180 KANS-AS CITY REVIEW OF SCIENCE. 



MEDICINE AND HYGIENE. 



THE RELATIONS OF THE SOIL TO HEALTH, i 



GEORGE H. ROHE, M. D. 



I. The Soil. — That wisest and most learned of the ancients, Hippocrates, 

 called the Father of Medicine, treated at length in one of his works of the sani- 

 tary influence of the soil. Other of the older writers, especially Herodotus and 

 Galen, called attention to the same subject, and Vitruvius, the celebrated Roman 

 architect, who flourished about the beginning of the Christian era, taught that a 

 point of first importance in building a dwelling was to select a site upon a healthy 

 soil. 



From this time until the beginning of the eighteenth century, very little of 

 value is found in medical literature bearing upon this subject. In 1717, 

 however, Lancisi published his great work on the causes of malarial fevers, in 

 which he laid the foundation for the modern theory of malaria and pointed out 

 the relations existing between marshes and low-lying lands and those diseases, 

 by common consent, called malarial. Other authors of the eighteenth and the 

 early part of the nineteenth century refer to the connection between the soil and 

 disease, but exact investigations have only been made within the last thirty years. 

 The general want of definite knowledge upon this subject, even among well- 

 educated people, is the occasion of the following pages. 



When we consider that the air we breathe, and much of the water we drink, 

 are influenced in their composition by the matters in the soil, the great impor- 

 tance of possessing a thorough knowledge of the physical and chemical conditions 

 of the soil becomes evident to every one. 



In the hygienic, as in the geological sense, we include rock, sand, and gravel 

 in the consideration of soils. 



The soil, as it is presented to us at the surface of the earth, is the result of 

 long ages of disintegration of the primitive rocks by the action of the elements, 

 of the decomposition of organic remains, and possibly of accretions of cosmical 

 dust. The principal factor, however, is the action of water upon rock, in level- 

 ing the projections of the earth's surface, produced by volcanic action. 



Soils vary considerably in physical and chemical constitution. We may 

 have, for example, a soil consisting exclusively of sand, of clay, or of disinte- 

 grated calcareous matter. Other soils may consist of a mixture of two or more 

 of these, together with vegetable matter undergoing slow oxidation. In forests, 

 we find a layer of this slowly decomposing vegetable matter of varying thickness 

 covering the earthy substratum. This organic layer is called humus, and when 



1. From the Third Annual Report of the State Board of Health of "West Virginia. 



