Doors.
Doors are the greatest problem in a room. They monopolize the space on the floor and wall that should be free for pictures and large articles of furniture, and otherwise completely demoralize the apartment. To do away with this inconvenience substitute heavy curtains whenever an impassable barrier is unnecessary; closet doors, for instance, and those between parlors. Again, doors that are much open may be made to slide into the walls. Then, for ornament and as a screen, the doorway may be furnished with hangings, costly or not, as the purse may dictate.
The outer doors are intended as a defense from intrusion from without. It is not really good taste to have these doors of plate glass as that militates against the primal idea of strength and protection.