64 Walter H. Burkholder 



Cultural characteristics 

 (All cultures incubated at 27° C. unless otherwise stated) 



Beef-extract agar slants (pH 7.0). Growth appears along the streak within 

 twenty-four hours. At the end of three days there is a very good growth, 

 filiform, smooth, glistening, and translucent. The bacteria become 

 cream-colored to definite yellow with age. Cultures are butyrous in 

 consistency. A slight green fluorescent pigment is dissolved in the 

 medium. 



Beef-infusion agar slants (pH 7.0). A very good growth occurs, creamy to 

 yellow but otherwise similar in appearance to the growth on beef-extract 

 agar. A very marked yellowish green fluorescent pigment is produced, 

 which is dissolved in the medium. 



Beef -extract agar plates (pH 7.0). At the end of a week the colonies are 

 approximately 5 to 7 millimeters in diameter, smooth, naples yellow 

 to cream color, with edges undulating. A weak green fluorescent pig- 

 ment is dissolved in the medium. 



Beef-extract bouillon (pH 7.0). The medium becomes cloudy in twenty-four 

 hours, and very cloudy in forty-eight hours. A light flocculation occurs 

 throughout the tube, and in some cases a delicate pellicle is formed. A 

 sediment, white and stringy, gradually accumulates. 



Gelatin stab (pH 6.6). (Temperature 21° C.) Growth appears along the 

 stab within twenty-four hours, with slight liquefaction at the surface. 

 Liquefaction proceeds rapidly, being complete in seven to ten days. 

 It is turnip-shaped at first, and later stratiform. A heavy white sediment 

 is formed, and the liquefied medium becomes cloudy at the surface. 



Milk. Clearing of the milk begins at the surface on the fourth to the 

 sixth day, and extends throughout the tube by the end of a week. With 

 age the medium becomes a brownish, muddy liquid, with a slight 

 sediment. 



Litmus milk. At the end of three days a clearing begins at the surface, 

 and this gradually extends throughout the medium. Litmus turns 

 slightly blue and is reduced. The milk then becomes muddy, often with 

 a purple tinge. 



Brom cresol purple milk. On the third day the medium has become purple, 

 and a light clearing has begun at the surface of the milk which later 

 extends throughout the tube. Within a week the milk is a clear red- 

 purple liquid by transmitted light. At the end of six weeks little further 

 change has occurred. 



Uschinsky's solution. The solution is slightly cloudy in twenty-four 

 hours, and very cloudy in several days. A green fluorescent pigment is 

 formed, which is very pale at first and changes through various shades 

 of green until at the end of a week it is an olive-yellow. An orange- 

 yellow sediment is formed. 



