utterly inconsistent with good health in the sense of attaining the highest physical and mental efficiency and power.

Future advances of knowledge will doubtless occasion additions to, or modifications of, the conclusions stated herein, and these will form the subject of subsequent publications by the Institute.

In order that the Institute may have at its disposal the latest and most authoritative results of scientific investigations, its Hygiene Reference Board was created. The present book is the first general statement of the conclusions of this Board after a year of careful consideration. These conclusions are the joint product of the members of the Board, with the active co-operation of the Director of Hygiene of the Institute. They may fairly be said to constitute the most authoritative epitome thus far available in the great, but hitherto neglected, realm of individual hygiene.

The Chairman of the Board has exercised the function of editor, and is responsible for the order and arrangement of the material.

Friends of the Institute may help its work by spreading the ideas given in the following pages and by increasing the number of its readers. Such profits as may be received by the Institute from the sale of this book will be devoted to further philanthropic effort by the Institute.

Irving Fisher,
Eugene L. Fisk.

New York, Sept., 1915.

CONTENTS

•   PAGE
• Introduction 1

CHAPTER I
AIR

•  SECTION

1. Housing 7
2. Clothing 14
3. Outdoor Living 18
4. Outdoor Sleeping 20
5. Deep Breathing 24

CHAPTER II
FOOD

1. Quantity of Food 28
2. Protein Foods 35
3. Hard, Bulky, and Uncooked Foods 40
4. Thorough Mastication 44

CHAPTER III
POISONS

1. Constipation 51
2. Posture 57
3. Poisons from Without 64
4. Teeth and Gums 78

CHAPTER IV
ACTIVITY

1. Work, Play, Rest and Sleep