PRESIDENTIAL ADDRESS. 273 



(with a breadth and sweep of view how difficult of attain- 

 ment !) ; and, above all, I desire to see it sabmitted to the 

 touchstone of patient, well-planned, rigorous, and decisive 

 experimental observation. Whatever the answer may be to 

 this particular question, I am convinced that the nature and 

 origin of variations on which I have ventured to address 

 you to-night is a question which will occupy an increasing 

 share of attention on the part of evolutionists in the near 

 future. 



