Scripture says that "a man's foes shall be they of his own household," and this is true of disease germs. They grow and flourish—and, so far as history tells us, the diseases they cause seem to have started—only where people are crowded together in huts or houses, breathing one another's breaths and one another's perspiration, and drinking one another's waste substances in the well water. This fact has, however, its encouraging side; for, since this habit of crowding together, which we call civilization, or "citification," has caused and keeps causing these diseases, it can also cure them and prevent their spread if all the people will fight them in dead earnest. No amount of money, or of time, that a town or a county can spend in stamping out these infectious diseases would be wasted. Indeed, every penny of it would be a good investment; for, taken together, they cause at least half, and probably nearly two-thirds, of all deaths. Not only so, but most of the so-called chronic diseases of the heart, kidneys, lungs, bones, and brain are due to the after-effects of their toxins, or poisons.
How Disease Germs Grow and Spread. But perhaps you will ask, "If these bacteria and protozoa are so tiny that we have to use a microscope, and one of the most powerful made, in order even to see them, how is it that they can overrun our whole body and produce such dangerous fevers and so many deaths?" The answer is simply, "Because there are so many millions of them; and because they breed, or multiply, at such a tremendously rapid rate." When one of these little bacilli breeds, it doesn't take time to form buds and flowers and seeds, like other plants, or even the trouble to lay eggs like an insect or a bird, but simply stretches itself out a little longer, pinches itself in two, and makes of each half a new bacillus.
This is known as fission or "splitting," and is of interest because this is the way in which the little cells that make up our own bodies increase in number; as, for instance, when a muscle is growing and enlarging under exercise, or when more of the white blood cells are needed to fight some disease. Remember that we and the disease germs are both cells; and that, if they are numbered by millions, we are by billions; and that we are made up of far the older and the tougher cells of the two. Except in a few of the most virulent and deadly of fevers, like the famous "Black Death," or bubonic plague, and lock-jaw, or tetanus, ninety-five times out of a hundred when disease germs get into our bodies, it is our bodies that eat up the germs instead of the germs our bodies. Keep away from disease germs all that you reasonably and possibly can; but don't forget that the best protection against infectious diseases, in the long run, is a strong, vigorous, healthy body that can literally "eat them alive."
Grow that kind of body, keep it perfectly clean inside and out, and you have little need to fear fevers, or indeed any other kind of disease; for you will live until you are old enough to die—and then you'll want to, just as you want to go to sleep when you are tired. Remember that this fight against the fevers is a winning fight, this study of disease germs a cheering and encouraging one, because it will end in our conquering them, not merely nine times out of ten, but ninety-nine times out of a hundred.
We are not making this fight just to escape death; what we are fighting for is to live out a full, useful, and happy life. And we already have five chances to one of gaining this, and the chances are improving every year; for science has already raised the average length of life from barely twenty years to over forty. Broadly speaking, if you will keep away from every one whom you know to have an infectious disease; wash your hands always before you eat, or put anything into your mouth; keep your fingers, pencils, pennies, and pins out of your mouth,—where they don't belong; live and play in the open air as much as possible and keep your windows well open day and night, you will avoid nine-tenths of the risks from germs and the dangers that they bring in their wake.
Children's Diseases. We have already studied two of the greatest and most dangerous diseases, and the way to conquer them—tuberculosis, or consumption, in the chapter on the lungs; and typhoid fever, in the chapter on our drink. One of the next most important groups of "catching" diseases—important because, though very mild, they are so exceedingly common,—is that known as the "diseases of childhood," or "diseases of infancy" because they are most likely to occur in childhood. So common are they that you know their names almost as well as you know your own—measles, mumps, whooping cough, scarlet fever, and chicken-pox. Though they are in no way related to one another, so far as we know (indeed, the precise germs that cause two of them—measles and scarlet fever—have not yet positively been determined), yet they can be practically taken together, because they are all spread in much the same way, they all begin with much the same sort of sneezing and inflammation of the nose and throat, they can all be prevented by the same means, and, if properly taken care of, they result in complete recovery ninety-five times out of a hundred.
THE WINNING FIGHT
Statistics for the population of the old City of New York. The chart shows a decrease from 95 out of every 1,000 in 1891-92 to 48 out of every 1,000 in 1909. This is due very largely to the careful methods of prevention enforced by the Board of Health, especially the inspection of milk.
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.