i6 



INTRODUCTION 



A corn field in the Mississippi Valley. 



cultivated plants became more and more different from the 

 wild plants which were their ancestors until now the fine 

 fruits and grains are very different from those dwarfish forms 

 from which they came. Yet even to-day the wild plant- 

 ancestors survive. 

 Even to-day a 

 wild and hardy 

 plant from which 

 wheat was derived 

 grows among the 

 sterile hills of 

 Palestine, while in 

 tropical America 

 thrives the an- 

 cient parent of 

 the corn. 



These are wonderful results which in the past have been 

 attained in agriculture, yet even more wonderful results 

 are being attained to-day. Agriculture has become a 

 science. In the past men found that certain things they 

 did to plants changed them; some of these changes were 

 improvements, and so the crops were improved. Nowa- 

 days men are finding out more than that. They are finding* 

 out why plants change. They are learning just what to do 

 in order to get the results they want. They are learning 

 how to breed plants just as they have bred horses and 

 cattle. They are finding just what to do in order to make 

 the fields yield more than they did before, and they are 

 finding how to make farm plants grow where they never 

 grew before. 



It is the knowing why as well as how that makes agricul- 

 ture a science. Success in farming depends very much on 



