98 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 

 transition, 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 struc- 

 ture 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 observation was 

 required to see that trees differ among them- 

 selves within the same species, but it is also true 

 that these divergences always fall within certain 

 limits and that on the whole they may be re- 

 garded 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 shag- 



