Abstract
An apparatus is described which can be employed for the measurement of the oxygen consumption of one to six small animals in the weight range 25–500 g. The normal oxygen consumption of mice, rats and guinea pigs at 25° has been determined. The values obtained agree adequately with those of others. Evidence is given to support a claim that the guinea pig is, in some ways, a more suitable animal for the assay of metabolic stimulants than the rat or the mouse. Preliminary experiments have been made on the stimulant action of dinitrophenol and thyroxine on the oxygen consumption of guinea pigs.