Since the agitation for fresh air has become so extensive and the knowledge of the dangers of tuberculosis so widespread, much more attention has been given to the ventilation of bedrooms, and whereas formerly the night air was religiously excluded from a sleeping room, it is not at all uncommon now for a window to be kept wide open, even through the coldest nights of winter. From what has already been said on the subject of ventilation, it is plain that to breathe over and over one's expired air is not healthy, and while it is possible that a bedroom may be so large that the concentration of the organic matter in the air may not affect an individual sleeping in the room, yet in most cases it must be admitted that the bedroom is so small or the number of people in the bedroom so large that this possibility does not exist. It is, again, possible that the structure of the house may be so poor that it is not necessary to open a window to get plenty of fresh air; the writer remembers sleeping in rooms where, with the windows shut, paths of snow across the floor in the morning showed the intimate connection between the inside and the outside of the room. But the tendency nowadays is to build better houses, to cover the walls with paper, to put on double windows, and even to paste up the cracks to make the room as air-tight as possible. To sleep in such a room without a window open may not be committing suicide, but it is a deliberate method of reducing the vitality, of insuring a headache or a numbed and stupid mental condition, and of loading up the system with poisons which ought to be eliminated by the oxygen which fresh air supplies. It would add many years to the lives of the people of this country if, from childhood up, the habit was formed of sleeping with the window open. Nor need one fear that a cold would result from such exposure. A cheesecloth screen in the window prevents any draft and yet allows perfect ventilation. The face is trained to all kinds of exposure without any danger of catching cold, and there is no reason why, if the bed clothing be sufficient, the night air should not be thoroughly enjoyed without danger. Of course, the bed clothing must be sufficient; two lightly woven blankets are always better than one heavy one. Wool is better than cotton; if a cotton quilt is used, it should be loose and not tied tightly. _Bathing._