iv PREFACE 



forth my own little book if I had not succeeded in 

 securing beforehand his kind sanction. That sanction, 

 however, was at once so frankly and cordially given, that 

 all my hesitation upon such a score was immediately 

 laid aside ; and as I have necessarily had to deal rather 

 with Darwin's position as a thinker and worker than 

 with the biographical details of his private life, I trust 

 the lesser book may not clash with the greater, but to 

 some extent may supplement and even illustrate it. 



Treating my subject mainly as a study in the inter- 

 action of organism and environment, it has been neces- 

 sary for me frequently to introduce the names of living 

 men of science side by side with some of those who 

 have more or less recently passed away from among us. 

 For uniformity's sake, as well as for brevity's, I have 

 been compelled, in every instance alike, to omit the 

 customary conventional handles. I trust those who thus 

 find themselves docked of their usual titles of respect 

 will kindly remember that the practice is in fact adopted 

 honoris causa ; they are paying prematurely the usual 

 penalty of intellectual greatness. 



My obligations to Professor Huxley, to Professor 

 Fiske, to Mr. Herbert Spencer, to Professor Sachs, to 

 Hermann Miiller, to Dr. Krause, to Charles Darwin him- 

 self, and to many other historians and critics of evolu- 

 tionism, will be sufficiently obvious to all instructed 



