384 Journal of Agricultural Research voi. xiii, no. 7 



tan color, but is still thin, and the medium is unchanged. In 13 to 

 16 days (PI. E, 6) the color of the growth is warm-bufF and the potato 

 has darkened slightly. In 30 days there is no further change. There 

 is feeble diastasic action on potato starch. 



OTHER CULTURAL FEATURES OF THE ORGANISM 



Indol. — No indol is produced. 



Nitrates. — There is a good reduction of nitrates. Tests were made 

 \vith nitrate bouillon cultures in which the organism grew very well. 

 One c. c. potato-starch solution was added to each culture; then one 

 c. c. of a fresh potassium-iodid solution (i :25o), after which five drops 

 of dilute sulphuric acid (2:1) were added. A dark-blue color, indicating 

 reduction, followed immediately. 



Hydrogen sulphid. — No hydrogen sulphid was detected. 



Ammonia. — The organism produces ammonia. Cultures of bouillon 

 agar, and Uschinsky's solution (2 to 6 weeks old) were tested with 

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

 solution and suspended in the tubes to be tested. A brownish-red 

 color appeared on the filter paper immediately, indicating the presence 

 of ammonia. 



Toleration of acids. — There is a moderate toleration of citric, malic, 

 and oxalic acids. In the tests these acids were added to neutral beef 

 bouillon. 



A good growth occurred in two days in the bouillon containing citric 

 acid titrating -I-37 on Fuller's scale, but no growth occurred in that 

 titrating -^39. 



With malic acid there was a good growth in four days in the solution 

 titrating +38, but none occurred in that titrating -{-40. 



With oxalic acid there was a good clouding in -|-37jn six days, but no 

 growth in -f 40. 



Toleration of sodium hydroxid. — ^The toleration of sodium hydroxid 

 by this bacterium is moderate. There is heavy clouding and pellicle 

 in —20 beef buillon, fair clouding in —25, and faint clouding in— 30 in 

 two days. No growth occurs in —40. 



Gas formation. — The organism is aerobic, and does not form gas. 

 Tests were made in fermentation tubes with water containing i per cent 

 of Witte's peptone to which was added i per cent of each of the follow- 

 ing carbon compounds: Dextrose, lactose, saccharose, maltose, glycerin, 

 and mannit. Growth occurred in the open end of the tubes, but none 

 took place in the closed end and no gas was produced. Dextrose and 

 saccharose gave an acid test with litmus after the cirganism had been 

 growing in the tubes for six weeks. Glycerin, maltose, mannit, and 

 lactose gave an alkaline test. 



