The production of cancer by pure hydrocarbons. - Part II

The experiments described in this and the preceding communications form part of a systematic search for cancer-producing activity among the whole group of polycyclic aromatic hydrocarbons. In selecting for study the compounds to be discussed in the present communication, attention has been directed mainly to three considerations:— (a ) A pure hydrocarbon of known chemical structure which should have the same fluorescence spectrum as carcinogenic mixtures of unknown composition has been sought. (b ) The rapid appearance of tumours in mice upon application of certain carcinogenic tars and mixtures affords some evidence for the existence of pure compounds of more powerful carcinogenic activity than 1 : 2 : 5 : 6-dibenzanthracene, and the production of such substances has been attempted. (c ) The chief object has been to ascertain the molecular conditions which are necessary for the development of carcinogenic activity, and to establish a relationship between cancer-producing power and chemical constitution.