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ARSENIOUS ACID. I95 ; —
ACIDUM ARSENIOSUM—ARSENIOUS ACID.
WHITE OXIDE OF ARSENIC ARSENIOSUM OXIDUM.
Formula.—AS2O3.
Arsenic-Arsenicum, the metal from which arsenious acid is
obtained, is not employed as a medicine in its native state. It is
combined with sulphur and certain metals, and is hard, brittle,
crystalline, of a steel-gray color. When heated to a dull red-
ness, it volatilizes in the form of a colorless vapor, with an odor
like that of garlic— alliaceous. It is generally found in cobalt
ore. It is a powerful poison.
Derivation.—Arsenious Acid is obtained by roasting arsenical
ores, and purifying by sublimation. It is in the form of a fine
white powder, which is often adulterated with chalk, lime, etc.
hence it is better to procure it in the solid form or lump, which
is of a milk-white color externally, and often perfectly transpar-
ent internally. It has no odor, and is therefore liable to be mis-
taken for more innocent substances, and scarcely any taste, or
merely a faint, sweetish impression.
Medical Properties and Action.— Arsenious Acid in large doses
is a virulent irritant poison, but in doses of one-sixtieth to one-
twelfth of a grain, properly administered, is a tonic increasing
the appetite and improving the secretions, both in quality and
quantity. In large doses, in the form of Fowler's Solution
Liquor Potassii Jrsenitis (prepared by boiling 64 grains of arsen-
ious acid and bicarbonate of potassium, each in half a fluid ounce
of distilled water, then adding 12 fluid ounces more of distilled
water, half a fluid ounce of compound spirit of lavender, and
afterwards water enough to make the solution measure a pint)— it
is a powerful antiperiodic. In small doses, administered for a
considerable time, it modifies the blood, and through it nutrition,
so as to remove various morbid conditions. When continuously
used, a sensation of heat in the throat, oesophagus and stomach
is sometimes experienced, nausea, pain in the stomach and occa-
also, great languor or depression of spirits, with
sional vomiting ;
redness of the eyes, swelling of the eyelids and oedema of the
face ; hence, at the first evidence of such symptoms, the remedy
should be discontinued until they have passed away. When