This condition is not inevitable. Before the beginning of the present war, death rates at all ages were decreasing in England, Sweden, and other European countries. In America also degenerative diseases can be checked or prevented to a large extent, and it is highly important that their causes should be generally understood.

The two groups following include some of the probable causes:

1. Conditions of life which result in continued overwork, and mental overwork in particular; worry, excitement, insufficient recreation and exercise, and other kinds of nervous strain typical of modern life, especially in cities.

2. Irritating substances in the body, including poisonous substances resulting from infectious diseases, and from syphilis in particular; poisons from chronic infections, alcohol, and industrial poisons such as lead and other metals; overeating and improper eating, especially of meat and other proteins, and rich or highly seasoned food; faulty digestion, constipation, and imperfect elimination through the kidneys.--(See Dr. A. E. Shipley, in bulletin of the N. Y. City Dept. of Health, Feb., 1915.)

The importance of early recognition cannot be overemphasized. In many of these troubles the symptoms are not p.r.o.nounced, and the victims have no knowledge of their condition until they happen to be examined for life insurance, or until the disease is far advanced. And even when they realize that trouble exists, as for example constipation or overwork, most people absolutely fail to realize how serious the consequences may be. The first step toward remedy is periodic complete physical examination by a competent physician, in order to learn in time how to prevent these degenerative diseases, if present, from growing worse. The custom of undergoing an annual physical examination is becoming more common, and "such a course, conservatively estimated, would add 5 years to the average life of persons between 45 and 50."--(Winslow.)

"Recently, we have been making examinations of the employees of whole inst.i.tutions, large banks and other industrial concerns in New York City, and we find almost the same conditions there. Out of 2000 such examinations among young men and women of an average age of 33, just in the early prime of life, men and women supposedly picked because of their especial fitness for work, only 3.14% were found free of impairment or of habits of living which are obviously leading to impairment. Of the remaining persons, 96.69% were unaware of impairment; 5.38% of the total number examined were affected with chronic heart trouble; 13.10% with arteriosclerosis; 25.81% with high or low blood pressure; 35.65% with sugar, casts or alb.u.men in the urine; 12.77% with combination of both heart and kidney disease; 22.22% with decayed teeth or infected gums; 16.03% with faulty vision uncorrected.... The fact of greatest import, however, was that impairment, sufficiently serious to justify the examiner in referring the examinee to his family physician for medical treatment, was found in 59% of the total number of cases, while 37.86% were on the road to impairment because of the use of "too much alcohol," or "too much tobacco," constipation, eye-strain, overweight, diseased mouths, errors of diet, and so forth....

"And what is the cause of this appalling increase, in the United States, of these and other degenerative diseases? I believe it can be shown to the satisfaction of any reasonable person that the increase is largely due to the neglect of individual hygiene in United States....

"If a man were suddenly afflicted with smallpox or typhoid fever or any other acute malady, he would lose no time in getting expert advice and applying every known means to save his life. But his life may be threatened just as seriously, though possibly not so imminently, by arteriosclerosis, heart disease, or Bright's disease, and he will do nothing to prevent the encroachment of these diseases until it is too late, but will continue to eat as he pleases, drink as he pleases, smoke as he pleases, or overwork, and worry himself into a premature grave."--("Conservation of Life at Middle Age," Prof.

Irving Fisher, Am. Journal of Public Health, July, 1915.)

Periodic physical examinations are as necessary for children as for adults, in order to detect physical defects. These defects are known to have such an immense bearing upon health that routine examinations of all children have become an integral part of the work of enlightened public schools.

Prevention of degenerative disease, then, as well as of the enormous numbers of preventable accidents and injuries, depends in large measure upon proper living conditions and proper personal habits. The infectious diseases, according to Dr. Hill, cost us annually at least 10 billion dollars in addition to the loss of life, and he adds: "The infectious diseases in general radiate from and are kept going by women."--(Hill-- New Public Health, p. 30.) Women, it is true, can prevent many of the infections, but they can do still more, for hygienic habits to be effective must be acquired early, and mothers and teachers, because they have practically the entire control of children, have the power to prevent many cases of degenerative as well as of communicable disease.

EXERCISES

1. Distinguish between communicable and non-communicable disease.

2. Describe the part played by micro-organisms in causing disease.

3. Describe the structure of bacteria and their method of multiplication.

4. In what ways are pathogenic germs transmitted from person to person?

5. Upon what preventive measures does the control of communicable diseases depend?

6. What is meant by immunity?

7. Against what diseases may immunity be acquired artificially? How has the practice of immunizing affected death rates from communicable diseases?

