Compound Celluloses 161 



weight. The conditions of its formation point to its being a 

 product of hydration rather than oxidation ; it is probable 

 that more complex ketonic acids are first produced, and 

 further resolved on distillation, especially in presence of excess 

 of the oxidant. 



It appears from this that the lignone complex contains, 

 associated with the oxyquinone groups, a large proportion of 

 CO.CH 2 groups, the configuration of which remains undeter- 

 mined. It is probable that groups allied to dehydracetic acid 

 are represented, and a pyrone grouping of a portion of the 

 complex would account for the production of acetone as a 

 first product of destructive distillation (pp. 154-206). 



(2) Other Types of ' Annual ' Lignocelluloses. The 

 chemistry of the jute fibre might be presumed to cover the 

 essential features of the lignification of bast fibres generally ; so 

 far as investigation has gone, this appears indeed to be the case. 

 This statement, of course, must not be taken as suggesting 

 identity of constitutional features. Comparative investigation 

 of the bast tissues of the dicotyledonous annuals generally has 

 not as yet been attempted. Such work is called for, and it is 

 impossible to predict the influence which the results might 

 have in extending our grasp of the physiology of the exogenous 

 stem. Of those which are lignocelluloses, jute is undoubtedly 

 typical, and the methods adopted for this fibre may be ex- 

 tended to the group. 



The process of lignification, however, is by no means limited 

 to particular tissues, and we have now to deal with other 

 representative cases of the formation of lignocelluloses in 

 ' annual ' structures. 



* GLYCODRUPOSE.' The hard concretions of the flesh of the 

 pear are composed of a lignocellulose giving the typical re- 

 actions of the jute fibre. This product was investigated some 

 years ago by Erdmann (Annalen, 138, 9). The concretions 



M 



