IN THE FLOWER GARDEN 



petunias that had acquired the tobacco habit. Un- 

 fortunately they seemed incapable of forming a 

 good root system and hence they lacked vitality. 

 Mr. Burbank has since regretted that he did not 

 graft them on tobacco roots, as in that way they 

 might perhaps have been preserved. 



It would be well worth while for someone to try 

 the experiment over again, carrying out this sug- 

 gestion. 



/ ^\ 



PRODUCING AND FIXING NEW VARIETIES 



It will be recalled that Darwin based his cele- 

 brated hypothesis of natural selection on the ob- 

 served fact that plants and animals in a state of 

 nature vary. He spoke of this variation as 

 "spontaneous," thereby confessedly begging the 

 question. Mr. Burbank believes that in a large 

 number of cases such "spontaneous" variation is 

 in reality due to hybridization. In the same way 

 he explains the occurrence of those variations 

 which, because of their wide departure from the 

 parent form, have been described as "mutants." 



The case of the mutants was brought prom- 

 inently to the attention of the biological world a 

 few years ago by Professor Hugo De Vries, the 

 celebrated Amsterdam botanist. His observations 

 were chiefly made with the evening primrose, and 

 he founded on these observations the theory of 

 evolution by mutation, that is, by sudden vaults, 

 as a modification of the theory of evolution by 

 the accumulation of minute changes. 



[151] 



