THE DECOMPOSITION OF CELLULOSE IN SOILS 457 



3. Flagella : 1 to 3 in number ; 3 to 4 ^ in length. 



4. Staining reactions : Gram negative. Stains readily with the aniline 



dyes. 

 II. Cultural Characteristics. 



5. Agar strokes, 5 days. 



Beef agar: Scant, grayish white, filiform growth. 

 ^ Potato agar: Abundant, glistening, grayish white, filiform growth. 



Peptone starch agar: Moderate, grayish while, filiform growth. 



6. Potato cylinders, 30 days : Scant, glistening, colorless growth when 



very heavily inoculated. Light inoculation produces no growth. 



7. Gelatin ,stab: Moderate growth at surface and along track of needle 



in 5 days ; napiform liquefaction in 30 days. 



8. Beef broth, 5 days : Heavily clouded. 



9. Litmus milk: Reddened in 5 days; neither coagulated nor digested in 



30 days. 

 10. Plate cultures. 



Ammonia cellulose agar, IS days. 



Form : Round. 



Size : 1.5 to 2.5 mm. in 15 days ; 3 to 3.5 mm. in 25 days. 



Enzymic zone : Clearing sometimes all within colony after 15 

 days. After 20 days all colonies show an enzymic zone of 

 1 mm. or more. 



Elevation : Flat. 



Chromogenesis : Semi-transparent, light grayish white ; some- 

 times contoured by light whitish lines. 



Internal structure: Granular. 



Edge : Entire. 

 Peptone cellulose agar, 15 days. 



Form : Irregularly round. 



Size : 5 to 8 mm. in 15 days ; no increase in size after 15 days. 



Enzymic zone : 2 to 3 mm. The zone continues to increase in 

 width up to 30 days, in which time it is frequently 5 mm. 



Elevation : Slightly convex. 



Chromogenesis : Central portion of colony is white ; the outer por- 

 tion gray-white ; sometimes forms a white nucleus and rim. 



Internal structure : Central portion of colony coarsely granular, 

 outer portion finely granular. 



Edge: Undulate to lobate. 

 Peptone starch agar, 5 days. 



Form : Irregularly round. 



Size: 1.5 to 2 mm. in 15 days; 2.5 mm. in 25 days. 



Enzymic zone: 1 nam. or less. 



Elevation: Capitate. (The colonies on starch agar are raised in 

 a characteristic jelly-like mass.) 



Consistency : Gelatinous. 



Chromogenesis : Grayish white. 



Internal structure : Fine granules loosely arranged. 



Edge : Lancelate. 

 Beef agar, 5 days. 



Form : Surface colonies round ; imbedded colonies, lenticular. 



Size: 1.5 to 2 mm. 



Elevation : Convex. 



