A Calorimeter for Rapid Determination of Heat Loss and Heat Production in Laboratory Animals

• Published in: Review of scientific instruments 1954-04, Vol.25 (4), p.370-377
• Main Authors: Lawton, Richard W., Prouty, Lawrence R., Hardy, James D.
• Format: Article
• Language: English
• ISSN: 0034-6748; 1089-7623
• DOI: 10.1063/1.1771067

A rapid calorimeter of the gradient type, suitable for laboratory animals, has been built and tested. A thin gradient layer (0.015‐inch woven glass tape) of relatively high thermal conductivity is used to line the walls of the calorimeter. The heat flow rate across the gradient layer is measured by means of 2152 copper‐constantan thermal junctions wired in series. With an input of 1 kcal/hour, 83.26 μv output is obtained. Total response time of the instrument together with the animal holder and metabolic equipment in place is of the order of 10–12 minutes. Heat loss by vaporization is measured by electric hygrometer sensing elements. Heat production is determined by a continual analysis of oxygen consumption using a Pauling analyzer. Heat loss, heat production, and rectal, skin, air, and wall temperatures are continuously recorded. Electric and alcohol calibrations and preliminary observations on monkeys are presented. The calorimeter should make possible critical experiments on thermoregulatory mechanisms of animals.