“…In regard to the transformation of benign into malignant tumours, Ewing concludes that some benign growths appear to originate from inflammatory processes and that the involved tissues may present all gradations between single proliferative activity, adenoma, and carcinoma. Laurens (1941) has pointed out that since carcinogenesis by ultra-violet irradiation is usually preceded by severe erythema, it is possible that the production of neoplasia is related to chronic inflammation. In general, *Aided by grants from the U.S. Public Health Service.…”