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 pa.s.sage 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 appet.i.te, and anemia.

The tuberculosis movement has clearly shown the benefits both for the sick and the well of living in the open air, and has caused great and beneficial changes within a generation. The more time spent in the open air the better; since however most persons who work must spend the greater part of the day indoors, ventilation is a matter of great importance.

Although fresh air enthusiasts are still too few, yet some go to the extreme and think that because cool air in motion is good, the colder the air and more violent the motion the better. On the contrary, chilling the whole body or a part of the body lowers resistance.

Draughts of air have no bad effects upon persons in good health, particularly those accustomed to changes in temperature. But draughts are likely to be injurious to aged or sick persons and babies, by diminishing their resistance to such infections as common colds and pneumonia. It should be remembered that draughts or cold alone cannot cause colds; the specific germs must be present.

LIGHTING.--Amount and direction of light are physiologically important.

Defects of the eyes, too prolonged use, and insufficient light are the commonest causes of eye strain. Most eye defects can be relieved by gla.s.ses. Children's eyes should be examined upon entering school, and as often afterward as the oculist advises. Prolonged use causes fatigue of the eyes, especially when the illumination is poor; within limits, the amount of light needed depends on the nature of the work. Light should come from the left side of right handed people; never from the front.

Light reflected from snow, sand, glazed white paper of books, or other bright surfaces is fatiguing from its intensity, and from the unusual angle at which it enters the eyes. Too much light is harmful, and probably causes some of the effects, such as nausea and headache, commonly attributed to poor ventilation.

Almost all blindness is preventable, and blindness due to industrial accidents and processes is no exception to this rule. Surely no individual precautions or legal measures are too great in order to guard against this saddest of all physical defects.

CLEANLINESS OF HOUSES.--A clean, well-cared for house is desirable from every point of view, but certain kinds of cleanliness affect health more than others.

The most scrupulous care should be exercised wherever food is stored or prepared. The kitchen is in reality a laboratory; in it either intelligently or ignorantly are formed chemical compounds which have a far-reaching effect upon family health. From the standpoint of health no other room in the house is so important. It should be bright, airy, and easy to clean. In cleaning kitchen tables and woodwork water should not be allowed to soak into cracks and dark corners, carrying with it particles of food for the nourishment of bacteria and insects. Linoleum, if used to cover the floor, should be well fitted at the edges to prevent water from running underneath. There should be neither cracks nor crevices in wall or floor, and no dark corners or out-of-the-way cupboards in which dust, food particles, and moisture can acc.u.mulate.

Such conditions not only attract mice and roaches, but furnish favorable soil for the development of moulds and fungi which by their growth affect food deleteriously. Waging a constant warfare against the development of bacteria const.i.tutes a large part of good housekeeping.

All cooking utensils should be thoroughly washed, scalded, and dried before they are put away; the use of carelessly washed dishes is bad.

Enameled or agate ware which has begun to chip should be discarded.

Dish-cloths and towels should be washed and boiled after using, and if possible dried in the sun.

Every place in which food is kept should have constant care. The refrigerator is particularly important. Its linings should be water-tight, and the drain freely open at all times; otherwise the surrounding wood will become foul and saturated with drainings. At least once a week it should be entirely emptied and cleaned in the following way: The racks should be thoroughly washed in hot soapsuds to which a small amount of washing soda has been added, rinsed in boiling water, dried and placed in the sun and air. All parts of the refrigerator should be washed in the same manner, especially grooves and projections where food or dirt may lodge. The drainpipe should be flushed, the whole interior rinsed again with plain hot water, thoroughly dried with a clean cloth, and left to air for at least an hour. The drainage pan should be washed and scalded frequently. Food showing the slightest evidence of spoiling should be removed from the refrigerator at once.

Even more attention should be paid to the hands of the cook. They should be washed always before handling food, and always after visiting the toilet, using the handkerchief, or otherwise coming in contact with nose, mouth, or other bodily secretions. Theoretically coughing and sneezing ought not to occur in the neighborhood of food, especially of food to be eaten raw; and persons with coughs, colds, or other communicable disease, however slight, ought not to handle food. If this rule were observed in practice, more persons would go hungry, but fewer would be sick.

Thorough cleaning of rooms involves soap, water, sunshine, air, and elbow grease, just as it did before germs were discovered. Cleaning means actually removing dirt and dust, not merely stirring it up to settle again; consequently dry sweeping and dusting are ineffectual.

Vacuum cleaning, and sweeping and dusting with damp or "dustless" mops and dusters are good. Deodorants and disinfectants do not take the place of ordinary cleanliness.

Dust does not carry living disease germs to an appreciable extent; the fact is now well established that diseases formerly thought to be transmitted by dust or even supposed to travel directly through the air, are carried on tiny particles of moisture and mucus expelled in coughing and sneezing. This mode of transmission is called droplet or spray infection; it is one of the most active agents in spreading certain kinds of communicable diseases.

