LUTHER BURBANK 



to-day along the same lines that have character- 

 ized it in the past. 



To accept the doctrine of evolution at all re- 

 quired the overturning of the most fundamental 

 ideas. After the conception had been grasped that 

 in the past there had been eras of change and 

 development, it was a long time before even the 

 most imaginative scientist fully grasped the notion 

 that our age also is a time of change and transi- 

 tion, and that the metamorphoses of plants and 

 animals through which new forms have evolved 

 in the past are being duplicated under our eyes 

 in our own time. 



And in particular, as regards so massive and 

 seemingly stable a structure as the tree, was it 

 peculiarly difficult for botanists to conceive of 

 flexibility and propensity to change, or to evolve, 

 in the present time. 



It is true that no very keen eye was required 

 to observe that trees differ among themselves 

 within the same species, but it is also true that 

 these divergencies always fall within certain lim- 

 its and that on the whole they may be regarded as 

 insignificant when weighed in the balance against 

 numberless characteristics in regard to which the 

 trees of a species seem practically identical. 



Take, for example, all the individuals that one 

 could observe of, let us say, the common shagbark 



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