ORIGIN.--Belladonna is the leaves of a plant known as deadly nightshade.
It grows wild in some parts of Great Britain, and is also cultivated to
a great extent. The dried leaves of atropa belladonna yield, when
assayed by the U. S. P. process, not less than 0.35 per cent of
mydriatic alkaloids. Usually of a dull brownish-green color, the leaves
much wrinkled and matted together, frequently with the flowering tops
intermixed; odor distinctly narcotic, especially on moistening; taste
somewhat bitter and acrid. Contains not less than 0.5 per cent atropine.
The powdered leaves are characterized by few hairs and numerous small
arrow-shaped crystals of calcium oxalate.
DOSE.--Of the powdered leaves, horses and cattle, ¹⁄₂ to 1 oz.; sheep
and pigs, ¹⁄₂ to 2 dr.; dogs, 1 to 5 grs.