PURPOSE OF VENTILATION.
By A. J. Sanderson, M.D.
UPON the atmosphere above and the earth beneath all living matter depends. One is as essential as the other. The air furnishes the gaseous material for the sustenance of life, and the earth furnishes the solid, which is first organized into tissue by plant life. No living organism can exist without air, with perhaps one exception, a class of germs known as the anaerobic form of bacteria. To expose properly a living organism to air in its natural and perfect state is the purpose of ventilation. With life in the vegetable kingdom there is no hindrance to obtaining these conditions, unless it may be in the case of flowers grown in the house, or other plants that have been thus transplanted from their natural environment. In the animal world there are also perfect conditions, except in the case of man and those animals which he has domesticated and compelled to live in such unnatural atmospheric conditions as those in which he often abides. Houses, and all buildings where man or beast lives, should be so ventilated that there will be free communication between the air without and that within. Air should be changed in an apartment in order to remove impurities with which it has been impregnated, and pure air should be admitted in equal volume, that the occupants may be supplied with fresh oxygen. A house, in order to have such a circulation of air, needs to be so constructed and arranged that the physical properties of the air within and without will create proper currents. Unhealthful drafts should be avoided, and in cold weather the principles of economy and equity in heating the air should be considered. These conditions for free ventilation of a room are essential, in order to make any room habitable. A proper flow of pure air to the lungs is a prerequisite to health, as in this way only can the oxygen be conveyed to the blood. This necessitates natural and perfect breathing, also a reasonable amount of muscular work. For not only do the lungs breathe, but every cell in the body breathes, as truly in the foot and brain as in the chest. Thus a perfect circulation of the blood is required. The organs which aerate the body are the lungs, the blood, and the circulatory system. The respiratory organs transfer oxygen to the body; and the individual cells eat it. To understand the requirements and methods of ventilation, one must consider mathematically how much oxygen the person or persons occupying the room need, the laws of physics which govern the circulation of air through the house, and the individual modes of breathing and exercise. The clothing for the body also needs consideration, as the poisonous vapors given off by the skin need the influence of air for evaporation and removal. It is only when all these conditions are perfect that air can have its proper effect on the body. Nature's supply is inexhaustible; yet man, with his unnatural and artificial habits, often shuts himself away from it, to the starvation or deterioration of his own life. We would shrink with abhorrence from putting on a garment another has worn, or using a tooth-brush that belongs to a friend, or tasting food some one else has masticated; and yet we often thoughtlessly, repeatedly, reinhale the atmosphere that many others have several times used. Perhaps no law of hygiene is more frequently violated.