In 1906 Morgan isolated, from the stools of infants with "summer diarrhea," a previously undescribed gram-negative bacterium, Morgan's bacillus No. 1, which he considered of possible etiologic significance. Numerous papers have appeared since, denoting the pathogenicity of this organism not only in gastrointestinal disturbances but in other conditions as well. The purpose of this paper is to present a fatal case of Morgan's bacillus septicemia, to record the failure of sulfanilamide and sulfapyridine therapy and to review some of the literature on Morgan's bacillus infections. Septicemias due to Bacterium morgani are rare. Morgan grew the organisms from the heart blood taken after death from three children with summer diarrhea. Kendall, Day and Bagg cultured Bacterium morgani, also the Shiga bacillus, Bacillus alkaligenes and streptococci from the blood two days before death in a case of infantile diarrhea (antemortem invasion?). Probably the first recorded case of sepsis is that of Magath