We experience the truth of the saying of Sanctorius, "that melancholy is overcome by a free perspiration, and that cheerfulness, without any evident cause, proceeds from perspiration succeeding well." It is a curious, but at the same time an obvious fact, with regard to perspiration, that it depends very materially on the habit and training of the skin. The beginner in the use of the bath perspires slowly, languidly, partially, incompletely, while the accustomed bather is known by the freedom of his perspiration. The apprentice-hand has no thirst in the bath, for a small portion only of the excess of watery fluid is abstracted from his tissues and from his blood. But the practised bather has no such excess, his blood yields its diluting water with great freedom, he thirsts in the bath, and he drinks freely. I know a gentleman who sometimes consumes a gallon of water in the bath, but none remains when he comes out: all has been dissipated by perspiration. In a chemical analysis of the perspiration of a group of bathers, recently made, that fluid was found loaded with saline and organic matter in the recruits, but was almost pure in the veteran bather: his blood was washed as clean as that of the working man who eats the bread of labour--that sweetest of all bread, the bread that has been earned with the sweat of his brow. I hardly know a more curious or more beautiful sight than that of the healthy skin of a practised bather, spangled over with limpid drops of perspiration like dew-drops on the petals of a rose, or like beads of crystal, as I heard a Doctor of Divinity once call them, in the bath. The Reverend Doctor, although a distinguished member of the Protestant Church, was, as a witty friend remarked, "devoutly counting his beads." Among the labourers in hot rooms, or in proximity with hot furnaces, as in the manufacture of glass, enamel, porcelain, and gas, the working of engines, and the smelting of metals, perspiration is very profuse, and the lost fluid is replaced by the drinking of water, or more commonly of thin gruel; restoring the balance of fluids not by mere water, but actually by a nutritive drink. Look at these men, working in the open air, or in the midst of thorough draughts, with rivers of perspiration streaming down their athletic frames, and ask their history; they are healthy, long-lived and happy. In the copper-smelting works at Swansea, the heat between the furnaces at which the men work is 200° of Fahrenheit; they drink a gallon of thin gruel every hour, working four hours at a stretch, and the ground on which they stand is a pool of perspiration.