(Chromic Anhydride; Chromic Acid. U. S. P.)

Origin - Dissolve potassium bichromate in sulphuric acid and water; decant; heat with more sulphuric acid; cool, and crystallize.

Description and Properties. - Small, needle-shaped crystals or rhombic prisms, of a dark purplish-red color and metallic luster; odorless; destructive of animal and vegetable tissues; deliquescent in moist air. Very soluble in water, forming an orange-red solution. When brought in contact with alcohol, ether, glycerin, and other organic solvents decomposition takes place, sometimes with dangerous violence. Chromium trioxide should be kept in glass-stoppered bottles, and great caution should be observed to avoid bringing it in contact with organic substances, such as cork, tannic acid, sugar, alcohol, etc., as dangerous accidents are liable to result. Used externally.

Physiological Action and Therapeutics. - Chromium trioxide is a powerful caustic, deodorant, and disinfectant. It coagulates albumin and oxidizes organic matter. Its action is slow, and the pain following its application is usually of shorter duration than that of most caustics. Weak solutions are stimulant, astringent, and alterative.

Chromic acid is used in the form of a paste or in solutions of various strengths for the removal of syphilitic warts, vegetations, condylomata, etc. As a caustic and stimulant application in many diseases of ear, nose, and throat it serves a valuable purpose, as in nasal polypi, enlarged tonsils, chronic and syphilitic laryngitis, laryngeal papillomata, chronic superficial glossitis, tuberculosis of the tongue, ozena, ulcerations of the mouth, etc.

A 10 per cent. solution of chromic acid has been found serviceable in the treatment of hyperidrosis.

A solution of I part of chromic acid in 40 parts of water makes an efficient lotion for disinfecting foul ulcers and as an injection in gonorrhea, leucorrhea, etc.

Sessile piles and salivary fistulae are efficiently treated by touching the parts with pure chromic acid.