DURING the summer of 1948, an investigation of the antimicrobial therapy of typhoid was started in Guadalajara, México The study was conducted as a joint project between investigators from the University of Guadalajara and the New York Hospital—Cornell University Medical College. Three drugs were studied: polymyxin B, aureomycin, and chloramphenicol.1 Ample clinical and laboratory facilities were available at the Hospital Civil, the teaching hospital for the University of Guadalajara. Nevertheless, it was necessary to study approximately one half of the series of patients in their homes in the city or in the neighboring villages because of the reluctance of some patients to enter any hospital. During the period of the study, a total of 51 patients with typhoid were treated with one of these drugs. Six of the series were treated in New York city2 and 3 in Mexico D. F., Mexico, by the same group of investigators.