248 GENERAL MICROBIOLOGY 



MARSHALL: Microbiology, pp. 246-249. 



McBETH and SCALES: The destruction of cellulose by bacteria and 

 filamentous fungi. Bui. 266, B. P. I., U. S. Dept. Agr. (1913). 



EXERCISE 5. TO ILLUSTRATE THE ANAEROBIC DE- 

 COMPOSITION OF CELLULOSE BY SOIL AND 

 FECAL ORGANISMS 



Apparatus. Six (large) tubes of Omelianski's synthetic 

 medium for anaerobic cellulose fermentation; tall Novy 

 jar; vacuum pump. 



Culture. Fresh and decayed manure. 



Method. 1. Inoculate one tube with small amounts 

 of fresh horse or cow manure, a second with partially de- 

 cayed manure. 



2. Place some cotton in the bottom of the Novy jar, 

 insert the inoculated tubes in it, replace the stopper and 

 exhaust the air by means of the vacuum pump. (Pyro- 

 gallic acid and sodium hydroxide may be substituted.) 



3. Incubate the tubes in the Novy jar at 34 to 35 C. 

 for four to six weeks. 



4. From time to time note any changes occurring in the 

 filter paper. 



5. After the latter has been wholly or partially diges- 

 ted, make transfers to new tubes of the medium and incu- 

 bate anaerobically as before. 



6. Repeat this procedure from the cultures made just 

 previously. (The jar is evacuated each time after obser- 

 vations are made.) 



7. Examine the organisms causing the disintegration of 

 the filter paper both in the hanging drop and with some 

 ordinary stain (not the ink preparation). Make permanent 

 stained preparations. 



8. Starch, cotton, straw, etc., digestion may be com- 

 pared if these substances are substituted for filter paper 

 in Omelianski's medium. 



Not taking soil into consideration, where do anaerobic 



