Artificial and Natural Selection 823 



of his method that Von Lochow decided to give 

 it to the public. 



W. M. Hays has made experiments with wheat 

 at the Minnesota Agricultural Experiment 

 Station. He chose a hundred grains as a 

 proper number for the appreciation of each 

 parent-plant, and hence has adopted the name 

 of ^^centgener power" for the hereditary per- 

 centage. 



The average of the hundred offspring is the 

 standard to judge the parent by. Experience 

 shows at once that this average is not at all pro- 

 portional to the visible qualities of the parent. 

 Hence the conclusion that the yield of the 

 parent-plant is a very uncertain indication of its 

 value as a parent for the succeeding generation. 

 Only the parents with the largest power in the 

 centgener of offspring are chosen, while all 

 others are wholly discarded. Afterwards the 

 seeds of the chosen groups are propagated in 

 the field until the required quantities of seed are 

 obtained. 



This centgener power, or breeding-ability, is 

 tested and compared for the various parent- 

 plants as to yield, grade, and percentage of ni- 

 trogenous content in the grain, and as to the 

 ability of the plant to stand erect, resist rust, 

 and other important qualities. It is evident that 

 by this test of a hundred specimens a far better 



