i8o 



Cellulose 



comparison, on the more essential points, with the typical 

 ' annual ' lignocellulose viz. jute. 



In regard to the number thus obtained for beech, i.e. after 

 merely boiling in water, it is necessary to point out the cause of 

 the difference from the number given on p. 195, viz. 8*0 obtained 

 after exhaustion with alkali, and calculated on the product so 

 exhausted. The alkaline treatment removes a complex made up 

 of pentosan, acetic residue, and keto-hexene constituents, the 

 removal of which gives a residue approximating in composition to 

 the jute lignocellulose ; whereas in the complex removed, the pro- 

 portion of the R. hexene groups, which react with chlorine ? 

 is much higher ; and hence the increased proportion of Cl com- 

 bining. 



It is unnecessary to enlarge upon the simple relationships of 

 these numbers. Sachsse's theory of lignification, it must be 

 remembered, was based upon purely physiological grounds, 

 and could only be supported by the meagre evidence of such 

 empirical determinations as were then available. Now that 

 we bring to bear the results of quantitative determinations 

 based upon specific constitutional features, and find these 

 perfectly consistent with this theory, the time has arrived to 

 press its consideration as a generalisation of wide import, con- 

 cerning the constructive processes of the organic world. The 

 theory briefly expressed, and in its more enlarged scope, is this : 

 that the process of lignification consists in a series of pro- 

 gressive and intrinsic modifications of a cellulose or oxycellulose 



