=207. Public drinking cup.=--When you touch your lips to a cup, you leave some saliva and cells from your mouth on the cup. If a cup is used by a number of persons, some one is almost sure to leave germs of sickness on it, and others are likely to take them into their own mouths when they drink. So a public drinking cup is a dangerous thing. Each school child should have his own cup. Public drinking fountains should be so made that we may drink by putting our lips to a stream of running water. [Illustration: =A safe drinking fountain.= A stream of water gushes up from the middle of the cup.] [Illustration: =An unsafe drinking place.= Photograph taken in the basement of a schoolhouse.] =208. Sweeping.=--Dusty air in a room is dangerous to health, for disease germs are likely to be found in it. We can get rid of dust by keeping our floors swept clean. After sweeping we should wipe the dust from the tables and furniture. A feather duster or dry cloth will only stir up the dust and make it float in the air again. We should use either a damp cloth, or a dry duster made of tufts of wool, so that the dust will stick to the duster. [Illustration: =House fly, magnified.= The hairs on its body and legs catch dirt and disease germs.] =209. Foul air.=--If we live in a closed room, the air soon becomes foul and dusty, and is likely to have disease germs in it. Foul air is one of the greatest of the causes of sickness. We should change the air of a room often so as to keep it fresh and free from dust and disease germs (pp. 65-67). =210. House flies.=--House flies come from garbage heaps and filth of all sorts. So they carry disease germs on their bodies. They light on our food and on our faces, and so they often make us sick. They are often the cause of typhoid fever, stomach aches, and stomach sickness in babies. [Illustration: =Life history of house flies.=] Flies are hatched in manure piles and garbage heaps. At first they look like white worms, and are called _maggots_. Every maggot is a young fly. We can get rid of flies by cleaning up every garbage heap and manure pile. [Illustration: =Young mosquitoes hanging head downward in water.=] =211. Mosquitoes.=--Mosquitoes carry malaria and yellow fever from sick persons to the well. If there were no mosquitoes, there would be no malaria or yellow fever. Mosquitoes are hatched in water, and the young are called _wigglers_. We may often see them in rain barrels. We may get rid of mosquitoes by emptying all rain barrels and pails and cans of dirty water, at least once a week, and by drying up swamps and marshes. WHAT WE HAVE LEARNED 1. We catch a fever by taking disease germs into the body. 2. Disease germs cannot be seen without a strong microscope. 3. The germs may be found in dust and dirt. 4. Slops from our houses are often full of the germs.