A Botanical ami Economic Study. 155 



The Nahuas borrowed their arts, sciences and agriculture 

 largely from the Mayas. Agriculture, the chief occupation 

 of the Aztec race, spread to the Pueblo Indians on the Rio 

 Grande River, and from there it extended eastward to the 

 Mississippi. A comparative linguistic study shows that the 

 Chahta-Maskokis had loan-words, indicating that the cereal 

 came from the West across the " Father of Waters.'' Some 

 of these Southern tribes are identical with the mound-build) rs, 

 who were driven south by the Iroquois-Algonquian eruption. 

 During times of movement and conquest the impulse is power- 

 ful toward imitation, and inter-tribal imitation is even more 

 strong than that between one individual and another. It is 

 easy to show how, under the bracing influence of race com- 

 petition, the forces of change would operate to initiate new 

 habits and progress toward a higher state of existence. This, 

 tribal interchange of culture happened when the Algonquins 

 and Iroquois moved southward, where they simultaneously 

 learned the germs of agriculture. 



The northern extension was limited by the isothermal line 

 of 50 F. (13° C. ), or the latitude of the great lakes. Corn 

 can be raised in Maine with certainty a few miles south of 

 Umbagog. It is raised with less certainty on the lake shores, 

 and on the upper stretches of the Penobscot the corn crop is 

 precarious. 



In South America, east of the Andes, the cultivation was 

 limited to districts comparatively free of forest, and where 

 the ground was sufficiently elevated for the best growth of 

 the plant. 



The map of the western hemisphere ( Plate XVII) accom- 

 panying this chapter displays the original home of maize and 

 its distribution in space and time. 1 It is probable that maize 

 reached the Rio Grande about 700 A.D., for Humboldt states 

 that the Aztecs learned of maize in 666 A.D. By the year 

 1000 A.D. it had reached the coast of Maine. The Incas used 



1 The squared areas on the map (Plate XVI]) show the position of the agricultural 

 tribes in North and South America. It is evident that the position of the agricultural 

 tribes and the area of maize distribution are identical. See explanation accompanying 

 map. See also chapter on Ethnology for position of said tribes and the grade of their, 

 culture. 



1 1 



