CLOSTRIDIUM HISTOLYTICVM 877 



media, smooth lobate outgrowths may arise from a rhizoidal centre. Occasionally 

 round dew-drop colonies are formed. Haemolysis for 2-4 mm. around colony. 



Agar Slope.— 4: days at 31° C. Moderate, confluent, effuse, glistening, greyish-yellow, 

 translucent growth, with beaten-copper surface and cigarette-in-water edge. 



Oelatin. — 2 days at 37° C. Liquefied. 



Broth. — 4 days at 37° C. Good growth with moderate turbidity, and moderate powdery or 

 irregularly granular sediment, not disintegrating completely ; strong putrid odour. 



Loefjler's Serum. — 15 days at 37° C. Serum digested and rendered turbid; medium 

 dark blue. 



Coagulated Egg. — 15 days at 37° C. Poor, effuse growth ; slight digestion. In alkahne 

 egg broth the white coagulum is digested. 



Cooked Meat Medium. — 15 days at 37° C Heavy growth with dense turbidity ; gas 

 production ; meat digested and blackened ; putrid odour. 



Resistance. — Withstands moist heat at 100° C. for 10 to 150 minutes, at 105° C. for 4 to 

 45 minutes, and at 110° C. for 1 to 12 minutes. 



Metabolic. — Anaerobic, but not strictly so. Opt. temp. 37° C. Haemolysis on horse blood 

 agar plates. Haemolyses human but not sheep's red cells. Nutritional : grows 

 well on ordinary media, and in media containing very little nutrient material, 

 such as tap water containing fragments of coagulated egg white. Certain amino- 

 acids, such as tryptophan, leucine, phenylalanine, tyrosine, and arginine, as well 

 as the sporogenes vitamin, are essential. Growth not improved by glucose. Green 

 fluorescent colonies on MacConkey plate. 



Biochemical. — Acid and gas in glucose and maltose. No action on mannitol, lactose, or 

 sucrose. Some strains ferment saUcin. Indole — ; vanillin violet + (Spray 1936) ; 

 M.R. — ; V.P. — ; nitrites not produced in nitrate broth ; NHg -{- ; HgS + + + ; 

 M.B. reduction — ; catalase weak -f . Litmus milk : casein precipitated and almost 

 completely digested in 15 days ; reduction, and marked alkaline reaction ; acid in 

 young cultures. 



Antigenic Structure. — Can be divided by agglutination into at least two groups. 



Pathogenicity. — Not naturally pathogenic. Experimentally is non-pathogenic to labora- 

 tory animals, but enhances the pathogenicity of other anaerobes, such as CI. welchii, 

 in mixed cultures. No exotoxin formed, but a broth filtrate is toxic to guinea- 

 pigs in a dose of 1 ml. ; this is due apparently to a volatile substance, possibly 

 an ammonium base. Forms a fibrinolysin. 

 (See von Hibler 1908, Wolf and Harris 1917, Weinberg and Seguin 1918, Report 1919, 



Hall 1922, de Smidt 1924, Weinberg and Ginsbourg 1927, Knight and Tildes 1933, Fildes 



and Richardson 1935, Stickland 1934, 1935, Pappenheimer 1935, Spray 1936.) 



Clostridium histol3rticum 



Isolation. — Described by Weinberg and Seguin in 1916 (1916, 1918). 



Habitat. — Soil ; possibly intestinal canal of man and animals. 



Morphology.- — Rod-shaped, 3-5 // X 0-5-0-8 fi ; parallel sides, rounded ends, axis gener- 

 ally straight ; occur singly and as diplobacilh. In cultures more than a day old 

 irregular forms appear^long curved filaments, and irregularly stained forms. 

 Spores are readily formed in all media ; they are oval, subterminal, and wider 

 than the bacillus ; become free in old cultures. Motile by about 20 peritrichate 

 flagella. Gram-positive in young cultures. No capsule. 



Agar Plate. — 4 days at 37° C. Variable. Colonies may be delicate and flat with crenated 

 edges ; or may be cuttle-fish-like, umbonate, amorphous, and glistening, with 

 very finely granular surface and a fimbriate edge ; greyish-white by reflected 

 Ught, bluish-grey by transmitted light ; differentiated into opaque yellowish 

 centre and greyish translucent periphery ; butyrous and easily emulsifiable. 



