POWDERED DRUGS. 
276 
Rounded masses 203. Heavy Magnesia 
Very light 204. Light Magnesia 
3. Insoluble in acetic acid. 
* Soluble in nitric acid. 
Tetragonal or cubical crystals, 
205. Precipitated Calcium Phosphate 
Acicular crystals 206. Calcium Sulphate 
Rhombic prisms or crystals of various sizes, 
207. Barium Sulphate 
Irregular fragments 208. Terra Alba 
POWDERS OF A GREENISH COLOR. 
In this group are included all those drugs which in 
a powdered condition are of a light-green, yellowish- 
green or dark-green (sap-green) color. Most of the 
powders of the leaves and herbs belong to this class. 
I. CRYSTALS OF CALCIUM OXALATE 
PRESENT. 
A. CALCIUM OXALATE CRYSTALS ROSETTE- 
SHAPED. 
a. Secretion and Non-Secretion Hairs Present. 
1. Cannabis Indica. — Dark green ; non-secretion hairs 
one-celled, more or less curved, with numerous slight 
projections, and sometimes with cystoliths of calcium 
carbonate ; secretion hairs two kinds — either with 
short unicellular or multicellular stalks and eight to 
sixteen-celled glandular heads; calcium oxalate crystals 
rosette-shaped, about 20 p in diameter ; numerous oil 
globules and resin fragments; few nearly spherical 
pollen grains 25 to 35 p in diameter, with numerous 
centrifugal projections, in among club-shaped unicel- 
lular hairs of style; ducts spiral or with simple or 
bordered pores ; sclerencliymatous fibers long, thin- 
walled, non-lignified, and with few simple pores; lati- 
ciferous vessels with reddish-brown contents. When 
mature seeds are present, palisade-like stone cells occur, 
which are very thick-walled, and have a small lumen. 
