122 VARIOUS FOOD-PLANTS 



us with energy which shall be immediately available at any 

 niouiont for the work of life. 



45. Food-plants in general. When considering the cereal 

 grains, we found that important facts regarding their special 

 value and present use were explained by the original geo- 

 graphical range and economic history of the species. AVe 

 have now to conclude our study of food-plants by a com- 

 parison, from this point of view, of the other kinds with 

 these, so that we may arrive at some further general ideas 

 concerning them. 



In the tabular view on pages 120-121 is given for each of 

 the species already referred to, a brief statement of its native 

 home and period of earliest cultivation, according to the 

 opinion of recent authorities. Where these are doubtful 

 an interrogation mark in parenthesis has been placed after 

 the point in question. 



46. The primitive centers of agriculture. We have al- 

 ready seen that the three grains, wheat, rice, and maize, which 

 have played a supremely important part in the history of 

 mankind, are each native to a region which is widely separ- 

 ated from the homes of the other two, — wheat being in- 

 digenous to Mesopotamia, rice to southeastern Asia, and 

 maize to tropical America. 



There is abundant evidence to show that it was in these 

 regions, and in the lands immediately adjacent, that agri- 

 culture was first systematically pursued, and thus made pos- 

 sible the development of the great civilizations of antiquity. 



It is certainly a fact of profound significance in human 

 history that wheat, the most valuable of the grains, should be 

 native to a region so near the junction of the three continents 

 of the eastern hemisphere. Antiquarian scholars are of the 

 opinion that from the fertile valley of the Tigris and Eu- 

 phrates as a center, agriculture, with the civilization which 

 it implies, extended to all the great peoples of Africa, Europe, 

 and southern and western Asia. A more restricted civiliza- 

 tion of later development and less importance was that which 

 arose in the valley of tlu^ lioangho and Yangtse-Kiang, and 

 formed the beginning of the present Chinese Empire. Still 

 later, although many centuries before the coming of Colum- 



