THE GREAT RELAY RACE 453 



still practiced with gratifying results by practical breeders, namely, 

 mass selection, pedigree breeding, and progeny breeding. 



Mass Selection. In mass selection a general population, exhibit- 

 ing desirable qualities on the average, is drawn upon to furnish pro- 

 genitors for the following generation in the faith that "like produces 

 like." There are two ways in which a desirable population to breed 

 from may be obtained. A crop, for example, may be grow^n under 

 the most favorable conditions of cultivation and environment and 

 the improved individuals resulting chosen as seed. This method of 

 procedure is based upon the questionable belief that acquired charac- 

 ters reappear in the next generation. Or the same crop may be grown 

 under adverse conditions and those individuals which are pheno- 

 typically most promising chosen, with the idea that, since they have 

 made good in spite of unfavorable surroundings and poor nurture, 

 they must obviously possess desirable inherent or hereditary qualities. 



The limitations of this common practice of mass selection lie in the 

 fact that selection must be made over and over again, since nothing 

 dependable has been established. Moreover, the best individuals in 

 this wholesale procedure are often swamped by the average ones, so 

 that all are reduced to a mediocre level. 



Pedigree Breeding. Pedigree breeding, based likewise upon the 

 fallacy that like always produces like, narrows selection definitely to 

 single individuals or lines, rather than hopefully employing a confusion 

 of many unknown lines. It is a method that has been particularly 

 successful in breeding race horses and various kinds of domestic 

 animals, and depending upon stud-books and zealously recorded pedi- 

 grees. Even human beings are known to indulge in "blue books" 

 and proud genealogical records that characterize pedigree breeding. 



Progeny Selection. Progeny selection depends upon the princi- 

 ple that the only way to determine the character of the essential 

 germplasm in plants and animals is to see what kind of somatoplasms 

 it produces. In the poultry pens at the Massachusetts Agricultural 

 Station at Amherst, for example. Hays and Sanborn established a 

 strain of hens in which the annual egg production was raised from 145 

 to 235. This was done by selecting cocks that bred pullets which 

 made good by producing an increased yield of eggs. Thus it was 

 demonstrated that the male has a hand in the heredity of egg pro- 

 duction, although it is the female that does the real work. 



In similar fashion, bulls siring heifers that prove to be high milk- 

 producers are selected for building up a herd of dairy cows. Bulls 



