Foul air contains germs which cause disease and often death.
4.

Persons sick with "catching" diseases should be carefully avoided.
Such persons should be shut away from those who are well, and their rooms and clothing should be carefully cleansed and disinfected.
5.

The breath poisons the air about us.

Each breath spoils half a barrelful of air.
6.

We should change the air in our houses, or ventilate them, so that we may always have pure air.
7.