A common cold is attended with a running of the nose, hoarseness, and cough, with a considerable degree of feverish heat, an dryness of the skin.--Now it is universally agreed, that this disorder is an inflammation, or is of an inflammatory nature; it is an inflammation of the smooth, moist skin which lines the nostrils, and goes down the wind-pipe into the lungs; but as cold is only a diminution of heat, or a diminution of a stimulus acting upon the body, it is impossible that such a diminution can cause a greater action or excitement; we might as well expect to fill a vessel by taking water out of it. But let us see how a cold, as it is commonly called, is usually produced. When a person in cold weather goes out into the air, every time he draws in his breath, the cold air passes through his nostrils and windpipe into the lungs, and in thus diminishing the heat of the parts, allows their excitability to accumulate, and renders them more liable to be affected by the succeeding heat. So long as that person continues in the cold air, he feels no bad effects; but if he come into a warm room, he first perceives a glow within his nostrils and breast, as well as all over the surface of the body. Soon afterwards, a disagreeable dryness and huskiness will be felt in the nostrils and breast. By and by a short, dry, tickling cough comes on. He feels a shivering, which makes him draw nearer to the fire, but all to no purpose; the more he tries to heat himself, the more chill he becomes. All the mischief is here caused by the violent action of the heat on the accumulated excitability. For want of a knowledge of this law, these disagreeable, and often dangerous complaints are brought on; when they might be avoided with the greatest ease.