146 Cellulose 



lignocellulose is changed in colour to a bright yellow which 

 gradually changes to lemon yellow, and after some hours' diges- 

 tion, to white. If the digestion be interrupted at the yellow 

 stage, the fibre washed and digested with boiling alcohol, a 

 bright yellow solution is obtained ; and on driving off the 

 alcohol a gummy body is left, characterised by great instability, 

 reducing Fehling's solution in the cold, yielding furfural on 

 boiling with acids, and progressively decomposed on heating at 

 1 00 (in presence of water) with evolution of gaseous products. 

 The substance retains from 1-2 p.ct. N, but in a very un- 

 stable form, being entirely split off on heating with water. 

 This ill-defined product we may term, for obvious reasons, the 

 intermediate body. These results will be appreciated from 

 the following statement of the final products of the decom- 

 position. 



Ligitocellulose and Dihite Nitric Acid. 



.*. 



Solid products : Cellulose a Oxalic acid Intermediate 



63-66 p.ct 4*0-5-5 p.ct. body, 5-3-5-8 

 Volatile acid: Acetic acid, 14-18 p.ct. 



Gaseous products \ From HN0 3 From fibre- sub stance 



N 2 4 . N 2 2 . N 2 0. N 2 . HCN CO,. CO. HCN 

 (Representing about 50 p.ct. 

 oftheNoftheHNOJ 



The most notable features of the decomposition are 

 (i) As regards theHNO 3 (a) The reaction depends upon 

 the presence of nitrous acid ; the addition of urea entirely 

 arrests the specific action of the acid, and it then behaves 

 exactly as the non-oxidising mineral acids, (b) The direct 

 deoxidation of nitric acid never proceeds beyond the formation 

 of NO ; the presence of N 2 O indicates the formation of a 

 hydroxime, and its decomposition by further reaction with 

 nitrous acid. The formation of HCN also appears to result from 

 the dehydration of a product of this nature, and this conclu- 

 sion is confirmed by the observation that HCN appears in 



