BIOLOGY OF CLOSTRIDIUM WELCHII 387 



ing again diffuse cloudiness, which quickly settles upon standing. 

 In a few cases the broth is stringy and very viscuous, yet the 

 sediment settles out leaving the supernatant fluid as in the other 

 cases. After the development is complete, the reaction is 

 decidedly acid. The odor of the cultures is not putrescent but 

 resembles sour, stale glue as in agar and gelatin cultures. Glucose, 

 galactose, plain liver, sucrose, maltose, lactose, starch, dextrin 

 and in a few cultures inulin, lead to a most violent fermentation 

 when added to plain broth. Different strains vary widely in 

 their fermentative ability with glycerol and inulin. An extreme 

 acid production is obtained with all the sugars, the maximum 

 reaction being reached in about forty-eight hours. In peptone 

 water containing coagulated egg-white, physiological salt solution 

 and coagulated egg-white, and an aqueous solution of coagulated 

 egg-white, Clostridium Welchii causes the so-called "stormy 

 fermentation" which is characteristic in milk. Mannitol broth, 

 1 per cent casein solution, plain peptone water and Dunham's 

 solution are not fermented appreciably, less than 10 per cent of 

 gas appearing after three days. In media containing coagulated 

 egg-white a black deposit occurred in the white sediment. 



If.. Milk. After twenty-four to forty-eight hours' incubation 

 at 37°, milk tubes inoculated with pure cultures of Clostridium 

 Welchii showed the so-called "stormy fermentation," coagulation 

 and derangement of the curd with gas bubbles rising to the top 

 of the tube. After an incubation of forty-eight hours the diges- 

 tion is complete, leaving a yellowish whey. Market milk which 

 has been heated for fifteen minutes at 82° and incubated at 

 37° shows after twenty-four to seventy-two hours variations of 

 the typical reaction from the typical "stormy fermentation" to 

 a slight digestion of the curd, with little or no gas formation. 

 Where gas formation failed to appear the reaction was due, 

 presumably, to insufficient anaerobiosis of the medium. Fre- 

 quently a culture from a milk tube showing no gas, when inocu- 

 lated in other milk tubes freshly sterilized, would cause "stormy 

 fermentation" after incubation. Much acid is produced from this 

 fermentation, its production ceasing only upon the exhaustion 

 of the fermentable materials present. Butyric acid is produced 



