Any child who has sneezing, running at the nose or eyes, sore throat, or cough, especially with headache or backache, a flushed face and feverishness, ought to be kept at home from school and placed in a well-ventilated, well-lighted room by himself for a day or two, until it can be seen whether he has one of these children's diseases, or only a common cold. If it turns out to be measles, scarlet fever, or whooping cough, he should then be kept entirely away from other children in a separate room, or, where that is impossible, in a special hospital or ward for the purpose; he should be kept in bed and given such remedies as the doctor may advise. Then no one else will catch the disease from him; and within from two to five weeks, he will be well again. The most important thing is not to let him get up and begin to run about, or expose himself, too soon; five times as many deaths are caused by taking cold, or becoming over-tired, or by injudicious eating, during recovery after measles, scarlet fever, and whooping cough, as by the disease itself. This one caution will serve two purposes; for, as a sick child's breath, and the scales from his skin, and what he coughs out from his mouth and nose are full of germs, and will give the disease to other children from two to four weeks after the fever has left him, he ought to be kept by himself—"in quarantine," as we say—for this length of time, which is just about the period needed to protect him from the dangers of relapse or taking cold. Boards of Health fix this period of quarantine by law and put a colored placard on the house to warn others of the danger of infection.

Colds and Sore Throats. A milder and even more common kind of infection is that known as common colds. These, as shown by their name, were once supposed to be due to exposure to cold air, or drafts, or to becoming wet or chilled. But, while a few of them are so caused, at least eight, and probably nine, out of ten are due to germs caught from somebody else. They are never caught in the open air and very seldom in cold, pure fresh air of any sort, but almost always in the hot, foul, stuffy, twice-breathed air of bedrooms, schoolrooms, churches, theatres, halls, sleeping cars, etc. The colds, for instance, that you catch when traveling, are usually due not to drafts or damp sheets, but to the crop of cold germs left behind by the last victim.

You have probably known of colds that have run through a family or a school or a shop. It is well worth trying to keep away from the infection of colds, because not only is their coughing and sore throat and hoarseness and running at the nose very disagreeable and uncomfortable, but they may cause almost as many different kinds of serious troubles in heart, kidneys, and nervous system as any of the other infections. In fact, they probably cause more than any other, because they are at least ten times as common and frequent. For instance, many cases of rheumatism, or rheumatic fever, come after attacks in the nose and throat, which cannot be distinguished from a common cold or ordinary tonsilitis. Indeed, it is more than probable that one of the ten or a dozen different germs that may get into your nose or throat and give you a cold, is the germ that causes rheumatism. At all events, it would be fairly safe to say, "No colds, no rheumatism."

Whenever you have a cold, keep away from everybody that you possibly can and stay at home from school or business for a day or two. You will do no good to yourself or others, working in that condition; and you may infect a dozen others. If you find anyone in your class or room or shop, sneezing or coughing or running at the nose, report him to your teacher or foreman; and if he won't send him home, keep away from him as much as possible.

Diphtheria. Another common and serious disease, until quite recently very fatal, is diphtheria. This is caused by getting into your mouth or nose the germs from another case of the disease. This disease also is most likely to occur in childhood, though it may attack a person of any age, and is always serious. It may be prevented from spreading by keeping children who have it shut up in rooms, or wards, by themselves and keeping all other children away from them, or from their nurses or those who have anything to do with them. Up to about thirty years ago, it was one of the deadliest and most terrible diseases that we had anything to do with. We knew absolutely nothing that would cure it, or even check its course; and nearly half of the children attacked by it died.

About that time, however, two scientists, Klebs and Loeffler, discovered that, by taking some of the membrane, or tough growth that forms in the throat in this disease, and by rubbing it over a plate of gelatin jelly, they could grow on that gelatin a particular kind of germ. This germ, or bacillus, they then put into the throats of guinea pigs, and found that it would give them diphtheria.

This is the way disease germs are discovered, or, as we say, identified; but of course this did not give at once any remedy for the disease. Scientists soon found, however, that, if a very small number of these bacilli were put into a guinea pig's throat, it would have diphtheria, but in a very mild form. If, when it had recovered, it was again infected, it would stand a much larger dose of the bacilli without harm. This made them suspect that some substance had been formed in the guinea-pig's blood that killed the bacillus or worked against its toxin, or poison; and soon, to their delight, they succeeded in finding this substance, which they called antitoxin (meaning "against poison"). Then came the idea that if they could only get enough of this antitoxin, and inject it into the blood of a child who had diphtheria, it might cure the disease. A guinea pig is such a tiny animal that the amount of antitoxin which it could form would be far too small to cure a man, or even a child. So larger animals were taken; and it was finally found that the largest and strongest of our domestic animals, the horse, would, if the diphtheria germs were injected into its blood, make such large amounts of antitoxin that merely by drawing a quart or two of the blood—and closing up the vein again—enough antitoxin could be got to cure fifty or a hundred children of diphtheria. This treatment has not the slightest harmful effect upon the horse. The pain of injecting is only like sticking a pin through the skin, while the pain of bleeding is no greater than cutting your finger. There are now at our great manufacturing laboratories whole stables full of horses, for the production of this wonderful remedy.

