The arrangement of the modern bath is modified from that of the Ancients and Orientals to suit the accepted form of practice in this country, so that the order of the different processes through which the bather passes governs the disposition of the various apartments. The chief object to be attained is to induce a more or less vigorous perspiration by the application of heat. This heat is now generally applied through the medium of the air, which is raised to a high temperature by being passed over and in contact with the heated surfaces of stoves of various designs, or by direct radiation from hot metal or firebrick. Theoretically, the generally-adopted method of applying the heat to the bather might be greatly improved, but practically it has been found the best. Into these questions, however, I shall enter when treating of the heating and ventilating of the bath. For the present, it will suffice to say that the chief object to be attained in the bath is the supplying of an abundance of _pure hot air_ to the various sudorific chambers, and the rapid withdrawal of the foul air and exhalations. Since the disposition of the various apartments is governed by the methods of bathing in vogue, it will be necessary to first give the reader a brief account of the various processes undergone by the bather. The object of the profuse perspiration to be attained is twofold--(1) To cleanse the blood of impurities; and (2) to loosen the dead scales of the epidermis, or scarf-skin, that spreads itself everywhere over the true skin or cuticle. Besides this, however, physiologists tell us that the heat itself has a beneficial effect on the body in other ways, and is, in cases of disease, a most powerful curative and remedial agent. This latter fact explains the necessity for the high temperatures employed, as mere perspiration could be attained with a comparatively low degree of heat. The course of treatment to be undergone by the bather, as given by Sir Erasmus Wilson, is--(1) Exposure of the naked body to hot dry air. (2) Ablution with warm and cold water. (3) Cooling and drying the skin. In addition to these, however, there should be added the process of "massage" or shampooing before washing. The perspiration is attained in the various hot rooms--the _Tepidarium_, _Calidarium_, and _Laconicum_. The nature of these apartments--which I shall hereinafter consider in detail--must be determined by the pretensions of the establishment.