CHAPTER IV.
AIR.
Though air is not generally considered a food, the oxygen secured from the air is really more essential to life than any food element. We can live without food for months; we can live without water for many days, but we cannot live without oxygen for five minutes. This fact is not recognized generally, and the breathing of impure air which has been enclosed and breathed over and over again, has caused many very serious diseases. There is hardly a home in which proper precaution is taken to secure thorough ventilation during the winter months.
Air is really a food. It must be looked upon as a food because, as I have already mentioned, oxygen is more necessary to life than any other element.
No matter what precaution we may take to build up vigorous health by eating and drinking proper food in proper quantities, but little
