886 CLOSTRIDIUM 



(See von Hibler 1908, Meyer 1915, Weinberg and Seguin 1918, Wolf 1918-19, Report 

 1919, Heller 1920, Gaiger 1922, 1924, Hall 1922, Weinberg and Ginsbourg 1927, Henderson 

 1934.) 



Clostridium welchii 



Synonyms. — B. aerogenes capsulatus, B. phlegmonis emphysematosoe, B. perfringens, B, 

 saccharobutyricus immobilis, B. enteritidis sporogenes, Granulobacillus butyricus. 

 B. cadaveris butyricus, B. vaginae emphysematosoe, Achalme's bacillus. 



Isolation. — First complete description by Welch and Nuttall in 1892, who isolated it from 

 a cadaver. Various organisms closely resembling CI. welchii, but differing from it 

 in type of toxin production, have been isolated from diseased sheep, and called the 

 lamb dysentery bacillus (Dalling 1926), CI. paludis (McEwen 1930), and CI. ovitoxi- 

 cum (Bennetts 1932). Exact relation of these organisms to CI. welchii and to one 

 another is doubtful, but Wilsdon's (1931) classification into A, B, C, and D types 

 corresponding respectively to the welchii, lamb dysentery, paludis, and ovitoxicum 

 types may be accepted provisionally. 



Habitat. — Found in soil, water, milk, dust, sewage, and intestinal canal of man and animals. 



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Fig. 205. — Clostridium welchii. Fig. 206. — Clostridium welchii. 



From a surface agar culture, anaerobically, 2 Surface colony on agar anaerobi- 



days, 37° C. ( X 1000). caUy, 5 days, 37° C. ( X 8). 



Morphology. — Rather stout rods, varying considerably in length; 4-8 [x X 0-8-1 -0 n; 

 sometimes shorter and more slender ; filaments not uncommon. Parallel sides, 

 ends truncated or slightly rounded ; axis straight. Arranged singly, often side 

 by side forming small bundles. Variation in depth of staining ; involution forms 

 ■ — clubs, filaments, tadpoles, granular forms — frequent in old cultures. Spores 

 large, oval, and subterminal. Sporulation occurs more readily with some strains 

 than with others, and is favoured by an alkaline reaction ; does not occur below 

 pH 6-6, and hence is unusual in media containing a fermentable carbohydrate. 

 Spores are seldom seen in cultures, but are commonly formed under natural 

 conditions. Non-motile. Capsules formed in animal body. 



Agar Plate.— 4^ days at 37° C. 2 main types of colony formed. One round, 2-4 mm. in 

 diameter, low convex, amorphous, greyish-yellow, opaque, with smooth surface 

 and entire edge ; butyxous and easily emulsifiable. Other is umbonate, and is 

 differentiated into an opaque brownish centre and a lighter, more translucent. 



