An Easily Constructed Rat Metabolism Apparatus Which Automatically Records Oxygen Consumption and Animal Activity

Abstract

An apparatus is described for determination of the respiratory metabolism of rats, the significant feature of which is a means of obtaining continuous graphic record of oxygen consumption of sufficient sensitivity to permit selection and accurate measurement of strictly basal intervals of even short duration. This is effected by a modification of Hanan's micro-spirometer which permits registration of the water siphoning into the oxygen reservoir to replace oxygen as it is used by the animal. Carbon dioxide is measured only for longer intervals of ½ hour or more by absorption and titration in barium hydroxide; the carbon dioxide absorbers serve also as the pumps to keep the air within the closed system in circulation.