4 SPRENGEL'S OBSERVATIONS. [CHAP. 



itself, so full of curious and careful observations, was 

 allowed to fall. For there is an obvious incon- 

 sistency in the coexistence of two elaborate sets 

 of arrangements, one tending to preclude, the other 

 to effect, self-fertilisation ; in supposing that in the 

 first place the stamens and pistil were so arranged 

 that the pollen of the one might not fertilise the 

 other ; and, secondly, that elaborate contrivances 

 were devised to promote the visits of insects, and 

 compel them to transfer the pollen from the stamens 

 to the pistil : a result which might have been ob- 

 tained so much more simply by a slight alteration 

 of the flower itself. 



It is the more remarkable that this did not strike 

 Sprengel, because he -expressly observes in one pas- 

 sage that, " Die Natur nicht will dass irgend einer 

 Zwitterblume durch ihren eigenen Staub befruchtet 

 werden solle " (Nature does not choose that any com- 

 plete flower should be fertilised by its own pollen). 

 Yet though thus so near the truth, he failed to per- 

 ceive the true importance of the visits of insects. 

 Subsequent observers, though in some cases recog- 

 nising the advantage of fertilising one flower by 

 pollen from another, did not connect these observa- 

 tions with Sprengel's discoveries ; and our illustrious 

 countryman Mr. Darwin was the first to bring into 

 prominence the fact that the importance of insects to 

 flowers consisted in their transferring the pollen not 

 merely from the stamens to the pistil, but from the 

 stamens of one plant to the pistil of another. 



While then from time immemorial we have known 

 that flowers are of great importance to insects, it is 



