326 THE VALUE OF GREEN PLANTS TO MAN 



cation of plants and animals marks epochs in the advance of civili- 

 zation. The man of the stone age hunted wild beasts for food, 

 and lived like one of them in a cave or wherever he happened to 

 be ; he was a nomad, a wanderer, with no fixed home. He may 

 have discovered that wild roots or grains were good to eat; per- 

 haps he stored some away for future use. Then came the idea of 

 growing things at home instead of digging or gathering the wild 

 fruits from the forest and plain. The tribes which first cultivated 

 the soil made a great step in advance, for they had as a result a 

 fixed place for habitation. The cultivation of grains and cereals 

 gave them a store of food which could be used at times when other 

 food was scarce. The word " cereal " (derived from Ceres, the 

 Roman goddess of agriculture) shows the importance of this crop 

 to Roman civilization. From earliest times the growing of grain 

 and the progress of civilization have gone hand in hand. As 

 nations have advanced in power, their dependence upon the cereal 

 crops has been greater and greater. 



" iDdian corn," says John Fiske, in The Discovery of America, " has played 

 a most important part in the history of the New World. It could be planted 

 without clearing or plowing the soil. There was no need of threshing or win- 

 nowing. Sown in tilled land, it yields more than twice as much food per acre 

 as any other kind of grain. This was of incalculable advantage to the English 

 settlers in New England, who would have found it much harder to gain a se- 

 cure foothold upon the soil if they had had to begin by preparing it for wheat 

 or rye." 



To-day, in spite of the great wealth which comes from our 

 mineral resources, live stock, and manufactured products, the 

 surest index of our country's prosperity is the size of the corn 

 and wheat crop. According to a recent report, the value of farm 

 property in the United States is more than $78,000,000,000, a much 

 greater amount than is invested in manufacture. 



Corn. — More than 3,000,000,000 bushels of corn were raised in 

 the United States during the year 1923. This -figure is so enor- 

 mous that it has but little meaning to us. Iowa and Illinois are 

 the greatest corn-producing states in this country, each having a 

 yearly record of over 400,000,000 bushels. The figure on page 327 

 shows the principal corn-producing areas in the United States. 



Indian corn is put to many uses. It is a valuable food. It 



