THE OXIDASES IN RELATION TO PIGMENTATION 285 



corollas of Cobosa scandens, Rose was led to adopt Combes's 

 view of the formation of anthocyanin by direct synthesis. 

 In Table LXV. are quoted Rose's interesting analyses of 

 the corollas gathered at the four stages in the development 

 of the flower. 



TABLE LXV. 

 CORRELATION OF SUGARS AND ANTHOCYANIN IN FLOWERS. 



From these figures Rose concludes that the sugars 

 increase up to the stage at which the anthocyan pigment 

 is formed, and then diminish, whereas it is only in this last 

 stage that glucosides are found in the corollas of Cobcea 

 scandens. 



As previously mentioned, Overton noted the destructive 

 effect of high temperatures upon anthocyanin in the living 

 cell. This subject has been studied by Fitting (1912) more 

 recently. He showed that flowers of Erodium gruinum, 

 which have an intense blue colour when plucked on a cool 

 morning, change through light wine red to a clear rose 

 within a few seconds of their being placed under a glass 

 shade at a temperature of 40 to 42. This process is 

 reversible, but the return to the original colour takes place 

 more slowly. Other genera, such as Geranium, Iris, Viola, 



