118 Darwin- Wallace Celebration. 



less adapted to the actual conditions, the fittest alone would 

 continue the race. But this would only tend to the 

 persistence of those best adapted to the actual conditions ; 

 and on the old idea of the permanence and practical 

 unchangeability of the inorganic world, except for a few 

 local and unimportant catastrophes, there would be no 

 necessary change of species. 



But along with Malthus I had read, and been even more 

 deeply impressed by. Sir Charles Lyell's immortal ' Principles 

 of Geology,' which had taught me that the inorganic world 

 the whole surface of the earth, its seas and lands, its 

 mountains and valleys, its rivers and lakes, and every detail 

 of its climatic conditions, were and always had been in 

 a continual state of slow modification. Hence it became 

 obvious that the forms of life must have become continually 

 adjusted to these changed conditions in order to survive. 

 The succession of fossil remains throughout the whole 

 geological series of rocks is the record of this change ; and 

 it became easy to see that the extreme slowness of these 

 changes was such as to allow ample opportunity for the 

 continuous automatic adjustment of the organic to the 

 inorganic world, as well as of each organism to every other 

 organism in the same area, by the simple processes of 

 " variation and survival of the fittest." Thus was the 

 fundamental idea of the " origin of species " logically 

 formulated from the consideration of a series of well- 

 ascertained facts. 



[Received 28th August, 1908.] 



