When packs are applied, the bed may be protected by spreading an oilcloth over the mattress under the sheet. But in no case should oilcloth or rubber sheeting be used for the outer covering of packs. This would interfere with some of the main objects of the pack treatment, especially with heat radiation. The outer covering should be warm but at the same time porous, to allow the escape of heat and of poisonous gases from the body. Local Compresses In case of local inflammation, as in appendicitis, ovaritis, colitis, etc., separate cooling compresses may be slipped under the pack and over the seat of inflammation. These local compresses may be removed and changed when hot and dry without disturbing the larger pack. In all fevers accompanied by high temperature, it is advisable to place an extra cooling compress at the nape of the neck (the region of the medulla and the back brain), because here are located the brain centers which regulate the inner temperature of the body (thermotaxic centers), and the cooling of these brain centers produces a cooling effect upon the entire organism. Enemas While ordinarily we do not favor the giving of injections or enemas unless they are absolutely necessary, we apply them freely in feverish diseases in order to remove from the rectum and lower colon any accumulations of morbid matter, and thus to prevent their reabsorption into the system. In cases of exceptionally stubborn constipation, an injection of a few ounces of warm olive oil may be given. Allow this to remain in the colon about thirty minutes in order to soften the contents of the rectum, and follow with an injection of warm water. Just How the Cold Packs Produce Their Wonderful Results (1) How Cold Packs Promote Heat Radiation Many people are under the impression that the packs reduce the fever temperature so quickly because they are put on cold. But this is not so, because, unless the reaction be bad, the packs become warm after a few minutes' contact with the body. The prompt reduction of temperature takes place because of increased heat radiation. The coldness of the pack may lower the surface temperature slightly; but it is the moist warmth forming under the pack on the surface of the body that draws the blood from the congested interior into the skin, relaxes and opens its minute blood vessels and pores, and in that way facilitates the escape of heat from the body. In febrile conditions the pores and capillary blood vessels of the skin are tense and contracted. Therefore the heat cannot escape, the skin is hot and dry, and the interior of the body remains overheated. When the skin relaxes and the patient begins to perspire freely, we say the fever is broken.