1. A model of anthrax infection in rhesus monkeys closely simulating human inhalation anthrax has been employed to study the course of the illness and methods of recognition and therapy.
2. Roentgenographic evidence of mediastinitis was detected early in the illness and served as a suitable indication for starting treatment.
3. Therapy with either penicillin or tetracycline appeared efficacious when started at the time chest roentgenograms first evidenced disease.
4. Isolation of penicillin-resistant B. anthracis from an animal dying during treatment with penicillin is reported.