=Too Much Sickness.=--Many diseases are caused by our own carelessness and our bad habits of living. We have about one doctor for every one hundred families. There are enough people sick every day to make a city as large as New York or to equal the number of people living in the thirteen states of Idaho, Nevada, Wyoming, Arizona, New Mexico, Utah, Delaware, Montana, Vermont, New Hampshire, North Dakota and South Dakota, and Oklahoma. A careful study of disease and its cause shows that at least one half of all the sickness in our land can be avoided by right living. =The Cause of Sickness.=--Some people are so foolish as to make themselves sick. They weaken the body by using much beer or wine, by breathing bad air, by lack of exercise, or by fast eating. When the body becomes weak, it is likely to get sick at any time. [Illustration: FIG. 93.--The germs of diseases. Much enlarged.] It is not always our own fault when we are sick. It may be caused by the carelessness of others who have let germs escape from their bodies so that they are able to reach us. One half of the sickness in our land is catching sickness. That is, it is sickness which passes from one person to another and is caused by tiny germs or microbes. A catching sickness is called a _contagious disease_. Some of the common catching diseases are sore throat, colds, diphtheria, pneumonia, typhoid fever, measles, grippe, and whooping cough. =How we get a Catching Sickness.=--We get a catching sickness by taking into our bodies the germs from some other person. The germs of the sick do not pass off in the breath, but in the spit or anything else which comes from their bodies. This is why the spit and all slops from the sick room should be burned, buried, or destroyed in some way. [Illustration: FIG. 94.--How the germs of disease start on their mission of death. This sewer carries slops from the houses of the sick and well and empties into a stream used below for drinking water.] We should think it very wicked if a showman should turn his lions and tigers loose in a crowd of women and children. Somebody would surely be killed and others hurt. It is just as wrong to turn loose the germs of the sick by throwing the spit and the slops where they will get into a stream or where the flies may find them and by soiling their feet leave death in their trail wherever they crawl. =How the Germs of Sickness catch Us.=--The germs of sickness have no feet to walk and no wings to fly, yet they easily travel from the sick to the well. They are not killed by being frozen, or drowned by floating in water, or destroyed by drying. For this reason they can travel with the ice, water, milk, and dust. In Buffalo, New York, fifty-seven children caught the scarlet fever in one week by using milk cared for by a boy who was getting well from the scarlet fever.