the other sorts. This constituent, with 
the starch, is the cause of the whiteness of this sort of rhu- 
barb. 
