( Ixxix ) 



Max Muiler's special criticism falls to the gi'onnd, but his 

 general exhortation remains, and I think we shall do well to 

 be guided by it, and attempt to apply it to this difficult and 

 elusive woi'd species. 



The passage I have quoted was Darwin's prediction of the 

 meaning which would be attached to the word " species " by 

 the naturalist of the future. Nearly half-a-century has passed 

 since those words were written. For more than a generation 

 the central ideas of the "Origin" have been an essential part 

 of the intellectual equipment, not only of every naturalist, but 

 of every moderately intelligent man. What then is the 

 meaning of the word " species " to-day, and how does it differ 

 from that of the years before July 1, 1858, when the Darwin- 

 Wallace conception of natural selection was first launched 

 upon the world t 



The present occasion is especially favoiu'able for this inquiry, 

 because we have just been given two additional volumes of 

 the letters of Charles Darwin. After the three volumes 

 published in 1887, naturalists were certainly unprepared for 

 the welcome revelation of such a mine of wealth. The work 

 is all the more valuable because it contains many letters from 

 Alfred Russel Wallace and Sir Joseph Hooker, thus giving 

 both sides of a part of their correspondence with Darwin. 

 Then in 1900 the " Life and Letters of Thomas Henry Huxley " 

 appeared, so that we are now admitted " behind the veil," and 

 can read, as never before, the central thoughts of the great 

 makers of biological history. On the publication of the last- 

 named work, I took occasion to combat the view that the 

 thousand closely-printed pages might have been reduced by 

 omitting and condensing many of the letters. The serious 

 student of those stirring years requires the opportunity of 

 thinking over and comparing all the available thoughts and 

 opinions of the chief actors in the memorable scene ; and the 

 very repetition of certain ideas, which proves their pex'sistence 

 and dominance in the writer's mind, is a matter of deep 

 importance and interest. However it may be to the general 

 reader, the student would deprecate the omission or condensa- 

 tion of any of the writings of Darwin or Hurley. The special 

 interest and value in the letters of these men depend on the 



