Page:Bergey's manual of determinative bacteriology.djvu/251

 II. Crescent-shaped to spiral cells that are frequently united into spiral chains of cells.


 * A. Cells not embedded in zoogloeal masses.


 * 1. Spiral cells with polar flagellation.


 * a. Possess a tuft of polar flagella.


 * aa. Possess a single, polar flagellum.


 * 2. Crescent-shaped cells with a tuft of flagella attached to the middle of the concave side of the cell.


 * B. Crescent- to spiral-shaped cells embedded in a spherical mass of jelly. Found in fresh water.

Vib'ri.o. L. v. vibro to move rapidly to and fro, to vibrate; M.L. mas.n. Vibrio that which vibrates.

Cells short, curved, single or united into spirals. Motile by means of a single, polar flagellum which is usually relativel}^ short; rarely two or three flagella in one tuft. Grow well and rapidly on the surfaces of standard culture media. Heterotrophic organisms varying greatly in their nutritional requirements. Aerobic, facultative anaerobic and anaerobic species. Widely distributed as saprophytic forms in salt- and fresh-water and in soil; also occur as parasites and as pathogens.

See Genus I, Pseudomonas, of Family IV, Pseudomonadaceae, for a discussion of the borderline between the genus Vibrio and the genus Pseudomonas.

Few comparative studies have been made on the species in this genus; it is therefore impossible to prepare a really satisfactory differential key. The type species is Vibrio comma (Schroeter) Winslow et al.

I. Aerobic species.


 * A. Produce acid but no gas from glucose and usually from other sugars (one luminescent, one halophilic and several agar-digesting species fail to produce acid from glucose).


 * 1. Not luminescent, not able to digest agar and do not attack benzene ring compounds or oxidize oxalates so far as known.


 * a. Found in fresh water or in the body fluids of animals, including man.


 * b. Liquefy gelatin.


 * c. Indole produced.


 * d. Nitrites produced from nitrates.


 * e. Milk not coagulated.


 * f. Cause of cholera.


 * ff. Cholera-like vibrio from fresh water.