A Simple Calorimeter for the Simultaneous Determination of Heat Loss and Heat Production in Animals

Abstract

This paper describes a new type of gradient calorimeter which permits the rapid simultaneous measurement of respiratory metabolism and heat loss. It uses the temperature difference between the inner and outer aspect of a fixed transitional layer of air rather than adiabatic principles. (W. O. Atwater and F. G. Benedict, ``A respiration calorimeter with appliances for the direct determination of oxygen,'' Publication 42, Carnegie Institute of Washington (1905); G. Lusk, Arch. Int. Med. 15, 793 (1915); E. F. DuBois, Basal Metabolism in Health and Disease (Lea and Febiger, Philadelphia, 1936), third edition; Forester, Ferris, and Day, Am. J. Physiol. 146, 600 (1946); L. Love and H. C. Bazett, Fed. Proc. 7, 74 (1948); C. P. Yaglou, ``Thermal insulation of clothing,'' unpublished data; T. Benzinger, personal communication.) Application of gradient principles to calorimetry so simplifies heat loss determinations that they become the easiest and most accurate part of the procedure.