Unfortunately most people can not live out doors all of the time, and many are so situated that they even can’t secure ventilation, granted that they want it. But everybody has high proportion of time out of the twenty-four hours when he can completely control their own air supply. This is at night. We approximately spend one third of our time in bed. Most of us live such confined lives during the day that we should all the more avail ourselves of our opportunities to practice air hygiene at night.

It is the universal testimony that the best ventilated sleeping-room is far inferior in healthfulness to an outdoor sleeping-porch or balcony. And those who sleep out-of-doors have good health and vigor to those who sleep inside. For generations, outdoor sleeping has occasionally been used as a health measure in certain favorable climates and seasons. But only in the last two decades has it been used in ordinary climates and all the year round. Out-door sleeping is very much recommended for people suffering Tuberculosis. Following the same recommendation, results have been found that workers working in sanitary working-places (where they still continued to work while being treated for tuberculosis), they often conquered the disease in a few months. Nad this experience has lead to the general adoption, irrespective of climate, of outdoor sleeping for the treatment of Tuberculosis. The practice has since been recommender for nervous troubles and for other diseases, including pneumonia. Latterly the value of outdoor sleeping for well persons of all classes, infants and children, as well as for adults has come to be widely recognized.

Outdoor sleeping increases the power to resist disease or immunity, and greatly improve physical vigor, endurance, and working power.

Many people are still discouraged from sleeping out by a mistaken fear of night air and of the malaria, which they imagine this dreaded night air may bring. But fact is that malaria is communicated by the bite of the anopheles mosquito and never by the air.

The moral of this is not to shut out the night air, but, when necessary, to shut out the mosquito by screens. The experiment has been made of sleeping out-of-doors in screened cages in the most malarial places and no malarial infection resulted. The truth is that night air, especially in cities, is distinctly purer than day air, because of much less traffic at night to stir up dust and pollution.