The modern investigation of how man's adaptation to his environment affects his health dates from Claude Bernard. During the succeeding century, there has been a continued interest in the field in which Bernard pioneered, and the number of those working in the area has increased steadily. Information has been gathered from sources as diverse as neurology, endocrinology, cultural anthropology, and the statistics of time series,1 each part of which has contributed to general concepts which could not have been constructed even so recently as 10 years ago. The purpose of the present paper is to describe some of the findings from a study carried out by us and our colleagues,* which is concerned with the distribution of illness in three population groups, the influence of environmental factors upon this, and its significance in the light of our knowledge derived from laboratory experiments.
Over the past five years, members