196 THE METHOD OF DARWIN. 



was given in Darwin's researches. The evi- 

 dence was not all in. The structural evidence, 

 instead of serving as a basis for a true inference 

 concerning the functions of the organs, was 

 found to be in contradiction with them. Darwin 

 showed that both sets of facts were dependent 

 on a hitherto altogether unknown phenomenon, 

 the differentiation of the flowers of a species 

 into distinct sets with marked structural differ- 

 ences for the purpose of making cross-fertiliza- 

 tion almost absolutely certain. 



The following case is perhaps as interesting 

 as it could be made, to illustrate the danger of 

 accepting as truth inferences that fall short of 

 demonstration, and only represent a high degree 

 of probability. In all the books that Darwin 

 had consulted Enonymus Europeans (spindle- 

 tree) is called hermaphrodite. But he found 

 from an examination of the species that about 

 half of the individuals had both stamens and 

 pistils of normal size, and were therefore her- 

 maphrodite; and that the remaining half had 

 pistils of the normal size, but short stamens with 

 rudimentary anthers without pollen, and were 

 therefore properly females. The ovules were 

 of equal size in the two forms. There could 

 not possibly be any other conclusion from the 

 structure of the flowers than the one he sug- 



