“…Clinical experience argued for the possibility that arsenic works as a carcinogen primarily in pathologically altered terrain-skin hyperkeraroses, cirrhotic liver, (vineyards) chronic bronchitis from industrial irritants, and so on. Nevertheless, activation analysis of epitheliomas has shown smaller quantities of arsenic in the epitheliomas themselves than in the neighboring healthy skin (36). It is well known, however, that substances with delayed effects, e.g., beryllium, are not present in the affected tissue in important quantities at the time pathological changes manifest themselves.…”