Optimum temperature, 37° C. Antigenic structure: 6, 7: c: 1, 5. Pathogenicity: Lethal for mice and rab- bits on subcutaneous inoculation. Comment: Schiitze et al. (Jour, of Hyg., 1934, 341) have given a special name to the hydrogen sulfide-producing variety of this species. Habitat: The natural host is the pig, where it is an important secondary invader in the virus disease hog cholera. Does not occur as a natural pathogen in other ani- mals. Occasionally gives rise to acute gas- troenteritis and enteric fever in man. 2. Salmonella typhimuriuni (Loeffler, 1892) Castellani and Chalmers, 1919. {Bacil- lus typhi murium Loeffler, Cent. f. Bakt., 11, 1892, 192; Castellani and Chalmers, Man. Trop. Med., 3rd ed., 1919, 939.) ty.phi.mu'ri.um. Gr. noun typhus a stupor, here used in the sense of typhoid; L. noun mus the mouse; L. gen. noun m^irium of mice; M.L. gen. noun typhimuriuni of typhoid of mice. See Edwards and Bruner (Kentucky Agr. Exp. Sta. Bull. 400, 1940, 43) for a discus- sion of this species. Rods, 0.5 by 1.0 to 1.5 microns, occurring singly. Motile by means of peritrichous flagella. Gram-negative. Gelatin colonies: Small, circular, grajdsh, granular, becoming j^ellowish brown. Gelatin stab: Flat surface growth. No liquefaction. Agar colonies: Small, circular, grayish, entire to undulate. Agar slant: Filiform, grayish, moist, en- tire growth. Broth: Turbid. Litmus milk: Slightly acid, becoming alkaline. Potato: Grayish white streak. Indole not produced. Hydrogen sulfide is produced. Acid and gas from glucose, mannitol, maltose, sorbitol and arabinose. Mucate and l-tartrate are attacked. Action on dulci- tol, inositol, rhamnose, trehalose, xj^lose, d-tartrate and dl-tartrate is variable. No action on lactose, sucrose, salicin or adoni- tol. Sodium citrate may or may not be uti- lized. Nitrites produced from nitrates. Trimethylamine produced fromtrimethyl- amine oxide (Wood and Baird, Jour. Fish. Res. Board Canada, 6, 1943, 198). Aerobic, facultatively anaerobic. Optimum temperature, 37° C. Antigenic structure: 1, 4, 5, 12: i: 1, 2. Comment: A variety of this organism which lacks antigen 5 has been reported by Kauffmann (Ztschr. f. Hyg., 116, 1934, 368). Source: Isolated during a mouse tj^phoid epidemic in the Hygienic Institute of Greifs- wald, Germany. Habitat: Causes food poisoning in man. A natural pathogen for all warm-blooded animals. This type occurs more frequently than any other type not confined to a spe- cific host. Also found in snakes by Hinshaw and McNeil (Amer. Jour. Vet. Res., 6, 1945, 264). 3. Salmonella enteritidis (Gaertner, 1888) Castellani and Chalmers, 1919. (Ba- cillus enteritidis Gaertner, Correspond, d. Allgemein. Artzl. Verein Thuringen, 17, 1888, 573; Castellani and Chalmers, Man. Trop. Med., 3rd ed., 1919, 930.) en.te.ri'ti.dis. Gr. noun enterum gut, intestine; M.L. noun enteritis a disease of the intestines, enteritis; M.L. gen. noun enteritidis of enteritis. Rods, 0.6 to 0.7 by 2.0 to 3.0 microns, oc- curring singly, in pairs and occasionally in short chains. Motile by means of peri- trichous flagella. Gram-negative. Gelatin colonies: Circular, gray, trans- lucent, granular, entire. Gelatin stab: Abundant surface growth. No liquefaction. Agar colonies: Circular, gray, translu- cent, moist, smooth, entire. Deskowitz and Buchbinder (Jour. Bact., 29, 1935, 294) describe a variant that produces a soluble yellow pigment where certain peptone is present in the agar. Antigenic structure not determined. Agar slant: Grayish white, opalescent, smooth, moist, undulate growth. Broth: Turbid; thin pellicle; grayish white sediment. Litmus milk: Slightly acid, becoming
