CELLULOSE FERMENTATION 185 



in 1,000 cc. of water and inoculated with mud. The containers 

 were so arranged that the gaseous products were collected over 

 mercury. These he kept at room temperature for four years. 

 During the first year there was considerable gas evolved, but 

 the evolution gradually became slower, until at the end of four 

 years the evolution of gas had practically ceased. An analysis 

 showed that 15 gm. of the cellulose had been decomposed with 

 the formation mainly of carbon dioxid and methane. He was 

 unable to find any of the true sugars, although he thought it pos- 

 sible that there were some of the dextrin compounds in the solu- 

 tion. When air was excluded he found that there was a greater 

 production of methane and a smaller production of carbon diox- 

 id. From his work he considered that the reaction proceeded in 

 two stages. First, the cellulose is made to take up water and 

 form a six-carbon sugar. Second, from this carbon dioxid and 

 methane were produced, or perhaps acetic acid was first formed 

 and then carbon dioxid and methane produced from this. 



Later workers studied the decomposition of cotton, manure, 

 Straw, and filter paper, and always with the same results — that 

 there was formed considerable quantities of carbon dioxid, other 

 gases, and various acids. The quantity and kind of each varied 

 with the substance which was fermenting and the material which 

 was added to it. 



Discovery of the Organisms. — Although the evidence was 

 clear that cellulose decomposed in soil with the production of 

 gases and acids, nothing definite was known concerning the causa- 

 tive organism until 1895. At this time a Russian investigator 

 started to study the process, and after years of careful work ob- 

 tained two anaerobic oiganisms which decomposed cellulose — one 

 with the formation of hydrogen, the other methane or marsh 

 gas. 



Most individuals have noted that on stirring water which has 

 stood some time over vegetation, bubbles come to the surface. If 

 this gas is collected and ignited it burns. These anaerobic micro- 

 organisms are probably the bacteria which bring about this change, 

 but the true cellulose ferments of soil were not obtained until re- 



