THE gracious reception given to my several reports of field studies among primitive racial groups and the many requests for copies of those brief reports and for further data, together with the need for providing interpretations and applications of the data, have induced me to consolidate my investigations. There have also been many requests from my patients and from members of the medical and dental professions for concise statements as to what I have found that would be useful as preventive procedures. In addition I have been conscious of an opportunity for helpfulness to the members of the various primitive races that I have studied and who are so rapidly declining in health and numbers at their point of contact with our modern civilization. Since they have so much accumulated wisdom that is passing with them, it has seemed important that the elements in the modern contacts that are so destructive to them should be discovered and removed.

    There has been a deep sense of obligation to the officials of many countries for the great kindness and assistance that they have so cheerfully given by providing the opportunity for these investigations. The list of these individuals is much too long to mention them all by name. One of the joys of my work has been the privilege of knowing the magnificent characters that are at the outposts earnestly striving to better the welfare of the natives whom they are ministering to, but who are distraught with the recognition that under the modernization program the natives decline in health and become afflicted by our modern types of degenerative diseases. It would be fortunate if each of these field workers could be provided with a copy of this report which they have helped to make possible.

    In order to make this information available to as wide a group as possible, I have avoided technical language and will ask the indulgence of professional readers.

    There are some individuals whose assistance I must acknowledge specifically: Reverend Father John Siegen and Doctor Alfred Gysi of Switzerland; Mrs. Lulu Herron and Doctor J. Romig of Alaska; the Indian Department at Ottawa; the Department of Indian Affairs at Washington, D. C.; the officials of the eight archipelagos studied in the Pacific; Colonel J. L. Saunders of New Zealand; the Minister of Health, New Zealand; Dr. W. Stewart Ziele of Sydney, Australia; Sir Herbert Gepp of Melbourne, Australia; Doctor William M. Hughes, Minister of Health, Canberra; Dr. Cummiston, Director-General of Health, Australian Commonwealth, Canberra; Doctor Rapael Cilento of Queensland, Australia; Mr. E. W. Saranealis, Thursday Island; the Department of Health of Kenya, Africa; the Department of Health for Belgian Congo, Brussells; the Department of National Parks, Belgian Congo; Minister of the Interior, Peru; Doctor Albert Giesecke and Esther Giesecke of Peru; the Directors of Museums in Sydney and Canberra, Australia; Auckland, New Zealand; Vancouver, and Toronto, Canada; Washington, New York and Chicago, the United States; Juneau, Alaska; Rome, Italy; and Cairo, Egypt; the publishers of the Ohio State Medical Journal, the Journal of the American Dental Association, the Dental Digest and the Dental Items of Interest; my faithful secretary, Mrs. Ruth MacMaster; Professor W. G. Garnett who so kindly provided the critical reading of the manuscript, and the publishers who furnished constructive suggestions and cooperation. To these and a host of others I am deeply indebted and profoundly grateful.