III. The experimental induction of pulmonary tumors and changes in the respiratory epithelium in C57BL mice following their exposure to an atmosphere of ozonized gasoline

PREVIOUS publications we have reported I the production of skin tumors in C57BL mice after painting with the oxidation products of aliphatic hydrocarbons and the production of pulmonary tumors in strain A mice after exposure to an atmosphere of ozonized gasoline.*+10 This report presents the pulmonary findings in C57BL mice after the simultaneous exposure with strain A mice to an atmosphere of ozonized gasoline.The production of pulmonary tumors and changes in the respiratory tract epithelium in these mice will be discussed. METHODThe technique of smog synthesis and its chemical properties have been described by Haagen-Smit,S and the adaptation of his technique for our experimental studies has already been reported.'*8 In the same publications we outlined the methods of animal housing, feeding, and care and described the chamber used for the exposure of the test and control experimental animals.In reporting the data from our studies with strain A mice we noted that C57BL mice were being simultaneously exposed under identical environmental conditions.The C57BL mice, because of their low incidence of spontaneous pulmonary tumors, were undisturbed throughout their life in