MINERAL COMPOSITION OF CEOPS 6 



develops some sense of values in regard to the healthfulness of its 

 foods, and when, as in ancient times, it was allowed to roam over 

 large areas of the better lands, nutritional disorders were probably not 

 often observed. However, the ever-increasing population forced the 

 adoption of fundamental changes in the habits of the herdsman. He 

 was required to confine his cattle to that portion of the landscape that 

 he controlled, or he was required to move them to an entirely new 

 and probably much less desirable environment to which they were not 

 adapted. Those who were fortunate enough to have chosen or to 

 have preempted the better lands experienced no difficulties with their 

 cattle, but those to whom fell the less desirable lands or who were 

 driven to some other locality deficient in some respect soon found that 

 their cattle developed disorders that could not be combatted by any 

 known methods. The fact that cattle thrived better on some lands 

 than on others was thus quickly noticed, and we have many references 

 as early as the eighteenth century of the adverse effects of grazing of 

 cattle on certain lands while often adjacent lands were found to be 

 healthful. 



Man, in general, has derived his food, in modern times, from such a 

 variety of localities that mineral deficiencies are seldom traceable to 

 any specific soil cause, although such disorders as goiter are confined 

 largely to persons living in areas where the soils and waters are deficient 

 in iodine. Because of the varied diet and the modern methods of food 

 processing and transportation, the fundamental problem of the rela- 

 tion of sources of food to human disease is more difficult to solve. 

 However, some of our people do live in restricted localities and on 

 highly restricted diets, and it should be possible to approach the 

 problem of human nutritional diseases in such localities in much the 

 same manner as one would for animals. Such relationships between 

 the soil as an environmental factor and the occurrence of human dis- 

 orders have already been observed, but it is very probable that some 

 of these are quite accidental or at least very indirect, such as the 

 observation of Virtanen (576) in 1928 that tuberculosis in Finland is 

 more prevalent among people who live on acid soils than among those 

 living on soils that are more nearly neutral. Many such observations of 

 cause and effect are, however, quite direct, as, for example, the fact 

 observed by Byers (102) that in certain localities in Mexico the 

 inhabitants exhibit the characteristics of selenium poisoning, while 

 in the selenium areas in South Dakota "a high incidence of symptoms 

 pointing to gastric or intestinal dysfunction, and a few instances of 

 apparent hepatic dysfunction, both probably the result of continual 

 selenium ingestion/' have been reported (531). 



Thus, even cursory observations throughout the past two or three 

 centuries have indicated that certain soils were good while others were 

 poor, and Corlette (123) has stated: 



In working through veterinary literature on osteomalacia, rickets and associated 

 conditions of disease, I found my attention over and over again attracted to the 

 character of the soil, climate and vegetation in their relation to the prevalence of 

 cases. 



The nutritional diseases of animals which have been traced to soil 

 characteristics may be divided into two general classes. The first, and 

 more important, are those reported to be due to a deficiency of one or 



