768 Fluctuations 



remains the same. The result is that many- 

 thousands of seedlings are required to go be- 

 yond the ordinary range of variations, and that 

 every further improvement requires the doub- 

 ling of the whole culture. If ten thousand do 

 not give a profitable deviation, the next step re- 

 quires twenty thousand, the following forty 

 thousand, and so on. And all this work would 

 be necessary for the improvement of a single 

 quality, while practice requires the examination 

 and amelioration of nearly all the variable 

 characters of the strain. 



Hence the rule that great results can only be 

 obtained by the use of large numbers, but it is 

 of no avail to state this conclusion from a scien- 

 tific point of view. Scientific experimenters 

 will rarely be able to sacrifice fifty thousand 

 plants to a single selection. The problem is to 

 introduce the principle into practice and to 

 prove its direct usefulness and reliability. It is 

 to Luther Burbank that we owe this great 

 achievement. His principles are in full har- 

 mony with the teachings of science. His meth- 

 ods are hybridization and selection in the 

 broadest sense and on the largest scale. One 

 very illustrative example of his methods must 

 suffice to convey an idea of the work necessary 

 to produce a new race of superlative excel- 

 lency. Forty thousand blackberry and rasp- 



