Definition of Caustic:
Escharotics (Gr. a scab, scar) and Caustics are Irritants or Counter-irritants which destroy tissue when applied, by abstracting its water, or by combining with the albumin of the skin, or by corrosive deoxidation of the tissues, thus causing a slough: mineral acids, phenol, chromic acid, lime, potassium and sodium hydroxides, dried alum, silver nitrate, zinc chloride, copper sulfate, corrosive mercuric chloride, mercuric oxide and nitrate, bromine, high heat, electric cautery, boiling water, arsenic trioxide [Culbreth1927, pg 46].