POWDERED DRUGS. 
289 
pores; parenchymatous cells large, thin-walled, with 
large simple pores. Powder containing seeds with 
numerous oil globules, outer epidermal cells with re- 
ticulated thickenings ; stone cells nearly isodiametric 
or irregular, walls straight or undulate, more or less 
thickened, strongly lignified and with simple pores. 
60. Linum. — (Linseed or Flaxseed Meal). Lemon- 
yellow ; fragments of seed-coat with mucilaginous epi- 
dermal cells, light-brown tabular pigment cells, and 
small yellowish stone cells ; parenchyma-cells thin- 
walled, containing oil and aleurone; starch none or 
not more than ten granules to a milligramme of pow- 
der; a fixed saponifiable oil not less than 30 per cent.; 
ash not more than 35 per cent. 
61. Sinapis Alba. — Light yellow ; fragments of seed- 
coat with mucilaginous epidermal cells, a sub-epider- 
mal collenchymatous layer, a yellowish or nearly col- 
orless pigment layer, and a layer of stone cells ; oil 
globules and aleurone grains numerous ; starch none or 
not more than ten granules to a milligramme of powder. 
62. Sinapis Nigra. — Yellowish brown ; fragments of 
seed-coat with mucilaginous epidermal cells, a layer of 
brownish-red pigment cells and a layer of stone cells; oil 
globules and aleurone grains numerous ; starch none or 
not more than ten granules to a milligramme of powder. 
p STONE CELLS, IF PRESENT, NOT WELL DEFINED. 
1. CONTAINING POLLEN GRAINS. 
63. Arnicse Flores. — Yellowish brown ; pollen grains 
spherical, with numerous centrifugal projections, three- 
pored, 25 to 35 / j . in diameter; non-secretion hairs of 
three kinds — either unicellular, five or six-celled or 
consisting of a pair of united unicellular hairs with 
numerous pores on the dividing wall ; secretion hairs 
of three kinds — either with a large unicellular stalk 
