208 Cellulose 



This strongly confirms the view we have taken of the con- 

 stitution of the hexene constituents of the lignocelluloses. The 

 completion of the benzene ring under the conditions of the 

 distillation indicates its occurrence in the ordinary life- history 

 of the wood. Unfortunately the mechanism of the condensa- 

 tion is too complex to follow, and so, in fact, of the entire 

 process. What is required is an extended investigation of this 

 destructive decomposition under the conditions of variations 

 determined by the addition of reagents, added to promote 

 reaction in one or other direction. All that we can deduce 

 from the results of investigations as they stand is a general con- 

 firmation of previous discussions of the constitutional relation- 

 ships of the constituent groups of the lignocelluloses. 



(2) PROCESSES OF DISINTEGRATION BY REAGENTS. A. 

 Proximate resolutions. The various processes of preparing 

 a papermaker's pulp from the woods admit of a simple 

 theoretical classification on the basis of the foregoing treat- 

 ment of the subject. The table on p. 209, from a paper of 

 the authors (Forestry Exhibition Reports, Edinburgh, 1886, 

 No. 20), gives such a comparative survey, together with the 

 names of the inventors more prominently associated with the 

 origination of the several methods. 



The general principles of the classification are briefly these : 

 The lignocelluloses are readily attacked by hydrolysing agents, 

 even water. The attack of these agents is accompanied by the 

 inverse processes of condensation, which may be and are many- 

 sided, owing to the presence of OH groups of the most varied 

 function. A limit is therefore reached when the product is 

 sufficiently condensed to resist further attack. There are two 

 general ways of extending the limit : (i) strengthening the 

 hydrolysing action, either by concentration of the reagent, or 

 by increase of temperature ; (2) preventing the reverse action 

 by fixing reactive groups in combination. These more active 



