Med. Veter., N.S. 60, 1898, 836); Bacillus septicaemiae haemorrhagicae Sternberg, Man. of Bact., 1893, 408; Bacterium muUocidum Lehmann and Neumann, Bakt., Diag., 2 Aufl., 2, 1899, 196; Rosenbusch and Mer- chant, Jour. Bact., 37, 1939, 85.) mul.to'ci.da. L. adj. multus many;L. v. L. adj .suffix -cidus from L. v. caedo to cut, kill; M.L. adj. muUocidus many-killing, i.e., killing many kinds (of animals) . Description taken from Schiitze (Med. Res. Council, Syst. of Bact., London, 4, 1929, 451) who prepared it from studies of 230 strains described by 17 authors during the years 1908 to 1926. Short, ellipsoidal rods, 0.3 to 1.25 microns in length, occurring singly, in pairs, rarely in chains. Non-motile. Show bipolar stain- ing. Gram-negative. Gelatin: No liquefaction. Agar: Fine, translucent growth; charac- teristic odor. A complex dissociation pattern is shown. Many strains recovered from nor- mal respiratory passages and from some chronic infections are in the mucoid phase and generally show a relatively lower viru- lence. Strains from acute cases of fowl chol- era and hemorrhagic septicemia are in the fluorescent (iridescent) phase and are highly virulent (Carter, Canadian Journal Comp. Med. and Vet. Sci., 16, 1952, 150). Blood agar: No hemolysis. Broth: Uniform turbidity; characteristic odor. Milk: No change in reaction; no coagula- tion. Potato: No visible growth. Indole is produced. Hydrogen sulfide is produced. Acid but no gas from glucose, mannitol (usually), sucrose, fructose, sorbitol, galac- tose, mannose, xylose (usually) and tre- halose (usually). No acid from lactose, dulcitol, arabinose (usually), amygdalin, maltose (usually), raffinose, rhamnose, adonitol, dextrin, inulin, glycerol, salicin (usually) or erythritol. Groupings based on differences in sugar fermentations using xylose, arabinose, dulcitol, etc. do not ap- pear to be natural ones. Nitrites produced from nitrates. Temperature relations: Optimum, 37° C. Killed at temperatures above 45° C. Aerobic to facultatively anaerobic. Four distinct serological types. A, B, C and D, have been recognized (Carter, Amer. Jour. Vet. Res., 16, 1955, 481). Virulent for laboratory animals, espe- cially mice and rabbits. Distinctive characters : Grows on ordinary media. Bile salts inhibit growth. Relationships of this species: Few species of bacteria have been given so many differ- ent names as the organism causing the so- called chicken cholera of birds and the hemorrhagic septicemia of mammals. Pas- teur (Compt. rend. Acad. Sci., Paris, 90, 1880, 230, 952 and 1030) was one of the first to recognize this species in chickens, but the earliest scientific name given to the species appears to be the completely forgotten Micrococcus gallicidus given by the early American bacteriologist, Burrill (Amer. Naturalist, 17, 1883, 320; also see Jour. Roy. Micro. Soc, London, 3, 1883, 399). The spe- cific epithet given by Zopf (Die Spaltpilze, 3 Aufl., 1885, 57) in the binomial Micrococcus choleraegallinarum has been much more widely used, especially for the organism iso- lated from birds. At about the same time, Bollinger (Micro- parasiten bei eine neue Wild- und Rinder- seuche, Miinchen, 1879) had found the hemorrhagic septicemia organism in ani- mals, and apparently the first name given this organism was the trinomial Bacterium bipolare multocidum Kitt (Sitz. Gesell. Morphol. u. Physiol., Miinchen, 1, 1885, 24). This trinomial was changed to a binomial, Bacterium multocidum, by Lehmann and Neumann (Bakt. Diag., 2 Aufl., 2, 1899, 196). Later, as indicated above, this was changed to Pasteurella nmltocidum (Rosenbusch and Merchant, Jour. Bact., 37, 1939, 85). Be- cause of the early use of the epithet multo- cidum and because of its appropriateness, it was used in the 6th edition of the Manual on the recommendation of many students of animal diseases, and its use is continued in this edition. Meanwhile, Topley and Wilson introduced the entirely new binomial Pasteurella septica (Princip. Bact. and Immunol., 1st ed., 1, 1931, 488), and this name is currently widely used in England because of its appropriateness and because of the widespread use of -septica as a com-
