THE LEAVES 69 



has the power of moving the masses of pigment 

 toward and away from the surface so that the tone 

 of color may change in the same leaf during the 

 course of a few hours. 



Besides the green, other coloring matter may be 

 present in the cells, or the walls may be dyed. The 

 leaf may show a certain color because of the contents 

 of its cells, or because of the color of its walls, in 

 the same manner that a bottle of liquid may appear 

 blue because of the color of the liquid, or the tint 

 of the glass. 



66. Hidden chlorophjl. — Chlorophyl may be 

 hidden because of the presence of other colors. 

 The leaves of the amaranth, cockscomb, and many 

 other species appear to be dark red in color, and no 

 chlorophyl is to be seen. That it is j^i'esent, how- 

 ever, may be shown by the following experiment: 

 Place a colored leaf as above, in a dish of cold water, 

 and bring it to a boil over a stove or spirit lamp. If 

 this is continued for a few minutes, the red color 

 will be extracted, and the normal green of the leaf 

 will be visible. The experiment also shows that red 

 coloring matter is soluble in water, while chlorophyl 

 is not. 



