HERITAGE OF THE INDIVIDUAL 263 



great advances, in knowledge of the underlying factors of 

 heredity, the data already accumulated are so vast that we 

 can attempt no more than to indicate the character and 

 promise of the principles already discovered. 



We may survey the field before us by a concrete example. 

 A score of years ago, just at the opening of the modern con- 

 centrated attack on genetic problems, an association of Brit- 

 ish millers awoke to the fact that some active means must be 

 taken to offset the increasingly great deficiency in quantity 

 and quality of the wheat yield. Accordingly they com- 

 missioned a specially trained biologist to investigate the mat- 

 ter. He collected many different varieties of domestic and 

 foreign wheat, each known to have one or more good qualities, 

 and studied how these were inherited. Making use of the 

 data thus secured, in the course of a few years he produced a 

 wheat which combined the good qualities of several varieties; 

 including high content of gluten, beardlessness, immunity to 

 rust, and large yield. And this 'made to order' wheat has 

 proved successful in the British Isles. But with the opening 

 up of new territory in western Canada another obstacle was 

 encountered: the growing season was too short for the finest 

 varieties of wheat. This contingency was quickly met by 

 transferring the quality of early ripening from an inferior 

 grade of wheat to a wheat possessing several valuable charac- 

 ters. 



In a similar fashion, a host of workers have performed the 

 impossible of a few years ago. Corn of desirable percentage 

 content of starch or sugar; cotton with long fibers of exotic 

 varieties and quick maturing qualities to escape insect 

 ravages; sheep combining choice mutton qualities of one 

 breed with the fine wool of another and the hornlessness of 

 a third, and so on almost ad infinitum. Furthermore, there 

 is no end in sight of the new stable races of plants and 



