CROSSINGS IN MELANIUM-VIOLETS 



261 



The violet, hliu' and red colour is due to anthocyan. Wittkock 

 (1897) liolds that this changing o( the colour depends on dilterences 

 in the temperature, and this may he the case. I found by warming 

 up a solution of the violet flower colour that it became pale and 

 almost colourless. 



The light yellow colour of V. arucnsis is due to anthochlor in the 

 cell-sap. When concentrated sulphur acid is added it becomes of a 

 high yellow colour; it is thus shown to be different from the antho- 

 chlor of Antirrliiiiiim and LinarUi which becomes brown-coloured. 



