DARWIN. 103 



" Origin of Species " he had in course of publication 

 several important botanical papers, on the two forms of 

 flower in the Primrose genus (1862), and in the genus 

 Linum (flax), 1863, on the forms of Loosestrife, 1864, all 

 published in the Linnean Society's Journal. 



In 1862 he brought out his first botanical book, the 

 "Fertilisation of Orchids," more fully entitled, "On the 

 various Contrivances by which Orchids are Fertilised by 

 Insects." These most singular flowers had long attracted 

 great attention owing to their peculiar shapes and often 

 their great beauty, while their marked deviation from 

 typical forms of flowers perplexed botanists extremely. 

 The celebrated Robert Brown, in a well-known paper in 

 the Linnean Society's Transactions, 1833, expressed the 

 belief that insects are necessary for the fructification of 

 most orchids ; and as far back as 1793, Christian Sprengel 

 (in " The Newly Discovered Secret of Nature ") gave 

 an excellent account of the action of the several parts m 

 the genus Orchis, having discovered that insects were 

 necessary to remove the pollen masses. But the rationale 

 of the process was not fully known until Darwin revealed 

 it, and illuminated it by the light of natural selection. 

 He had, in the " Origin of Species," given reasons for the 

 belief that it is an almost universal law of nature that the 

 higher organic beings require an occasional cross with 

 another individual. He here emphasised that doctrine 

 by a series of proofs from a peculiar and otherwise 

 inexplicable order of plants, and showed that the arrange- 

 ments by which orchids are fertilised have for their main 

 object the fertilisation of the flowers with pollen brought 

 by insects from a distinct plant. 



