Abstract
In confirmation of the report by Andjus (1951) it has been found possible to reanimate rats that have been cooled to 2[degree]-3[degree]C and maintained at this temperature for periods up to 1 hour without cardiac or respiratory activity. The accumulation of metabolic carbon dioxide within the sealed vessel is an important part of the procedure if subsequent reanimation is to be attained. When the carbon dioxide is absorbed during the cooling phase, the animals remain active, their fall in body temperature is delayed and they do not recover from the hypothermia. Preliminary rewarming of the chest was unnecessary in the reanimation procedures described but rapid rewarming of the animal seems advantageous. The animals do not recover unless they are ventilated artificially when they are being rewarmed.