BACILLUS MYCOIDES 853 



Gelatin Stab. — Abundant filiform growth with infundibiiliform or saccate liquefaction ; 



no surface membrane. 

 Broth. — Moderate, finely floccular, turbidity, with slight ring growth and a powdery 



deposit, later becoming heavy and viscous. 

 Blood Serum. — Abundant, moist, creamy, yellowish growth, with granular structure and 



finely contoured surface. No liquefaction. 

 Potato. — Thick, greyish-yellow, mealy growth. 

 Resistance. — Spores are said to withstand 18 lbs. steam pressure for 1 hour ; killed by 



20 lbs. for 1 hour. 

 Metabolism. — Aerobe, facultative anaerobe. Opt. temp. 35° C. Limits 10-45° C. 

 Pigment. — None. 

 Hcemolysis. — Powerful haemolysin produced, acting especially on the red cells of man, 



monkeys, and guinea-pigs. 

 Toxin. — The hsemolysin is fatal to laboratory animals. 



Nutritional. — Grows well on ordinary media ; not improved by blood, serum, or glucose. 

 Biochemical. — Acid, no gas, in glucose, maltose, and sucrose. Indole — ; M.R. — ; 



V.P. ^. Nitrates reduced to nitrites, sUght ; NH3-J- ; H2S — ; methylene blue 



reduced; catalase-)-- Litmus milk sometimes clot, followed by peptonization 



and decolorization. Starch is hydrolysed. 

 Pathogenicity. — Non-pathogenic under natural conditions. The hfemolysin is fatal in 1-2 



ml. doses to mice and guinea-pigs injected intraperitoneally. P.M. haemorrhagic 



exudate in peritoneum and pleura. 



B. mycoides Fliigge. 



First described by Fliigge (1886) ; common in milk, water, soil, and dust. Is 

 easily distinguishable from other members by its typical rliizoid growth on agar. 

 It is a highly proteolytic organism, which is said to convert half the protein 

 nitrogen of the medium into ammonia ; when growing in the soil it therefore 

 plays an important part in the process of denitrification. Some strains are said 

 to secrete a highly active proteolytic ferment capable of lysing cultures of certain 

 bacteria (Schubert 1928). Variant morphological and colonial types have been 

 described by Lewis (1932, 1933) and den Dooren de Jong (1933). 



Bacillus mycoides 



Synonyms. — B. ramosus Eisenberg. Root bacillus. 



Habitat. — Found in milk, water, soil and dust. 



Morphology. — Rod-shaped, 3-5 /ti X I'O fi ; truncated or slightly rounded ends, occurring 

 singly, in pairs, small groups, and chains ; long unjointed threads not uncommon. 

 Motile by peritrichate flagella. Spores are large, equatorial and ellipsoidal, measur- 

 ing 1-8 jii X 0-8 /<, not bulging ; germinate by absorption of spore coat. Non- 

 capsulated. Cells store fat as reserve material. Gram-positive. Non-acid-fast. 



Agar Plate. — Large, spreading, raised, greyish-white, dull, opaque and rhizoid colonies, 

 with finely granular surface ; denser nuclei, dark in colour, are visible from which 

 the peripheral shoots arise ; membranous consistency ; emulsification fairly easy. 



Agar Slope. — Abundant, confluent, spreading, rhizoid, opaque growth, greyish-white and 

 slightly glistening ; surface honeycombed, due to the presence of arborescent 

 ridges forming a raised network. Growth penetrates the medium, and is hence 

 firmly adherent to it. 



Oelatin Stab. — Arborescent, filamentous growth ; saccate liquefaction ; clearing of gelatin 

 with formation of a deposit and a surface membrane. 



Broth. — No turbidity ; firm, sometimes wrinkled, surface membrane, depositing later. 



Blood Serum. — Luxuriant, rhizoid growth ; no digestion, 



