The faculty of preventing disease, as exercised by the skin, besides being indirect and operating on the general health of the body, is also direct. The skin repels the depressing effects of cold, of alternations of temperature, of extreme dryness or moisture, by virtue of its own healthy structure; by its intrinsic power of generating heat; and it also repels other causes of disease, such as animal and miasmatic poisons, by its emunctory power, which enables it to convey them directly out of the body. In unwholesome states of the atmosphere, in an atmosphere of malaria, which must necessarily pass into the body with the inhaled air, and being in the lungs must be absorbed by the blood, we naturally inquire by what means we escape the morbid effects of such malaria? The answer is:--the malaria is conducted out of the body as rapidly as it is introduced, by the emunctory organs--by the liver, kidneys, and notably by the skin. If the powers of the skin be weak, then the poisons are detained in the blood, and disease is the result; but if the skin be healthy and active, then they can do no evil; and ultimately they become innocuous. Thus the bath, by conducing to the health of the skin, becomes a direct means of preventing disease. Reasoning, on the same premisses, shows us how the bath may be employed in the cure of disease. We can, at our will, so far excite the emunctory power of the skin as to make it the means of carrying off the elements together with the seeds of disease. If we wish to comprehend the operation better, we have only to watch Nature's own processes. A morbid poison is in the blood, it produces a shock to the whole system, that shock is represented by a chill; next to the chill succeeds a fierce fever, which marks the furious battle waged between the poison and the blood; then follows the perspiration, which hurries the contending poison out of the system; the perspiration, for the time being, is the cure. The observation of this well known series of symptoms suggested to the inventive mind of Mr. Urquhart the notion, that by raising artificially, as by the bath, the temperature of the body above fever-heat, the proper stages of fever might be stepped over; the chill fit would pass at once into the hot fit, and the hot fit be resolved by perspiration. The suggestion is worthy of mature thought.