With this remedy, our entire feeling toward diphtheria is changed. Instead of dreading it above all things, we know now, from hundreds of thousands of cures, that, if a case is seen on the first day of the disease, and this antitoxin injected with a hypodermic needle, it is almost certain that the patient will recover; not more than two or three cases out of a hundred will fail. If the case is seen and treated on the second day, all but four or five out of a hundred will recover; and if on the third day, all but ten. In fact, the average death rate of diphtheria has been cut down now from forty-five per cent to about six per cent.

We now have antitoxins, or vaccines, for blood-poisoning; for typhoid fever; for one of the forms of rheumatism; for boils; for the terrible cerebro-spinal meningitis, or "spotted fever"; and for tetanus, or lock-jaw. And every year there are one or two other diseases added to the list of those that have been conquered in this way.

None of these vaccines is so powerful, or so certain in its effects, as the diphtheria antitoxin. But they are very helpful already; and some of them, particularly the typhoid vaccine, are of great value in preventing the attack of the disease, as small doses of it given to persons who have been exposed to the infection, or are obliged to drink infected water, as in traveling or in war, very greatly lessen their chances of catching the disease.

Vaccination, the Great Cure for Smallpox. Another valuable means of preventing disease by means of its germs is by putting very small doses of the germs into a patient's body, so that they will give him a very mild attack of the disease, and cause the production in his blood of such large amounts of antitoxin that he will no longer be liable to an attack of the violent, or dangerous, form of the disease. Vaccines, for this purpose, usually consist either of a very small number of the disease germs, or of a group of them, which have been made to grow upon a very poor soil or have been chilled or heated so as to destroy their vitality or kill them outright. When these dead, or half-dead, bacilli are injected into the system, they stir up the body to produce promptly large amounts of its antitoxin. In some cases the reaction is so prompt and so vigorous that the antitoxin is produced almost without any discomfort, or disturbance, and the patient scarcely knows anything about it. In others there will be a slight degree of feverishness, with perhaps a little headache, and a few days, or hours, of discomfort. When this has passed, then the individual is protected against that disease for a period varying from a few months to as long as seven or eight years, or even for life.

The best-known and oldest illustration of the use of these vaccines is that of smallpox. A little more than a hundred years ago, an English country doctor by the name of Jenner discovered that the cows in his district suffered from a disease accompanied by irritation upon their skins and udders, which was known as "cowpox." The dairymaids who milked these cows caught this disease, which was exceedingly mild and was all over within four or five days; but after that the maids would not take smallpox, or, as we say, were immune against it. Smallpox at that time was as common as measles is now. Nearly one-fourth of the whole population of Europe was pock-marked, and over half the inmates in the blind asylums had been made blind by smallpox. So common was it that it was quite customary to take the infectious matter from the pocks upon the skin of a mild case and inoculate children with it, so as to give them the disease in mild form and thus protect them against a severe, or fatal, attack; just as in country districts, a few years ago, some parents would expose their children to measles when it happened to be a mild form, so as to "have it over with."

It occurred to Dr. Jenner that if this inoculation with cowpox would protect these milkmaids, it would be an infinitely safer thing to use to protect children than even the mildest known form of inoculation. So he tried it upon two or three of his child patients, after explaining the situation to their parents, and was perfectly delighted when, a few months afterward, these children happened to be exposed to a severe case of smallpox and entirely escaped catching the disease. This was the beginning of what we now call vaccination.

The germ of cowpox, which is believed to be either the cow or horse variety of human smallpox, is cultivated upon healthy calves. The matter formed upon their skin is collected with the greatest care; and this is rubbed, or scraped, into the arm of the child. It is a perfectly safe and harmless cure; and although it has been done millions of times, never has there been more than one death from it in 10,000 cases. In a little over a hundred years it has reduced smallpox from the commonest and most fatal of all diseases to one of the rarest. But in every country in the world into which vaccination has not been introduced, smallpox rages as commonly and as fatally as ever. For instance, between 1893 and 1898 in Russia, where a large share of the people are unvaccinated, 275,000 deaths occurred from smallpox; in Spain, where the same condition exists, 24,000. In Germany, on the other hand, where vaccination is practically universal, there were in the same period only 287 deaths—1/1000 as many as in Russia; and in England, only a slightly greater number.

Another illustration, which comes closer home, is that of the Philippine Islands. Before they were annexed by the United States, vaccination was rare, and thousands of deaths from smallpox occurred every year. In 1897, after the people had been thoroughly vaccinated, there was not a single death from this cause in the whole of the Islands.

This discovery of Jenner's was most fortunate; for vaccination remains until this day absolutely the only remedy of any value whatever that we possess against smallpox.

