454 SOIL SCIENCE 



8. Beef broth, 5 days : Slightly clouded. 



9. Litmus milk: Reddened in 6 days; neither coagulated nor digested in 



30 days. 

 10. Plate cultures. 



Ammonia cellulose agar, 15 days. 



Form : Round to irregularly round. 



Size : 2 to 3 mm. 



Enzymic zone : Entire colony semi-transparent ; enzymic zone not 

 more than 1 mm. 



Elevation : Flat or slightly depressed. 



Chromogenesis : Semi-transparent, grayish white, usually show- 

 ing a small white nucleus. 



Internal structure: Granular. 



Edge : Entire to undulate. 

 Peptone cellulose agar, 15 days. 



Form : Round. 



Size : 2 to 4 mm. 



Enzymic zone: 1.5 to 2 mm. in 15 days; 3 to 4 mm. in 25 days. 



Elevation : Slightly concave. 



Chromogenesis : Grayish white, frequently showing a small white 

 nucleus, usually forms a thin grayish white semi-transparent 

 rim beyond the enzymic zone. 



Internal structure : Granular. 



Edge : Entire. 

 Peptone starch agar, 5 days. 



Form : Round to irregularly round. 



Size : 2 to 3 mm. 



Enzymic zone : 1 to 1.5 mm. 



Elevation : Slightly convex. 



Consistency : Soft, becoming brittle after 10 days. 



Chromogenesis : Grayish to yellowish white. After 10 days the 

 colonies become quite yellowish. 



Internal structure : Granular. 



Edge : Entire to undulate. 

 Beef Agar, 5 days. 



Form : Round. 



Size : Surface colonies 1 to 2 mm. ; bottom colonies 3 to 3.5 mm. 



Elevation : Convex. 



Consistency : Soft. 



Chromogenesis : After 3 days the colonies are grayish to yellow- 

 ish white ; the yellow color increases with the age of the 

 colony and after 10 days they are distinctly yellow. 



Internal structure: Coarsely granular. The granules are fre- 

 quently formed into clumps. 



Edge : Entire. 

 Potato agar, 5 days. 



Form : Round. 



Size : 2 to 3 mm. 



Elevation : Convex. 



Consistency : Butyrous. 



Chromogenesis : Canary yellow ; some colonies show brownish 

 rings. 



Internal structure: Granular. 



Edge : Entire. 



