84 BROOMALL : FLOWER PIGMENTS. 



As regards the chemistry of flower pigments but little is 

 known and it is perhaps doubtful whether any of them have 

 been isolated in the pure state. It is interesting to note, 

 however, that despite their extreme susceptibility to change of 

 reaction they are really quite stable. Thus, in some pansies 

 (of the variety with both purple and yellow petals) which 

 had lain between the leaves of an old book, boxed up and 

 packed away with others since about :86o, the respective 

 purple and yellow pigment reactions were shown very nicely. 

 And again, a purple pansy which had lain pressed away in 

 an envelope in a book since " Easter Sunday, 1847," accord- 

 ing to the label, changed back and forth between green and 

 purple almost as markedly as a fresh flower. 



