ANCESTRY INFLUENCES DEVELOPMENT 



311 



of milk. The ability to produce a large 

 quantity of milk is a trait transmitted 

 from parent to offspring. If the farmer 

 is interested in eggs for market, he 

 selects hens that lay over 200 eggs a 

 year, and uses these eggs for hatching 

 purposes. These offspring, with a few 

 exceptions, are good egg-layers. This 

 trait, too, seems to be an hereditary one. 

 For centuries, those engaged in plant 

 and animal industries have selected the 

 best individuals and the best seeds for 

 continuing or improving their stock. 



Certain differences are found among 

 cotton plants and corn plants, among 

 cows and horses, among human beings, 

 and, in fact, among all organisms that 

 seem to have nothing to do with the 

 kind of treatment they get. Some cot- 

 ton plants produce long fibers and 

 others short fibers, because they come 

 from certain stock. They belong to a 

 particular breed. Some calves become 

 Holstein cows and others become Jersey 

 cows, no matter how they are fed. 



St. Bernard 

 from the same ancestor. 



Mastiff 



English bulldog 



Scotch terrier 



Greyhound 



Dachshund 



American fox hound 



