OLD TYPES AND NEW 205 



Nilsson of Svalof in Sweden, upon peas, potatoes, 

 clovers, grasses and grains. 



Among others in America, Hays has isolated pedi- 

 grees of wheat at the Minnesota Agricultural Experi- 

 ment Station, which within a decade have been grown 

 on thousands of acres and have "made possible the 

 increased production of wheat throughout the northern 

 States and Canada." 



An isolation method that has been successfully ap- 

 plied to the sugar-beet industry is that of Vilmorin. 

 The seeds from each plant to be tested are sown in 

 separate beds from which upon maturity samples are 

 taken and tested for sugar content. The plants from 

 the bed furnishing the sample containing the highest 

 percentage of sugar are then used as the seed pro- 

 ducers for the next generation. In this way by con- 

 tinual selection an improved strain is maintained. 



C. INBREEDING 



When breeding is kept up between individuals of 

 the same stock it tends to perpetuate or preserve the 

 distinctive characteristics of that stock, a practice 

 that was advocated in the Mosaic law, "Thou shalt 

 not let thy cattle gender with a diverse kind; thou 

 shalt not sow thy field with mingled seed." (Levit. 

 XIX :19.) 



Numerous experiments to test the effect of inbreed- 

 ing have been carried out upon various organisms. 



Darwin, for instance, planted morning-glories, 

 derived from the same stock of seeds, in two 



