"BACILLUS ANTHRACOIDES" 847 



animal body, and on serum media ; lost on agar ; surrounds entire chain of bacilli. 

 Gram-positive. Non-acid-fast. 



Aga?- Plate. — Irregularly round, 2-3 mm. in diameter, raised, dull, opaque, greyish- 

 white, plumose colonies, with a tessellated or reticular structure, an uneven surface 

 and a curled edge. Membranous consistency, emulsifiability difficult ; colony 

 consists of parallel interlacing chains of bacilli, and is characteristic. After about 

 a week irregular round scales appear on the surface of the colony. Several colonial 

 variants have been described. 



Agar Slope. — Thick, raised, spreading, greyish-yellow growth, with an uneven surface 

 and an undulate edge showing little curled projections ; moist and slightly glisten- 

 ing. Looks as if there were innumerable tiny air bubbles beneath the surface. 

 After about a week irregular round scales appear on the surface of the growth. 



Gelatin Stab. — Poor fihform growth followed by outgrowth of delicate lateral extensions, 

 longest at the upper part of the culture, giving an inverted fir-tree or lamp-brush 

 effect. Liquefaction crateriform ; occurs very slowly. 



Broth. — No turbidity, or very fine floccular turbidity ; moderate floccular deposit, con- 

 sisting of interwoven threads, and disintegrating partly on shaking. No surface 

 growth. 



Blood jSerwtn.— Abundant, creamy-yellow, confluent, curled growth with uneven surface. 

 No liquefaction. 



Potato. — Raised, dry, greyish-white, shghtly spreading growth, with undulate or serrated 

 edge. 



Resistance.- — Spores killed by boiling in 10 minutes. In dry state remain alive for years. 



Metabolic. — Aerobic ; facultative anaerobe. Opt. temp. 37° C. Limits 12° to 44° C. 

 Pigment none. Haemolysis : some strains are stated to hsemolyse sheep's red cells. 

 Nutritional ; grows well on ordinary media ; growth not improved by blood, 

 serum or glucose. 



Biochemical. — Acid, no gas, in glucose, maltose, sucro.se, and later in saliein ; final pH 

 5-5-5-9. Indole — ; M.R. ± ; V.P. ± ; nitrates reduced to nitrites. HjS — ; 

 NH3-I--I-; methylene blue reduced; catalase-(-. Litmus milk coagulated and 

 decolorized ; later peptonized. 



Antigenic Structure. — There is a capsular polypej^tide- containing antigen and a somatic 

 polysaccharide -containing antigen ; the former has some group relationship to 

 capsular antigens found in certain other members of the Bacillus groujJ. Both 

 antigens react specifically with precipitating antisera. 



Pathogenicity. — Naturally pathogenic to man, cattle, sheep (not Algerian), goats, pigs, 

 and camels ; rarely to carnivores. Experimentally mice, guinea-pigs, and rabbits, 

 injected sc. or im., die in 12 to 40 hours ; p.m., hsemorrhagic local exudate, enlarged 

 spleen, and bacilli in blood. Rats less susceptible. Birds, except sparrows and 

 young pigeons, cold-blooded animals, and fish are resistant. 



"Bacillus anthracoides," or "Bacillus pseudoanthracis." 



Bacilli more or less closely resembling the anthrax bacillus have been isolated 

 by numerous workers from such substances as soil, water, meat-, fish- and bone- 

 meal, wool, dust, oil-cake, and less frequently from animals and man. These 

 organisms have frequently been termed B. pseudoanthracis or B. anthra- 

 coides. Reference to the available papers renders it evident that more than 

 one species has been described. We do not propose to consider these organisms 

 in more detail, since their differential diagnosis from the anthrax bacillus has 

 already been dealt with. It is sufficient to point out that most of them are 

 motile, non-capsulated, form spores abundantly within 24 hours on agar, produce 

 an even turbidity or a surface pellicle in broth, give rise to colonies on agar which 

 are less curled and have fewer and less regular outgrowths at the edges, are more 



