ABSTRACT
In the Americas, patterns of incidence of disease are clearly to vaguely related to patterns of geologic materials. Soils of tropical America, in contrast with soils of tropical Africa, are extensively deficient in calcium and phosphorus. The incidence of soil erosion in the Americas is appalling, despite some very good work to control accelerated translocation, and to protect bodies of water and of wetlands from inwash of soil debris. An equation of the factors that influence the level of health of animals and human beings provides a framework for the study of geomedical phenomena. Soil erosion that has been accelerated for a century or more by human activity has decreased food production on the land and has polluted streams and lakes in many areas of the US Even military maneuvers in 1940 in the Mojave Desert in the south-western USA have left their marks on soils in the 1980s.
