The Typical Cellulose and the Cellulose Group 7 



by long immersion in alcohol confers upon the cellulose a much 

 greater resistance to hydrolytic actions, with the effect of in- 

 creasing the proportion of cellulose surviving the treatments 

 previously described as necessary for the elimination of the non- 

 cellulose constituents. 



Some more important aspects of these phenomena are dealt 

 with in a paper upon 



The Hydration of Cellulose (J. Soc. Chem. Ind. 4). In an 

 investigation of the celluloses of green fodder plants the authors 

 showed that by a preliminary artificial dehydration by long im- 

 mersion in alcohol the quantity of cellulose isolated by the usual 

 process of alkaline hydrolysis and oxidation was considerably in- 

 creased. 



The following numbers obtained with a ^:rop of oats may be 

 cited as typical. 



Percentage Cellulose Isolated* 



(a) (3) 



Directly After alcoholic dehydration Difference 



Leaves 28-2 35'4 7'2 



Stems 29-5 34-5 5-0 



It is a matter of ordinary observation that the maturing of 

 vegetable tissues is attended by loss of water, and it is clear from 

 these results that the growing plant contains hydrated modifications 

 of cellulose, which by mere dehydration are converted into the more 

 resistant forms. It must also be recognised that the line of cellu- 

 lose has to be drawn in an arbitrary manner. Products which are 

 the residues of treatments of a certain degree of intensity must be 

 so defined, and are not to be regarded as chemical individuals in 

 the strict sense of the term. 



The hydrates of cellulose generally react with iodine in 

 aqueous solution, giving an indigo-blue colouration. They also 

 exhibit an increased ' affinity ' for those colouring matters which 

 dye cellulose directly. 



In all the more essential properties, however, no distinction 

 can be drawn between the celluloses and their hydrated modifi- 

 cation. 



