THE DECOMPOSITION OF CELLULOSE IN SOILS 463 



' Beef agar, 5 days. 



Form : Surface colonies, round ; imbedded colonies, lenticular ; 

 bottom colonies, irregularly round. 



Size : 1 to 1.5 mm. 



Elevation : Slightly convex. 



Consistency : Soft ; in 10 days growth becomes somewhat gelatin- 

 ous. 



Chromogenesis : Very small white nucleus ; remainder of colony 

 semi-transparent grayish white. 



Internal structure : Granular. 



Edge : Entire. 

 Potato agar, 5 days. 



Form : Surface colonies, round ; bottom and imbedded colonies, 

 irregularly round. 



Size: 1.5 to 2 mm. 



Elevation : Convex. 



Consistency : Butyrous after 5 days ; somewhat gelatinous after 

 10 days. 



Chromogenesis: Yellowish to grayish white; after 10 days colo- 

 nies become quite yellowish. 



Internal structure : Coarsely granular. Some colonies are gru- 

 mose. 



Edge : Entire. 



10. Filter paper broths, 15 days. Paper is reduced to pulpy grayish white 



mass consisting of very short fibers which separate on slight agi- 

 tation. The paper is decomposed rapidly in the ammonium sul- 

 phate and peptone broths, but more slowly in the broths contain- 

 ing casein or potassium nitrate. 

 III. Biochemical Characteristics. 



11. Dunham's solution, 10 days. No ammonia produced ; nitrite produced. 



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



duced. 



13. Peptone nitrite solution, 10 days. No indol produced. 



14. Carbohydrate broths. No gas produced. Per cent of acidity (Fuller's 



Scale) with: Dextrose, .20; Lactose, .10; Saccharose, .00; Malt- 

 ose, .15; Glycerine, .00; Mannite, .05; Starch, .15. 



Bacterium paludosum, n. sp. 



Source: Soil from Berkeley, California; Whittier, California. 



I. Morphology. 



1. Vegetative cells : Average dimensions 1.5 x .4 fx,. 



2. Endospores : Form, elliptical; size, 1.2 x .6^^,; germination, equatorial; 



rod, swollen. Abundantly produced on potato agar cultures 3 or 

 4 days old. 



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



dyes. 



II. Cultural Characteristics. 



4. Agar strokes, 5 days. 



Beef agar: Moderate, flat, grayish white growth. 



Potato agar: Abundant, moist, glistening, grayish white growth. 



Peptone starch agar: Moderate, flat, grayish white growth. 



