The Typical Cellulose and the Cellulose Group 49 



The reaction may be described, therefore, as a progressive 

 hydrolysis of the cellulose through a series of dextrins, to a 

 carbohydrate of minimum molecular weight. This transform- 

 ation of cellulose to a sugar was established early in the cen- 

 tury (Braconnot, 1819). Recent investigation has established 

 the identity of this sugar with dextrose (rotation, [n] = 53*0). 

 The process of. hydrolysis consists in the following stages : the 

 cellulose (50 grms.) is dissolved in strong sulphuric acid (250 

 gr. H 2 SO 4 -f 84 gr. H 2 O) in the cold, and the solution allowed 

 to stand ; diluted till the acidity equals 2 p.ct. H 2 SO 4 , and 

 boiled 3 hours. The isolation of the dextrose in the crystal- 

 line form is accomplished in the usual way. (Flechsig, Zeitschr. 

 f. Physiol. Chem. 7, 523.) 



The reaction between cotton cellulose as well as other cellu- 

 loses of the cotton group (p. 79) and sulphuric acid is, in regard 

 to ultimate products, of the simplest character, resulting in their 

 conversion into dextrose, and in quantitative proportion (Flechsig). 



The reaction in the case of other celluloses, e.g. wood cellulose, 

 is more complicated. The initial solution in the concentrated acid 

 is dark coloured, and on diluting and boiling there is a consider- 

 able formation of insoluble products. Although dextrose is 

 obtained as one of the ultimate products of the hydrolysis, it is 

 only in relatively small quantity (Lindsey and Tollens, Annalen, 

 267, 371), and appears to be accompanied by other carbohydrates. 

 It will be shown subsequently that the celluloses of this group are 

 oxycelluloses, containing reactive CO groups and very readily con- 

 densing to furfural. The hydrolysis in such cases would, no doubt, 

 be attended by condensations and other complications. 



The subject has been recently and more exhaustively in- 

 vestigated by A. L. Stern (Thesis for D.Sc. Lond. Univ. 1894), 

 and we give a short extract of the results which he obtained. 



( i ) Composition of body produced by dissolving cellulose in sul- 

 phuric acid. In addition to the determination of the empirical 

 ratios of the constituents in the products isolated as Ba salts, 

 they were examined in solution for optical rotation and reduction 







