Abstract
The purpose of these experiments was to decide whether the protection against the toxic effects of O2 afforded by adrenalectomy or treatment with COCl2 might be explained by a generalized depression of the pO2 in the tissues. The pO2 in the tissues was estimated by injecting pockets of 7% CO2, plus 7% O2 in N under the skin on the backs of mice and analyzing the gas the following day. The Co injections produced an increase in the pO2 of the gas pockets which began the first day after beginning treatment. Adrenalectomy had no effect on the pO2. Since a decreased pO2 was not observed it was concluded that the protection of the two treatments against O2 toxicity is not due to diminished gas transport or utilization and must be ascribed to other factors.