On the Reflection and Re-emission of Electrons from Metal Surfaces: and a Method of Measuring the Ionizing Potential of Such Surfaces.

at 17 years. The insensible perspiration for these girls per kilogram of body weight per hour was as follows: 0.72 gram at 13 years, 0.71 gram at 14 years, and 0.77 gram at 15 years. The respiratory quotients of groups of 12 girls each, about 7 to 8 hours after a light meal, were 0.81, 0.81, 0.78, and 0.79. The basal heat production per kilogram of body weight per 24 hours decreases regularly with increasing age from 29.9 calories at 12 years 2 months to 21.7 calories at 17 years. The heat production per square meter of body surface per 24 hours likewise decreases, but not so regularly, with increasing age, ranging from 928 calories at 14 years to 745 calories at 16 years. The metabolism of groups of young girls can be predicted from the general curve indicating the heat production per kilogram of body weight referred to age to within an average error of = 3.1%. The prediction of the heat production per unit of body weight is somewhat better than that per unit of surface area. The curves representing the heat production per kilogram of body weight referred to weight and per square meter of body surface referred to weight for these groups of girls from 12 to 17 years of age blend with remarkable uniformity with similar curves based upon the measurement of a large number of normal girls from birth to 12 years of age. No influence of puberty or the prepubescent stage is clearly proven in any of the results. The details of the entire research are shortly to appear in the Boston Medical and Surgical Journal.