IX THE HISTORY AND SCOPE OF ZOOLOGY 305 



of births there is a struggle for existence and a sur- 

 vival of the fittest, and consequently an ever-present 

 necessarily -acting selection, which either maintains 

 accurately the form of the species from generation to 

 generation, or leads to its modification in correspond- 

 ence with changes in the surrounding circumstances 

 which have relation to its fitness for success in the 

 struggle for life. 



Darwin's introduction of Thremmatology into the 

 domain of scientific Biology was accompanied by a 

 new and special development of a branch of study 

 which had previously been known as Teleology, the 

 study of the adaptation of organic structures to the 

 service of the organisms in which they occur. It 

 cannot be said that previously to Darwin there had 

 been any very profound study of Teleology, but it had 

 been the delight of a certain type of mind that of 

 the lovers of nature or naturalists par excellence, as 

 they were sometimes termed to watch the habits of 

 living animals and plants, and to point out the re- 

 markable ways in which the structure of each variety 

 of organic life was adapted to the special circum- 

 stances of life of the variety or species. The astonish- 

 ing colours and grotesque forms of some animals and 

 plants which the museum zoologists gravely described 

 without comment were shown by these observers of 

 living nature to have their significance in the eco- 

 nomy of the organism possessing them ; and a general 

 doctrine was recognised, to the effect that no part or 

 structure of an organism is without definite use and 

 adaptation, being designed by the Creator for the 