Quarantine, inoculation, improvement of living and sanitary conditions, the use of drugs and medicines of all sorts other than vaccination, have no effect whatever upon either the spread or the fatality of the disease. The author, when State Health Officer of Oregon, saw the disease break out in a highly-civilized, well-fed, well-housed community, and kill eleven out of thirty-three people attacked, just as it would have done in the "Dark Ages." Not one of the cases that died had been vaccinated; and, with but one exception (and in this the proof of vaccination was imperfect), every vaccinated case recovered. Vaccination will usually protect for from five to ten years; then it is advisable to be re-vaccinated, and in six to eight years more, another vaccination should be attempted. This third vaccination will usually not "take," for the reason that two successful vaccinations will usually protect for life.

Unexpected as it may seem, vaccination is not only a preventive of smallpox, but a cure for it. The reason being that vaccinia, the disease resulting from successful vaccination, being far milder than smallpox, runs its course more quickly,—taking only two days to develop,—while smallpox requires anywhere from seven to twenty days to develop after the patient has been infected, or exposed. So, if anyone who has been exposed to smallpox is vaccinated any time within a week after exposure, the vaccine will take hold first, and the patient will have either simple vaccinia, with its trifling headache and fever, or else a very mild form of smallpox.

Some persons object to having children deliberately infected with even the mildest sort of disease; but this is infinitely better than to allow, as was the case before vaccination, from one-fourth to one-fifth of them to be killed, twenty-five per cent of them to be pock-marked, and ten per cent of them to be blinded by this terrible disease. So far as any after-effects of vaccination are concerned, careful investigation of hundreds of thousands of cases has clearly shown that it is not so dangerous as a common cold in the head.

Infantile Paralysis. Another disease that has been unpleasantly famous of late is also caused and spread by a germ. This is a form of laming or crippling of certain muscles in childhood known as infantile paralysis. It is not a common disease, though during the last two years there has been an epidemic of it in the United States, especially in New York and Massachusetts. The only things of importance for you to know about it are that it begins, like the other infections, with headache, fever, and usually with "snuffles" or slight sore throat, or an attack of indigestion; and that its germ is probably spread by being sneezed or coughed into the air from the noses and throats of the children who have it, and breathed in by well children. The best known preventive of serious results from this disease is the same as in the rest of infectious diseases, namely, rest in bed, away from all other children, which at the same time stops the spread of it. It furnishes one more reason why all children having the "snuffles" and sore throat with fever and headache should be kept away from school and promptly put to bed and kept there until they are better.

The reason why the disease produces paralysis is that its germs specially attack the spinal cord, so as to destroy the roots of the nerves going to the muscles. Unless the harm done to the spinal cord is very severe, other muscles of the arm or the leg can very often be trained to take the place and to do the work of the paralyzed muscles, so that while the limb will not be so strong as before, it will still be quite useful.

Malaria. Practically the only disease due to animal germs, which is sufficiently common in temperate or even subtropical regions to be of interest to us, is malaria, better known perhaps as ague, or "chills-and-fever." This disease has always been associated with swamps and damp marshy places and the fogs and mists that rise from them; indeed its name, mal-aria, is simply the Italian words for "bad air." It is commonest in country districts as compared with towns, in the South as compared with the North, and on the frontier, and usually almost disappears when all the ponds and swamps in a district are drained and turned into cultivated land or meadows.

About four hundred years ago, the Spanish conquerors of America were fortunate enough to discover that the natives of Peru had a bitter, reddish bark, which, when powdered or made into a strong tea, would cure ague. This, known first as "Peruvian bark," was introduced into Europe by the intelligent and far-sighted Spanish Countess of Chincon; and, as she richly deserved, her name became attached to it—first softened to "cinchona" and later hardened to the now famous "quinine." But for this drug, the settlement of much of America would have been impossible. The climate of the whole of the Mississippi Valley and of the South would have been fatal to white men without its aid.

But although we knew that we could both break up and prevent malaria by doses of quinine large enough to make the head ring, we knew nothing about the cause—save that it was always associated with swamps and marshy places—until about forty years ago a French army surgeon, Laveran, discovered in the red corpuscles of the blood of malaria patients, a little animal germ, which has since borne his name. This, being an animal germ, naturally would not grow or live like a plant-germ and must have been carried into the human body by the bite of some other animal. The only animals that bite us often enough to transmit such a disease are insects of different sorts; and, as biting insects are commonly found flying around swamps, suspicion very quickly settled upon the mosquito.

