Mayis. I920 Halo-BHght of Oats 151 



Soyka's rice medium. — The growth and medium in all cases except one 

 were cream colored. A culture marked "stock b" turned the medium a 

 buff-pink. 



Nutrient broth pIvUS carbon compounds. — To tubes of + 10 beef- 

 peptone bouillon I per cent asparagin was added and to other tubes i 

 per cent asparagin plus i per cent dextrose were added. The growth 

 was equally good in both kinds of media. The organisms seem to obtain 

 their carbon as readily from asparagin as from dextrose. 



Indol production. — Feeble or absent in beef-peptone bouillon or i 

 per cent peptone water containing 0.5 disodium phosphate and o.i mag- 

 nesium sulphate. 



Hydrogen sulphid. — Hydrogen sulphid is not produced. Lead ace- 

 tate paper suspended over broth cultures is not blackened, and the medium 

 is unchanged when streaks are made on lead carbonate agar plates. 



Ammonia production. — Moderate. Made tests with Nessler's reagent. 



Nitrate in nitrate broth. — No gas is produced in fermentation 

 tubes. Nitrates are not reduced. Tests were made at the end of 9 days 

 and at the end of 2 months. 



Temperature relations. — The maximum temperature for growth, 

 tested on beef broth and on agar and potato, is 31° C. The minimum 

 temperature for growth is below 0°. Tubes surrounded with ice showed 

 clouding. The optimum temperature for growth is 24° to 25°. The 

 thermal death point is between 47° and 48^. 



Moisture relations. — The organisms are very readily killed by 

 drying. Smears were made from 5-day-old broth cultures to sterile 

 cover glasses and placed in sterile Petri dishes. Pieces of these cover 

 glasses transferred to sterile bouillon after 3 hours showed growth in all. 

 All were dead at end of 24 hours. In a repetition, transfers after 6 hours 

 gave no growth. 



Fermentation tests: (i) Potato juice. — Undiluted potato juice 

 was expressed after passing the pared tubers through a meat grinder. 

 Moderate clouding in open arm of fermentation tubes. No growth in 

 closed arm and no gas. 



(2) Milk. — At the end of a week the milk at the open end had cleared 

 without evident curdling. Two days later the milk in the closed end had 

 curdled. This curd was gradually peptonized, about a third of it remain- 

 ing at the end of 2 months. The cleared liquid in the open arm was 

 browned — a chestnut to auburn brown at the surface and gradually 

 changing to a lighter shade through the open arm and a third of the way 

 up the closed arm. No gas was formed. 



(3) Carbon compounds. — Tests were made in the fermentation tubes 

 with 2 per cent solutions of dextrose, saccharose, maltose, lactose, man- 

 nit, glycerin, and levulose in 2 per cent water solutions of Difco's and 

 Witte's peptones. Bacillus coli Escherich was used as a control and 

 produced gas in the closed arm. The oat organism produced no gas and 



