MUTATIONS 135 



if cattle had acclimated less successfully. Native grains other 

 than maize would have been developed had it not been for this 

 competition, and native grasses have not lived up to their possi- 

 bilities. This is through no fault of theirs, though we still lack 

 4 'the best American grass." 



SECTION V ECONOMIC SIGNIFICANCE OF MUTATIONS 



Because of the waywardness of sports, the impossibility 

 of predicting their appearance, the readiness with which they 

 disappear when interbred with the parent stock, and their very 

 frequent inability to reproduce at all, because of all these con- 

 siderations it has become fashionable to declare sports in general 

 to be of slight economic importance and unworthy the breeder's 

 serious attention. The only course left open for improvement is, 

 therefore, the slow one of gradual accumulation through selec- 

 tion of minute but favorable variations, according to the theory 

 of Darwin. 



The best of evidence exists, however, for believing that this 

 is a hasty and unwarranted conclusion, and that many, if not 

 indeed most, of our really valuable new types have arisen sud- 

 denly as mutations and not gradually through infinitesimal differ- 

 ences, as is commonly supposed. The experiments of DeVries 

 and the American varieties of fruits both come near enough to 

 the origin of types to more than warrant this view of the situa- 

 tion and to afford ground for the greatest hope that unsuspected 

 possibilities still exist in many if not most domesticated species, 

 possibilities of spontaneously giving off varieties representing 

 essentially new combinations of the characters of the species and 

 consequently possessed of different and perhaps enhanced eco- 

 nomic value. The work of Luther Burbank 1 and of our commer- 

 cial seedsmen add confirmation to this hope, which, if well 

 founded, promises new methods in breeding and vastly increased 

 possibilities for improvement. 



The small numbers involved in animal breeding reduce enor- 

 mously the chances of mutations appearing ; and yet nearly every 



1 W. S. Hanvood, in The Century Magazine, March and April, 1905; also New 

 Creations in Plant Life [The Macmillan Company, 1906]. 



