ARSENUM—ARSENIC
Origin.—The world’s supply of arsenic and arsenic compounds at the present time is obtained from Germany, Spain, England, Canada and portions of the United States, as Montana and Washington, where considerable quantities of arsenic are being produced as a by-product in the smelting of copper ores. Arsenic ore is roasted and purified by sublimation, before it is used for medical purposes.
ARSENI TRIOXIDUM—ARSENIC TRIOXIDE
ACIDUM ARSENOSUM—ARCENOUS ACID
(White Arsenic)
Derivation.—Arsenical ores are roasted or conducted into condensing chambers and purified by sublimation.
Properties.—A heavy solid, occurring either as an opaque, white powder, or in irregular masses of two varieties; the one amorphous, transparent and colorless, like glass; the other crystalline, opaque, and white, resembling porcelain. Frequently the same piece has an opaque, white outer crust enclosing the glassy variety. Contact with moist air gradually changes the glassy into the white opaque variety. Both are odorless and tasteless. The glassy variety dissolves slowly in thirty parts of water; the porcelain-like in eighty parts of water. Arcenous acid is sparingly soluble in alcohol, but soluble in glycerin, hydrochloric acid and solutions of the alkali hydrates and carbonates. When heated to 424°, arcenous acid is completely volatilized without melting.
Incompatibles.—Lime water, salts of iron and magnesia.
Dose.—Horses, 1 to 5 grs.; cattle, 2 to 8 grs.; sheep and pigs, 1 to 2 grs.; dogs, 1⁄30 to 1⁄10 gr.