=Questions.= 1. Name three ways by which germs get into our bodies. 2. How do germs get into our food? 3. Why should foods be screened? 4. Trace the fly from his birth-place to our food. 5. How do we know that flies have germs on their feet? 6. Tell how we can get rid of most of the flies. 7. How can we keep flies out of the house? 8. What can boys and girls do to help keep them out? =Remember.= 1. Always wash an apple, pear, or any other fruit before you eat it. 2. All foods are handled by many people, and are not clean until they have been washed. 3. Flies like to live in dirty places, and their feet and legs are covered with germs; get rid of the flies. 4. Flies hatch in manure piles and other dirty places; keep your yard and lot clean so that flies will have no place to lay their eggs. 5. Put screens on the house to keep flies out, and keep the screens closed. CHAPTER XIX HOW DISEASE GERMS GET INTO WATER The water that we drink frequently contains disease germs. It is not always the clearest water that is freest from disease germs, for the germs do not make the water cloudy. [Illustration: FIG. 45. An improperly located well; notice lines of seepage.] [Sidenote: Why sewage should not be put into streams] Water does not get disease germs from the ground, but from man. Almost every town has a sewer system that empties into some stream. This practice was started a long time ago when men thought that running water would purify itself in the course of a few miles. We have learned, however, that this is not true. Germs will continue to live in running water just as they do in any other water, and disease germs will live in a stream from twenty-five to thirty-five days. Estimate how far a stream will flow in that length of time, and you will know how far disease germs will travel in that way. No sewage should ever be allowed to get into a stream until the germs in the sewage have been killed. [Sidenote: Other sources of germs in streams] Sewage is not the only means by which disease germs are carried into streams. Often we find people building barns, slaughterhouses, and mills on the banks of a stream. The filth from barns and slaughterhouses always contains disease germs, and often the filth of mills contains poisons that are just as harmful as germs when taken into our bodies. None of these things should ever be allowed to get into a stream. Water is a very important article of food, and we should take every care to keep it pure. [Illustration: FIG. 46. A properly located well.] [Sidenote: How germs get into wells]