4 INTRODUCTORY [ch. 



builds up the new variety bit by bit, on the other 

 the appearance of the new variety is entirely inde- 

 pendent of it. From this there follows a radical 

 difference with regard to the meaning of all the varied 

 characters of plants and animals. Those who uphold 

 the all-powerfulness of natural selection are bound 

 to regard every character exhibited by an animal or 

 plant as of service to it in the struggle for existence. 

 Else it could not have arisen through the operation of 

 natural selection. In other words every character in 

 plant or animal must be adaptive. On the mutationist 

 view this of course does not follow. If the new 

 character which arises independently of natural selec- 

 tion is neither of service nor disservice to its possessors 

 in the struggle for existence, there seems no reason 

 why it should not persist in spite of natural selection. 

 In attempting to decide between the two conflicting 

 views the study of adaptation is of the first importance. 

 It was perhaps in connection with adaptation that 

 Darwin obtained the most striking evidence in support 

 of his theory, and it is clear from his writings that it 

 was in this field he labom-ed with most delight. The 

 marvellous ways in which creatiures may be adapted 

 in structure and habit for the life they lead had not 

 escaped the attention of the older naturalists. John 

 Ray wrote a book^ upon the subject in which he 

 pointed out that all things in the Universe, from the 

 fixed stars to the structiu-e of a bird, or the tongue of 



1 The Wisdom of God manifested in the Works of the Creation, London, 

 1691. 



