ful attention may be given to your diet, if you do not realize the importance of pure air, and see that you secure it at all times, there will be but little chance of developing any great degree of strength. When air is breathed over and over again it reeks with carbonic acid gas which is exhaled from the lungs of every living being. This is a poison which is most baneful in its effects, and a diseased condition of any character is greatly encouraged under such abnormal conditions.
At night the windows should be open at both top and bottom, winter and summer, if one expects to retain vigorous health. Without pure air you can no more retain health than you can live without eating. Of course one may be able to apparently enjoy vigorous health for a prolonged period and still give little attention to the necessity of pure air, but this merely indicates the possession of a very vigorous constitution, and a continuance of the habit of breathing foul, enclosed air will in every case ultimately produce serious disease. No matter where you may be, whether in office,
