PREFACE. Vll 



appeared, the great difficulties I felt in accepting 

 natural selection as any real origin of species lay, 

 first, in the seeming impossibility of the histological 

 minutige of the organs in adaptation having been selected 

 together; and, secondly, in the idea that all those 

 wonderful and "purposeful" structures which Paley 

 thought could only have been " designed," could be the 

 ultimate result of any number of accidental and appa- 

 rently at first " purposeless " variations. In a broad 

 sense natural selection seemed obviously true ; for 

 Geology had revealed the fact that the world had been 

 peopled over and over again by old forms dying out and 

 new forms coming in ; so that although it might account 

 for the extinction of the former, it did not seem to me 

 capable to account for the origin of the latter. I, there- 

 fore, still looked to the environment as affording a better 

 clue to the source of variations.* 



In 1869, when watching a large humble-bee hanging 

 on to the dependent stamens of Epilohiutn angusti- 

 folium, the idea first occurred to me that insects them- 

 selves might be the real cause of many peculiarities in 

 the structure of flowers. The thought passed through 

 my mind that the way the stamens hung down might 

 perhaps have become an hereditary effect from the 

 repeatedly applied weight of the bees. 



In 1877, I advanced this idea as a speculation 



* See Letter to Nature, vol. v., p. 123. 



