1. The resistance of adrenal-deficient rats to bacterial intoxication has been significantly increased by an extract of the adrenal cortex. 2. This is shown both for acute intoxication with killed Bacillus typhosus and for chronic intoxication with killed Staphylococcus aureus. 3. During the height of the bacterial intoxication relatively large amounts of the cortical hormone are apparently required to maintain the animals. 4. It is considered probable that a human pyogenic infection imposes a severe load upon the adrenal cortex.