BOOTS AND RHIZOMES. 
145 
light-brown powder; fracture somewhat granular; 
internally light brown; odor distinct; taste bitter, 
astringent and gritty. 
Light and spongy rhizomes should be rejected. 
Constituents. — The principal constituent appears 
to be a glucoside which yields chrysophanic acid, 
emodin and rhein ; the drug also contains tannin, several 
resins, considerable starch, calcium oxalate, and yields 
about 15 per cent, of ash. 
Allied Plants. — The rhizomes of other species of 
Rheum are also used to a limited extent, as English 
or Austrian rhubarb from Rheum rhaponticum ; they 
are more or less cylindrical, distinctly radiate, and con- 
tain, besides chrysophanic acid, rhapontin. Rheum 
palmatum, which is cultivated in France, Germany 
and Russia, produces rhizomes that are lighter in color 
and less valuable than the Chinese rhubarb, the con- 
stituents being similar to those of Austrian rhubarb. 
ACONITUM (Aconite). 
The tuberous root of Aconitum Napellus (Fam. Ranun- 
culacese), a perennial herb growing in the mountainous 
districts of Europe, Asia and Western North America. 
It is also cultivated in temperate regions. The com- 
mercial supplies are obtained from England and Ger- 
many, and in England the root is collected in autumn 
from cultivated plants after the overground parts have 
died down, whereas in Germany the roots are collected 
from wild plants during the flowering period, this 
being done to distinguish the particular species yield- 
ing the drug. The root should be carefully dried. 
Description. — More or less conical or fusiform, 4 to 
10 cm. long, 5 to 20 mm. in diameter; externally dark 
brown, smooth or somewhat wrinkled, the upper por- 
tion with a bud, remains of bud-scales or stem-scars, 
