434 EXPERIMENTS WITH PLANTS 



seed; for, after selection has achieved the ideal, it 

 has still the task of "fixing" it so that it will come 

 true to seed. 



In order to achieve our ideal, we have had to set 

 in motion the tendency to variation, or, as we say, we 

 have "broken the type." When the ideal is achieved, 

 this same tendency which we have set in motion will 

 destroy our ideal unless selection is able to suppress 

 the tendency, and so "fix the type," or, in other 

 words, bring the plant again to a state of equilibrium. 

 This we can do to a great extent, but not so fully 

 that continued selection is unnecessary. And it often 

 happens that, after an ideal is achieved, years elapse 

 before it is sufficiently fixed to put it on the market. 



The great possibilities of selection are well illus- 

 trated in the case of corn -breeding as carried on 

 by Professors Hopkins and Shamel at the Illinois 

 Experiment Station. 1 At the same time, these ex- 

 periments illustrate the great value of a thorough 

 acquaintance with the plant and its possibilities, com- 

 bined with a knowledge of the desirability of the 

 various possible lines of improvement as shown by 

 the demands of the market. Suppose you were to 

 undertake the production of an improved variety of 



!See "Corn Culture and Breeding," Thirteenth Report Kansas Board of 

 Agriculture, XVIII, 785-817. Also Bulletin No. 82, Illinois Agricultural 

 Experiment Station, 525-539. Also articles by Professor Shamel in the 

 Cosmopolitan for May, 1903; by W. S. Harwood in World's Work 

 for September, 1902, and by C. P. Hartley in Year - Book of the United States 

 Department of Agriculture for 1902. 



