A constant pressure respirometer for medium-sized animals.

A constant pressure respirometer, in which the manometer is drilled from a solid block of perspex and in which the volumetric measuring device is a standard micrometer head, is described. The apparatus has a wide mouthed respiration chamber and will therefore accomodate larger animals than the conventional constant volume and differential respirometers. With a kerosene manometer the sensitivity of the respirometer corresponds to a volume change of 1.8 cu.mm.