574 THE BEGINNINGS OF LIFE. 



the phrase c Natural Selection/ although, so far as 1 

 know, there was no indication that the two meanings 

 of the phrase had ever been thoroughly distinguished by 

 Mr. Darwin. On this subject Mr. Spencer wrote as fol- 

 lows : c That organisms which live thereby prove them- 

 selves fit to live, in so far as they have been tried; 

 while organisms which die, thereby prove themselves 

 in some respects unfitted for living; are facts no less 

 manifest than is the fact that this self-acting purifi- 

 cation of a species must tend ever to insure adaptation 

 between it and its environment. This adaptation may 

 be either so maintained or so produced. . . . To recog- 

 nize Natural Selection as a means of preserving an 

 already established balance between the powers of a 

 species and the forces to which it is subject, is to 

 recognize it only in its simplest and most general mode 

 of action. It is the more special mode of action with 

 which we are here concerned. This more special mode 

 of action Mr. Darwin has been the first to perceive *. 

 To him we owe the discovery that Natural Selection is 

 capable of producing fitness between organisms and their 

 circumstances; and he, too, has the merit of appre- 

 ciating the immensely important consequences that 

 follow from this. He has worked up an enormous 



1 It is now very generally known that the discovery was independently 

 made and almost simultaneously published by Mr. A. W. Wallace 

 although Mr. Wallace does not claim to have elaborated the theory 

 with anything like the thoroughness or breadth of illustration which has 

 characterized Mr. Darwin's work. (See Wallace's ' Contribution to the 

 Theory of Natural Selection,' 2nd ed. 1872.) 



