26 Walter H. Burkholder 



purplish in appearance. The brown pigment is then formed. At the 

 end of six weeks the upper half of the medium is a clear purple-brown 

 liquid, but the lower part is muddy in appearance. 



Brom cresol purple milk. A yellow ring is formed in four days. On the 

 fifth day a clear purple layer of liquid is produced at the surface, and on 

 the eighth day the entire medium is clear and is a reddish purple by 

 transmitted light. It is difficult to determine whether or not a brown 

 pigment is formed. In six weeks the upper part of the tube is a clear 

 wine-colored liquid but the lower part is muddy. 

 Uschinsky's solution. On the tenth to the twelfth day a light clouding 

 appears in the medium. There is no further development at the end 

 of six weeks. 



Fermi's solution. There is no growth. 



Cohn's solution. There is no growth. 



Potato cylinders. In twenty-four hours a good watery growth, primrose 

 yellow in color, appears along the streak and soon covers the entire 

 surface. The growth appears slimy, and after a week's time the potato 

 cylinders begin to dissolve. A slight brown color appears and the tuber 

 assumes an olive-ocher color. At the end of five weeks certain tubes are 

 almost black, while others are only a light brown. This is possibly 

 owing to differences in cylinders from different potato tubers. 



Cellulose digestion. A good growth appears in the broth, but there was 

 no indication that the filter paper is attacked. A brown coloration 

 appears both in the liquid and on the paper above the broth. 



Starch agar plates (pH 6.6). Plates of starch agar streaked five or six 

 times, and tested for starch digestion with a saturated solution of iodine 

 in 50-per-cent alcohol, show a slight digestion of starch at the end of two 

 days and an excellent digestion at the end of six days. 



Dextrose broth. The broth in the open arm of a fermentation tube becomes 

 cloudy in twenty-four hours, and later excellent growth is produced. At 

 the end of seven days the brown coloration is distinctly noticeable. No 

 acid nor gas is produced. 



Saccharose broth. There is a light cloudy growth in twenty-four hours. 

 A brown color appears within ten weeks. No acid nor gas is produced. 



Lactose broth. In twenty-four hours there is a light cloudy growth in the 

 open arm of a fermentation tube. A brown color develops later. No 

 acid nor gas is produced. 



Maltose broth. There is a cloudy growth followed by the production of a 

 brown color in the open arm of a fermentation tube. No acid nor gas 

 is produced. 



Czapek's agar. An abundant, watery, pale yellow growth is produced, but 

 no brown color is formed in the medium. The production of gum is 

 very noticeable. 



Shake agar culture. When a beef-extract agar with 1 per cent of glucose 

 (pH 7.0) is used, there is only a surface growth and no colonies are 

 formed in the depth of the medium. 