Nevertheless dust in motion is harmful; it irritates the lining membranes of the nose, throat, bronchial tubes, and lungs, even causing tiny wounds through which disease germs enter. Thus tuberculosis is especially prevalent among stone cutters, felt workers, and others engaged in dusty trades. Metallic dust is especially harmful, because it is harder and sharper than dust from organic substances like wool and cotton. Furthermore, presence of dust indicates a low standard of cleanliness. People who tolerate it generally tolerate uncleanliness in other forms, more serious though less apparent.

Cleaning would not be so great a problem if most houses were not littered with such dust catchers as carpets, so-called ornaments, carved and upholstered furniture, banners, draperies, and a vast collection of articles that can only be cla.s.sified as Christmas presents. In actual practice things that are difficult or expensive to clean seldom are cleaned; carpets for example are considered unhygienic, not because they cannot be cleaned, but because they are not. William Morris' advice to exclude from houses all articles not known to be useful or believed to be beautiful would, if followed, add years to the lives of housekeepers.

GARBAGE, has little bearing on health, except in so far as it affords a breeding place for flies. If it contains disease germs it may be dangerous, but statistics show that garbage handlers, although they can hardly be called especially careful, are not more subject to sickness than other men of their cla.s.s. Garbage disposal is chiefly a question of preventing a public nuisance; it is a matter of cleanliness and public decency.

INSECTS.--Flies, c.o.c.kroaches, and other scavenging insects may carry disease germs on their feet and thus infect food on which they walk.

Typhoid, cholera, dysentery, and other diseases have been carried by flies. Flies are always a menace, and should not be tolerated; moreover, the thought of their coming to food directly from manure piles and privy vaults is disgusting. Houses should be thoroughly screened in the fly season, but it is better to destroy the nuisance at its source. The chief breeding places of flies are garbage cans and manure piles. If the garbage can is water tight, closely covered, frequently emptied, and thoroughly cleaned, flies will not develop in it; about ten days must elapse from the time when the egg is laid until the insect is ready to fly. Fly traps to fit on the garbage can are useful. Manure should be screened and removed frequently, or it can be treated chemically.

Methods for treating it are given in "Preventive Medicine and Hygiene."--Rosenau, p. 255, and in Bulletin No. 118, of the U. S. Dept.

of Agriculture, July 14, 1914.

[Ill.u.s.tration: FIG. 8.--A FLY WITH GERMS (GREATLY MAGNIFIED) ON ITS LEGS. (_U. S. Dept. Agri._)]

Other diseases carried by insects are malaria and yellow fever, each by a special species of mosquito; typhus fever, by lice; and bubonic plague, by rat fleas. Various diseases less common in this country are carried by other insects. Even when mosquitoes are not carrying disease germs their bites may be harmful since they are often rubbed, especially by children, until the skin is broken, and various infections may enter through the wounds. Insects of every kind, rats, mice, and vermin should be excluded from houses.

SEWAGE.--Discharges from the bowels and bladder contain various germs, and const.i.tute one of the most important routes by which germs of typhoid fever, cholera and certain other diseases travel from person to person. Keeping sewage out of the water supply is consequently of great importance. Where a system of sewage disposal exists, the responsibility of making the system adequate and thus safeguarding public health rests upon the community as a whole. Communities ordinarily get just as much, or just as little typhoid fever as they are willing to endure.

[Ill.u.s.tration: FIG. 9.--HOW A WELL MAY BE POLLUTED. (_From "The Human Mechanism."_ Copyright by Theodore Hough and William T. Sedgwick. Ginn and Company, publishers. Used by permission.)]

In places having no system of drainage privies must be used. They can be made harmless, as army camps prove, but they require scrupulous care.

Fecal matter must be prevented from draining into wells and other water supplies, and must be screened from flies. The privy should be located at a distance from the well. The minimum distance that is safe depends in each case upon the nature of the soil and the direction of the natural drainage. Even when the privy is situated below the well on sloping ground, drainage may still occur from the privy to the well; however, a well-made, properly located pit privy is safe unless it is near a limestone formation. The dry earth system is satisfactory in places having an efficient public scavenger system; in this system pails or cans are used to receive the discharges, which are then covered with sand, ashes, earth or, preferably, chloride of lime. The buckets are frequently emptied and the contents buried at least one foot below the surface of the ground. The objection to this method for more extended use is that proper care of the cans is a disagreeable duty of which most households soon tire.

PERSONAL CLEANLINESS.--The main functions of the skin are three: to protect underlying tissues, to excrete waste matter, and to regulate bodily heat by checking or allowing the evaporation of perspiration.

After perspiration has evaporated solid matter is left upon the skin, and oily matter also is deposited on it by the glands that keep the skin lubricated. Removing these and other materials at least once a day is desirable to improve the bodily tone and sense of well-being. Real cleanliness is impossible without frequent use of warm water and soap.

Cold baths are stimulating, though not very efficacious for cleansing purposes. They are valuable tonics if properly used, but delicate or elderly persons should use them only by a physician's advice. Chilly feelings or depression following should be the signal for any person to discontinue cold bathing or swimming in cold water.

Warm baths are soothing in their effects, and are appropriate at bed time, particularly for persons inclined to sleeplessness. Very hot baths, especially if prolonged, may be harmful, and should not be taken often.

There is no clear connection between general cleanliness and disease.

