One of the most frequent illustrations of this reciprocated action, is afforded by a convivial meeting in cold weather. The heat of the room, the food, and the excitement, quicken the circulation, and perspiration is evolved. When the company passes into the cold air, a sudden revulsion takes place. The increased circulation continues, for some time after; but the skin being cooled, the blood retreats, and the internal organs are obliged to perform the duties of the skin as well as their own. Then, in case the lungs are the weakest organ, the mucous secretion becomes excessive; so that it would fill up the cells, and stop the breathing, were it not for the spasmodic effort called coughing, by which this substance is thrown out. In case the nerves are the weakest part of the system, such an exposure would result in pains in the head or teeth, or in some other nervous ailment. If the muscles be the weakest part, rheumatic affections will ensue; and if the bowels or kidneys be weakest, some disorder in their functions will result. But it is found, that the closing of the pores of the skin with other substances, tends to a similar result on the internal organs. In this situation, the skin is unable perfectly to perform its functions, and either the blood remains to a certain extent unpurified, or else the internal organs have an unnatural duty to perform. Either of these results tends to produce disease, and the gradual decay of the vital powers. Moreover, it has been shown, that the skin has the power of absorbing into the blood particles retained on its surface. In consequence of these peculiarities, the skin of the whole body needs to be washed, every day. This process removes from the pores the matter exhaled from the blood, and also that collected from the atmosphere and other bodies. If this process be not often performed, the pores of the skin fill up with the redundant matter expelled, and being pressed, by the clothing, to the surface of the body, the skin is both interrupted in its exhaling process, and its absorbents take back into the system portions of the noxious matter. Thus the blood is not relieved to the extent designed, while it receives back noxious particles, which are thus carried to the lungs, liver, and every part of the system. This is the reason why the articles worn next to the skin should often be changed; and why it is recommended that persons should not sleep in the article they wear next the skin through the day. The alternate change and airing of the articles worn next the body by day or night, is a practice very favorable to the health of the skin. The fresh air has the power of removing much of the noxious effluvia received from the body by the clothing. It is with reference to this, that on leaving a bed, its covering should be thrown open and exposed to the fresh air.