This section is from the "Nature Cure: Philosophy and Practice Based on the Unity of Disease and Cure" book, by Henry Lindlahr.
If at all possible, air baths should be taken out of doors. Every house should have facilities for air and sun baths, that is, an enclosure where the nude body can be exposed to the open air and the sunlight.
If the air bath out of doors is impracticable, it may be taken in front of an open window. But indoor air, even in a well-ventilated room, is more or less stagnant and vitiated, and at best only a poor substitute for the open air.
It is the breezy, moving outdoor air, permeated with sunlight and rich in oxygen and ozone, that generates the electric and magnetic currents which are so stimulating and vitalizing to everything that draws the breath of life.
This is being realized more and more, and air-bath facilities will in the near future be considered as indispensable in the modern, up-to-date house as is now the bathroom.
We predict that before many years the roofs of apartment houses will be utilized for this purpose and people will wonder how they ever got along without the air bath.
Our sanitarium has two large enclosures on its roof, open above and surrounded on all sides by wooden lattice work, which allows the air to circulate freely, but excludes observation from neighboring roofs and windows and the streets below. One compartment is for men and one for women, each provided with gymnastic apparatus and a separate spray room.