Frequent bathing does not protect a person from any particular disease, except in so far as bathing necessarily includes washing the hands. If typhoid germs for example have actually been swallowed, a clean bodily exterior is of no avail in preventing typhoid fever or in diminishing its severity. The same is true of other diseases.

But it is impossible to emphasize unduly the importance of clean hands.

Hands are prime offenders in distributing fresh bodily secretions, and germs both innocent and harmful. All health authorities agree on this point.

"Perhaps 90% of all infections are taken into the body through the mouth. They reach the mouth in water, food, fingers, dust, and upon the innumerable objects that are sometimes placed in the mouth. The fact that the great majority of infections are taken by way of the mouth gives scientific direction to personal hygiene. Sanitary habits demand that the hands should be washed after defecation and again before eating, and fingers should be kept away from the mouth and nose, and that no unnecessary objects should be mouthed. All food and drink should be clean or thoroughly cooked. These simple precautions alone would prevent many a case of infection."--(Rosenau: Preventive Medicine and Hygiene, p. 366.)

As Dr. Chapin says:

"Probably the chief vehicle for the conveyance of nasal and oral secretion from one to another is the fingers. If one takes the trouble to watch for a short time his neighbors, or even himself, unless he has been particularly trained in such matters, he will be surprised to note the number of times that the fingers go to the mouth and the nose. Not only is the saliva made use of for a great variety of purposes, and numberless articles are for one reason or another placed in the mouth, but for no reason whatever, and all unconsciously, the fingers are with great frequency raised to the lips or the nose. Who can doubt that if the salivary glands secreted indigo the fingers would continually be stained a deep blue, and who can doubt that if the nasal and oral secretions contain the germs of disease these germs will be almost as constantly found upon the fingers? All successful commerce is reciprocal, and in this universal trade in human saliva the fingers not only bring foreign secretions to the mouth of their owner, but there exchanging them for his own, distribute the latter to everything that the hand touches. This happens not once, but scores and hundreds of times during the day's round of the individual. The cook spreads his saliva on the m.u.f.fins and rolls, the waitress infects the gla.s.ses and spoons, the moistened fingers of the peddler arrange his fruit, the thumb of the milkman is in his measure, the reader moistens the pages of his book, the conductor his transfer tickets, the "lady" the fingers of her glove. Every one is busily engaged in this distribution of saliva, so that the end of each day finds this secretion freely distributed on the doors, window sills, furniture and playthings in the home, the straps of trolley cars, the rails and counter and desks of shops and public buildings, and indeed upon everything that the hands of man touch. What avails it if the pathogens do die quickly? A fresh supply is furnished each day."--(Chapin: The Sources and Modes of Infection, p.

188.)

ORAL HYGIENE.--Cleanliness and proper care of the mouth and teeth can hardly be over emphasized. Their bearing upon health is direct. Long ago it was recognized that persons with decayed or missing teeth frequently suffered from dyspepsia, a natural result of inability to masticate properly, but only within recent years has it been realized that decayed teeth give rise to many other diseased conditions. Bacteria are constantly present in the mouth. If the mucus of the mouth is not removed, it forms a sticky coat upon the surfaces of the teeth and gums.

In this bacteria collect, and pus or matter may also be formed, which, if carried by the blood to other parts of the body, may cause digestive troubles, rheumatism, and diseases of heart and kidneys. (See Dr. T. B.

Hartzell, Health News, Oct., 1915, "The Importance of Mouth Hygiene and How to Practise it.")

To keep the mouth and teeth healthy they must have:

1. Proper use.

2. Proper care.

3. Proper treatment.

1. Teeth, like other parts of the body, need exercise. Foods that require a considerable amount of chewing should be included in the diet.

Such food is needed by children as soon as their first teeth have come, but care must be exercised to see that the food is actually chewed before it is swallowed.

2. A good brush should be provided. The stiffness of the bristles should be regulated according to the individual. The brush should be thoroughly rinsed after using, and discarded as soon as it is worn.

Dental floss is generally needed to remove particles that have lodged between the teeth.

Brushing the teeth by pa.s.sing the bristles across them is not efficacious. They should be brushed not across but with the cracks, as a good housewife sweeps a floor.

"In the light of recent investigation conducted by some of the leading students of mouth hygiene, the most effective way to use the toothbrush is to place the bristles of the brush firmly against the teeth, applying firm pressure, as though trying to force the bristles between the teeth, using a slight rotary or scrubbing motion.... After a little practice the user of this method will be surprised at the results obtained. Care should be used to go over all the surfaces of the teeth in this manner."--(See Dr. W. G.

Ebersole. "The Importance of Mouth Hygiene and How to Practice it," Health News, Oct., 1915.)

After brushing the teeth, the mouth should be rinsed by forcing lukewarm water about the teeth, using all the force that can be brought to bear by the cheeks, lips, and tongue.

3. TREATMENT.--The teeth, including the first teeth of children, should be inspected by a competent dentist at least twice a year. Periodic cleansing by a dentist, and early attention to small cavities, may prevent serious ill health and impairment of the body, as well as the acute suffering generally accompanying treatment of advanced dental defects.