Attempts at ventilation are made by utilizing the heat due to the numerous flames of the central chandelier over the auditorium, to create an ascending draught, and thereby cause a removal of the contaminated air, but seldom is provision made for the introduction of fresh air from outdoors, hence the scheme of ventilation results in failure. In other buildings, openings for the introduction of pure air are provided under the seats or in the floor, but are often found stuffed up with paper because the audience suffered from draughts. The fear of draughts in a theater also leads to the closing of the few possibly available outside windows and doors. The plan of a theater building renders it almost impossible to provide outside windows, therefore "air flushing" during the day can not be practiced. In the case of the older theaters, which are located in the midst or rear of other buildings, the nature of the site precludes a good arrangement of the main fresh-air ducts for the auditorium. Absence of fresh air is not the only sanitary defect of theater buildings; there are many other defects and sources of air pollution. In the parts devoted to the audience, the carpeted floors become saturated with dirt and dust carried in by the playgoers, and with expectorations from careless or untidy persons which in a mixed theater audience are ever present. The dust likewise adheres to furniture, plush seats, hangings, and decorations, and intermingled with it are numerous minute floating organisms, and doubtless some germs of disease. Behind the curtain a general lack of cleanliness exists--untidy actors' toilet rooms, ill-drained cellars, defective sewerage, leaky drains, foul water closets, and overcrowded and poorly located dressing rooms into which no fresh air ever enters. The stage floor is covered with dust; this is stirred up by the frequent scene shifting or by the dancing of performers, and much of it is absorbed and retained by the canvas scenery.