The most strategic point of attack is almost universally unrecognized. That is the child's mouth. Here the germs find lodgment, here they find a culture medium--at the gateway of the human system. The mouth is never out of service and is almost never in a state of true cleanliness. Solid particles from the breath, saliva, food between the teeth, and other débris form a deposit on the teeth and decompose in a constant temperature of ninety-eight degrees Fahrenheit. In the normal mouth from eight to twenty years of age the teeth present from twenty to thirty square inches of dentate surface, constantly exposed to ever-changing, often inimical, conditions. This bacterially infected surface makes a fairly large garden plot. Every cavity adds to the germ-nourishing soil. Dental caries--tooth decay--is a disease hitherto almost universal from birth to death. Thus the air taken in through the mouth becomes a purveyor of its poisonous emanations and affects the lung tissues and the blood. Food and water carry hostile germs down into the stomach. Thence they may be carried into any organ or tissue, just as nourishment or poison is carried.
Moreover, the child with an unclean mouth not only infects and reinfects himself but scatters germs in the air whenever he sneezes or coughs. In a cold apartment where there is no appreciable current of air a person can scatter germs for a distance of more than twenty-two feet. Germs are also scattered through the air by means of salivary or mucous droplets. It is this fact that makes colds so dangerous.
=INFECTIOUS OR CONTAGIOUS DISEASES IN SCHOOLS INFORMATION FOR TEACHERS=
Four columns are omitted: (1) Interval between Exposure to Infection and the First Signs of the Disease; (2) Day from Onset of Illness on which Rash appears; (3) Period of Exclusion from School after Exposure to Infection; (4) Period of Exclusion from School of Person suffering from the Disease