In 1889 Charrin (" La maladie pyocyanique,") published a thorough research concerning the bacillus pyocyaneus. Before that time practically nothing was known concerning this organism in connection with diseases of man or in animals, although its occurrence in green or blue pus had already been observed by Gessard. Experimenting upon rabbits, Charrin soon found that the bacillus gives rise to a disease of definite clinical entity, and to this he gave the name maladie pyocyanique. Others have studied pyocyaneus infection in the dog, as well as other animals, but the rabbit is the most susceptible.
Infections with the bacillus pyocyaneus in man bear a marked resemblance to the experimental forms, at the same time it may, like other pathogenic organisms, occur in a purely saprophytic condition in various parts of the human body. Thus it has been found in the saliva, sputum and sweat, also in the stomach, and Koch early