Previous workers who have used the balance to measure the insensible perspiration of infants have not adequately controlled the technic of the measurements or fully recognized the influence of extraneous factors. One group of observers1 held that the insensible perspiration, measured by the method of weighings, varies from day to day, even under the same conditions; whereas another group2 maintained that the rate is intrinsically constant and that the variations so frequently reported arise from extraneous factors not carefully controlled. Studies with the calorimeter and the respiration chamber offer presumptive evidence in favor of the latter view. They show a striking correlation in adults,3 children4 and infants5 between the production of heat and the vaporization of water through the skin and the lungs under basal and other conditions.
The meager and conflicting evidence available in the literature prompted these preliminary studies of the various physiologic