By a brilliant series of investigations by French, Italian, English, and American scientists, the malaria germ was discovered in the body of the mosquito, and was transmitted by its bite to birds and animals. Then a score or more of eager students and doctors in different parts of the world offered themselves for experiment—allowed themselves to be bitten by infected mosquitoes, and within ten days developed malaria. At first sight, this discovery was not very encouraging; for to exterminate mosquitoes appeared to be as hopeful a task as to sweep back the Atlantic tides with a broom. But luckily it was soon found that the common piping, or singing, mosquito (called from his voice Culex pipiens) could not carry the disease, but only one rather rare kind of mosquito (the Anopheles), which is found only one-fiftieth as commonly as the ordinary mosquito. It was further found that these malaria-bearing mosquitoes could breed only in small puddles, or pools, that were either permanent or present six months out of the year, and that did not communicate with, or drain into, any stream through which fish could enter them. Fish are a deadly enemy of the mosquito and devour him in the stage between the egg and the growth of his wings, when he lives in water as a little whitish worm, such as you may have seen wriggling in a rain-barrel.

It was found that by hunting out a dozen or twenty little pools of this sort in the neighborhood of a town full of malaria, and filling them up, or draining them, or pouring kerosene over the surface of the water, the spread of the malaria in the town could be stopped and wiped out absolutely. This has been accomplished even in such frightfully malarial districts as the Panama Canal Zone, and the west coast of Africa, whose famous "jungle fever" has prevented white men from getting a foothold upon it for fifteen hundred years. Since the young mosquitoes, in the form of wrigglers, or larvæ, cannot grow except in still water, draining the pools kills them; and, as they must come to the surface of the water to breathe, pouring crude petroleum over the water—the oil floating on the surface and making a film—chokes them.

The common garden mosquito, while not dangerous, is decidedly a nuisance and can be exterminated in the same way—by draining the swamps and pools, or by flooding them with crude petroleum,—or by draining swamps or pools into fresh-water ponds and then putting minnows or other fish into these ponds. There is no reason why any community calling itself civilized should submit to be tormented by mosquitoes if it will spend the few hundred, or the thousand, dollars necessary to wipe them out. It is prophesied that the use of quinine will soon become as rare as it is now common, because malaria will be wiped out by the prevention of the mosquito.

Disinfectants. So far we have been considering how to attack the germs after they have got into our bodies, or to prevent them from spreading from one patient to another; but there is still another way in which they may be attacked, and that is by killing, or poisoning them, outside the body. This process is generally known as disinfection, and is carried out either by baking, boiling, or steaming, or by the use of strongly poisonous fluids or gases, known as disinfectants.

While fortunately none of these disease germs can breed, or reproduce their kind, outside the human body, and while comparatively few of them live very long outside the human body, they may, if mixed with food or caught upon clothing, hangings, walls, or floors, remain in a sort of torpid, but still infectious, condition for weeks or even months. Consequently, it has become the custom to take all the bedding, clothing, carpets, curtains, etc., that have touched a patient suffering from a contagious disease, or have been in the room with him, and also any books that he may have handled, any pens or pencils that he may have used, and either destroy them, or bake, boil, or fumigate them with some strong germicidal, or disinfectant, vapor.

This is usually done by closing up tightly the sick-room, putting into it all clothing, bedding, pictures, books, hangings, and other articles used during the illness (except wash-goods, which, of course, can be sterilized by thorough boiling; and dishes and table utensils, which also can be scalded and boiled); draping the carpet over chairs so as to expose it on all sides, opening closets and drawers, and then filling the room full of some strong germ-destroying fumes.

One of the best disinfectants, and the one now most commonly used by boards of health for this purpose, is formaldehyde—a pungent, irritating gas, which is an exceedingly powerful germ-destroyer. This, for convenience in handling is usually dissolved, or forced into water, which takes up about half its bulk; and the solution is then known as formalin.

When formalin is poured into an open dish, it rapidly evaporates, or gives up its gas; and, if it be gently heated, this will be thrown off in such quantities as to completely fill the room and penetrate every crevice of it, and every fold of the clothing or hangings. One pound, or pint, of formalin will furnish vapor enough to disinfect a room eight feet square and eight feet high, so the amount for a given room can thus be calculated. The formalin vapor will attack germs much more vigorously and certainly if it be mixed with water vapor, or steam; so it is usually best either to boil a large kettle of water in the room for half an hour or more, so as to fill the air with steam, before putting in the formalin, or to use a combination evaporator with a lamp underneath it, which will give off both formalin and steam. This, if lighted and placed on a dish in the centre of a wash-tub or a large dishpan, with two or three inches of water in the bottom of it, can be put into the room and left burning until it goes out of its own accord.

Another very good method is to take a pan, or basin, with the required amount of formalin (not more than an inch or two inches deep) in the bottom of it, get everything ready with doors and windows fastened tight and strips of paper pasted across the cracks, pour quickly over the formalin some permanganate of potash (about a quarter of a pound to each pound of formalin), and then bolt for the door as quickly as possible to avoid suffocation. The resulting boiling up, or effervescence, will throw off quantities of formaldehyde gas so quickly as to drive it into every cranny and completely through clothing, bedding, etc. The room should be left closed up tightly for from twelve to thirty-six hours, when it can be opened—only be careful how you go into it, first sniffing two or three times to be sure that all the gas has leaked out, or holding your breath till you can get the windows open; and in a few hours the room will be ready for use again.

