The Bacterial Diseases of the Bean 57 



three weeks as an olivine to malachite green. At the end of six weeks 

 the culture is a pale grass green. 



The Q strain is white until the tenth day. The color is not likely to 

 become as intense as with the other strain. 



Fermi's solution. Slight clouding appears in twenty-four hours, and 

 increases until a good growth is reached in forty-eight hours. A good 

 pellicle is formed by the fourth day. The culture becomes white and 

 milky, and a heavy sediment is formed. No further change occurs in 

 six weeks. 



Colin 1 s solution. There is no growth. 



Potato cylinders. At the end of two days the growth is scarcely visible. 

 The medium becomes gray, but there is no further change at the end 

 of seven weeks. 



Cellulose digestion. A good growth takes place in broth, but there is no 

 indication of cellulose digestion. 



Starch agar plates (pH 6.6). Plates streaked and tested with a saturated 

 solution of iodine in 50-per-cent alcohol at the end of two, six, and ten 

 days show no noticeable digestion. 



Dextrose broth. A cloudy growth occurs in the open arm of a fermentation 

 tube in twenty-four hours, and the medium becomes slightly acid. The 

 acidity increases, but by the tenth day a reaction occurs and at the end 

 of sixteen days all cultures appear alkaline. A cloudy growth appears 

 in the closed arm of the fermentation tube. No gas is produced. 



Saccharose broth. A light cloudy growth is noticeable in the open arm 

 of a fermentation tube at the end of twenty-four hours. The broth is 

 slightly acid, and reaches its maximum acidity within three days. The 

 acidity is never so pronounced in test tubes as in fermentation tubes, 

 and the broth in the test tubes reverts to the alkaline side very quickly. 

 A cloudy growth occurs in the closed arm. Acid is produced, but no gas. 



Lactose broth. A light cloudy growth occurs in the open arm of a fermenta- 

 tion tube in twenty-four hours. No further change in the broth is 

 noted. No acid nor gas is produced. 



Maltose broth. A cloudy appearance may be seen in twenty-four hours in 

 the open arm of a fermentation tube, but there is no acid reaction. The 

 culture appears the same at the end of five weeks, except that there is 

 a pale yellow-brown sediment which has formed gradually. 



Shake agar culture. In beef-extract agar with 1 per cent of dextrose 

 (pH 7.0), colonies may be observed from 5 to 8 millimeters below the 

 surface at the end of six days. No further colonies appear after that 

 time. 



Indol production. The organism produces no indol when grown in try to- 

 phane broth. The Ehrlich-Bohme test was used at the end of one and 

 of four days. Positive results were obtained on this medium with 

 Escherichia coli. 



