If, after our first entrance into the Calidarium, we place the hand on any part of our skin, it gives the sensation of coldness, as compared with the temperature of the apartment. Soon, however, the skin becomes warm and dry; shortly afterwards it is moist and clammy; and later still, the perspiration begins to flow with greater or less activity. The freedom of perspiration follows the known structure of the skin in reference to the sudatory organs; it is first perceptible and most abundant on the face and hands, where the sudatory glands are most numerous and most developed; it succeeds on the chest and shoulders, then on the rest of the body, and lastly, on the legs below the knees. The perspiration at first issues from the pores in minute drops, the drops swell to the size of peas, and the skin looks as if it were garnished, with crystal beads; the beads run into little rills, and the rills trickle down the hollow ways of the surface in small streams. It is at this period that the whole body admits of being washed by means of the water that issues from itself, and that the secret of the small quantity of water provided for the baths by the Romans is discovered. It is when the perspiration commences to flow in abundance, that the beginner in the use of the bath, or the owner of a susceptible constitution, becomes aware of an increase of rapidity of the heart's pulsations; and this sensation is commonly associated with a feeling of oppression, something approaching to faintness. On the first hint of this sensation, the bather should retire to the Tepidarium or to the Frigidarium, and sit there for a few minutes, or until the sensation has ceased; he may then return to the Calidarium, and upon each recurrence of the sense of oppression always quit the Calidarium for the cooler temperature without. The sensation which I am now describing is the only disagreeable one attendant upon the use of the bath; it is unknown to the practised bather, and to the strong or callous constitution, and may be effectually obviated, even in the most sensitive, by the simple precaution which I have just suggested. Strange to say, these passages from the hot to the cold temperature are not attended with a check to the perspiration, they only moderate it, while the stimulus of the fresh air provides more ample chest-room for the oxygenization of the lungs.