330 CELLULOSE-DECOMPOSING ORGANISMS 



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bonate containing finely divided straw with manure. At the end 

 of three months, when the evolution of carbon dioxid and methane 

 had nearly ceased, he examined the residue with the following 

 results : 



At beginning At end 



Substance in the straw. of experiment. of process. Loss. 



Cellulose 14.12 6.18 56.2 



Wood gum 10.00 4.67 53.3 



Vasculose 14.01 11.75 16.1 



Deherain studied the substances given off in the decomposition 

 of manure with the following results: 



Top layer of Middle of Bottom of 



manure heap, manure heap, manure heap , 



per cent. per cent. per cent. 



Carbon dioxid 21.6 31.0 37.1 



Oxygen 0.0 0.0 0.0 



Methane 0.0 33.3 58.0 



Nitrogen 78.4 35.5 4.9 



In the layers in which there was considerable oxygen, as may 

 be seen, the amount of combustible gas given off was zero, but in 

 the middle and lower layers of the manure heap the resulting 

 methane was over half of the gaseous product. Similar results 

 were obtained by Gayon, who studied the changes resulting with 

 a limited and free access of air and found that methane was obtained 

 in much larger quantities when the air had been excluded. From 

 this, he concluded that methane fermentation is due to an anaerobic 

 organism. 



Preceding this work was that of van Senus, who found that 

 cotton and plant tissues were decomposed by microorganisms with 

 the formation of carbon dioxid, methane, hydrogen, butyric acid, 

 acetic acid, alcohol, aldehyd and a trace of the higher fatty acids. 

 He thought the methane was formed through the reduction of 

 acetic acid by means of hydrogen. He considered the action as 

 being brought about by two organisms one the amylobacter of 

 Trectil, and another very small bacillus which he had isolated from 

 the alimentary canal of a rabbit. He considered that they acted 

 by means of an excreted enzyme, which he precipitated by means 

 of alcohol and found an aqueous solution of the same had the 

 power of decomposing cellulose. 



Work of Omelianski. As may be seen from the preceding brief 

 summary of the work, practically all that had been done on the 

 subject prior to 1895 was directed at a study of the chemistry of 

 the process and little had been done in trying to isolate in 

 pure cultures the specific organism or organisms which had the 

 property of decomposing cellulose. It was at this point that the 

 work was taken up by Omelianski, who studied very carefully the 

 chemical and bacteriological phases of cellulose fermentation. 



