BOTANIC MATERIA MEDICA, 161 
a neutral crystallizable substance resembling 
crysophanic acid, and a peculiar ferment, 
The dose of the fluid extract is from % to 1 fluid 
drachm ; it is an efficacious and safe laxative in 
habitual constipation. 
Rubus, Blackberry, Rubus Villosus, Rubus 
Trivialis, and Rubus Canadensis.—-Natural order 
Rosacez, or Amygdalacez. The first being the 
high blackberry, and the second the low or trail- 
ing blackberry, but this latter genus was con- 
sidered by the late Professor Gray more properly 
the Rubus Canadensis and the true dewberry, 
which is a small trailing shrub, bearing its fruit 
rather earlier than the other species, The stems 
of the Rubus are recovered with prickles, with 
ovoidal leaves, usually having three to five ina 
group, with very distinctly marked edges, 
sharply serrated ; flowers white, with five petals; 
stamens numerous, with many pistils. The 
fruit is rather an aggregation of small fruits, 
conical in shape, very succulent, .and each little 
globe containing a hard seed. The berry is 
familiar to every one in the United States as a 
table fruit. The bark of the root is the part 
used in medicine, and occurs in tough, flexible 
pieces of a dark gray color, somewhat incliried 
to brown; odor little or none; taste strong and 
astringent. Theconstituents are tannin, gum, 
and resin, but no very thorough analysis has 
been made of the bark up to this time. Its 
medicinal properties are tonic and astringent; 
it has been, and is still, considered by the pro- 
fession a useful astringent, and the fluid extract 
is officinally recognized as a remedy, the dose of 
which is from 30 to 60 drops (2 to4c.c.) The 
