BIOLOGY OF CLOSTRIDIUM WELCHII 393 



a. Classification of Clostridium Welchii by fermentative re- 

 actions in glycerol and inulin broths. The fermentative reactions 

 of glycerol and inulin broth with sporulation in these neutral 

 media, showed that the members of this group were divided into 

 four subgroups. Fifty-six strains of Clostridium Welchii isolated 

 from the following sources: Milk (pasteurized and raw) 42; 

 human stools (normal) 5; cow feces 9; were subjected to this test. 

 All conditions were standardized as far as possible. Pure 

 cultures were obtained through sufficient plating of these organ- 

 isms and were grown in glucose-liver broth tubes and incubated 

 for another twenty-four hours, after which two drops of these 

 cultures were inoculated into glycerol and inulin. The broths 

 were prepared by rendering neutral to phenolphthalein a 1 per 

 cent solution of peptone and inulin and a 1 per cent solution of 

 peptone and 6 per cent of glycerol. After a forty-eight hour 

 incubation at 37°, the tubes were removed from the incubator 

 and titrated against ■& NaOH with phenolphthalein as an indicator 

 and the acidity recorded. Gas fermentation and sporulation was 

 also determined for all the strains. 



Tables 2 and 3 give the results of this study of 56 strains, the 

 four principal subgroups being characterized as follows: 



Subgroup 1. Cultures not producing acid or gas from either 

 inulin or glycerol and forming spores in both inulin and glycerol 

 broths. Pathogenicity variable. 



Subgroup II. Producing acid with or without gas in inulin 

 but not from glycerol and forming spores in glycerol broth. 

 Pathogenic for guinea-pigs in most cases. 



Subgroup III. Producing acid without gas from glycerol but 

 not from inulin and forming spores in inulin broth. Patho- 

 genicity variable. 



Subgroup IV. Producing acid from both glycerol and inulin 

 with or without gas production with no formation of spores. 

 Pathogenic in most cases. 



The source of the culture gives no indication as to the subgroup 

 to which it belongs as shown by the grouping of the above 

 strains. 



THE JOURNAL OF BACTERIOLOGY, VOL. V, NO. 4 



