I o DEG EN ERA TIO .V. 



animals, but having no hypothesis as to the causes of 

 what they were studying, the naturahsts of twenty 

 years ago, and before that day, though they collected 

 facts, made slow progress and some strange blunders. 

 Suddenly one of those great guesses which occa- 

 sionally appear in the history of science, was given 

 to the science of biology by the imaginative insight 

 of that greatest of living naturalists — I would say 

 that greatest of living men — Charles Darwin. 



In the form in which Mr. Darwin presented his 

 view to the world it was no longer a mere guess. He 

 had already tried it and proved it in an immense 

 series of observations ; it had already been converted 

 by twenty years' labour on his part into an estab- 

 lished doctrine, and the twenty years which have 

 passed since he published the Origin of Species have 

 only served to confirm, by thousands of additional 

 tests, the truth of his original guess. 



Space will not allow me to go fully into the history 

 of the Darwinian theory, but it is necessary for my 

 present purpose that I should state precisely what 

 that theory is. It involves a number of subordinate 

 hypotheses which, together with the main hypothesis, 

 furnish us with a complete "explanation," as it is 



