I] INTRODUCTORY 5 



a chameleon, or the means whereby some seeds are 

 wind distributed, are "argumentative of Providence 

 and Design"- and must owe their existence to "the 

 Direction of a Superior Cause." Nor have there been 

 wanting other authors who have been equally struck 

 by the wonders of adaptation. But their studies 

 generally led to the same conclusion, an exhortation 

 to praise the infinite Wisdom of Him Who in the days 

 of Creation had taken thought for all these things. 



The advent of natural selection threw a new light 

 upon adaptation and the appearance of design in 

 the world. In such books as those on The Fertiliza- 

 tion of Orchids and The Forms of Flowers Darwin 

 sought to shew that many curious and elaborate 

 structures which had long puzzled the botanist were of 

 service to the plant, and might therefore have arisen 

 through the agency of natural selection. Especially 

 was this the case in orchids where Darwin was able 

 to bring forward striking evidence in favour of regarding 

 many a bizarre form of flower as specially adapted 

 for securing the benefits of cross-fertiUzation through 

 the visits of insects. In these and other books Darwin 

 opened up a new and fascinating field of investigation, 

 and thenceforward the subject of adaptation claimed 

 the attention of many naturalists. For the most part 

 it has been an observational rather than an experi- 

 mental study. The naturalist is struck by certain 

 peculiarities in the form or colour or habits of a species. 

 His problem is to account for their presence, and as 

 nearly aU students of adaptation have been close 



