M. Wheldale and H. Ll. Bassett 107 



presence of oxidising enzymes. Anthocyanin is therefore formed in 

 tissues in which oxidation most readily takes place. The above authors 

 have latterly inclined to the view that reduction precedes oxidation, but 

 this view rests on the supposition that the products of reduction of the 

 flavones are anthocyanins. 



It is difficult to reconcile Everest's assumption that anthocyanins 

 are reduced flavones, with the fact that they are shown to occur only 

 in those parts of plants where oxidases, and therefore oxidations, occur. 



There remains then the question of the derivative from quercetin 

 which gives a gi'een alkali reaction. This substance was prepared by 

 us from an alcoholic solution of quercetin ; the residue, after evaporation, 

 was extracted with ether containing a little alcohol and several com- 

 bustions were made of the product. The results showed the product to 

 be a reduced derivative of quercetin. 



A determination of the molecular weight by the raising of the 

 boiling point of alcohol gave a molecular weight approximately equal 

 to that of quercetin. Hence the substance is a simple reduction 

 product of quercetin, whereas the natural anthocyanins derived from 

 apigenin are both oxidised and condensed products. Nothing can be 

 gained at present by comparing the composition of the reduction 

 product from quercetin with other analyses of natural anthocyanins, 

 since the antecedent chromogens of the latter are not known. 



Further discussion on the matter is useless in the absence of exact 

 experimental evidence. In the case of quercetin, in order to secure any 

 convincing evidence, it would be necessary to isolate a natural antho- 

 cyanin known to be derived from quercetin and to compare the results 

 of its analysis with those obtained for the reduction product. 