8. What factors tend to lower resistance? Do they act equally in the case of all diseases?

9. Define a carrier, and explain the importance of carriers in the spread of disease.

10. Name some of the characteristics and causes of degenerative diseases.

11. Whom do the degenerative diseases most commonly affect?

12. Describe methods that should be employed to prevent degenerative diseases.

FOR FURTHER READING

The New Public Health--Hill, Chapters I-IX.

Health and Disease--Roger I. Lee, Chapters XV-XXIV.

Principles of Sanitary Science and the Public Health--Sedgwick, Chapters I, II, III.

Scientific Features of Modern Medicine--Frederic S. Lee, Chapters II, IV-VI.

Disease and Its Causes--Councilman, Chapter I.

Preventive Medicine and Hygiene--Rosenau.

Publications of the Life Extension Inst.i.tute--25 West 45th Street, New York City.

CHAPTER II

HEALTH AND THE HOME

Of all the considerations that determine health, heredity is the one unalterable factor. Although certain characteristics are obviously hereditary,--complexion, height, and mental and physical traits in great variety,--yet in the past heredity has been little understood. In consequence it has served too often as a scape goat for faults and failings not beyond an individual's control. Our first clear understanding of the principles underlying heredity resulted from experiments made by Mendel, an Austrian monk, during the last century, and it is now possible to predict with a high degree of accuracy the inheritance of certain characteristics.

Many diseases, formerly considered hereditary because their actual causes were unknown, are now known to be communicable. Thus, it is now understood that tuberculosis is not hereditary, although little children may be infected by tuberculous parents. No germ diseases are inherited in the strict sense of the word; but a baby may be infected with syphilis before birth if his father or his mother has the disease.

It is true, however, that certain tissue weaknesses of the body seem to be hereditary, and in consequence one family is more susceptible to digestive disorders, another to diseases of the lungs, a third to deafness, and so on. Moreover, general low vitality may be inherited. It should be emphasized, however, that hereditary weakness does not inevitably lead to disease. Many persons have succeeded in preventing the development of active disease by guarding against strain in directions where they are weak by inheritance.

Of all tissue weaknesses that may be inherited, defects of the nervous system are the most serious. Nervous disorders of every degree of severity, from slight nervous instability even to insanity, may result when these tissues are defective; but it is now a recognized fact that nervous disorders in many cases can be prevented from developing.

Feeblemindedness, another condition due to defective tissue, is known to be inherited in the majority of cases, and in all cases it is incurable.

HYGIENE OF ENVIRONMENT AND PERSON

By environment is meant everything outside the body that affects it; taken in its complete meaning the word might include everything that is or ever was in the whole universe. It is possible to consider here a few only of the many environmental and personal factors affecting the health of individuals.

The home const.i.tutes the important part of environment for most persons, and for children in particular, since they spend the greater part of their time in or about it, and get there the foundation on which their health in later years depends. For persons employed away from home, industrial and occupational hygiene is hardly less important; but those subjects are too extensive to be considered here.

Most people live where they must, and few have any part in planning the construction of their own houses. In choosing a house, however, one should remember that rooms where sunshine never enters are unfit for continued occupation. For children in particular fresh air and sunshine are essential, and it may be economy in the end to pay a comparatively high rent for an apartment having sunshine during at least a part of the day. Ignorance and carelessness, unfortunately, can spoil the best living conditions, and sometimes even in the country fresh air and sunshine are excluded from sleeping and living rooms.

VENTILATION.--Ventilation has a direct bearing on health, although, contrary to former belief, the actual amount of oxygen in the air is not ordinarily the most important factor; even badly ventilated rooms contain more than enough oxygen to support life. The factors of prime importance in ventilation are temperature, humidity, air movement, and the number of persons in a given s.p.a.ce since the greater the distance from one another the less is the probability that diseases will be spread.

Room temperature should not be above 70 F. and, except for the aged or sick, it is better to be between 60 and 65. Some moisture in the air is desirable; the amount needed is from 50% to 55% of the total moisture that the air can hold at a given temperature. We have no apparatus to decrease humidity in the air of houses, and in summer we are obliged to endure humidity, if excessive, no matter how uncomfortable we may be.

But in winter the air in most houses is too dry, so that the mucous membranes of the nose and throat often become irritated and susceptible to infection. Most heating systems, particularly in small buildings, make no provision for supplying moisture. Keeping water in open dishes on or near radiators is often recommended, and would greatly improve the condition of the air, if people remembered to keep the dishes filled.

The following is a simple but effective device to increase humidity: Roll an ordinary desk blotter into a cone about 8 inches in diameter at the base, and keep it constantly submerged for about one inch in a dish of water. The water rises to the top of the blotter and a large surface for evaporation is thus afforded.

[Ill.u.s.tration: FIG. 7.]