Any dust that blows about the streets is likely to be carrying disease germs with it. That is why we have sprinklers driven through the streets to wet them and to keep down the dust; and why, in large cities, the streets are thoroughly flooded at night. If the streets are kept damp and clean, then the air above them is cool and fresh and pure. How does the city get rid of all the dirt and waste? From every house there are two kinds of waste. Some is taken away in pipes from the sink and bathroom out into pipes that run under the street, and these carry it away from the city to some stream or deep water that takes it entirely away from the town. The waste stuffs that are not watery, but solid--cabbage leaves, apple cores, potato parings, and other scraps from the kitchen are carted away and burned or fed to pigs. The ashes and tin cans are carted away, also, and used in making new land or filling up hollow places. Besides taking away the dirt, cities are careful to get clear, pure drinking water. They are very, very careful about this; and they usually have the water tested often, because, as you have learned, even water that looks perfectly pure may give people typhoid fever. That is why, when you are out in the country, on a picnic perhaps, you must not drink from the streams. They may receive the drainage from a farmer's barnyard, or the sewage from some house. The more we all learn about these things, the more careful will the city be to protect her people. To be sure, most cities now have Boards of Health who employ men and women to go about and see that the food in the stores is clean--no flies, no dust, and no tobacco smoke on it. They have laws, too, about keeping milk clean; and in New York alone these laws have saved the lives of thousands of babies. And they have laws about the care of streets and buildings and cars and parks and a great many other things. In all these things we have been talking about, I want you to be thinking how you can help. For a city is made up of people--boys and girls and men and women. The city is what its people make it; and everyone must help, even the smallest children, no older than little Claude. The first and most important thing for you to do is to keep yourself clean and tidy. And the next thing is for you to keep your back yard as well as your front yard and the school yard and the street free from papers and sticks and cans and old playthings. You can put away your things when you are through playing; or, if you are making a railroad or a town or a playhouse, you can leave it looking nice and tidy. You can help chiefly by putting away your own things. You know the old saying, "A workman is known by his chips"; and a good workman always works in an orderly way.