Med., 23, 1925, 569; and others). Furth (Jour. Immunol., 12, 1926, 273) and Shaffer (Jour. Path, and Bact., 40, 1935, 107) on this basi.s divided Mycobacterium avium into 1 or 2 subgroups. Distinctive characters: Tubercle bacilli pathogenic for fowls but not for guinea pigs or rabbits; culturally distinguished from the mammalian types by the absence of pellicle formation in fluid media and the habit of growth on most solid media; anti- genically distinguished from other species. Source: Isolated from tubercles in fowls; widely distributed as the causal agent of tuberculosis in t>irds and less frequently in pigs- Habitat: The cause of tuberculosis in chickens. Transmissible to pigeons, other birds, mice, rabbits and pigs. 12. Mycobacterium paratuberculo-sis Bergey et al., 1923. (Darmtuberculose bacil- len, Johne and Frothingham, Deutsch. Ztschr. f. Tiermed., 21, 1895, 438; Pseudo- tuberkulose bacillen. Bang, Berl. tierarztl. Wochschr., 22, 1906, 759; Bacillus of Johne's Disease, M'Fadyean, Jour. Comp. Path., 20, 1907, 48; also see Twort, Proc. Roy. Soc, B, 83, 1910, 156; Bergey et al.. Manual, 1st ed., 1923, 374; Mycobacterium enteritidis Lehmann and Neumann, Bakt. Diag., 7 Aufi., 2, 1927, 755; Bacterium paratuberculo- sis Meissner and Berge, in Kolle and Wasser- man, Handbuch d. path. Mikroorganismen, 3 Aufl., 6, 1927-29, 788; Mycobacterium johnei Francis, Jour. Comp. Path., 53, 1943, 140.) pa.ra.tu.ber.cu.lo'sis. Gr. pref. para beside, related; M.L. noun tuberculosis tuberculosis; M.L. fem.n. paratuberculosis tuberculosis-like, paratuberculosis. Common name: Johne's bacillus. Description taken from M'Fadyean (op. cit., 1907, 48) and Twort and Ingram (A Monograph on Johne's Disease, London, 1913). Plump rods, 1 to 2 microns in length, staining uniformly, but occasionally the longer forms show alternately stained and unstained segments. Non-motile. Acid-fast. This organism is difficult to cultivate, and, in primary cultures, it has been grown only in media containing dead tubercle ba- cilli or other dead acid-fast bacteria (Bo- quet, Ann. Inst. Past., 37, 1928, 495). In a few instances cultures have been acclima- tized to a synthetic medium free from added dead bacteria (Dunkin, Jour. Comp. Path, and Therap., ^6, 1933, 159; Watson, Canad. Pub. Health Jour., 26, 1935, 268). Colonies on glycerol agar containing heat- killed Mycobacterium phlei: After 4 to 6 weeks, just distinguishable, dull-white, raised, circular. Colonies on Dorset's glycerol egg medium containing heat-killed M. phlei: After 4 to 6 weeks, minute, dull-white, raised, circular, with a thin, slightly irregular margin. Older colonies become more raised, radially striated or irregularly folded and dull yellowish white. Dorset's glycerol egg medium containing sheep's brain and heat-killed M. phlei: Growth slightly more luxuriant than that described immediately above. Glycerol broth containing heat-killed M. phlei: Thin surface pellicle which later be- comes thickened and folded. Dorset's synthetic fluid containing heat- killed M. phlei: Growth as in glycerol broth with Mycobacterium phlei. Pathogenicity: Produces Johne's disease, chronic diarrhoea, in cattle and sheep. Ex- perimentally produces a similar disease in bovine animals, sheep and goats. Guinea pigs, rabbits, rats and mice are not affected. Very large doses in laboratory animals pro- duce slight nodular lesions comparable with those pi'oduced by M. phlei. Antigenic structure: Johnin, prepared as is tuberculin, gives positive reactions in cattle with Johne's disease. According to M'Fadyean et al. (Jour. Comp. Path, and Therap., 29, 1916, 62), tuberculous animals may also give a reaction. Plumb (Den Kong. Vet. Landboh0jskole Arssk., 1925, 63) has shown that a reaction may be produced in animals sensitized to avian tuberculin and that avian tuberculin causes a reaction in some animals infected with Johne's bacillus. Distinctive characters: Small acid-fast bacilli which produce characteristic lesions in cattle; grow only in the presence of dead acid-fast bacilli. Comment: The organism isolated from a similar disease in sheep is probably identi-
