PARTS OF ROOTS AND STEMS. 
167 
tion of heat to the bark is said to produce the same 
result. 
Description. — In single or double quills and trans- 
versely curved pieces, 2 to 20 cm. long, 1 to 3 cm. in 
diameter, bark 0.3 to 1 mm. thick ; outer surface dark 
brown or purplish black, longitudinally wrinkled, with 
numerous lenticels 1 to 3 mm. long, and with grayish 
patches of foliaceous lichens and groups of light-brown 
or brownish black apothecia ; inner surface yellowish 
or dark brown, smooth, longitudinally striate, and 
reddened by alkalies; fracture short, with projecting 
bast fibers in inner bark; odor slight; taste slightly 
bitter. 
Constituents. — Frangulin, a crystalline glucoside, 
which yields emodin; frangulic acid, another crystal- 
line glucoside resembling the cathartic acid of senna ; 
rhamnoxanthin, a coloring principle; resin; tannin; 
starch; calcium oxalate, and 5 to 6 per cent, of ash. 
RHAMNCJS PUKSHIANA (Cascara Sagrada). 
The bark of Rhamnus Purshiana (Fam. Rhamnacese), 
a shrub indigenous to Northern California, Washington 
and Oregon. The bark is collected in spring and early 
summer, and kept at least one year before being used. 
Description. — Usually in flattened or transversely 
curved pieces, occasionally in quills 2 to 10 cm. long, 
1 to 3 cm. in diameter, bark 1 to 3 mm. thick ; outer 
surface dark brown or brownish red, frequently com- 
pletely covered with grayish or whitish lichens, several 
of which are peculiar to this bark, and with small 
groups of brownish apothecia, longitudinally wrinkled, 
sometimes with numerous lenticels 3 to 6 mm. long; 
inner surface light yellow or reddish brown, smooth, 
longitudinally striate, turning red when moistened 
with solutions of the alkalies; fracture short, with pro- 
