Selection of Elementary Species 95 



the race above its average, and must guard 

 constantly against the regression towards this 

 average which usually takes place. 



Hays has repeatedly insisted upon the prin- 

 ciple of the choice of the most favorable varie- 

 ties as the foundation for all experiments in 

 improving races. He asserts that half the bat- 

 tle is won by choosing the variety which is to 

 serve as a foundation stock, while the other half 

 depends upon the selection of parent-plants 

 within the chosen variety. Thus the choice of 

 the variety is the first principle to be applied in 

 every single case; the so-called artificial selec- 

 tion takes only a secondary place. Calling all 

 minor units within the botanic species by the 

 common name of varieties, without regard to 

 the distinction between elementary species and 

 retrograde varieties, the principle is designated 

 by the term of '^ variety-testing." This test- 

 ing of varieties is now, as is universally known, 

 one of the most important lines of work of the 

 agricultural experiment stations. Every state 

 and every region, in some instances even the 

 larger farms, require a separate variety of 

 corn, or wheat, or other crops. They must be 

 segregated from among the hundreds of gen- 

 erally cultivated forms, within each single bo- 

 tanic species. Once found, the type may be 

 ameliorated according to the local conditions 



