Compound Celluloses 197 



After three minutes' exposure, therefore, in both cases 

 oxidation supervened, accompanied by conversion into soluble 

 products ; this destructive oxidation being much more marked 

 in the case of the raw wood substance. Jute, under similar 

 conditions of treatment, would have given a maximum of 145 

 p.ct., and the nitrate is much more resistant to the continued 

 action of the acid mixture. 



These results are, of course, of slight value only ; but they 

 serve to give emphasis to the general conclusion that lignifica- 

 tion is a process of condensation and etherification of OH 

 groups, accompanied, and in part conditioned, by condensa- 

 tion in regard to carbon configuration. Similarly, also, the 

 woods show considerably more resistance to the actions of 

 solvents of cellulose than jute lignocelluloses ; notably to the 

 thiocarbonate reaction, to which they yield only in very slight 

 degree and after prolonged exposure. 



From this general view of the reactions of the woods con- 

 sidered as a class of the lignocelluloses, we proceed to consider 

 special investigations of particular woods. 



Woods of the Coniferae. These woods are of very 

 great industrial importance, not merely for their uses as such, 

 but as the raw material for the preparation of the * sulphite 

 wood pulp,' now produced on an enormous scale in connection 

 with the paper industry. The ultimate fibres of these woods 

 are of greater length than those of the dicotyledonous woods ; 

 in addition there are well-marked features of distinction in 

 chemical composition from the latter, which have already been 

 noted. 



The chemistry of these woods was investigated some years 

 ago by Erdmann (Annalen, Suppl. 5, 223). The wood of 

 Pinus abies purified from adventitious constituents by boiling 

 in acetic acid, and subsequent exhaustion with water, alcohol 

 and ether gave, on ultimate analysis, constant numbers, viz. 



