BIOLOGICAL FORMATION OF METHANE 



therefore called Microzyma cretae. The description of this 

 organism was remarkably vague; it was reported to be so 

 small that even when examined under the highest magnifi- 

 cation of the microscope it appeared only as a motile point. 

 For some reason, now not altogether clear, Bechamp decided 

 to find out whether the chalk and its microbe could also 

 cause an anaerobic decomposition of ethyl alcohol. He 

 was rewarded after some weeks by seeing the development 

 of a vigorous fermentation which produced a large amount 

 of methane, a little carbon dioxide, and a mixture of vari- 

 ous fatty acids. Bechamp reported that when the gas evo- 

 lution stopped the only "ferment" to be seen was M. cretae! 

 Despite the naive interpretation of the microscopic obser- 

 vations, Bechamp's experiment clearly showed that methane 

 can be formed from ethyl alcohol and calcium carbonate 

 by a process probably caused by microorganisms. This was 

 the first demonstration of biological methane formation 

 from simple carbon compounds. Unfortunately, Bechamp's 

 work was overlooked by most subsequent investigators. 



More adequate proof of the microbiological origin of 

 methane was provided by Tappeiner in 1882. 3 He set up 

 three identical anaerobic cultures provided with plant 

 materials as substrate and with considerable amounts of 

 the intestinal contents of ruminants as an inoculum and 

 a possible source of soluble catalysts. One of the three 

 cultures was treated with an antiseptic to inhibit bacteria 

 without inactivating soluble "ferments," the second was 

 boiled to destroy both bacteria and "ferments," and the 

 third was left untreated. The microbial nature of the 

 fermentation was deduced from the observation that only 

 the untreated culture produced methane. 



During the last quarter of the 19th century, interest in 

 the methane fermentation centered largely on the utiliza- 

 tion of cellulose as a substrate. Since cellulose is the most 



