It has long been known that certain benign and malignant cutaneous tumors tend to appear more frequently in older persons, but progressive extenion of the life span has magnified their importance. The usual chart, presenting incidence of tumors according to ages, diagrams the total number of the tumors in each age group. This method is subject to misinterpretation because the percentage of the population at large in each age group is not considered. For instance, the highest numerical incidence of melanoma is at about 54.5 years of age; then the curve falls until it is low in very old persons. However, the relative age incidence is highest between 60 and 70 years of age. It was emphasized by Weller, that for estimating the real age incidence of microscopically proven carcinoma (1913) and sarcoma (1915), the percentage of tumors in each age group must be divided by the percentage of that