144 Decomposition of Cellulose 



compound — in the form of cellulose — becomes potentially active by its 

 resolution into simpler jjroducts. 



Although for many years the typical fermentation of cellulose was 

 regarded as being an essentially anaerobic one. and due to the methane 

 and hydrogen producing organisms described by Omelianski^, it is 

 nevertheless an indisputable fact that many of the changes in nature 

 indicate the operation also of an aerobic process. 



In this connection may be mentioned the known differences in 

 behaviour of coarse sandy, and of clay, soils in their capacity to retain 

 reserves of organic matter and humus. The former are reputedly 

 " hungry," since decomposition changes proceed in them at the maximum. 

 On the other hand, close textured or clayey soils present conditions 

 which are less suitable for the degradation of organic matter. Apart 

 from the physical constitution of the soil, the presence of excessive 

 moisture, by the exclusion of air, also makes for less rapid decomposition; 

 soils in districts of high rainfall, or those subject to flooding by surface 

 springs, are generally characterised by a high content of undecomposed 

 matter or crude humus. From the fact that cultivation and aeration of 

 a soil lead to a reduction of organic matter, and that the recent work 

 of Russell and Appleyard^ shows that the composition of the free soil 

 atmosphere differs onh^ slightly from the normal, some direct relationship 

 between decomposition and air supply may be deduced. 



The first observations on the aerobic decomposition of cellulose 

 appear to have been made by C. van Iterson^, in Delft, who found that 

 when a medium consisting of paper and mineral salts was distributed in 

 shallow layer, inoculated with ditch mud, and incubated at 28°-35°, an 

 energetic decomposition of the paper took place. In addition to the 

 various organisms, sporogenous bacteria, spirilli and infusoria, that 

 developed under these conditions, two others were encountered, the 

 one being a very small rod-shaped organism, to which the name Bacillus 

 ferrugineus was given, and the other a large micrococcus which was re- 

 garded as being unable to decompose the paper itself but which faciUtated 

 the decomposition in some manner not precisely indicated. 



Decomposition of filter paper was further demonstrated by placing, 

 in a glass dish, two pieces of Swedish filter paper between which some 

 powdered ammonium magnesium phosphate had been introduced and 



1 OmeUanski, W., Compt. rend. 1895, 121, 653-655; 1897, 125, 970-973, 1131-1133. 

 Arch. d. Set. Biol. 1899, 7, 411-434. Cent. Bakf. Par. n. 1902, 8. 

 - Russell, E. J. and Appleyard, A. This Journal, 1915, 7, 1—48. 

 = Iterson, C. van, Cent. Bait. Par. ii. 1904, 11, 689-698. 



