218 VIGNETTES FROM NATURE. 



and minutely demonstrated. But it is a sug- 

 gestive and striking fact that hues like these 

 should exist always unseen in the very struc- 

 ture of the living plant, ready to be developed 

 at any time by proper selective or accidental 

 circumstances. Some of the colours are pro- 

 duced by the oxidation of the green chloro- 

 phyll in person ; others are actually present 

 in the green leaf itself, though completely 

 masked during the period of vigour by the 

 preponderance of the natural pigment, which 

 owes its colour to a due admixture of them 

 all. When we consider, however, that 

 colours like these lie ready and waiting in the 

 tissues of every plant, showing themselves 

 wherever chlorophyll is not present in its 

 most active form, alike in the young leaves 

 or sprouting shoots of spring and in the 

 dying foliage of autumn, it is easier to under- 

 stand how the beautiful and brilliant petals of 

 flowers have been developed by the selective 

 action of insects. The red and orange and 



