438 



PRINCIPLES OF SOIL MICROBIOLOGY 



The anaerobic bacillus isolated by Khouvine 34 from the human in- 

 testinal tract was found to be capable of using cellulose as the only- 

 source of energy; sugars could not be utilized. One gram of cellulose 

 was decomposed in 16 days; but, in the presence of other bacteria, five 



Fig. 23. Apparatus for study of cellulose decomposition, under anaerobic 

 conditions (after Pringsheim) . 



times as much cellulose was decomposed. Among the decomposition 

 products, C0 2 , H 2 , ethyl alcohol, acetic and butyric acids, traces of 

 lactic acid, products precipitated by alcohol and a yellow pigment 

 could be demonstrated. 



" Khouvine, 1923 (p. 193). 



