may well be reckoned as very
important among the causes which retarded the progress of mankind in
this part of the world.

[Footnote 26: The case of Peru, which forms an apparent but not
real exception to this general statement, will be considered
below in chap. ix.]

[Sidenote: Importance of Indian corn.]

On the other hand the ancient Americans had a cereal plant peculiar to
the New World, which made comparatively small demands upon the
intelligence and industry of the cultivator. Maize or "Indian corn" has
played a most important part in the history of the New World, as
regards both the red men and the white men. It could be planted without
clearing or ploughing the soil. It was only necessary to girdle the
trees with a stone hatchet, so as to destroy their leaves and let in the
sunshine. A few scratches and digs were made in the ground with a stone
digger, and the seed once dropped in took care of itself. The ears could
hang for weeks after ripening, and could be picked off without meddling
with the stalk; there was no need of threshing and winnowing. None of
the Old World cereals can be cultivated without much more industry and
intelligence. At the same time, when Indian corn is sown in tilled land
it yields with little labour more than twice as much food per acre as
any other kind of grain. This was of incalculable advantage to the
English settlers of New England, who would have found it much harder to
gain a secure foothold upon the soil if they had had to begin by
preparing it for wheat and rye without the aid of the beautiful and
beneficent American plant.[27] The Indians of the Atlantic coast of
North America for the most part lived in stockaded villages, and
cultivated their corn along with beans, pumpkins, squashes, and tobacco;
but their cultivation was of the rudest sort,[28] and population was too
sparse for much progress toward civilization. But Indian corn, when
sown in carefully tilled and irrigated land, had much to do with the
denser population, the increasing organization of labour, and the higher
development in the arts, which characterized the confederacies of Mexico
and Central America and all the pueblo Indians of the southwest. The
potato played a somewhat similar part in Peru. Hence it seems proper to
take the regular employment of tillage with irrigation as marking the
end of the lower period of barbarism in the New World. To this Mr.
Morgan adds the use of adob