Another older and much less expensive disinfectant for this purpose is common sulphur. From one to three pounds of this, according to the size of the room, is burned by a specially prepared lamp in a pan placed in the centre of a dishpan of water, and the vapor thus made is a very powerful disinfectant. This, however, is a very poisonous and suffocating gas (as you will remember if you have ever strangled on the fumes of an old-fashioned sulphur match) and, compared with formalin, is nearly five times as poisonous to human beings, or animals, and not half so much so to the germs. Where formalin cannot be secured, sulphur is very effective; but its only merit compared with formalin is that it is cheaper, and more destructive to animal parasites and vermin such as bugs, cockroaches, mice, rats, etc., when these happen to be present. Formalin has the additional advantage of not tarnishing metal surfaces, as sulphur does.

It is a good thing for every household and every schoolroom to have a bottle of formalin on hand, so that you may sniff the vapor of it into your nostrils and throat if you think you have been exposed to a cold, or other infectious disease, or make a solution with which to wash your hands, handkerchiefs, pencils, etc., after touching any dirt likely to contain infection. Half a teaspoonful in a bowl of water is enough for this. A saucerful of it placed in an air-tight box, or cabinet, will make a disinfecting chamber in which pencils, books, etc., can be placed over night; and a teaspoonful of it in a quart of water will make an actively germ-destroying solution, which can be used to soak clothing, clean out bedroom utensils, or pour down sinks, toilets, or drains. It is a good thing also to pour a few teaspoonfuls occasionally on the floor of the closets in which your shoes, trousers, dresses, and other outdoor clothing are kept, as these are quite likely to be contaminated by germs from the dust and dirt of the streets.

Formalin is one of the best and safest general disinfectants to use. Its advantages are, that it is nearly ten times as powerful a germicide as carbolic acid, or even corrosive sublimate, so that it may be used in a solution so weak as to be practically non-poisonous to human beings. It is so violently irritating to lips, tongue, and nostrils as to make it almost impossible for even a child to swallow it, while the amount that would be absorbed if taken into the mouth and spit out again would be practically harmless, so far as danger to life is concerned, though it would blister the lips and tongue.

Bacteria, our Best Friends. While, naturally, the bacteria that do us harm by producing disease are the ones that have attracted our keenest attention and that we talk about most, it must never be forgotten that they form only a very, very small part of the total number of bacteria, or germs. These tiny little germs swarm everywhere; and the mere fact that we find bacteria in any place, or in any substance, is no proof whatever that we are in danger of catching some disease there.

All our farm and garden soil, for instance, is full of bacteria that not only are harmless, but give that soil all its richness, or fertility. If you were to take a shovelful of rich garden earth and bake it in an oven, so as to destroy absolutely all bacteria in it, you would have spoiled it so that seeds would scarcely grow in it, and it would not produce a good crop of anything. These little bacteria, sometimes called the soil-bacteria, or bacteria of decay, swarm in all kinds of dead vegetable and animal matter, such as leaves, roots, fruits, bodies of animals, fishes, and insects, and cause them to decay or break down and melt away. In doing this they produce waste substances, particularly those that contain ammonia, or nitrates, or some other form of nitrogen, which are necessary for the growth of plants or crops.

This is why soil can be made richer by scattering over it and plowing into it manure, waste from slaughter houses, or any other kind of decaying animal or vegetable matter. This is promptly attacked by the bacteria of the soil and turned into these easily soluble plant foods. The roots of the plants grown in the soil could no more take this food directly from dead leaves or manure than you could live on sawdust or cocoanut matting.

So, if it were not for these bacteria, or lower plants, there could be no higher, or green, plants. As animals live either upon these green plants, such as grass and grains, or upon the flesh of other animals that live upon plants, we can see that without the bacteria there would be no animal life, not even man. No bacteria, no higher life. It would be safe to say that, out of every million bacteria in existence, at least 999,999 are not only not harmful but helpful to us.

One large group of bacteria produces the well-known souring of milk; and while this in itself is not especially desirable, yet the milk is still wholesome and practically harmless, and its sourness prevents the growth of a large number of other bacteria whose growth would quickly make it dangerous and poisonous. Many races living in hot countries deliberately sour all the milk directly after milking, by putting sour milk into it, because, when soured, it will keep fairly wholesome for several days, while if not soured it would entirely spoil and become unusable within twenty-four hours.

Another group of bacteria, which float about in the air almost everywhere, are the yeasts, which we harness to our use for the very wholesome and healthful process of bread-making. Millions upon millions of bacteria of different sorts live and grow naturally in our stomachs and intestines; and while they are probably of no special advantage to us, yet at the same time the majority of them are practically, within reasonable limits—not to exceed a few billions or so—harmless.

