Acidum Chromicum. CrO3. Occurs in the form of brilliant crimson-red prisms, very deliquescent and readily soluble in water.

Med. Prop. and Action. Powerful caustic; used in substance made into a paste with water, its action is exceedingly slow and gradual, but deeply penetrating. In saturated solution its action is less penetrating and less gradual. By using a solution more or less dilute, the action may be graduated according to the degree of effect desired. It is a powerful oxidizer, yielding its oxygen readily to organic matter, which is thereby dissolved. Smaller animals (mice, birds, &c.; were so completely dissolved by the acid in fifteen or twenty minutes that no trace of their bones, skin, hair, claws, or teeth could be discovered. It is not given internally.

869. Therapeutic Uses

In Cancerous and other Ulcerations, in which a deeply penetrating gradual caustic is desired, Chromic Acid appears to be specially indicated. The trials of Dr. Ure,* Sigmund, Heller, and others have proved its efficacy and safety. The pain attendant on its use is incomparably less than that caused by Sulphuric or Nitric Acid, Vienna paste, &c, not even disturbing the patient's sleep. From its deeply penetrating action, however, much care is necessary in its use, and it should in no case be laid over a surface to be cauterized in a layer deeper than a line in thickness. The surrounding parts require to be carefully protected by folds of lint, strips of plaster, &c. Its tendency to penetrate too deeply is the great objection to its use. Sigmund employed with advantage a concentrated solution for the destruction of Syphilitic Condylomata, and Mr. Marshall found it effectual for removing Warts and other Morbid Growths from the Genital Organs. The solution employed was of the strength of 100 grains to fj. of distilled water. It has also been employed for the removal of External HAemorrhoids. Dr. Hairion§ employed it with advantage in the treatment of Obstinate Granular Ophthalmia. He applied a solution of equal parts of the acid and distilled water by means of a camel's-hair brush, at intervals of four, six, or eight days. Although he states that the application is neither very painful nor followed by any great amount of reaction, it admits of a great doubt how far so deeply a penetrating caustic can with safety be applied to so delicate an organ as the eye.

Cimicifuga Racemosa. See Actea Kacemosa.