Respirometer

A compact unit for comparing rates of absorption or evolution of gases by small organisms during respiration. The apparatus consists of two stoppered boiling tubes connected by three way taps to either limb of a graduated manometer. One tube holds the organisms and has a syringe for altering the level of liquid in the manometer during set up. The other tube acts as a control thermo-barometer. C0₂ given off by the respiring organism is absorbed by potassium hydroxide in the experimental chamber resulting in a change in the level of liquid in the manometer tube.