mined definitely, as Bacterium hepatis does not ferment lactose, rhamnose, sucrose or salicin while it does ferment xj'lose. Failure to infect guinea pigs and chickens also indi- cates a possible difference between the two species. There may also be other species (Sohier, Benazet and Piechaud, Ann. Inst. Past., 74, 1948, 54). Source and habitat: Isolated from lesions in organs, from meconium, and from blood and cerebrospinal fluid of man and at least twentj'-six species of other mammals and of birds, in all of which disease occurs. Many cases have proved fatal. Suggested as a cause of infectious mononucleosis in man by Anton, Nj-feldt and others (see Girard and Murra}^ Amer. Jour. Med. Sci., 221, 1951, 343). "Granulomatosis infantiseptica" of Potel (Ztschr. f. Kinderheilk., 73, 1953, 113; also see Wissensch. Ztschr. der Martin- Luther Univ., 3, 1953, 341). Isolated from ferrets (Morris and Norman, Jour. Bact., 59, 1950, 313) without apparent disease. In some species it causes metritis and abortion. Genus III. Erysipelothrix Rosenbach, 1909.* (Ztschr. f. Hyg., 63, 1909, 367.) E.ry.si.pe'lo.thrix. Gr. neut.n. erysipelas erysipelas; Gr. fem.n. thrix hair;M.L. fem.n. Erysipelothrix erysipelas thread. Rod-shaped organisms with a tendency to form long filaments. The filaments may also thicken and show characteristic granules. Non-motile. Gram-positive, older cultures having a tendency to become Gram-negative. Acid but no gas from glucose and from certain other carbohydrates. Catalase-negative. Esculin not hydrolyzed. Facultatively anaerobic. Par- asitic on mammals, birds and fish. The type species is Erysipelothrix insidiosa (Trevisan) Langford and Hansen. 1. Erysipelothrix insidio.sa (Trevisan, 1885) Langford and Hansen, 1953. (Bacillus der Septicfimie bei Mausen, Koch, Aetiolo- gie der Wundinfektionskrankheiten, Leip- zig, 1878, 43; Bacillus insidiosus Trevisan, Caratteri di alcuni nuovi generi di Batteri- acee. Atti della Acad. Fisio-Medico-Sta- tistica, Milano, Ser. 4, 3, 1885, 100; Bacillus des Schweinerotlaufs, Loeffler, Arb. a. d. k. Gesundheitsamte, 1, 1886, 46; Erysipelothrix porci Rosenbach, Ztschr. f. Hyg., 63, 1909, 3Q7 ; Erysipelothrix Erysipeloides (sic) Rosen- bach, loc. cit.; Erysipelothrix murisepticus (sic) Rosenbach, loc. cit.; Erysipelothrix rhusiopathiae Winslow et al.. Jour. Bact., 5, 1920, 198; Langford and Hansen, Riassunti delle Comunicazioni, VI Congresso Inter- naz. di Microbiol., Roma, 1, 1953, 18; also see Antonie van Leeuwenhoek, 20, 1954, 87; and Atti del VI Congresso Internaz. di Mi- crobiol., Roma, 1, (1953) 1955, 21.) in.si.di.o'sa. L. adj. insidiosus deceitful, dangerous. Description taken in part from Langford (Thesis, Univ. of Maryland, 1952) and Byrne, Connell, Frank and Moynihan (Can. Jour. Comp. Med. and Vet. Sc, 16, 1952, 129). Cells in smooth colonies are slender rods, 0.2 to 0.4 by 0.5 to 2.5 microns. Cells in rough and in some smooth colonies vary from short forms to long filamentous struc- tures. Thick rods may be present singly, in chains or in entangled masses. Non-motile. Predominantly Gram-positive, although some Gram-negative cells may be found, particularly in old cultures or in unfavorable media. Gelatin colonies: Hazy, bluish gray, ra- cemose. Gelatin stab: Filiform at first; most strains develop, in less than 48 hours, lat- eral, radiating projections resulting in the typical "test-tube brush" appearance. No spreading on the surface. No liquefaction. Agar colonies: Pinpoint and transparent in 24 hours at 33° C. increasing to about 1.0 to 1.5 mm in 48 to 72 hours. Fully devel-
- Revised by Dr. G. C. Langford, University of Florida, Gainsville, Florida, U. S. A.,
and Prof. P. Arne Hansen, University of Maryland, College Park, Maryland, September, 1953.
