American Red Cross Text-Book on Home Hygiene and Care of the Sick. American National Red Cross
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 Institute—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 constitutes 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 space 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.
Stagnant air is harmful. Air should be in constant though not necessarily perceptible motion. Air about the body, if motionless, acts like a warm moist blanket, preventing the passage of heat from the body.
The three factors, heating, humidity, and air motion, must be considered together. Every person requires each hour about 3000 cubic feet of air, and the problem of heating and ventilating is that of providing this amount in gentle motion, at a temperature of about 65° F., and of humidity from 50–55%. Higher temperatures and stagnant air cause disinclination to work, headache, nausea, restlessness, or sleepiness, and if continued are likely to result in loss of appetite, and anemia. The tuberculosis movement