Double doors and lobbies must be employed to prevent the transmission of the heated air to rooms where its presence would be injurious. To keep the hot air of the bath-rooms from the cooling-rooms, &c., should be the great aim of the architect. Many baths are rendered quite repulsive by what I may perhaps term the "sudorific smell" that assails the nostrils of the visitor entering the vestibule. The space allotted to the sudatory chambers may be divided into the various rooms, either by glazed brick walls or by framed and glazed partitions; or again, they may be formed by a combination of solid brickwork and glazed woodwork. Any piers in these rooms must be of brickwork, iron columns being inadmissible. Masonry, too, must be discarded throughout, or used with caution. Some stones--such as red Mansfield--become black with exposure to the heat, and others fare still worse. The employment of porous and absorbent materials must be guarded against throughout this portion of the bath, as it should be remembered that effete matters, particles of waste tissue, and possibly the germs of disease, are continually being given off by the perspiring bathers, and must be prevented from finding a lodgment. The best woods for use in the hot rooms are close-grained and free from essential oils. Mahogany is excellently adapted for the purpose, and so, also, is teak. Pitch pine must be discarded altogether. Deal, when employed, should be perfectly seasoned, and may then give trouble from the exudation of turpentine. The partitions, and the doorways in them, must be so placed as to govern the flow of hot air. So long as the main divisions be planned with this end in view, the separate rooms may be divided and broken up as the architect may fancy. But the constant flow of the heated air from the inlet in the hottest room towards the lavatorium must not be interfered with by recesses, nooks, and corners, or anything that would cause the current to stagnate. And here we may see the practical advantage possessed by a bath where the hot rooms are _en suite_, and in a line with one axis. For here the air sweeps uninterruptedly through the different chambers without eddying around corners and stagnating in recesses far out of the main stream. The doorways in the partitions should not be too lofty. They should not be hung with doors, as anything necessary in this way will be amply supplied by depending curtains.