364 Chemistry of Anthocycui Piymeiits in Plants 



brought by their showing that the decolourisalioii of anthocyans in 

 aqueous solution was produced by the addition of a molecule of water 



HO 



VI. 

 to the anthocyan molecule, the addition causing loss of a molecule of 

 hydrochloric acid ; addition of hydrochloric acid to the decolourised 

 product causes reversal of these changes, thus : 



■^'i -<^« -^ -o/Y'°-S ^IJJ- -^ -o^-, 



i^A t"" °" • — \XJ-o„^-o' ^- \XJ-'" -<'" 



■q -< V-OH 



o o 



H M 



Despite this they criticist-d the present author's conclusious that the 

 pigments obtained by hiiu by the reduction of flavone derivatives and 

 their glucosides were true anthocyanidins and anthocyanins. They 

 stated that such pigments were soluble in ether, and also differed in 

 stability from the natural anthocyans. 



To this criticism, Whcldale and Bassett {Journal of Genetics, 1914, iv. 

 No. 1, p. 103) added their support, but in a paper recently read before 

 the Royal Society (forwarded for publication July 15, read Nov. 12) and 

 in a note in the Journal of Genetics (1914, iv. No. 2, p. 191^ the 

 present author has shown that these criticisms are not well founded. 



Since these papers were sent for publication, a further paper by 

 Willstittter and collaborators has come to hand (Sitzber. k. Akad. Wiss., 

 Berlin, 1914, 769), in which, after repetition of the present author's 

 experiments, they withdraw their criticism of his conclusions, for they 

 find indeed that by reduction Quercetin really does produce the 

 anthocyan pigment Cyanidin. Their experiments show that whilst at 

 temperatures below 0°C., the hydrochloride of a new substance — which 

 they term Allocyanidin — is produced, at higher temperatures the product 

 of reduction of quercetin consists of a mixture of allocyanidin chloride 

 and cyanidin chloride, and moreover they were able to show that the 



