RECENT ADVANCES IN SCIENCE 545 



118, 1474), it is pointed out that the systematic investigation 

 on methylated sugars, carried out during the last twenty years 

 in the St. Andrews laboratory, were intended as a ground- 

 work to the study of the problems presented by the complex 

 carbohydrates. The principle involved in these investigations 

 is to substitute all free hydroxyl groups in a carbohydrate by 

 stable methoxyl groups, and so on hydrolysis to obtain a 

 methylated sugar or sugars. Determination of the number 

 and position of the alkyl groups in each of the hydrolytic 

 products thus gives direct evidence as to the linkage of the 

 constituents in the parent complex. The inulin employed in 

 this investigation was obtained from dahlia tubers ; after 

 repeated alternate solution in water and freezing out and 

 washing, it was still found to yield rather less than 0-2 percent, 

 of ash on ignition, from which it was concluded that the 

 organic constituents form a minute but definite part of the 

 molecular complex. The purified inulin had a specific rotation 

 of -35° on methylation with methyl sulphate and alkali, and 

 yielded a Isevorotatory dimethyl inulin which, on subsequent 

 treatment with methyl iodide and silver oxide, gave a dextro- 

 rotatory trimethyl inulin having [a]^ + 55*6°; the latter com- 

 pound being appreciably volatile at 196°/' 15 mm., it may be 

 concluded that the molecular weight of the polysaccharide is 

 much smaller than is generally supposed. The authors suggest 

 alternative formulae for inulin in which, to account for the 

 behaviour of the substance towards methylating agents, two 

 of the three hydroxyls in each Ce complex are differently 

 situated from the third. Hydrolysis of the trimethyl inulin 

 with I per cent, oxalic acid produces a very good yield of 

 trimethyl 7-fructose, which can be converted into a tetramethyl 

 fructose identical with that previously isolated from sucrose, 

 and it is argued that consequently the structural relationship 

 between sucrose and inulin is a close one. In the second 

 paper, dealing with " The Conversion of Cellulose into Glucose " 

 (Irvine and Soutar, /. Chem. Soc, 1920, 118, 1489), attention 

 is drawn to the fact that the confident statements made from 

 time to time by various authors to the effect that practically 

 quantitative yields of glucose had been obtained by the hydro- 

 lysis of cellulose were based entirely on observations of optical 

 activity or reducing power, and not on the isolation of a 

 pure material. Moreover, Willstatter and Zechmeister's claim 

 {Berickte, 191 3, 46, 2401) to have obtained 96-3 per cent, of 

 the theoretically possible yield of the hexose cannot be sub- 

 stantiated owing to the action of hydrochloric acid in promoting 

 the auto-condensation of glucose to iso-maltose. 



In the present instance, however, the authors have adopted 

 the principle that the yield of hexose obtained in their hydrolysis 



