20 Walter H. Burkholder 



Litmvs milk. Growth is very similar to that in plain milk, with the excep- 

 tion of the color reaction. Litmus is reduced, although there is always 

 a trace of purple in the tube. At the end of six weeks the upper part is 

 a slightly reddish liquid, while the lower part is a muddy yellowish brown 

 medium with crystals. 



Brom cresol purple milk. The medium soon becomes a rather clear reddish 

 purple liquid with a muddy sediment. As with all milk cultures, tyrosine 

 crystals are formed in abundance. 



Uschinsky's solution. A very faint clouding occurs in about ten days. 

 Within two weeks there is a fair cloudy growth, but no further change 

 takes place. 



Fermi's solution. As a rule there is no growth. In a few cases a light 

 cloudy growth has been observed. 



Cohn's solution. There is no growth. 



Potato cylinders. In twenty-four hours there appears a very good watery 

 growth along the streak, which is primrose yellow in color. The growth 

 soon covers the entire surface, and the potato cylinders begin to dissolve 

 into a rather slimy mass. This breaking-down of the potato is one of 

 the striking peculiarities of this pathogene. The color of the mass 

 soon becomes a reed yellow. 



Cellulose digestion. A light cloudy growth appears in the broth in twenty- 

 four hours. Within a week or two, a yellow color may be noticed on 

 the filter paper just above the surface of the liquid and at the end of the 

 paper an inch or so above the liquid. There is no digestion of the cellulose. 



Starch agar plates (pH 6.6). Plates streaked five or six times, and tested 

 with a saturated solution of iodine in 50-per-cent alcohol, show the 

 starch to be practically all digested at the end of two days. 



Dextrose broth. A cloudy growth occurs in twenty-four hours in the open 

 arm of a fermentation tube. No acid nor gas is produced. 



Saccharose broth. A cloudy growth occurs in twenty-four hours in the open 

 arm of a fermentation tube. No acid nor gas is produced. 



Lactose broth. A cloudy growth occurs in twenty-four hours in the open 

 arm of a fermentation tube. No acid nor gas is produced. 



Maltose broth. A cloudy growth occurs in twenty-four hours in the open 

 arm of a fermentation tube. No acid nor gas is produced. 



Indol production. The organism grows well in trytophane broth, and deter- 

 minations made at the end of one and of four days with the Ehrlich- 

 Bohme test show no indication of indol production. 



Nitrate reduction. The pathogene does not reduce nitrates to nitrites. 

 Tests made at the end of two, four, and eight days have all been negative. 

 The method used was that of sulfanilic acid and a-naphthalamine in 

 acetic acid. 



Hydrogen-sulfide production. The pathogene does not grow on Wilson's 

 medium. On lead-acetate agar there is a good growth along the stab 



