THE AMERICAN ORIGIN OF AGRICULTURE. 497 



to the great antiquity of this agricultural tendency, while archeology 

 gives equally vivid testimony to the same antiquity and diversity of 

 the prehistoric civilizations of America. From the mounds of Ohio 

 to the equally remarkable ruins of Patagonia, the American continents 

 and islands are, as it were, dotted with remains of rudimentary civiliza- 

 tions which must have required centuries and millenniums to rise from 

 surrounding savagery, culminate and perish. The constructive arts by 

 which the existence of these vanished peoples is made known took the 

 most diverse forms; some made mounds, some expended their energies 

 upon huge carvings on high inaccessible rocks, some dug devious under- 

 ground passages, some set up monoliths and carved statues, and some 

 built massive pyramids, temples and tombs, while still others are known 

 only from their pottery or their metal work. In civilization, as in 

 agriculture, the tropics of America stand in striking contrast to those 

 of the old world. Here men of the same race showed great diversity of 

 plants and arts; there races are diverse, while arts and staple food- 

 plants are relatively little varied. The early civilizations of the eastern 

 world resembled some of the primitive cultures of America more than 

 these resembled each other. 



The American origin of agriculture is thus not doubtful, since not 

 merely one, but several, agricultures originated in America. The same 

 cannot be claimed for Asia and Africa, where only root-crops shared 

 with America attained a wide distribution, an indication that they 

 reached those continents before the uses of the similar indigenous plants 

 had been discovered. 



Poisonous Root-Crops. 



The American habit of eating roots was not a simple and direct 

 transition from the use of fruits, which are commonly supposed to have 

 been the primitive food of man. The more important and the more 

 ancient of the distinctively old world root-crops, onions, leeks, garlic, 

 carrots, radishes and turnips, are eaten, or are at least edible, in the 

 raw state, while in America there seems to be no indication that the 

 natives used any of their root-crops in this way. Some of them, such 

 as the sweet potato, the artichoke and the 'sweet cassava,' can be eaten 

 raw, but throughout the tropics of America the Indians, like the 

 Chinese, prefer everything cooked. This habit must have been adopted 

 very far back to have made possible the obviously ancient domestica- 

 tion of Manihot (cassava), Colocasia (taro) and Xantliosoma (yautia), 

 since the fleshy underground parts of these plants contain substances 

 distinctly deleterious until disintegrated and rendered harmless by heat. 

 The same may have been true of the sweet potato, since the fleshy roots 

 of its uncultivated relatives are strongly purgative. Several of the 



yams, both wild and cultivated, are also poisonous in the raw state. 



vol. lxi. — 32. [ 



