

CHEMICAL CHANGES iii 



able conditions. " Rot-steep," or retting of flax, and skele- 

 tonizing of leaves, are processes of similar character. 



Von Senus, in 1890, proved the fermentation of fibre to be 

 anaerobic, that it v^as occasioned by a symbiosis, or concurrent 

 action of B. amylobacter with other organisms, and that gaseous 

 products of the above character finally remained. He isolated 

 an enzyme which dissolves fibre, and also a group of the 

 resolving bacteria from mud, stomach contents, and decaying 

 vegetable matter. Brown and Morris^ have also isolated from 

 fungi a similar or identical ferment called *' cytase," quickly 

 dissolving celluloses.^ Vignal found it in B. mesentericus vulgatus. 

 It is well known how rapidly M^rw/n^s lachrymans, or " dry rot," 

 softens the fibre of hard wood. 



In laboratory experiments with different kinds of cellulose, 

 paper, cotton- wool, etc., in water inoculated with sewage 

 organisms, I have observed gradual liquefaction with the pro- 

 duction of inflammable gases. Omeliansky believes that 

 B. amylobacter is not a separate species, but includes a number 

 of forms that act as butyric ferments, and that none of them 

 separately dissolve pure cellulose to any marked extent. Swedish 

 paper in a solution containing chalk, magnesium, and ammo- 

 nium sulphates and potassium phosphate, inoculated with Neva 

 mud, fermented actively, and both it and the chalk dissolved. 

 By Winogradsky's elective cultures he isolated the chief bacillus 

 causing the change, which he describes.^ 



The changes occurring in silos and in manure heaps may be 

 loticed as examples of the anaerobic breaking down of cellulose 

 ind fibrous matters. Macfadyen and Blaxall show that these 

 results are due to an extensive group of thermophilic bacteria, 

 rhich are widely distributed in Nature, and especially in sewage 

 Lnd in ensilage. The majority reduce nitrates and decompose 

 )roteid matter, but, in addition, they possess the important 

 )roperty of decomposing cellulose into probably CO2 and marsh 

 ^as. Swedish filter-paper in ten to fourteen days was com- 

 )letely disintegrated by these organisms. Omeliansky describes 

 B. fermentationis cellulusce, yielding 70 per cent, of fatty acids, 

 :hiefly acetic and butyric, and 30 per cent, of gases (CO2 and H).* 

 His subsequent work differentiates two organisms, which occur 



^ Transactions of the Chemical Society, i8go, p. 497. 



2 Annals of Botany, vii., 120 ; also see J. G. Green, Phil. Trans., 1887, clxxviii., 

 57 ; Marshall Ward, Annals of Botany, 1888, ii., 319 ; Reinitzer, Zeit. Phys. 

 Cliem., 1897, xxiii., 175 ; Biedermann and Moritz, Pfiilger's Archiv, 1898, Ixiii., 219. 



^ Compter rendus, cxxi., 653. 



^ Arch. Sci. Biol. St. Petersburg, 1899, vii., 41 1. 



