1. The carpet type of Barcroft respiration apparatus previously used by Gunn for cockroaches gives results comparable with those now obtained with a new basket type.
2. Desiccated cockroaches use oxygen at the same rate per animal as undesiccated specimens. If, however, the rates are calculated with reference to the weight of the animal at the time of the experiment, since the desiccated animals tested had lost about 25% of their original weight, their rates of oxygen consumption appeared to have gone up.
3. Both normal and desiccated animals used oxygen slightly faster in moist air than in dry. Part of this increase must be attributed to a higher body temperature in moist air at 25° C. than in drier air at 25° C. Part of it may be due to greater activity in moist air than in dry, slight though the activity was in both cases.
4. There is no reason to believe that, at a given body temperature, air humidity influences basal metabolic rate.
All the experimental work was done by C. A. C.