460 SOIL SCIENCE 



10. Filter paper broths, 15 days. Paper very completely disintegrated and 



reduced to a pulp-like mass which settles to the bottom of the 

 flask. The paper is vigorously attacked in solutions containing 

 ammonium sulphate, potassium nitrate, or peptone as the source of 

 nitrogen. Casein appeared to be less favorable for the rapid devel- 

 opment of this organism. 

 III. Biochemical Features. 



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



12. Starch nitrate broth, 10 days. No ammonia formed ; no nitrite formed. 



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



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



Scale) with: Dextrose, 1.50; Lactose, 1.10; Saccharose, 1.00; 

 Maltose, 1.45 ; Glycerine, .55 ; Mannite, .00 ; Starch, 1.40. 



Bacterium idoneum, n. sp. 



Source : Soil from Mentone, California ; and Whittier, California. 



I. Morphology. 



1. Vegetative cells : Average dimensions 1.5 to .5 ^. 



2. Endospores : None observed. 



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



dyes. 



II. Cultural Characteristics. 



4. Agar strokes, 5 days. 



Beef agar: Scant, yellowish white, glistening, filiform growth; in 10 



days growth becomes distinctly yellowish. 

 Potato agar: Abundant, moist, glistening, faint yellowish to glistening 



white ; becomes distinctly yellowish in 10 days. 

 Peptone starch agar: Moderate, flat, white, filiform growth; becomes 



faintly yellowish in 10 days. 



5. Potato cylinders: Abundant, moist, glistening, grayish white growth 



in IS days. 



6. Gelatin stab: Moderate, yellowish growth at surface and along track 



of needle in 10 days. SHght napiform liquefaction after 30 days. 



7. Beef broth, 5 days : Turbid. 



8. Litmus milk : Reddened in 3 days ; neither coagulated nor digested in 



30 days. 



9. Plate cultures. 



Ammonia cellulose agar, 15- days. 



Form : Irregularly round. 



Size: 1 to 1.5 mm. 



Enzymic zone: 1 mm. or less after 15 days; after 30 days the 

 enzymic zone has attained a diameter of 2 to 3 mm. 



Elevation : Flat. 



Chromogenesis : Opaque white or light grayish white. 



Internal structure : The colony is made up of rather coarse gran- 

 ules compactly arranged. 



Edge : Lobate. 

 Peptone cellulose agar, 15 days. 



Form : Irregularly round. 



Size : 1 to 1.5 mm. ; maximum development is reached in 15 days. 



Enzymic zone: .5 to 1.0 mm. in 15 days; 1.5 to 2 mm. after 30 

 days. 



Elevation : Flat. 



