Publisher Summary The members of the genus Vibrio are: short, bent rods, sometimes almost straight; motile by means of a single polar flagellum; aerobes, growing well on ordinary media; frequently liquefy gelatin; do not form spores; Gram-negative; some species are pathogenic to man and animals. Organisms resembling the cholera vibrio have been obtained from water and others from the feces of individuals suffering from diarrhea or intestinal conditions other than the true cholera; these were termed “para-cholera vibrios”, and included the El Tor vibrio, which is considered to be a true V. cholerae the Finkler-Prior vibrio, and many other varieties. Many saprophytic members exist, and they have added confusion to the study of this genus. A number of vibrios have been isolated from water, which appears to be their natural habitat. Other sources include the nasal secretion, carious teeth, cheese, hay-infusion and manure.