Insect Pests. One kind of "dirt" that should be avoided with special care is insects of all sorts. No one needs to be told to try to keep a house, or a room, clear of fleas, bed-bugs, or lice; indeed to have these creatures about is considered a mortal disgrace. Not only is their bite very unpleasant, but they may convey a variety of diseases, including plague and blood poisonings of various sorts. But there is another insect pest far commoner and far more dangerous than either fleas or bed-bugs, whose presence we should feel equally ashamed of; and that is the common house fly. This filthy little insect breeds in, and feeds upon, filth, manure, garbage, and dirt of all sorts, and then comes and crawls over our food, falls into our milk, wipes his feet on our sugar and cake, crawls over the baby's face, and makes a general nuisance of himself. Take almost any fly that you can catch, let him crawl over a culture plate of gelatin, put that gelatin away in a warm place, and you will find a perfect flower-garden of germs growing up all over it, following the pattern made by the tracks of his dirty feet. In this garden will be found not "silver bells and cockle shells and pretty maids all in a row," but a choice mixture of typhoid bacilli, pus germs, the germs of putrefaction, tubercle bacilli, and the little seeds which, if planted in our own bodies, would blossom as pneumonia or diphtheria.

The fly is an unmitigated nuisance and should be wiped out. No half-way measures should be considered. Fortunately, this is perfectly possible; for his presence is our own fault and nothing else, as he can lay his eggs and hatch only in piles of dirt and filth found about our own houses, barns, and outbuildings. He is not a wild insect but a domestic one and is practically never found more than a few hundred yards away from some house or barnyard. His favorite place for breeding is in piles of stable manure, especially horse manure; but neglected garbage cans, refuse heaps, piles of dirt and sweepings, decaying matter of all sorts, which are allowed to remain for more than ten days or two weeks at a time, will give him the breeding grounds that he needs.

It takes him about two weeks to hatch and get away from these breeding places; so that if everything of this sort is cleaned up carefully once a week, or if, where manure heaps and garbage dumps have to remain for longer periods, they are sprinkled with arsenic, kerosene, corrosive sublimate, chloride of lime, or carbolic acid, he will perish and disappear as surely as grass will if you wash away the soil in which it grows. The presence of a fly means a dirty house or a dirty yard somewhere, and to discover a fly in your house should be considered a disgrace. Until people are aroused to the need of such cleanliness as will make flies disappear entirely, in most places it will be necessary, as warm weather approaches, to screen all doors and windows, and particularly all boxes, pantries, or refrigerators in which food is kept. If you cannot afford screens, use fly paper. These are all, however, only half-way measures and will give only partial relief. The best prevention of flies is absolute cleanliness. No dirt, no flies.

Dust, a Source of Danger. Dust is an easily recognized form of dirt. It is dangerous in itself and nearly always contains germs of one sort or another mixed in with it. Shops and factories whose processes make much dust are usually very unhealthy for the workers, who are likely to show a high death-rate from consumption.

Dust should be fought and avoided in every possible way. City streets should have good modern pavements,—preferably asphalt or some crude petroleum, or sawmill-waste, "crust," or coating,—which will not make any dust, and which can be washed down every night with a hose. In smaller towns where there is no pavement, dust may be prevented by regular sprinklings during the summer, preferably with some form of crude oil. Two or three full sprinklings of this will keep down the dust for the greater part of the summer.

If these measures are properly carried out, they will prevent most of the dust that accumulates in houses, as nearly all of this blows in through the windows or is carried in on shoes or skirts. When this has once floated in and settled down upon the walls, furniture, or carpets, be very careful how you disturb it; for, as long as it lies there, it will do you no harm, however untidy it may look. The broom and the feather duster and the dry cloth do almost as much harm as they do good; for while they may remove two-thirds of the dust from a room, they drive the other third right into your nose and throat, where the germs it contains can do the most possible harm. Dusting should always be done with a damp cloth; sweeping, with a damp cloth tied over a broom; and, wherever possible, a carpet sweeper, or, better still, a vacuum cleaner, should be used instead of a broom.

Carpets, window curtains, and any hangings that catch dust should be abolished—rugs that can be rolled up and taken out of doors to be shaken and beaten should be used instead; and too many pieces of bric-à-brac and ornaments should be avoided. All surfaces of walls, ceilings, and floors should be made as smooth and hard and free from angles, ledges, and projecting lines as possible. The colds usually caught by members of the family during "spring cleaning" are usually due to the swarms of germs stirred up from their peaceful resting places. Let those sleeping germs lie, until you can devise some means of removing them without brushing, or whisking, them straight into your nostrils.

CHAPTER XXVII

Another cheering thing about accidents is that ninety-nine out of every hundred of them are not serious; and if you are only wise enough to know what to do—and still more what not to do—in taking care of them, you can recover from them safely and quickly. The bodies of healthy children have an astonishing power of repairing themselves. Their bones are not so brittle as those of "grown-ups"; and even when one of them is broken, if properly splinted and dressed, it will heal up in a little more than half the time required by the adult. And wounds and scratches and bruises, if kept perfectly clean, will heal very rapidly.

