MODERN SOIL SCIENCE—KELLOGG De Th 
causes of soil characteristics, because of failure to see the common 
characteristics of unlike soils found in the same ecological region. 
In a broader study one might reach altogether different conclusions. 
Suppose, for example, that one studies in detail the upland soils on 
smooth slopes from limestone and sandstone in West Virginia in con- 
trast to those on smooth slopes from limestone and sandstone in 
western North Dakota and in southern Arizona. Here again, striking 
differences are apparent, but the most important of these relate to 
differences in climate and vegetation; geology would seem relatively 
unimportant. 
Thus by grouping the local soil types into higher categories, the 
broad soil groups that dominate the landscapes of great regions are 
compiled. When one considers individual practices in the garden, on 
the farm, or in the forest, it is the local landscape and the local soil 
types that are important. When one considers the great movements 
of population, the potentialities of nations, and the historical trends 
of peoples, the significant factors are the great soil groups. Thus 
the gardener sees soil characteristics with a different emphasis than 
does the geographer, but soil science has much to contribute to both. 
PRIMITIVE SOCIETIES ON THE SOIL 
The soil supports plants, animals, and man himself. Primitive man 
must have been as much the helpless product of his environment as 
were the wild animals. He lived close to the soil and was a food 
gatherer. He took the plants and animals, including fish, that were 
available in his own landscape. Most of these were eaten with little 
change by cooking, storage, or refining. No doubt it was a risky busi- 
ness. Families might fail to get food because of drought, deep snows, 
wars, or other calamities, and starve. However, when things went 
well, although they might live on a few foods for a time, during the 
year there was usually a variety. Then too, primitive man ate vigor- 
ously. He ate whole foods—skins, hulls, seeds, and other parts that 
are now thrown away. It is only recently that modern man has 
attempted to create a balanced diet. Early man received or failed to 
receive his proteins, minerals, and vitamins, unconsciously. Of course, 
no scientist was available to study our savage ancestors at the time, 
but many studies have been made of relatively primitive peoples and 
of the physical degeneration caused by the substitution for native 
whole foods, like cereal grains, milk, cheese, fruits, and meat, of refined 
sugar, white flour, and similar products of more ‘‘advanced”’ societies 
(12). Thus native peoples may become degenerated, or even extinct, 
after contact with Western Europeans. ‘There are reasons to suggest 
that people, like plants and animals, over a long period come to an 
adjustment with their food supply (11). 
