Boothby has found that the metabolism of patients who have recovered their health after hospital operations and who have been confined in the hospital between twenty and fifty days does not vary from the normal standard of DuBois. It has been found by DuBois that the basal metabolism in boys of twelve is 25 per cent. higher than for an adult of the same height and weight, or {50} calories per square meter of body surface; and that in boys of fifteen the metabolism is 11 per cent. higher than for the adult of the same size and shape, or {44} calories per square meter of body surface (unpublished work of DuBois). These results explain the large appetites of boys. Women show a metabolism which is 7 per cent. lower than that of men, or {37} calories per hour per square meter of surface. From the charts of the average heights and weights of men varying between fifteen and fifty-five years old, given by American life insurance companies, Mr. H. V. Atkinson, of my laboratory, has calculated the basal metabolism in a table here presented. Unfortunately, the weights given in these statistics include clothes worn by the individuals. The calculated heat production, however, is in each case based upon the weight without clothes. The table is computed from the following values: Calories per square meter Age in years of surface 15 44 20-50 40 55 37 The table may also be used as follows: To find the metabolism of-- Women between twenty to fifty years, multiply values for man by 0.93. Boys of twelve to thirteen years, multiply values for boys of fifteen years by 1.10. THE BASAL METABOLISM OF MEN _Calculated from values of the basal metabolism determined by the methods of DuBois and applied to a table showing the average weights of 221,819 men of different ages and heights compiled from the statistics of the medico-actuarial investigation of 1912._