CELLULOSE DECOMPOSING POWER 247 



paper can be detected by holding the Petri dish towards the 

 light. 



4. With a sterile platinum needle, test the consistency 

 of the paper in the spots which have been most probably 

 attacked and compare with that of the undecomposed 

 spots. Describe the results. 



5. Add more of the K2HPO4 solution when necessary 

 to keep the filter paper moist. 



6. Start a second Petri dish in the same way but keep 

 it moist with 0.05% NH 4 NO 3 and 0.05% K 2 HPO 4 . Here 

 we find brown spots caused usually by fungi. 



7. Macerate some of the brown spots from each Petri 

 dish with water and make a Chinese ink preparation. 



8. What types of organisms are seen in each prepara- 

 tion? Make drawings. 



9. What organisms are especially active in the anaerobic 

 decomposition of cellulose? Which type, aerobic or anae- 

 robic, is responsible for the greater amount of cellulose 

 decomposition in nature? When may the other types take 

 precedence? 



What steps would you take to isolate the organisms 

 which are growing on your plates? 



Are the chemicals used above present in the soil? In 

 what form? In what forms does cellulose exist in culti- 

 vated soils? 



Are cellulose-decomposing bacteria ubiquitous? Are 

 they always found where cellulose in some form is depos- 

 ited? Are cellulose decomposing bacteria limited to soil? 



10. Data and results are to be given in full, also draw any 

 conclusions warranted and point out any possible practical 

 applications. 



REFERENCES 



LOHNIS: Laboratory Methods in Agricultural Bacteriology, pp. 



104-105. 

 LIPMAN and BROWN: Laboratory Guide in Soil Bacteriology, pp. 



62, 63, 65. 



