_Cusparia, or Angustura Bark._
QUALITIES. _Form_, pieces covered with a whitish wrinkled thin
epidermis; the inner surface is smooth, of a brownish yellow colour.
_Odour_, not strong, but peculiar. _Taste_, bitter, slightly aromatic,
and permanent. CHEMICAL COMPOSITION. Cinchonia, resin, extractive,
carbonate of ammonia, and essential oil. SOLUBILITY. Its active matter
is taken up by cold and hot water, and is not injured by long decoction,
but the addition of alcohol precipitates part of the extractive. Alcohol
dissolves its bitter and aromatic parts, but proof spirit appears to be
its most complete menstruum. INCOMPATIBLE SUBSTANCES. _Sulphate of
Iron_; _Sulphate of Copper_; _Oxy-muriate of Mercury_; _Nitrate of
Silver_; _Tartarized Antimony_; _Sub-acetate_, _and Acetate of Lead_;
_Potass_; and perhaps the _Mineral Acids_, for they produce
precipitates, as do also the _infusions of Galls_, and _Yellow
Cinchona_. MEDICINAL USES. Stimulant and tonic; it does not, like
cinchona, oppress the stomach, but imparts a degree of warmth, expels
flatus, and increases the appetite for food: with respect to its powers
in the cure of intermittents, many doubts are entertained. FORMS OF
EXHIBITION. In substance, infusion, decoction, tincture, or extract; its
nauseous taste is best disguised by cinnamon. DOSE of the powder, grs.
v. to ℈j; of the infusion or decoction, f℥j; in large doses all the
forms are liable to produce nausea. _Form. 58._ OFFICINAL PREP. _Infusum
Cuspariæ._ L. _Tinct. Bonplandiæ Trifoliatæ._ E. _Tinct. Angusturæ._ D.
ADULTERATIONS. There is found in the market a particular bark, which has
been called FINE ANGUSTURA, but which is of a different species, and is
a very energetic poison. This bark is characterized by having its
epidermis covered with a matter which has the appearance of rust of
iron, and which, moreover, possesses certain chemical properties of this
metal; for if water acidulated with muriatic acid be agitated in contact
with its powder, it assumes a beautiful green colour, and affords with
an alkaline prussiate, (_Hydro-cyanate of Potass_) a Prussian blue
precipitate. Late researches have detected the presence of an alkaline
element in this bark, on which the name of _Brucia_ has been bestowed.
When this alkali is dissolved in boiling alcohol, and crystallized by
spontaneous evaporation, it yields colourless and transparent crystals
in the form of oblique quadrangular prisms.