BIOLOGICAL SCIENCE 57 



from a few prototypes all the existing species of 

 living beings, gradually, throughout the long ages 

 of geological time, moulding each species to suit its 

 environment, and leaving it more fixed in type as 

 the need for variation disappeared. 



When this theory had overcome the opposition of 

 those who held a too literal interpretation of the 

 book of Genesis, it became the dominating idea of 

 the second half of the nineteenth century. Its influ- 

 ence extended far beyond the confines of biological 

 science. By giving a reasonable explanation of bio- 

 logical development, it justified the conception of 

 evolution in general, and that conception was applied 

 with varying measures of success to co-ordinate the 

 phenomena of cosmical processes, the development 

 of the human race, historical change, and social 

 evolution. Even the specific idea of natural selec- 

 tion, or the survival of the fittest the fittest for the 

 particular existing environment found application 

 in other realms of thought. In especial it illuminated 

 the tendencies of sociology, or the science of human 

 societies, where progress has followed along much the 

 same lines previously trodden by natural history. 

 From the mere collection of tales of the marvellous 

 and surprising, such as were at first brought back by 

 travellers, traders, and missionaries whose calling 

 took them among unknown peoples the study of 

 mankind has advanced into the careful, sympathetic, 

 and intelligent stage, which is now characteristic of 



