DED UCTION'. ANTICIPA TION. 1 43 



several foregoing facts led me to try the effects 

 of the two kinds of pollen on the stigmas of 

 the two forms." This "trial" consisted of a 

 long series of experiments to establish the 

 effects of legitimate and illegitimate unions of 

 the two forms. The reward of this effort to 

 establish the principle by physiological evi- 

 dence is summed up in his own words: "From 

 the facts now given the superiority of a legiti- 

 mate over an illegitimate union admits of not 

 the least doubt ; and we have here a case to 

 which no parallel exists in the vegetable, or 

 indeed in the animal kingdom." 1 



It had long been known that if pollen from 

 a distinct species is placed on the stigma of a 

 plant, and afterwards (sometimes many hours 

 afterwards) pollen from its own species is 

 placed on the same stigma, the latter obliter- 

 ates the effects of the former, and the plant 

 will be fertilized by the pollen of its own 

 species. He had shown that the two forms of 

 flowers of the cowslip were beautifully adapted 

 in structure for cross-fertilization, and that it 

 was essential to the vigor of the species that 

 there be cross-fertilization between the two 

 forms, and that cross-fertilization between 

 flowers of the same form, or fertilization of a 



1 Different Forms of Flowers, etc., p. 28. 