Probably the commonest of all accidents are cuts and scratches. So common is it for us to "bark" our knuckles, or our shins, or scratch ourselves on nails and splinters and drive pins into ourselves, or let our pocket knives slip and cut our fingers, that, if the human skin had not the most wonderful power of repairing itself,—not merely closing up the cut or the scratch, but making the place "as good as new,"—we should be seamed and lined all over our hands, arms, faces, and limbs like a city map, or scarred and pitted like a tattooed man, before we were fifteen years old. But of course, as you know, the vast majority of cuts and scratches and tears heal perfectly. They hurt when they happen; and they burn, or smart, for a few hours, or hurt, if bumped, for a few days afterward; but they heal soon and are forgotten.

On the other hand, some cuts and scratches will fester and throb and turn to "matter" (pus) and even give you fever and headache and blood poisoning. What makes the difference? It is never the size, or depth, of the scratch or cut itself, but simply the dirt that gets into it afterward. If a cut, or scratch, no matter how deep or ragged, be made with a clean knife-blade or sliver and kept clean afterward, it will never "matter" (suppurate) or cause blood poisoning. So if you know how to keep dirt out of cuts and scratches, you know how to prevent ninety-nine per cent of all the dangers and damage that may come from this sort of accident.

Not more than one cut or scratch in a thousand is deep enough to go down to an artery, so as to cause dangerous bleeding, or to injure an important nerve trunk. So, though no one would by any means advise you to be reckless about getting cut and scratched, yet it is better and safer to run some risk of cuts and scratches in healthy play when young, and learn how to keep them clean, than to grow up pale and flabby-muscled and cowardly.

How to Prevent Infection in Wounds. It is not just dirt that is dangerous,—although dirt of any sort is a bad thing to get into wounds and should be kept out in every possible way,—but dirt that contains those little vegetable bacteria that we call germs. The dirt most likely to contain these germs—called pus germs, because they cause pus, or "matter" in a wound—is dirt containing decaying animal or vegetable substances (particularly horse manure, which may contain the tetanus, or lock-jaw germ) and the discharges from wounds, or anything that has come near decayed meat or unhealthy gums or noses or teeth. This is why a cut or scratch made by a knife that has been used for cutting meat, or by a dirty finger-nail, or by the claw of a cat, or by the tooth of a rat, is often likely to fester and "run." Animals like rats and dogs and cats often feed upon badly decayed meat; and hence their teeth, or claws, are quite likely to be smeared with the germs that cause decay, and these will make trouble if they get into a wound.

Fortunately, the care of a cut or scratch is very simple and practically the same in all cases. Just make the wound thoroughly clean and keep it so until it is healed. For a slight clean cut or scratch, a good cleanser is pure water. Hold the hand or foot under the faucet or pump, and let the cool water wash it out thoroughly. If you are sure that the thing you cut it with was clean, let the blood dry on the cut and form a scab over it. If the wound is large, or there is any danger of the water of the well, or tap, having sewage in it (see chapter IX), it is better to boil the water before using it. Unless the blood is spurting in jerks from a cut artery, or bleeding very freely indeed, it is better to let the wound bleed, as this helps to wash out any dirt or germs that have got into it. When the bleeding has stopped, do not put on sticking plaster, because this keeps out the air and keeps in the sweat of the skin surrounding the wound, which is not healthful for the wound, and may also contain some weak pus germs.

If the wound is small, the old-fashioned clean white rag that has been boiled and washed is as good as anything that can be used for a dressing. Tear off a narrow strip from one to two inches wide and as many feet long, according to the position of the wound, roll it round the finger or limb three or four times, and then take a turn round the wrist or nearest joint, to keep the bandage from slipping off. If the wound be likely to keep on oozing blood, put on first a thickness of surgeon's cotton, or prepared cotton-batting, an ounce of which can be purchased for ten cents at any drugstore. This is an excellent dressing, because it not only sucks up, or absorbs any oozing from the wound, but is a perfect filter-protection against germs of all sorts from the outside. Ninety-nine simple wounds out of a hundred dressed in this way will heal promptly and safely without danger of pus, or "matter."

If the wound happens to have been made with a knife or tool that you are not absolutely sure was perfectly clean, or if the wound gets manure or road-dirt or other filth rubbed into it, then it is best to go at once to a doctor and let him give it a thorough antiseptic dressing, which consists of cleaning it out thoroughly with strong remedies, called antiseptics,—which kill the germs, but do not injure living tissues,—and then putting on a germ-proof dressing as before. This is one of the "stitches in time" which will save not only nine, but ninety-nine.

