470 SOIL SCIENCE 



Consistency : Very soft. 



Chromogenesis : Glistening, grayish white; surface colonies have 



a pearl-like luster. 

 Internal structure : Granular. 

 Edge : Lacerate. 



11. Filter paper broths, 15 days. Paper attacked along the edge nearest 



surface of solution; in 20 days the paper is very completely dis- 

 integrated. The paper decomposed at about the same rate in solu- 

 tions containing ammonium sulphate, potassium nitrate, peptone, 

 or casein as the source of nitrogen. 

 III. Biochemical Features. 



12. Dunham's solution, 10 days. Ammonia produced; no nitrite produced. 



13. Starch nitrate solution. Ammonia produced ; nitrite produced. 



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



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



(Fuller's Scale) with: Dextrose, 1.25; Lactose, .50; Saccharose, 

 1.10; Maltose, 1.20; Glycerine, .30; Mannite, .25; Starch, 1.50. 



Summary of Specific Characteristics of Cellulose-Dissolving 



Bacteria 

 The detailed description of the cellulose-dissolving bacteria known 

 today are scattered through several publications. In the identification of 

 newly isolated forms or in comparing the specific characteristics of de- 

 scribed forms, it is obviously desirable that the more important morpholo- 

 gical and cultural features of the cellulose-dissolving organisms known at 

 this time be brought together in such a way as to afford a ready compari- 

 son. The more important morphological and cultural features of the 

 cellulose-dissolving bacteria are briefly summarized in Table II. The bio- 

 chemical reactions of the different species are summarized in Table III. 



Provisional Key for Identifying and Comparing Species of Bac- 

 teria WHICH Dissolve Cellulose 

 In order to facilitate further the identification and classification of 

 cellulose-dissolving bacteria a diagrammatic key has been prepared. In 

 the preparation of a key of this character, it is desirable to use single 

 diagnostic features by means of which the organisms may be separated 

 into smaller and smaller groups until all species are finally separated from 

 each other. In such an arrangement, it is obvious that the features used 

 must have a high degree of constancy. In the preparation of the follow- 

 ing key, only those features which have remained constant through a 

 number of cultures have been used and it is believed that when the key is 

 used in conjunction with the data presented in Tables II and III, it will 

 be found of much help in separating a particular organism from its con- 

 geners or in assigning it a provisional place in a system of classification. 



Importance of Cellulose Destruction in Soils. 

 All organisms make up for the waste incurred in their vital activities 

 by the consumption of chemical energy. This necessary energy is for the 



