546 SCIENCE PROGRESS 



experiments should be calculated from the weight of crystalline 

 compound isolated in a state of analytical purity. The method 

 adopted was to hydrolyse and simultaneously condense the 

 sugar liberated with methyl alcohol so as to give a stable 

 derivative which would thereafter remain unaffected, and so 

 protect the glucose from the destructive effect of the hydrolytic 

 agents. To this end pure cotton cellulose was treated with a 

 large excess of acetic anhydride containing acetic and sulphuric 

 acids, and when the fibrous structure had disappeared the 

 mixture was poured into water. The resulting polysaccharide 

 acetates were then heated in an autoclave at ioo° with methyl 

 alcohol and 0'5 per cent, of dry hydrogen chloride ; this treat- 

 ment removed the acetyl groups as methyl acetate, whereupon 

 simultaneous hydrolysis and condensation with the solvent 

 ensued, resulting in the formation of methyl glucoside, which 

 was weighed. From this material no difficulty was experienced 

 in obtaining pure crystalline glucose by hydrolysis. In this 

 way it has been shown that the yield of glucose obtained by 

 the hydrolysis of cellulose is at a minimum 85 per cent, of 

 the theoretically possible. The unexplained margin of 1 5 per 

 cent, may possibly be accounted for by the presence of a 

 nucleus in the cellulose molecule which is resolved into a ketose 

 on hydrolysis. 



The methylation of polysaccharides is also attracting the 

 attention of other workers. Thus, Denham (/. Chem. Soc, 

 1920, 1 19), acting on cellulose with methyl sulphate in presence 

 of sodium hydroxide, obtained a product containing 44-6 per 

 cent, of methoxyl, which closely approximates to the 45-6 per 

 cent, required by theory for a trimethyl cellulose. On the 

 other hand, Karrer {Helv. Chem. Acta, 1920, 3, 620), by methy- 

 lating starch, has obtained three compounds containing respec- 

 tively one, one and a half, and two methoxyl groups to each 

 Ce complex. 



A new synthetic method for the preparation of a-mono- 

 glycerides is described by Fischer, Bergmann, and Barwind 

 {Berichte, 1920, 53 [B], 1589). The method depends on the 

 fact that " acetone glycerol," or z5o-propylidene glycerol, 



/O • CH2 



(CH3)2C<; I 



^O • CH • CH2OH 



reacts readily with acid chlorides in presence of quinoline, 

 yielding products from which the acetone may be readily 

 removed, leaving a-monoglycerides. 



The decomposition of Tartaric Acid by Heat has been re- 

 investigated by Chattaway and Ray (/. Chem. Soc, 1921, 119, 



