THE MICROBIOLOGY OF THE ATMOSPHERE.
The air we breathe, like our food and drink, varies in quality from time to time and from place to place. This fact was recognized many centuries before industrialized man assumed the right to pollute the atmosphere with poisonous chemicals and radioactive isotopes.
In Britain we hold that, `when the wind is in the East 'tis neither good for man nor beast'. Some places arc noted for invigorating air, and some for relaxing air; but it is not yet clear whether these properties are associated merely with differences in temperature, humidity, and move ment of a gaseous mixture consisting mainly of 78 per cent nitrogen, zt per cent oxygen, and o•03 per cent carbon dioxide with traces of the inert gases, or whether some other factor or factors are involved.