Origin. - Prepared by triturating in a mortar finely powdered metallic arsenic and iodine until they are thoroughly mixed; or by mixing solutions of arsenous and hydri-odic acids, and evaporating. It should contain not less than 82.7 per cent. of iodine and 16.3 per cent. of metallic arsenic.

Description and Properties. - Glossy, orange-red, crystalline masses, or shining, orange-red, crystalline scales, having an iodine-like odor and taste; gradually losing iodine on exposure to air and light. Soluble in 12 parts of water and in about 28 parts of alcohol. Arsenic iodide should be kept in glass-stoppered vials, in a cool place, protected from light.

Dose. - 1/32-1/8 grain (0.002-0.008 Gm.) [1/10 grain (0.005 Gm.), U. S. P.].

Official Preparation

Liquor Arseni et Hydrargyri Iodidi - Liquoris Arseni et Hydrargyri Iodidi - Solution of Arsenic and Mercuric Iodide - (Donovan's Solution). - Strength: 1 per cent., each, arsenic iodide and mercuric iodide.

Description and Properties. -A clear, pale-yellowish liquid, without odor, and having a disagreeable metallic taste.

Dose. - 1-10 minims (0.06-0.6 Cc.) [4 1/2 minims (1 Cc.) U. S. P.].