48 THE METHODS AND 



positive propositions as to the origin and 

 inter-relation of species in general, now, would 

 be a task as fruitless as that of a chemist 

 must have been who had tried to state the 

 relationship of the elements before their 

 properties had been investigated. 



For the first time Variation and Reversion 

 have a concrete, palpable meaning. Hitherto 

 they have stood by in all evolutionary debates, 

 convenient genii, ready to perform as little or 

 as much as might be desired by the conjuror. 

 That vaporous stage of their existence is 

 over ; and we see Variation shaping itself as 

 a definite, physiological event, the addition or 

 omission of one or more definite elements ; 

 and Reversion as that particular addition or 

 subtraction which brings the total of the 

 elements back to something it had been 

 before in the history of the race. 



The time for discussion of Evolution as 



