134 THE EVOLUTIONIST AT LARGE. 



some imaginary medicinal virtue in the herb 

 \\hich made it resemble the metal in the eyes 

 of old-fashioned practitioners. 



Dog's mercury is one of the oddest 

 English flowers I know. Each blossom has 

 three small green petals, and either several 

 stamens, or else a pistil, in the centre. 

 There is nothing particularly remarkable in 

 the flower being green, for thousands of 

 other flowers are green and we never notice 

 them as in any way unusual. In fact, we 

 never as a rule notice green blossoms at all. 

 Yet anybody who picked a piece of dog's 

 mercury could not fail to be struck by its 

 curious appearance. It does not in the least 

 resemble the inconspicuous green flowers of 

 the stinging-nettle, or of most forest trees: 

 it has a very distinct set of petals which at 

 once impress one with the idea that they ought 

 to be coloured. And so indeed they ought : 

 for dog's mercury is a degenerate plant 

 which once possessed a brilliant corolla and 

 was fertilised by insects, but which has now 



