"- DEFENCE, NOT DEFIANCE^ 137 



So far it is evident that the perfumes of flowers 

 perform a double duty — that of informing insects at 

 a distance of their neighbourhood, and that their 

 flowers are open and the nectar ready ; and, further, 

 of protecting them from devouring caterpillars and 

 browsing mammalia. It is possible they subserve a 

 third end, that of screening the delicate petals from 

 the consuming heat of the sun ; for these structures 

 remain untouched even when the hardier leaves are 

 withered up and browned. 



Six years ago I ventured an explanation of this 

 phenomenon, in Flozvers, their Origin^ Shapes, Per- 

 fumes, and Colours (p. 311); and subsequent obser- 

 vation has only confirmed me in the opinion there 

 expressed, and which may be here referred to in 

 explanation. Professor Tyndall has shown the 

 power which a spray of perfume possesses, when 

 diffused through a room, to cool it ; or, in other 

 words, to bar out the passage of the heat rays. May 

 not the possession by flowers of the ethereal oils or 

 perfumes be the means of effectually protecting them 

 from solar heat, and so enabling them to keep open 

 unimpaired, until the purpose for which they ex- 

 panded has been effected ? 



Every one knows that flowers possess different 

 and characteristic perfumes. Lubbock, Bennett, and 

 other botanists have proved the partiality of the more 

 highly-cerebrated insects, such as bees, for certain 

 eolours — blue, for example. There is reason to 



