548 Journal of A gricultural Research voi. xviii. no. lo 



end of the tubes clouded in from 2 to 3 days, and in two weeks the 

 growth was moderate to heavy. There was a very faint clouding in 

 the closed ends with mannit, saccharose, and levulose. In the dextrose 

 tubes the closed end seemed to be cloudy at first, but at the end of two 

 weeks these were entirely like the controls. No gas formed in the closed 

 arm in any media. When tested with litmus paper on the twentieth 

 day the dextrose cultures gave an acid reaction, glycerin cultures were 

 neutral, and the others — mannit, saccharose, maltose, lactose, and 

 levulose — were alkaline. The control tubes were acid. 



Nitrates are not reduced. — Growth in the nitrate-beef bouillon is 

 good, and a pellicle forms. Cultures were tested when 10, 17, and 24 

 days old. Starch water, potassium-iodid solution, and sulphuric acid 

 were used in testing for nitrite. No change of color occurred in any of 

 the cultures — that is, no nitrite is formed. 



Hydrogen sulphid is produced in small quantities as determined by 

 the slight browning of lead-acetate paper suspended over cultures 

 growing in beef bouillon, beef agar, and in milk. 



Indol is produced in small but definite amounts in the following 

 medium: i per cent peptone, 0.5 per cent disodium phosphate, and 

 0.1 per cent magnesium sulphate in distilled water. Cultures in i and 

 2 per cent peptone (Witte's), Dunham's solution, and Uschinsky formed 

 no demonstrable amounts of indol. 



Ammonia production is feeble. Beef bouillon cultures were t:isted 

 with Nessler's solution. Strips of filter paper moistened in the solution 

 were suspended over the cultures, which were then heated. A brownish 

 color developed on the paper. A second test was made, using filter 

 paper colored with haematoxylin. This changed from a reddish color to 

 purple in the heated culture tubes. 



Toleration of acids. — The toleration of acids was tested in -^ 10 

 peptone-beef bouillon to which were added different percentages of 

 citric, malic, tartaric, and hydrochloric acids. Sufficient acid was added 

 to the bouillon to make 0.05, o.io, 0.15, and 0.20 per cent solutions. 

 One cc. of 0.5, i, 1.5, and 2 per cent acid solutions, respectively, were 

 added to 9 cc. of the +10 bouillon. The acid was added under sterile 

 conditions and the solutions used four days later without heating. The 

 organisms grew well in the 0.05 and the o.io per cent solutions of citric, 

 malic, and tartaric acids. Growth was good within 24 hours. Heavy 

 pellicles formed and the media became green. One strain (No. 471) 

 grew in the o.i 5 per cent solutions of citric, malic, and tartaric acids. All 

 strains grew in the 0.15 per cent solution of hydrochloric acid. None 

 grew in a 0.15 per cent solution of oxalic acid. No growth was obtained 

 in any of the 0.20 per cent solutions with any of the strains of the or- 

 ganism. 



Temperature relations. — In -f- 10 peptone-beef bouillon the optimum 

 temperature is 25° to 28° C. The maximum is between 36° and 37°, 



