THE DECOMPOSITION OF CELLULOSE IN SOILS 453 



Elevation : Slightly convex. 



Consistency : Butyrous, old colonies become brittle. 



Chromogenesis : White nucleus, remainder semi-transparent, 



glistening, grayish white. 

 Internal structure : Finely granular with exception of nucleus 



which is made up of granular clumps. 

 Potato agar, 5 days. 



Form: Round. ^ 



Size: Surface colonies 2 to 3 mm.; bottom colonies 4 to 5 mm. 

 Elevation : Convex ; old colonies frequently become somewhat 



umbilicate. 

 Consistency : Butyrous. 

 Chromogenesis : Grayish to yellowish white. Sometimes shows 



brownish rings. 

 Internal structure: Finely granular. 

 Edge : Entire. 



11. Filter paper broths, 15 days. Paper is very completely disintegrated into 



a grayish white felt-like mass, which readily separates into 

 minute fibrous particles on slight agitation. The paper undergoes 

 rapid decomposition when the nutrient solution contains inorganic 

 nitrogen in the form of ammonium sulphate or potassium nitrate, 

 and also when organic nitrogen is added in the form of peptone 

 or casein. 

 III. Biochemical Features. 



12. Dunham's solution, 10 days. No ammonia produced ; no nitrite pro- 



duced. 



13. Starch nitrate solution, 10 days. No ammonia produced; nitrite pro- 



duced. 



14. Peptone nitrite solution, 10 days. Indol produced. 



15. Carbohydrate broths, 12 days. No gas produced. Per cent of acidity 



(Fuller's Scale) with: Dextrose, .50; Lactose, .40; Saccharose, 

 .00; Maltose, .65; Glycerine, .05; Mannite, .00; Starch, .60. 



Bacillus gihus, n. sp. 



Source: Soil from Azusa, California; Chula Vista, California; Davis, California; 

 Porterville, California ; and Riverside, California. 



I. Morphology. 



1. Vegetative cells: Average dimensions 1.5 x .5 fx. 



2. Endospores : None observed. 



3. Flagella : 1 to 4 in number ; 4 to 6 y^t in length. 



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



dyes. 



II. Cultural Characteristics. 



5. Agar strokes, 5 days. 



Beef agar: Scant, yellowish white, filiform growth. 



Potato agar: Abundant, canary yellow, growth spreading over a large 



part of the slope. 

 Peptone starch agar: Abundant, grayish white, glistening growth 



which becomes somewhat yellowish after 10 days. 



6. Potato cylinders: Abundant canary yellow in 5 days. 



7. Gelatin stab: Moderate yellowish w'hite growth at surface and along 



track of needle in 10 days ; no liquefaction in 30 days. 

 (32) 



