2i 4 SCIENCE PROGRESS 



wards becomes less soluble in higher concentrations of the 

 " solvent " acid. This behaviour is shown, for example, by 

 succinic acid in acetic or in formic acid, and by mandelic 

 acid in the same •' solvent acids. 



In view of these results and numerous others obtained 

 by different investigators — cited fully in the introduction to 

 Knox's paper — the generality of such oxonium compound 

 formation can be regarded as demonstrated very satisfactorily. 



ORGANIC CHEMISTRY. By P. Haas, D.Sc, Ph.D., St. Mary's 

 Hospital Medical School, London. 



With the object of establishing the constitutional formula of 

 maltose, Irvine and Dick {Jour. Chem. Soc, 1919, 115, 593) 

 subjected this compound to complete methylation followed by 

 hydrolysis, intending to carry out the following series of re- 

 actions : 



Maltose -> methylmaltoside -> heptamethylmaltoside, 



which latter compound should yield trimethylglucose and 

 tetramethylglucose. They have been able to confirm the earlier 

 observation of Purdie and Irvine (Jour. Chem. Soc, 1905, 87, 

 1022) that the non-reducing glucose component of maltose 

 possesses the butylene oxide structure by obtaining from it 

 crystalline tetramethylglucose, but have not succeeded in 

 isolating the trimethylglucose, which should form the other 

 product of hydrolysis, as shown by the formula — 



o- 



CH • [CHOH] 2 • CH • CH(OH) • CH 2 • OH 

 non-reducing glucose component. 







CH 2 • CH(OH) • CH • [CH • OH] a • CH • OH 



reducing glucose component. 



In place of the trimethylglucose, however, they obtained a 

 pentose as the result of an entirely unexpected degradation 

 occurring during the decomposition of maltose octa-acetate by 

 means of hydrogen iodide ; the resulting substance proved to 

 be a Cn sugar methylglucoarabinoside, since it gave on hydro- 

 lysis crystalline tetramethylglucose and a dimethylarabinose. 

 This observation opens the way to a new method of studying 



