5. _A COLD_.--We put on a thinner dress than usual, or, when heated, sit in a cool place. The skin is chilled, and the perspiration checked. The blood, no longer cleansed and reduced in volume by the drainage through the pores, sets to the lungs for purification. That organ is oppressed, breathing becomes difficult, and the extra mucus secreted by the irritated surface of the membrane is thrown off by coughing. The mucous membrane of the nasal chamber sympathizes with the difficulty, and we have "a cold in the head," or a catarrh. In general, the excess of blood seeks the weakest point, and develops there any latent disease [Footnote: A party go out for a walk and are caught in a rain, or, coming home heated from some close assembly, throw off their coats to enjoy the deliciously cool breeze. The next day, one has a fever, another a slight headache, another pleurisy, another pneumonia, another rheumatism, while some of the number escape without any ill feeling whatever. The last had vital force sufficient to withstand the disturbance, but in the others there were various weak points, and to these the excess of blood has gone, producing congestion.] Where one person has been killed in battle, thousands have died of colds. To restore the equipoise must be the object of all treatment. We put the feet in hot water and they soon become red and gorged with the blood which is thus called from the congested organs. Hot footbaths have saved multitudes of lives. It is well in case of a sudden cold to go immediately to bed, and with hot drinks and extra clothing open the pores, and induce free perspiration. This calls the blood to the surface, and, by equalizing and diminishing the volume of the circulation, affords relief. [Footnote: Severe colds may often be relieved in their first stages by using lemons freely during the day, and taking at night fifteen or twenty grains of sodium bromide. Great care, however, should be observed in employing the latter remedy, except under the advice of a physician.] 6. _Catarrh_ commonly manifests itself by the symptoms known as those of a "cold in the head," and is produced by the same causes. It is an inflammation of the mucous membrane lining the nasal and bronchial passages. One going out from the hot dry air of a furnace-heated room into the cold damp atmosphere of our climate can hardly avoid irritating and inflaming this tender membrane. If our rooms were heated less intensely, and ventilated more thoroughly, so that we had not the present hothouse sensitiveness to cold air, this disease would be far less universal, and perhaps would disappear entirely. [Footnote: Dr. Gray gives the following table: