PREVENT LIFE-WASTE—
UPBUILD NATIONAL VITALITY

Directors

Hon. William H. Taft
Henry H. Bowman
Francis R. Cooley
Robert W. de Forest
Irving Fisher
Eugene Lyman Fisk
Harold A. Ley
Elmer E. Rittenhouse
Charles H. Sabin
Frank A. Vanderlip

  • HON. WILLIAM H. TAFT
    Chairman, Board of Directors
  • ELMER E. RITTENHOUSE
    President
  • GEN. W. C. GORGAS
    Consultant, Sanitation
  • PROF. IRVING FISHER
    Chairman, Hygiene Reference Board
  • EUGENE L. FISK, M.D.
    Director of Hygiene
  • HAROLD A. LEY
    Vice-president and Treasurer
  • JAMES D. LENNEHAN
    Secretary

The Institute was established by a group of scientists, publicists, and business men, who desired to provide a self-supporting central institution of national scope devoted to the science of disease prevention—a responsible and authoritative source from which the public might draw knowledge and inspiration in the great war of civilization against needless sickness and premature death.

LIFE EXTENSION INSTITUTE, Inc.
25 WEST 45th STREET :: NEW YORK CITY

HOW TO LIVE

COPYRIGHT MOFFETT STUDIO

Hon. William Howard Taft
Chairman, Board of Directors Life Extension Institute, Inc.

HOW TO LIVE
RULES FOR HEALTHFUL LIVING BASED ON MODERN SCIENCE

AUTHORIZED BY AND PREPARED IN COLLABORATION
WITH THE HYGIENE REFERENCE BOARD OF THE
LIFE EXTENSION INSTITUTE, INC.

BY
IRVING FISHER, Chairman,
PROFESSOR OF POLITICAL ECONOMY, YALE UNIVERSITY
AND
EUGENE LYMAN FISK, M.D.,
DIRECTOR OF HYGIENE OF THE INSTITUTE

NINTH EDITION

FUNK & WAGNALLS COMPANY
NEW YORK AND LONDON
1916

Copyright, 1915, by
FUNK & WAGNALLS COMPANY
(Printed in the United States of America.)

Published, October, 1915
Second Edition, November, 1915
Third Edition, December, 1915
Fourth Edition, March, 1916
Fifth Edition, April, 1916
Sixth Edition, May, 1916
Seventh Edition, June, 1916
Eighth Revised Edition, September, 1916
Ninth Edition, September, 1916

FOREWORD

To one who has been an eye-witness of the wonderful achievements of American medical science in the conquest of acute communicable and pestilential diseases in those regions of the earth where they were supposed to be impregnably entrenched, there is the strongest possible appeal in the present rapidly growing movement for the improvement of physical efficiency and the conquest of chronic diseases of the vital organs.

Through the patient, intelligent and often heroic work of our army medical men, and the staff of the United States Public Health Service, death-rates supposedly fixed have been cut in half.

While it is true that to the public mind there is a more lurid and spectacular menace in such diseases as small-pox, yellow fever and plague, medical men and public health workers are beginning to realize that, with the warfare against such maladies well organized, it is now time to give attention to the heavy loss from lowered physical efficiency and chronic, preventable disease, a loss exceeding in magnitude that sustained from the more widely feared communicable diseases.

The insidious encroachment of the chronic diseases that sap the vitality of the individual and impair the efficiency of the race is a matter of increasing importance. The mere extension of human life is not only in itself an end to be desired, but the well digested scientific facts presented in this volume clearly show that the most direct and effective means of lengthening human life are at the same time those that make it more livable and add to its power and capacity for achievement.

Many years ago, Disraeli, keenly alive to influences affecting national prosperity, stated: “Public Health is the foundation on which reposes the happiness of the people and the power of a country. The care of the public health is the first duty of a statesman.” It may well be claimed that the care of individual and family health is the first and most patriotic duty of a citizen.

These are the considerations that have influenced me to co-operate with the life extension movement, and to commend this volume to the earnest consideration of all who desire authoritative guidance in improving their own physical condition or in making effective the knowledge now available for bringing health and happiness to our people.

WM. H. TAFT.
New Haven, June 12, 1915.

PREFACE

The purpose of this book is to spread knowledge of Individual Hygiene and thus to promote the aims of the Life Extension Institute. These may be summarized briefly as: (1) to provide the individual and the physician with the latest and best conclusions on individual hygiene; (2) to ascertain the exact and special needs of the individual through periodic health examinations; (3) to induce all persons who are found to be in need of medical attention to visit their physicians.

A sad commentary on the low health-ideals which now exist is that to most people the expression “to keep well” means no more than to keep out of a sick-bed. Hitherto, the subject-matter of hygiene has been considered in its relation to disease rather than to health. In this manual, on the other hand, it is treated in its relation to (1) the preservation of health; (2) the improvement in the physical condition of the individual, and (3) the increase of his vitality. In short, the objects of the manual are positive rather than negative. It aims to include every practical procedure that, according to the present state of our knowledge, an athlete needs in order to make himself superbly “fit,” or that a mental worker needs in order to keep his wits sharpened to a razor-edge. For this reason some suggestions, which might otherwise be regarded as of minor importance, have been included and emphasized. While it is true that a moderate infraction of some of the minor rules of health is not inconsistent with maintaining good health in the sense of keeping out of a sick-bed, such infraction, be it ever so moderate, is 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

[CHAPTER I]
AIR

  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] [89]
  2. [Serenity and Poise] [105]

[CHAPTER V]
HYGIENE IN GENERAL

  1. [The Fifteen Rules of Hygiene] [119]
  2. [The Unity of Hygiene] [121]
  3. [The Obstacles to Hygiene] [126]
  4. [The Possibilities of Hygiene] [135]
  5. [Hygiene and Civilization] [143]
  6. [The Fields of Hygiene] [157]

[SUPPLEMENTARY NOTES ON
SPECIAL SUBJECTS]

  1. [Notes on Food] [171]
  2. [Notes on Overweight and Underweight] [212]
  3. [Notes on Posture] [221]
  4. [Notes on Alcohol] [227]
  5. [Notes on Tobacco] [250]
  6. [Avoiding Colds] [272]
  7. [Signs of Increase of the Degenerative Diseases] [281]
  8. [Comparison of Degenerative Tendencies Among Nations] [286]
  9. [Eugenics] [293]

HYGIENE REFERENCE BOARD
OF THE LIFE EXTENSION INSTITUTE, Inc.

IRVING FISHER, Chairman
Professor of Political Economy
Yale University

Statistics

Public Health Administration

Medicine and Surgery

Chemistry, Bacteriology, Pathology, Physiology, Biology

Eugenics

Organized Philanthropy

Educational

Industrial Hygiene

Mouth Hygiene

Physical Training

Foreign Advisory Board

AUSTRIA
CANADA
ENGLAND
FRANCE
GERMANY
ITALY
JAPAN
RUSSIA

PORTRAITS OF MEMBERS
OF THE
HYGIENE REFERENCE BOARD

Dr. Lewellys F. Barker, Dr. John F. Anderson, Dr. Hermann M. Biggs, Dr. Alexander Graham Bell, Dr. William G. Anderson, Dr. John B. Andrews, Samuel Hopkins Adams

Prof. W. H. Burnham, Prof. Russell H. Chittenden, Dr. George W. Crile, Dr. Rupert Blue, Dr. Chas. H. Castle, Dr. George Blumer, Mrs. S. S. Crockett

Dr. Samuel G. Dixon, Prof. Henry W. Farnam, Dr. W. A. Evans, Dr. C. B. Davenport, Dr. W. G. Ebersole, Dr. Norman E. Ditman, Dr. Oscar Dowling

Dr. Eugene L. Fisk, Dr. Otto Folin, Dr. George J. Fisher, Prof. Irving Fisher, Dr. Alfred C. Fones, Dr. Burnside Foster, Dr. Henry B. Favill

Dr. Luther H. Gulick, Mr. Norman Hapgood, Mr. Lee K. Frankel, Gen. Wm. C. Gorgas, Dr. Frederick R. Green, Dr. S. S. Goldwater, Dr. John S. Fulton

Dr. J. H. Kellogg, Dr. S. Adolphus Knopf, Dr. J. N. Hurty, Chancellor David Starr Jordan, Prof. M. E. Jaffa, Mr. Calvin W. Hendrick, Mr. William J. Harris

Hon. Walter H. Page, Dr. Geo. M. Kober, Dr. J. N. McCormack, Prof. Lafayette B. Mendel, Dr. W. S. Rankin, Mr. Edward Bunnell Phelps, Prof. R. Tait McKenzie

Dr. Dudley A. Sargent, Dr. M. J. Rosenau, Prof. Leo. F. Rettger, Mr. Wickliffe Rose, Dr. Theodore B. Sachs, Dr. Edward A. Rumely, Prof. Mazyck P. Ravenel

Dr. J. W. Schereschewsky, Dr. Wm. Jay Schieffelin, Dr. Elmer E. Southard, Prof. Alonzo A. Stagg, Major Louis L. Seaman, Dr. W. F. Snow

Prof. A. E. Taylor, Dr. Chas. W. Stiles, Dr. Victor C. Vaughan, Dr. Thomas A. Storey, Prof. George C. Whipple, Dr. William H. Tolman

Prof. Walter E. Willcox, Dr. Henry Smith Williams, Dr. Cressy L. Wilbur, Prof. C. E. A. Winslow, Dr. Hugh Young, Dr. Harvey W. Wiley

HOW TO LIVE
INTRODUCTION

The purpose of the Life Extension Institute embraces the extension of human life, not only as to length, but also, if we may so express it, as to breadth and depth. It endeavors to accomplish this purpose in many ways, but especially through individual hygiene.

Thoroughly carried out, individual hygiene implies high ideals of health, strength, endurance, symmetry, and beauty; it enormously increases our capacity to work, to be happy, and to be useful; it develops, not only the body, but the mind and the heart; it ennobles the man as a whole.

Medieval Ideals

We in America inherit, through centuries of European tradition, the medieval indifference to the human body, often amounting to contempt. This attitude was a natural outgrowth of the theological doctrine that the “flesh is in league with the devil” and so is the enemy of the soul. In the Middle Ages saintliness was often associated with sickliness. Artists, in portraying saints, often chose as their models pale and emaciated consumptives.

We are beginning to cut loose from this false tradition and are working toward the establishment of more wholesome ideals. It is probably true, for instance, that the man or the woman who is unhealthy is now handicapped in opportunities for marriage, which may be considered an index to the ideals of society.

The Present Health Movement

A great health movement is sweeping over the entire world. Hygiene has repudiated the outworn doctrine that mortality is fatality and must exact year after year a fixed and inevitable sacrifice. It aims instead to set free human life by applying modern science. Science, which has revolutionized every other field of human endeavor, is at last revolutionizing the field of health conservation.

Medical Practise

The practise of medicine, which for ages has been known as the “healing art,” is undergoing a gradual but radical revolution. This is due to the growing realization that an ounce of prevention is worth a pound of cure. As teachers and writers on hygiene, as trainers for college athletes, as advisers for the welfare departments of large industrial plants, and in many other directions, physicians are finding fields for practising preventive medicine. Even the family physician is in some cases being asked by his patients to keep them well instead of curing them after they have fallen sick.

Furthermore, the preventive methods of modern medicine are being applied by the people themselves, as witness the great vogue to-day of sleeping out of doors; the popularity, not always deserved, of health foods and drinks; the demand for uncontaminated water supplies, certified milk, inspected meat and pure foods generally; the world-wide movement against alcohol, and the legislation to correct wrong conditions of labor and to safeguard the laborer.

Labor itself to-day is being held in honor, and idleness in dishonor. Ideals are being shifted from those of “leisure” to those of “service.” Work was once considered simply a curse of the poor. The real gentleman was supposed to be one who was able to live without it. The king, who set the styles, was envied because he “did not have to work,” but had innumerable people to do work for him. His ability to work, his efficiency, his endurance, were the last things to which he gave consideration. To-day kings, emperors, presidents are trying to find out how they can keep in the fittest condition and accomplish the greatest possible amount of work. Even among society women, some kind of work is now “the thing.”

High Ideals

One of the most satisfying tasks for any man or woman to-day is to take part in this movement toward truer ideals of perfect manhood and womanhood. Our American ideals, though improving, are far inferior to those, for instance, of Sweden; and these, in turn, are not yet worthy to be compared with those of ancient Greece, still preserved for our admiration in imperishable marble. With our superior scientific knowledge, our health ideals ought, as a matter of fact, to excel those of any other age. They should not stop with the mere negation of disease, degeneracy, delinquency, and dependency. They should be positive and progressive. They should include the love of a perfect muscular development, of integrity of mental and moral fiber.

There should be a keen sense of enjoyment of all life’s activities. As William James once said, simply to live, breathe and move should be a delight. The thoroughly healthy person is full of optimism; “he rejoiceth like a strong man to run a race.” We seldom see such overflowing vitality except among children. When middle life is reached, or before, our vital surplus has usually been squandered. Yet it is in this vital surplus that the secret of personal magnetism lies. Vital surplus should not only be safeguarded, but accumulated. It is the balance in the savings bank of life. Our health ideals must not stop at the avoidance of invalidism, but should aim at exuberant and exultant health. They should savor not of valetudinarianism, but of athletic development. Our aim should be not to see how much strain our strength can stand, but how great we can make that strength. With such an aim we shall, incidentally and naturally, find ourselves accomplishing more work than if we aimed directly at the work itself. Moreover, when such ideals are attained, work instead of turning into drudgery tends to turn into play, and the hue of life seems to turn from dull gray to the bright tints of well-remembered childhood. In short, our health ideals should rise from the mere wish to keep out of a sick bed to an eagerness to become a well-spring of energy. Only then can we realize the intrinsic wholesomeness and beauty of human life.

CHAPTER I
AIR

Section I—Housing

Air is the first necessity of life. We may live without food for days and without water for hours; but we cannot live without air more than a few minutes. Our air supply is therefore of more importance than our water or food supply, and good ventilation becomes the first rule of hygiene.

Living and working rooms should be ventilated both before occupancy and while occupied.

It must be remembered that the mere construction of the proper kind of buildings does not insure ventilation. We may have model dwellings, with ideal window-space and ventilating apparatus, but unless these are actually used, we do not benefit thereby.

Features of Ventilation

The most important features of ventilation are motion, coolness, and the proper degree of humidity and freshness.

Drafts

There is an unreasonable prejudice against air in motion. A gentle draft is, as a matter of fact, one of the best friends which the seeker after health can have. Of course, a strong draft directed against some exposed part of the body, causing a local chill for a prolonged time, is not desirable; but a gentle draft, such as ordinarily occurs in good ventilation, is extremely wholesome.

Air and Catching Colds

It goes without saying that persons unaccustomed to ventilation, and consequently over-sensitive to drafts, should avoid over-exposure while they are in process of changing their habits. But after even a few days of enjoyment of air in motion, with cautious exposure to it, the likelihood of cold is greatly diminished; and persons who continue to make friends with moving air soon become almost immune to colds.

The popular idea that colds are derived from drafts is greatly exaggerated. A cold of any kind is usually a catarrhal disease of germ origin, to which a lowered vital resistance is a predisposing cause.

The germs are almost always present in the nose and throat. It is exposure to a draft plus the presence of germs and a lowered resistance of the body which produces the usual cold. Army men have often noted that as long as they are on the march and sleep outdoors, they seldom or never have colds, but they develop them as soon as they get indoors again. See [Supplementary Notes], “[Avoiding Colds].”

Of course, one must always use common sense and never grow foolhardy. It is never advisable that a person in a perspiration should sit in a strong draft.

Windows

The best ventilation is usually to be had through the windows. We advise keeping windows open almost always in summer; and often open in winter.

One should have a cross-current of air whenever practicable; that is, an entrance for fresh air and an exit for used air at opposite sides of the room. Where there can not be such a cross-current, some circulation can be secured by having a window open both top and bottom.

Window-boards

In winter, ventilation is best secured by means of a window-board. This is a board the edge of which rests on the edge of the window-sill, the ends being attached firmly to the window-frame. It affords a vertical surface three or four inches high and situated three or four inches in front of the window, so as to deflect the cold air upward when the window is slightly opened. The air will then reach the breathing-zone, instead of flowing on to the floor and chilling the feet, which is the usual consequence of opening a window in winter. It seems tragic to think that for lack of some such simple device, which anyone can make or buy, there is now an almost complete absence of winter ventilation in most houses.

Air-fans

Air should never be allowed to become stagnant. When there is no natural movement in the air, it should be put in motion by artificial means. This important method of practising air-hygiene is becoming quite generally available through the introduction of electric currents into dwellings and other buildings and the use of electric fans. Even a hand fan is of distinct hygienic value.

Heating Systems

A wood or grate fire is an excellent ventilator. A heating-system which introduces warmed new air is better than one acting by direct radiation, provided the furnace is well constructed and gas-proof.

Cool Air

The importance of coolness is almost as little appreciated as the importance of motion. Most people enervate themselves by heat, especially in winter. The temperature of living-rooms and work-rooms should not be above 70 degrees, and, for people who have not already lost largely in vigor, a temperature of 5 to 10 degrees lower is preferable. Heat is depressing. It lessens both mental and muscular efficiency. Among the employes of a large commercial organization in New York who were examined by the Life Extension Institute, some of the men in one particular room were suffering from an increase of body temperature and a skin rash. On investigation it was found that the room in which they worked was overheated. There was no special provision for ventilation. A window-board was installed, with the result that the men recovered and no other cases of skin rash occurred in that room.

Dry air

As to dryness of air, there is little which the individual can do except to choose a dry climate in which to live or spend his vacations. Unfortunately, there is not as yet any simple and cheap way of drying house air which is too moist, as is often the case in warm weather.

Humidity

In the cold season, indoor air is often too dry and may be moistened with advantage. This may be done, to some extent, by heating water in large pans or open vessels. But for efficient moistening of the air, either a very large evaporating-surface or steam jets are required. The small open vessels or saucers on which some people rely, even when located in the air-passages of a hot-air furnace, have only an infinitesimal influence. Vertical wicks of felt with their lower ends in water kept hot by the heating apparatus yield a rapid supply of moisture. Evaporation is greatly facilitated if the water or wicks are placed in the current of heated air entering the room. By a suitable construction, the water may be replenished automatically. In very cold dry weather, the air-supply of an ordinary medium-sized house requires the addition of not less than 10 gallons of moisture every 24 hours, and sometimes much more.

Some authorities doubt any ill effects from extreme dryness. This is a subject yet to be cleared by experimental research.

Freshness

It is obvious that fresh pure air is preferable to impure air. Air may be vitiated by poisonous gases, by dust and smoke, or by germs. Dust and smoke often go together.

Lighting by electricity is preferable to lighting by gas, as some of the gas is liable to escape and vitiate the air.

Tobacco Smoke

A very common and at the same time injurious form of air-vitiation is that from tobacco smoke. Smoking, especially in a closed space such as a smoking-room or smoking-car, vitiates the air very seriously, for smoker and non-smoker alike.

Dust

As to dust, the morbidity and mortality rates in certain occupations, particularly those known as the dusty trades, are appreciably and even materially greater than in dustless trades.

An accumulation of house-dust should be avoided. The dust should be removed—not by the old-fashioned feather duster which scatters the dust into the air—but by a damp or oiled cloth. Dust-catching furniture and hangings of plush, lace, etc., are not hygienic. A carpet-sweeper is more hygienic than a broom, and a vacuum cleaner is better than a carpet-sweeper. The removable rug is an improvement hygienically over the fixed carpet.

Bacteria

The bacteria in air ride on the dust-particles. In a clean hospital ward, when air was agitated by dry sweeping, the number of colonies of bacteria collected on a given exposure rose twenty-fold, showing the effect of ordinary broom-sweeping.

Sunlight

The air we breathe should be sunlit when possible. Many of our germ enemies do not long survive in sunlight.

Section II—Clothing

Air may be shut out not only by tight houses but also by tight clothes. It follows that the question of clothing is closely related to the question of ventilation. In fact it is a reasonable inference from modern investigations that air-hygiene concerns the skin quite as much as the lungs. Therefore the hygiene of clothing assumes a new and hitherto unsuspected importance. A truly healthy skin is not the waxy white which is so common, but one which glows with color, just as do healthy cheeks exposed to the open air.

Porous Clothes

The hygiene of clothing includes ventilation and freedom from pressure, moderate warmth, and cleanliness. Loose, porous underclothes are already coming into vogue. But effective ventilation, namely such as will allow free access of air to the skin, requires that our outer clothes—including women’s gowns and men’s shirts, vests, vest-linings, and coat-linings—should also be loose and porous. Here is one of the most important but almost wholly neglected clothing reforms. Most linings and many fabrics used in outer clothes are so tightly woven as to be impervious to air. Yet porous fabrics are always available, including porous alpacas for lining. To test a fabric it is only necessary to place it over the mouth and observe whether it is possible or easy to blow the breath through it.

Air-baths

At times we can enjoy relief from clothing altogether. An air-bath promotes a healthy skin and aids it in the performance of its normal functions. Not every one can visit air-bath establishments or outdoor gymnasia or take the modern nude cure by which juvenile consumptives are sometimes treated (even in winter, after becoming gradually accustomed to the cold); but any one can spend at least a little time in a state of nature. Both at the time of rising in the morning and upon retiring at night, there are many things which are usually done while one’s clothes are on which could be done just as well while they are off. Brushing the teeth, washing the hands, shaving, etc., necessarily consume some time during which the luxury of an air-bath can be enjoyed. Exercises should also be taken at these times. Exercising in cold air, if not too cold, with clothing removed, is an excellent means of hardening the skin and promoting good digestion.

Tight Clothing

Shoes

The constriction from rigid or tight corsets, belts (the latter in men as well as in women), tight neckwear, garters, etc., interferes with the normal functions of the organs which they cover. All such constriction should be carefully avoided. The tight hats generally worn by men check the circulation in the scalp. Tight shoes with extremely high heels deform the feet and interfere with their health. The barefoot cure is not always practicable, but any one can wear broad-toed shoes with a straight inner edge and do his part to help drive pointed toes out of fashion. Such a reform should not be so difficult as to rid the women of China of their particular form of foot-binding. Several anatomical types of shoes, that is, shoes made to fit the normal foot instead of to force the foot to fit them, are now available. In all except cold weather, low shoes are preferable to high shoes. When possible, sandals, now fortunately coming into fashion, are preferable to shoes, especially in early childhood (but the adult, whose calf-muscles and foot-structure are not often adapted to such foot-gear, must be cautious in their use lest flat-foot result).

Cottons, Linens, Woolens

Only the minimum amount of clothing that will secure warmth should be worn. Woolens protect most, but they require the least exercise of the temperature-regulating apparatus of the body. While wool is also highly absorbent of moisture, it does not give off that moisture quickly enough. Hence, if worn next to the skin, it becomes saturated with perspiration, which it long retains to the disadvantage of the skin. Consequently woolen clothing is best confined to overcoats and outer garments, designed especially for cold weather. The underclothes should be made of some better conducting and more quickly drying material, such as cotton or linen. In winter light linen-mesh and medium wool over that, or “double-deck” linen and wool underclothes, can be worn by those who object to either linen or wool alone.

Color

As to color, the more nearly white the clothes the better. This is especially true in summer, but there is believed to be some advantage in white at all seasons.

Those who have learned to clothe themselves properly find that they have grown far more independent of changing weather conditions. They do not suffer greatly from extreme summer heat nor extreme winter cold. Especially do they note that “raw” or damp cold days no longer tax their strength.

Section III—Outdoor Living

Out-of-door Air

But we must not depend altogether on ventilating our houses and our clothes. We must turn our thoughts toward an outdoor life. The air of the best ventilated house is not as good as outdoor air. Those who spend much of their lives in the open enjoy the best health and the greatest longevity. It is a great advantage to go into camp in summer and to live in the country as much as possible.

Climate, of itself, is a secondary consideration. Not every one can choose the best climate in the world, and, after all, the main advantages of fresh air can be enjoyed in almost any locality. Even in a city, outdoor air is, under ordinary circumstances, wonderfully invigorating.

Dampness

The common prejudice against damp air greatly exaggerates its evils. While moderate dryness of air is advantageous, it seems nevertheless true that to live in damp, even foggy, air out-of-doors is, in general, more healthful than to live shut up indoors.

Outdoor Schools

Observations have shown that the pupils in outdoor and open-window schools are not only kept more healthy but learn more quickly than those in the ordinary schools. It is even claimed that tuberculous children in an outdoor school may make more rapid progress in their studies than the more normal children in a badly ventilated school. Parents should insist on fresh air for their children when at school. They should also insist on outdoor playgrounds.

Outdoor Recreations

For themselves, also, they should not neglect outings, picnics, and visits to parks. Whenever practicable, outdoor recreation should be chosen in preference to indoor recreation.

Occupations

Above all, outdoor occupations should, when possible, be chosen in preference to indoor occupations, such as working on a farm rather than in a factory. It would help solve some of the greatest problems of civilization, if, in consequence of an increased liking for outdoor life, larger numbers of our population should join the “back-to-the-farm” movement. Leaving the country for the city is often disastrous even for the purpose in view, namely to gain wealth. For wealth gained at the expense of health always proves in the end a bitter joke. The victim proceeds through the rest of his life to spend wealth in pursuit of health.

Section IV—Outdoor Sleeping

Unfortunately most people can not live out of doors all of the time, and many are so situated that they can not even secure ventilation, granted that they want it. But there is one important part of the twenty-four hours when most people can completely control their own air supply. This is at night. We spend a third of our time in bed. Most of us live such confined lives during the day that we should all the more avail ourselves of our opportunities to practise air hygiene at night.

Tuberculosis

Well Persons

It is the universal testimony of those who have slept out-of-doors that the best ventilated sleeping-room is far inferior in healthfulness to an outdoor sleeping-porch, open tent, or window tent (large enough to include the whole bed). For generations, outdoor sleeping has occasionally been used as a health measure in certain favorable climates and seasons. But only in the last two decades has it been used in ordinary climates and all the year round. Dr. Millet, a Brockton physician, began some years ago to prescribe outdoor sleeping for some shoe-factory workmen who were suffering from tuberculosis. As a consequence, in spite of their insanitary working-places (where they still continued to work while being treated for tuberculosis), they often conquered the disease in a few months. It was largely this experience which led to the general adoption, irrespective of climate, of outdoor sleeping for the treatment of tuberculosis. The practise has since been introduced for nervous troubles and for other diseases, including pneumonia. Latterly the value of outdoor sleeping for well persons of all classes, infants and children as well as adults, has come to be widely recognized.

Vital Resistance

Outdoor sleeping increases the power to resist disease, and greatly promotes physical vigor, endurance, and working power.

Night Air

Many people are still deterred from sleeping out by a mistaken fear of night air and of the malaria which they imagine this dreaded night air may bring. To-day we know that malaria is communicated by the bite of the anopheles mosquito and never by the air. The moral of this is not to shut out the night air, but, when necessary, to shut out the mosquito by screens. The experiment has been made of sleeping out-of-doors in screened cages in the most malarial of places and no malarial infection resulted, though those who were unprotected and were consequently bitten by mosquitoes contracted malaria as usual. The truth is that night air, especially in cities, is distinctly purer than day air, on account of the fact that there is much less traffic at night to stir up dust.

Protection From Cold

It is very important, in any sleeping balcony, to be protected from the wind by a sash on one or two or—in very windy places—three sides. But of course sleeping out-of-doors does not reach its maximum efficiency if there is too much protection, that is, if the sleeping-out place is so shut in that very free currents of air are not secured. An outdoor porch really ceases to be an outdoor porch, when enclosed on four sides.

A roll curtain (preferably rolling from the bottom) can be arranged on the open side or sides, to be used in case of storms only. In cold weather a thick mattress, or two mattresses, should be used. It is not only what is over the sleeper, but also what is under him, that keeps him warm. The body should be warmly clad, and the head and neck protected by a warm cap or helmet or hood. To prevent the entrance of cold air under the bedclothes, one or more blankets should be extended at least two feet beyond the head, with a central slit for the head. Early awakening by the light may, if necessary, be prevented by touching the eyelids with burnt cork, or by bandaging the eyes with a black cloth or stocking. Sheets should be well warmed in the winter-time before being used. They can easily be warmed with a hot-water bag, flat-iron, or soapstone. Blankets next to the skin are not hygienic.

Sleeping-tents

Sleeping out is really much easier than most people imagine. In fact, few, if any, of the other cardinal rules of hygiene are so easy to obey. Where a sleeping-porch is not available, an inward window tent can always be had which puts the sleeper practically out-of-doors and at the same time cuts off his tent from the rest of the room.

Outdoor Tents

An outdoor tent must be kept well opened. Otherwise it fails of its purpose. The common opinion that a tent is ventilated through the “meshes” of the canvas is erroneous. Canvas is a tightly woven fabric and impervious to air. That is why it makes good sails. One of the most modern boys’ camps has given up the use of tents altogether, employing instead open wooden “shacks,” because of the difficulty of keeping the tents sufficiently open, especially in rainy weather.

Complete directions for convenient out-of-door sleeping will be furnished, upon application, by the Life Extension Institute.

Section V—Deep Breathing

Ordinarily breathing should be unconscious, but every day deep breathing exercises should be employed. “A hundred deep breaths a day” is one physician’s recipe for avoiding tuberculosis. A Russian author, who suffered a nervous breakdown, found—after trying many other aids to health without success—that a retired life for several months in the mountains in which simple deep-breathing exercises practised systematically every day formed the central theme, effected a permanent cure. Deep breathing is a great resource for people who are shut in most of the day. If they will seize the chance, whenever it offers, to step out-of-doors and take a dozen deep breaths, they can partly compensate for the evils of indoor living.

In ordinary breathing only about 10 per cent. of the lung contents is changed at each breath. In deep breathing a much larger percentage is changed, the whole lung is forced into action, and the circulation of the blood in the abdomen is more efficiently maintained, thus equalizing the circulation throughout the body. The blood-pressure is also favorably influenced, especially where increased pressure is due to nervous or emotional causes.

Breathing Exercises

Breathing exercises should be deep, slow, rhythmic, and through the nose, not through the mouth. A certain Oriental deep-breathing exercise is particularly valuable to insure slowness and evenness of the breath. It consists of pressing a finger on the side of the nose, so as to close one nostril, breathing in through the other nostril, breathing out of the first nostril in the same manner and then reversing the process. Attention to the slight sound of the air, as it passes through the nose, enables one to know whether the breathing is regular or is slightly irregular. Such breathing exercises can be taken at the rate of three breaths per minute, and the rate gradually reduced until it is only two or even less per minute.

Muscular Exercise

Muscular exercises stimulate deep breathing, and, in general, the two should go together. But deep breathing by itself is also beneficial, if very slow. Forced rapid breathing is comparatively valueless, and indeed may be positively harmful. Oxygen is absorbed only according to the demand for it in the body and not according to the supply.

Singing

Singing requires deep breathing, and is for that and other reasons an excellent hygienic practise.

Mental State

The mode of our breathing is closely related to our mental condition; either influences the other. Agitation makes us catch our breath, and sadness makes us sigh. Conversely, slow, even breathing calms mental agitation. It is not without reason that, in the East, breathing exercises are used as a means of cultivating mental poise and as an aid to religious life.

CHAPTER II
FOOD

Section I—Quantity of Food

The body has often been compared to a blacksmith’s forge, the lungs being the bellows and food the coal. The comparison is a good one, for food is actually burned in the body by the aid of the air we breathe.

Calories

All food is capable of being used as body-fuel and by far the greater part of it is so used. Consequently, food is measured in fuel-units, called calories. Many people eat too much, that is, too many calories; some eat too little, that is, too few calories. In both cases the person is usually unaware of the fact, because he makes the mistake of measuring his food by its weight or bulk. Some foods are concentrated, that is, contain many calories of food value in a given bulk; others are bulky, that is, contain few calories in a given bulk. For instance, olive oil is concentrated, and most vegetables are bulky. A third of an ounce of olive oil contains 100 calories, which is as much as is contained in a pound or more of tomatoes, lettuce, celery, cucumbers, string beans, asparagus, or watermelon.

It will help to give a picture of food values if, before going further, we note how much it takes of some of the common foods to make a given amount of food value, say 100 calories. It is surprising in how many cases the ordinary amount of food served at table happens to contain about 100 calories. We find 100 calories in a small lamb chop (weighing about an ounce); in a large egg (about 2 ounces); in a small side-dish of baked beans (about 3 ounces); in 1½ cubic inches of cheese (about an ounce); in an ordinary side-dish of sweet corn (about 3½ ounces); in one large-sized potato (if baked, about 3 ounces; if boiled, about 4 ounces); in an ordinary thick slice of bread (about 1½ ounces); in one shredded wheat biscuit (about an ounce); in a very large dish of oatmeal (about 6 ounces); in a small piece of sponge-cake (about an ounce); in a third of an ordinary piece of pie (about 1½ ounces); in three teaspoonfuls or 1½ lumps of sugar (about 1 ounce); in a dozen peanuts (about ⅔ of an ounce); in eight pecans (about ½ an ounce); in four prunes (about 1 ounce); in two apples (about 7 ounces); in a large banana (about 4 ounces) in half a cantaloup (about 9 ounces); in seven olives (about 1½ ounces); in a very large orange (about 10 ounces); in an ordinary pat of butter (about ½ an ounce); in a quarter of a glass of cream (about 2 ounces); in a small glass of milk (about 5 ounces). (See [Supplementary Notes] for “[Table of Food Values].”)

The ordinary sedentary man needs about 2,500 calories per day. But the larger the person (provided the bulk is due to muscle and active tissue and not to fat) or the more muscular the work he does, the more food he needs. It has been found that the number and activity of cells forming the organs and muscles and blood affect the food requirement.

Favorable Weight

Life insurance experience has clearly shown that weight, especially in relation to age, is an important factor in influencing longevity.

Except in the earlier ages of life, overweight (reckoned relatively to the average for that age) is a more unfavorable condition, in its influence on longevity, than underweight.

The question of whether an individual is really underweight or overweight can not be determined solely by the life insurance tables. (See [Supplementary Notes], “[Influence of Build on Longevity].”) Some types who are of average weight according to the table, may be either underweight or overweight when considered with regard to their framework and general physical structure. Nevertheless, it should be remembered that notwithstanding the effort of life insurance companies to carefully select the favorable types of overweight and underweight, the mortality experience on youthful underweights has been unfavorable, and the mortality experience on middle aged and elderly overweights has been decidedly unfavorable. The lowest mortality is found among those who average, as a group, a few pounds over the average weight before age 35, and a few pounds under the average weight after age 35. That is, after the age of 35, overweight is associated with an increasingly high death rate, and at middle life it becomes a real menace to health, either by reason of its mere presence as a physical handicap or because of the faulty living habits that are often responsible for its development.

Overweight

If there is a family tendency to overweight, one should begin early to form habits that will check this tendency. If considerable overweight is already present, caution is necessary in bringing about a reduction. Barring actual disease, this can usually be done without drugs if the person will be persevering and faithful to a certain regime.

Constant vigilance is necessary, yet it is worth while when one considers the inconvenience as well as the menace of obesity.

After the age of 35, 15 to 20 pounds over the average weight should prompt one to take careful measures for reducing weight. Habits should be formed that will keep the weight down automatically, instead of relying upon intermittent attempts that are more than likely to fail. No matter how well one feels, one should take steps to keep out of the class that life insurance companies have found to be undesirable as risks.

Accessories

One reason why many people eat great quantities of food without realizing it, is the common delusion that many articles such as candy, fruits, nuts, peanuts, popcorn, often eaten between meals, “do not count.” Another common oversight is to overlook accessories, such as butter and cream, which may contain more actual food value than all the rest of a meal put together. Ice-cream and other desserts also have more food value than is usually realized. Nature counts every calory very carefully. If the number of calories taken in exceeds the number used by the body (or excreted unused), the excess accumulates in fat or tissue. Thus, if some 3,000 calories are taken in each day and the calories used up or excreted are only 2,800, then 200 must be retained and accumulated in the body.

Underweight

A person who is not heavy enough can usually gain weight by following the general rules of hygiene, especially in the matter of increasing the fuel or energy foods. But he should not force himself to eat beyond his natural capacity to digest and assimilate the food, while overfatigue and exhausting physical exertion should be carefully avoided.

Diet in Middle Life

As age advances, the consumption of meat and all flesh foods should be decreased and that of fruit and vegetables, especially those of bulky character and low food value, such as lettuce, tomatoes, carrots, turnips, salsify, oyster-plant, watercress, celery, parsnips, should be increased.

Diet in Hot Weather

Generally the quantity of food should be slightly decreased in hot weather, when fewer calories are needed to sustain the heat of the body. In particular, less meat should be eaten in the summer, on account of what is called the “specific dynamic action of protein,” that is, the special tendency of meats and like foods to produce immediate heat.

Each individual must decide for himself what is the right amount of food to eat. In general, that amount is right which will maintain the most favorable condition of weight. If the weight, endurance, and general feeling of well-being are maintained, one may assume that sufficient food is taken.

Brainwork and Eating

It is physical, not mental work, which uses up the greater part of our food. The common impression that brain-work or expenditure of mental energy creates a special need for food is erroneous. The sedentary brain-worker often gains weight without eating very much. What he really needs is exercise, to use up the food, but if he will not take exercise, then he should reduce his food even below the small amount on which he gains weight.

Eating When Fatigued

Which meal in the day should be heavy and which light depends largely on one’s daily program of work, the aim being to avoid heavy meals just before heavy work. When very tired it is sometimes advisable to skip a meal or to eat only lightly, as of fruits and salads. A man who eats heartily when he is very tired is likely to be troubled afterward with indigestion.

(See [Supplementary Notes] for specific directions regarding diet for underweight and overweight.)

Section II—Protein Foods

Protein, Fat, and Carbohydrate

In the last section it was stated that food is fuel. But there is one constituent of food which, while it can be used as fuel, is especially fitted for an entirely different purpose, namely, to build tissue, that is, to serve for the growth and repair of the body. This tissue-building constituent in food is called protein. The two other chief constituents in food are fat and carbohydrate, the last term embracing what are familiarly known as starch and sugar. Fats and carbohydrates are only for fuel and contain carbon as the essential element. Protein contains nitrogen as the essential element in tissue-building. The white of egg and the lean of meat afford the most familiar examples of protein. They consist entirely of protein and water. But meat and eggs are not the only foods high in protein. In fact, most ordinary foods contain more or less protein. The chief exceptions are butter, oleomargarine, oil, lard, and cream—which consist of fat (and water)—and sugar, sirups, and starch, which consist of carbohydrate (and water).

Proportion of Protein

Foods should be so selected as to give to the ration the right amount of protein, or repair-foods, on the one hand, and of fats and carbohydrates, or fuel-foods, on the other. A certain amount of protein is absolutely essential. While, for a few days, protein may be reduced to little or nothing without harm, if the body be long deprived of the needed protein it will waste away and ultimately death will result. Therefore, too little protein would be a worse mistake than too much.

The right proportion of protein has been the subject of much controversy. According to what are regarded as the best investigations, it is generally about 10 per cent. of the total number of heat-units consumed. This does not, of course, mean 10 per cent. of the total weight nor 10 per cent. of the total bulk, but 10 per cent. of the total nutriment, that is, 10 calories of protein out of every 100 calories of food.

Human Milk

Most persons in America eat much more protein than this. But that 10 calories out of 100 is not too small an allowance is evidenced by the analysis of human milk. The growing infant needs the maximum proportion of protein. In the dietary of the domestic animals, the infant’s food, the mother’s milk, is richer in protein than the food of the grown animal. Consequently an analysis of human mother’s milk affords a clue to the maximum protein suitable for human beings. Of this milk 7 calories out of every 100 calories are protein. If all protein were as thoroughly utilized as milk-protein or meat-protein, 7 calories out of 100 would be ample, but all vegetable proteins are not so completely available. Making proper allowance for this fact, we reach the conclusion that 10 calories out of every 100 are sufficient.

Excessive Use of High-Protein Foods

A chief and common error of diet consists, then, in using too much protein. Instead of 10 calories out of every 100, many people in America use something like 20 to 30. That is, they use more than double what is known to be ample. This excessive proportion of protein is usually due to the extensive use of meat and eggs, although precisely the same dietetic error is sometimes committed by the excessive use of other high-protein foods such as fish, shell-fish, fowl, cheese, peas and beans, or even, in exceptional cases, by the use of foods less high in protein when combined with the absence of any foods very low in protein. The idea of reducing the protein in our diet is still new to most people.

Injuries From Over-abundance of Protein

Prof. Rubner of Berlin, one of the world’s foremost students of hygiene, said, in a paper on “The Nutrition of the People,” read before the recent International Congress on Hygiene and Demography:

“It is a fact that the diet of the well-to-do is not in itself physiologically justified; it is not even healthful. For, on account of false notions of the strengthening effect of meat, too much meat is used by young and old, and by children, and this is harmful. But this meat is publicly sanctioned; it is found in all hotels; it has become international and has supplanted, almost everywhere, the characteristic local culinary art. It has also been adopted in countries where the European culinary art was unknown. Long ago the medical profession started an opposition to the exaggerated meat diet, long before the vegetarian propaganda was started. It was maintained that flour foods, vegetables, and fruits should be eaten in place of the overlarge quantities of meat.”

When protein is taken in great excess of the body’s needs, as is usually the case in the diet of Americans, added work is given the liver and kidneys, and their “factor of safety” may be exceeded.

Animal Proteins

Flesh food—fish, shell-fish, meat, fowl—when used in great abundance, are subject to additional objections. They tend to produce an excess of acids, are very prone to putrefaction, and contain “purins” which lead to the production of uric acid. This is especially true of sweetbreads, liver and kidney. The well-known deficiency in flesh foods of lime often needs to be taken into consideration in the dietary. Some of the vegetable foods, such as peas and beans, rich in protein, are likewise not free from objection. Their protein is not always easily digested and is, therefore, likewise liable to putrefaction. Unlike most vegetable foods, they contain some purins. These foods are, however, rich in iron, which renders them a more valuable source of protein for children and anemic people than meat. Also, an excess of protein is not so likely to be derived from such bulky foods as from meat, which is a concentrated form of protein.

We have spoken thus far only of the needed proportion of protein. The remainder of the diet, say 90 per cent. of the calories, may be divided according to personal preference between fats and carbohydrates in almost any proportion, provided some amount of each is used. A good proportion is 30 per cent. fat and 60 per cent. carbohydrate.

Section III—Hard, Bulky, and Uncooked Foods

The wise choice of foods does not consist entirely in balancing the ration as to protein, fat, and carbohydrate.

Hard Foods

Hard foods, that is, foods that resist the pressure of the teeth, like crusts, toast, hard biscuits or crackers, hard fruits, fibrous vegetables and nuts, are an extremely important feature of a hygienic diet. Hard foods require chewing. This exercises and so preserves the teeth, and insures the flow of saliva and gastric juice. If the food is not only hard, but also dry, it still further invites the flow of saliva. Stale and crusty bread is preferable to soft fresh bread and rolls on which so many people insist. The Igorots of the Philippines have perfect teeth so long as they live on hard, coarse foods. But civilization ruins their teeth when they change to our soft foods.

Bulk Versus Concentrated Foods

Most of the ordinary foods lack bulk; they are too concentrated. For this purpose it is found that we need daily, at the very least, an ounce of cellulose, or “woody fiber.” This is contained in largest measure in fibrous fruits and vegetables—lettuce, celery, spinach, asparagus, cabbage, cauliflower, corn, beets, onions, parsnips, squash, pumpkins, tomatoes, cucumbers, berries, etc.

Until recently would-be food reformers have made the mistake of seeking to secure concentrated dietaries, especially for army rations. It was this tendency that caused Kipling to say, “compressed vegetables and meat biscuits may be nourishing, but what Tommy Atkins needs is bulk in his inside.”

Raw Foods

Vitamins