The claim made for the escharotic paste (antimony trisulfide, zinc chloride, and bloodroot) was selectivity: that it destroyed malignant tissue while leaving healthy skin intact. Visible tissue destruction on contact is real and was the treatment’s one directly observable effect, which gave the selectivity claim surface plausibility. The American Cancer Society’s review states the paste “can severely burn, disfigure and scar the skin,” and a 2005 peer-reviewed dermatologic-history review of escharotic agents situates it within a caustic tradition that is not tissue-selective. The visible burn stands in as a surrogate for a genuine anti-cancer effect it does not demonstrate; deeper or non-cutaneous malignancy is untouched beneath a destroyed skin surface.