136 



THE AMERICAN NATURALIST [Vol. XLIII 



but his experiments were devised with very unusual ex- 

 pertness and, like his figures, made to reveal their own 

 defects and reenforce one another as indicating directions 

 of high probability even where they were seen to stop 

 far short of proof. 



The problems which Darwin here set before himself 

 for solution were primarily the explanation of natural 

 phenomena— most of which others had observed in a gen- 

 eral way— which in his belief could not be meaningless. 

 Though doubtless not his first essay, his first publication 

 on the subject, in 1857, primarily stated observed facts 

 in Phaseolus and attacked them in this spirit, but in- 

 cidentally he analyzed the reasons why and how bees 

 visit flowers and what their intelligence is, and faced the 

 broad question why varieties of beans do not freely mix 

 if their flowers are really so formed as to secure frequent 

 intercrossing. The behavior of introduced plants sepa- 

 rated from their natural pollinators, further came into 

 the next paper, with a distinct enunciation of Knight's 

 law. Why Vincas do not seed; what their pollinators 

 are; the details and meaning of what Dr. Gray has called 

 heterogony, understanding which gave him unparalleled 

 satisfaction; why flowers of two or even three nominal 

 genera should sometimes appear on one plant of Cata- 

 setum; the substantiation of Knight's law by detailed 

 arguments of adaptation selected from a single family 

 of plants; the reason why Lythrum salicaria is repre- 

 sented by three sets of individuals as distinct from each 

 other in floral characters as if they belonged to different 

 species, and incidentally why Lagerstrcemia should pos- 

 sess a (less clearly analyzed) stamen-variability; why the 

 wild oxhp should be held for a hybrid between other 

 closely related primroses and why these are specifically 

 distinct: an extensive experimental testing of the utility 

 mi< orl vino- Knight's law; and a comparative analysis 

 ot hotcrogony, sex-separation, and cleistogamy: these 

 were the questions set for answer in subsequent pnbli- 



