Since the proposal has been made that the production of curable cancer of the skin by irritations which are not carcinogenic to internal organs may save some lives by preventing cancer of the internal organs, it becomes important to examine the data on which this proposal rests. On the basis of their figures, Peller and Stephenson1assume that cancer of the skin and lip exerts a beneficial effect in preventing the development of cancer elsewhere. So startling a suggestion as this deserves careful analysis. They show that in a total of 875,000 person-years of observation of United States Navy personnel there were ninety-one cases of cancer of the skin and lip with eleven deaths in a total of 113 cancer deaths.2Of these person-years of observation, over half (496,830) represented subjects below 30 years of age and hence not particularly useful for a study of cancer incidence. They