84 Cellulose 



show in all other respects a close general agreement with the 

 normal cotton cellulose. 



(2) Celluloses from cereal straws^ from esparto, &v. These 

 celluloses are isolated from the matured stem, or haulm, by 

 digestion with alkaline lye at elevated temperatures. They are 

 also of considerable industrial importance, being largely used 

 in the manufacture of the cheaper kinds of writing and printing 

 papers. 



Recent investigation has shown that these celluloses are 

 strongly differentiated from the normal, and are in fact pro- 

 nounced oxycelluloses. The following are the characteristics 

 of difference : 



Ultimate composition, after treatment with hydrofluoric 

 acid to remove siliceous ash constituents : 



Oat straw cellulose Esparto cellulose 

 (i) (2) (0 (2) 



C . 42-4 42-4 4178 41-02 



H . . .5*8 5-8 5-42 5-82 



Yield of furfural by solution and hydrolysis (HC1) : 



Oat straw cellulose Esparto cellulose 



I2'5 12-2 



Reactions. In addition to those with Fehling's solution, 

 phenylhydrazine salts, and magenta-sulphurous acid indicating 

 the presence of active CO groups, the celluloses give a 

 characteristic rose-red colouration on boiling with solutions ot 

 aniline salts. This reaction serves to identify their presence 

 in papers, and from the depth of the colouration, the percentage 

 may be approximately estimated. 



Investigation has also established the following points in 

 regard to the oxidation and deoxidation of these oxycelluloses. 



They are gradually oxidised in dry air at the temperature 

 of the water-oven, undergoing discolouration \ the yield of fur- 

 fural, by hydrolysis, showing a progressive increase. They are 

 deoxidised, on the other hand, by neutral and alkaline reducing 