If you have a wound with dirt in it, and cannot reach a doctor, one of the best and safest antiseptics to use is peroxide of hydrogen. This is non-poisonous, and can be poured right into the wound. It will smart and foam, but will clean out and kill most of the germs that are there. Another safe antiseptic is pure alcohol. It is a good thing to have a bottle of one of these in the medicine-closet, or in your "war-bag" when camping out. A package of surgeon's cotton and two or three rolled bandages of old cotton, linen, or gauze also should be on hand.

Dog-bites, rat-bites, or cat-bites should always be dressed by a doctor, or made thoroughly antiseptic, mainly on account of the germs that swarm round the roots of the teeth of these animals, and also because treatment of this sort will prevent hydrophobia—although this danger is a rare and remote one, not more than a few score of deaths from mad-dog bites occurring in the whole United States in a year.

The wonderful progress made by surgery within the last twenty or thirty years has been almost entirely due to two things: first, the discovery of chloroform and ether, which will put patients to sleep, so that they do not feel the pain of even the severest and longest operation; and, second, but even more important, keeping germs of all kinds out of the wound before, during, and after the operation. That sounds simple, but it really takes an immense amount of trouble and pains in the way of baking the dressings; boiling the instruments, and scrubbing with soap, alcohol, hot water, and two or three kinds of antiseptics, or germ-killers, the hands of the surgeon and of the nurse and the body of the patient. How enormous a difference this keeping of the germs out of the wound has made may be gathered from the fact that, while in earlier days, before Lister showed us how to avoid this danger, surgeons used to lose seventy-five per cent of their amputations of the thigh, from pus infection, or blood poisoning, now they can perform a hundred operations of this sort and not lose a single case. We can open into the skull and remove tumors from the brain; open into the chest and remove bullets from the lungs, and even from the heart itself; operate in fact upon any part, or any organ, of the body with almost perfect safety and wonderful success. Whereas, before, two-thirds of the patients so operated upon would die, probably of blood poisoning.

How to Treat Bruises. Bruises are best treated either by holding the injured part under the faucet, or pump, if convenient, or by plunging it into very hot water and holding it there for ten or twelve minutes. Then if the bruise still continues to throb or ache, wrap it up lightly with a bandage of soft, loose cotton or linen cloth, and pour over it a lotion of water containing about one-fourth alcohol until the bandage is soaked, moistening it again as fast as it dries. This is also a useful treatment for wounds that have been made by a fall, or by something blunt and heavy, so that there is bruising as well as cutting. Most of the household applications for wounds or bruises, such as arnica, camphor, witch-hazel, etc., owe their virtues to the five or ten per cent of alcohol they contain, which, by evaporating, cools the wound and relieves inflammation, kills germs and so acts as an antiseptic, and cleans the wound and the skin around it very thoroughly and effectively.

Bruises of all sorts, however, unless very severe, are much safer than cuts or scratches, because they do not break the skin, and consequently no germs can get into the tissues of the blood. Our skin, as you remember, is one of the most wonderful water-proof, germ-proof, hot-and-cold-proof coatings in the world; and as long as it remains unbroken, none but a few of the most virulent disease-germs can get through it into the body.

Boils and Carbuncles, their Cause and their Cure. Boils and carbuncles are almost the only instances in which pus germs can get into the body without some actual cut, tear, or breaking of the skin. They come always from other boils or ulcers or discharging wounds and are caused by the pus germs in these either being rubbed into the skin until it is almost chafed through, or else being driven down into the mouth of one of the hair follicles, or "pores." Here they proceed to grow and form a little gathering, which soon turns to pus; and this stretches the skin and presses upon the sensitive nerves in it so as to cause much pain. The best way to treat them in the beginning is to give a thorough scrubbing with hot water and soap, and then to drop right over the point, or "head," of the gathering two or three drops of a strong antiseptic, like formalin or peroxide or carbolic acid. If this does not check them, then they had better be opened up freely with a sharp knife that has been held in boiling water, or a needle that has been held in a flame until it is red hot and allowed to cool. Then pour peroxide into the opening, put on a light dressing, and keep soaked with alcohol and water, as for a bruise. This evaporating dressing is far superior to the dirty, sticky, germ-breeding poultice. If this does not clear it up within twenty-four hours, go to a doctor and have him treat it antiseptically.

How to Stop Bleeding. If a cut should go deep enough to reach an artery the size of a knitting needle, or larger, then the blood will spurt out in jets. There is then some danger of so much blood being lost as to weaken one. Our blood, however, has a wonderful power of clotting, or clogging, round the mouth of the cut artery, so that the risk of bleeding to death, except from quite a large artery, like that of the thigh, or the armpit, is not very great.

For a wound in the hand or foot, that spurts in this way, it will usually be sufficient to grasp the arm firmly above the wrist or the elbow, or the ankle, as the case may be, with the thumb over the artery, or even to press directly over the wound, until the bleeding stops and the blood is thus given a chance to clot. If the wound is small and deep, like that made by the stab of a knife, or the slip of a chisel, then firm pressure directly over the wound itself with a thumb, or both thumbs, will usually be sufficient to stop the bleeding.