196 



Cellulose 



boiling alkali. The woods are not attacked as a whole as with 

 the jute fibre, the furfural-yielding constituents (pentosans) 

 yielding much more readily than the fundamental tissue or 

 lignocellulose proper. In systematic investigations following 

 the lines laid down in the case of the jute fibre, the latter 

 should be taken as the basis of observation, and not the entire 

 wood substance. 



The reactions which we have so far discussed are, in the 

 main, reactions of decomposition. Synthetical reactions of 

 the wood lignocelluloses have been still less investigated. 

 Here, again, there is little to attract the chemist in the pre- 

 sent state of our knowledge, owing to the necessary complexity 

 of the reactions involved. From such reactions as have been 

 studied, if only in a general and superficial way, it appears that 

 the proportion of reactive OH groups is still less in these ligno- 

 celluloses than in those of which jute is the type. Thus, to 

 select the reaction of nitration : The maximum yield of 

 nitrate is considerably lower in the woods than in jute ; more- 

 over, the reaction is complicated by a destructive oxidation 

 which supervenes at a very early stage of exposure to the 

 action of the mixed acids. The following series of determina- 

 tions of yield in the case of mahogany wood illustrate this 

 point. In (a) the wood was used in its raw state ; in (b) it was 

 previously purified by boiling in dilute alkaline solution. 



Nitrating acid : equal volumes of H 2 SO 4 and HNO 3 (i'43 

 sp.gr.) in excess. 



