In a recent communication1 it was shown that the relation between heat production and insensible perspiration was the same in children as in adults.2 Under standard conditions of temperature, humidity and clothing, both adults and children lose an average of 24 per cent of their calories in vaporization of water through the skin and lungs. This proportion is maintained in sleep, during activity (insufficient to cause sweating), following the ingestion of food, in disease and with fever, providing the body temperature does not change during the observation.
If it were found that infants when exposed to similar conditions lost the same percentage of calories in vaporization as adults and children, the evidence would be adequate to establish a uniform relation between production of heat and loss of heat by vaporization (elimination of water) from early infancy to old age, despite the enormous differences in metabolic rates. The present