A GENETlCO-PHYSIOIrOGICAL STUDY ON THE FORMATION ETC. 3 



jicidifiocl to check the fiji'iuation of the ctjluui'lesfs LSf>mer, is mixed with tho 

 »jhition containing active o>dcliziug enzymes, the clmracteristic i-ed colour 

 (limiiiislies gi-mlually and finally becomes pale yellow or practically colourless. 

 The aqueous solutions of liydrogen peroxide and certain other inorganic oxidiz- 

 ing agents have the same effect as the enzyme. Such phenomena have been 

 obseiTcd by Bouffaiid (1902), Kastle (1903), Kastij!; and Haden (1911), 

 Combes (1913), Atkins (191G) and Nagai (1917).' 



The reversible change of flavoue to the cfJoured sub.sLance of anthocyaniu- 

 11 ke natm-e by means of I'educing and oxidizing agents respectively lias been 

 observed by many. Allen (1901)- stated tliat when an acidified (by hydro- 

 chloric acid) alcoholic solution of quercetin was ti-eated wi^i s<xlium amalgam 

 tlio liquid assumed a fine pm"ple colour and on concenti'ation yielded red 

 prisms wliicli dissolved in alcohol and a little alkali forming a gi-een solution, 

 the solution being readily reoxidizod with formation of quercetin on exposui'e 

 to the air. Combes (1913)' obsen-ed a similar reversible change in the yellow 

 pigment isolated from the leaf of Ampelopsis Iiederacea. 



In the study of anthocyanin in tho corn flower, Willsatätter and 

 Everest (1913)^ found that when an alcoholic solution of cyanidin was 

 M-armed with dilute hjdrogen peroxide solution, the colour diminished. When 

 it was again warmed on the water bath with the addition of a few drops of 

 (hluto hydi-oclJoiic acid, the liquid Ixjcame j-ellow, and by exti'acting witli 

 ether, Ijeautiful bright yellow crystals were obtained which ^\•llen treated with 

 alkahes, yielded a deep yellow solution. Miss Wheldale (1914)* attempted 



1. BouFFARD, A., Action lie I'acid siüfureux sur I'oxydase et sur la matiere coloiante du via 

 ronge. Comp. Bend. Acad. Sei. Paris. 134 : 1380, 1902. Kästle, J. H., A Method for the Dttir- 

 mination of the Affinities of the Acids C'olorimetrically by lleans of Certain Vegetable Coloring 

 Matters. Am. Chem. Jotir. 33 : 4G, 1905. Kastle, J. H. and Haden, R. L., On the Color Changes 

 Occurring in the Blue Flowers of the Wild Chicory, Cichorium intybtis. Am. Chem. Jour. 36 ; 

 315, 1911. Combes, R., Pas-sage d'un pigment anthocyanique cxtrait des feuilles rouges d'automne 

 nn pigment jaitue continu dans les feuilles vertes de la raeme plante. Comp. Kend. Acail Sei. 

 Paris, 152 : 14,54, 1913. Atkixs. W R. G., Recent Researches in Plant Physiology. 1916. Magai, 

 I , The .\ction of Oxidase on Anthixjyanin. Rot. Mag. Tokyo, 31 : 65, 1917. 



2. Allen, A. F., Commer<-inl Organic Analysis. Vol. Ill, Part 1, 440, 1901. 



3. Combes, Eoc. cit 



4. Wlllstatter, R. and Eveke^t, A. E , Ueber den Farbstoff der Kornblume. Liebig. Ann. 

 401:189, 1913. 



5. Wheldale, M , Our Present Knowledge of the Chemistry of the MendeUan Factors for 

 Flower Colour. Jour. Gvnet. 4 ; 109, 1914. 



