494 Bulletin 167 



paper and sterilized in flowing steam on each of three consecutive 

 days. When inoculated this medium clouded promptly, becom- 

 ing milky. Ten day old cultures were slightly opalescent and 

 very milky, but neither pellicle nor sediment developed. The 

 reaction as shown by titration against phenolphthalein was -J-.81 

 Fuller's scale. Fermentation tubes filled with this medium 

 showed equally good growth in the open and closed arms, charac- 

 terized by a deep milky appearance and moderate gas production. 

 The material became viscid and sometimes a little stringy. From 

 5 to 15% of the closed arm was filled with gas consisting of 

 carbon dioxid and hydrogen. 



Physical and Biochemical Features 



Gas production in milk. — Fermentation tubes containing 

 milk inoculated with a 2 mm. loop of a young culture of the 

 organism and plated at 20 C. showed a small bubble of gas in 

 the closed arm at the end of two days ; otherwise the milk was 

 unchanged in appearance. Held at 25 ° C, the tubes of the same 

 age showed gas in 8% of the closed arm, while those held at 30 

 contained from 15 to 20 ( /o. On the third day at 20 , 5% had 

 developed, at 25 °, 15 to 20%, and at 30 °, 40 to 45%. The ap- 

 pearance of the milk still remained unchanged. Cultures 10 days 

 old showed varying amounts of gas up to 100% of the closed 

 arm. The milk was coagulated and the firm coagulum usually 

 remained in the closed arm attached to one side of the tube. 

 About 70% of the gas produced was absorbed by sodium hy- 

 droxid and the remainder gave a slight explosion upon ignition 

 in air. 



Carbohydrate broth. — Fermentation tube cultures of nutrient 

 bouillon containing dextrose, sucrose, lactose, maltose, glycerin, 

 and mannit were observed for gas production and acid produc- 

 tion. Titrations were made at the end of the first, second, and 

 fourth days, using 5 cc. of the culture in 45 cc. of boiling water 

 against phenolphthalein. Dextrose tubes showed rapid develop- 

 ment of the organism. At 20 the tubes became cloudy through- 





