168 Decomjwsitioji of Cellulose 



fat solvents, petroleum ether, benzol, chloroform, carbon bisulphide, 

 ether, etc. The first three yield a bright yellow solution, whilst that 

 with carbon bisulphide is orange yellow, and that with ether canary 

 yellow, in colour. This colour is intensified by alkali and destroyed b}* 

 weak mineral acids. 



The pigment gives reactions approaching those of the carotin group ; 

 the production of a blue colouration on exposure to the action of con- 

 centrated sulphuric acid is somewhat feeble, but strong hydrochloric 

 acid gives a deep dirty green colour. Hence it resembles the hpochrome 

 substances which are formed by many of the bacteria such, for example, 

 as Sarcina lutea and aurantiaca and Staphylococcus pyogenes aureus. 

 Up to the present we are unable to adduce any evidence as to the 

 physiological importance of the pigment. 



Acid products. During the decomposition of cellulose the reaction 

 of the medium undergoes a gradual change so that after 8-10 days the 

 liquid is distinctly acid to litmus. This is not due, as might be supposed, 

 to the abstraction of the ammonium radicle from the phosphates 

 supphed, and the formation of acid phosphates, since the same change 

 proceeds in culture solutions with sodium nitrate. On the other hand, 

 there are indications of the production of small quantities of volatile 

 fatty acids. Old cultures of the organism, when heated with concentrated 

 sulphuric acid, give rise to a distinct smell of butyric acid, and by the 

 addition of ethyl alcohol a smell resembHng that of ethyl butyrate is 

 evident. In this connection two cultures were prepared, each with 

 100 c.c. of mineral salt solution containing 0-287 grm. of precipitated 

 cellulose, in one case with, and in the other without, calcium carbonate. 

 At the end of eight days each culture was steam- distilled and gave a 

 distillate shghtly acid to htmus. On titration 2-5 and 3-1 c.c. of N/10 

 sodium hydroxide solution were required by the respective distillates; 

 this acidity if entirely due to butyric acid would be equal to approxi- 

 mately 7-9 per cent, of the original cellulose. By analogy with other 

 carbohydrate-fatty acid fermentations, it is not improbable that other 

 fatty acids are produced, but their identification and estimation lies 

 outside the scope of the present inquiry. 



Mucilage. By the continued growth of S. cytO])haga for a few days, 

 cellulose material at, or slightly above, the level of the culture solution 

 becomes distinctly mucilaginous and this property is also gradually 

 acquired by the culture solution. The latter is difficult to filter when 

 cold, but presents no difficulties when brought to the boil or after being 

 slightly acidified. It was originally supposed that this mucilaginous 



