When cold is unavailable or unpleasant to the patient, several layers of cotton cloth may be wrung out in very hot water and applied to the part with frequent renewal. The value attributed to witch-hazel and arnica is mainly due to the alcohol contained in their preparations. Cataplasma Kaolini (U. S. P.) is an excellent remedy for simple bruises when spread thickly on the part and covered with a bandage. An ointment containing twenty-five per cent of ichthyol is also a useful application. Following severe bruises, the damaged parts should be kept warm by the use of hot-water bags, or by covering a limb with cotton wool and bandage, until such time as surgical advice may be obtained. When the pain and swelling of bruises begin to subside, treatment should be pursued by rubbing with liniment of ammonia or chloroform, or vaseline if these are not obtainable. Moderate exercise of the part is desirable. =ABRASIONS.=--When the surface skin is scraped off, as often happens to the shin, knee, or head, an ointment containing sixty grains of boric acid to the ounce of vaseline makes a good application, and this may be covered with a bandage. The same ointment is useful to apply to small wounds and cuts after the first bandage is removed. =SPRAIN; NO DISPLACEMENT OF BONES.= _First Aid Rule 1.--Immerse in water, hot as hand can bear, for half an hour._ _Rule 2.--Dry and strap with adhesive plaster, if you know how. If not, bandage snugly, beginning with tips of fingers or with toes, and make same pressure all the way up that you do over injury._ _Rule 3.--Rest. If ankle or knee is hurt, patient must go to bed._ =Conditions, Etc.=--A sprain is an injury caused by a sudden wrench or twist of a joint, producing a momentary displacement of the ends of the bones to such a degree that they are forced against the membrane and ligaments surrounding the joint, tearing one or both to a greater or less extent. The wrist and ankle are the joints more commonly sprained, and this injury is more likely to occur in persons with flabby muscles and relaxed ligaments, as in the so-called "weak-ankled." The damage to the parts holding the joint in place may be of any degree, from the tearing of a few fibers of the membrane enwrapping the joint to its complete rupture, together with that of the ligaments, so that the bones are no longer in place, the joint loses its natural shape and appearance, and we have a condition known as dislocation. In a sprain then, the twist of the joint produces only a temporary displacement of the bones forming the joint, sufficient to damage the soft structures around it, but not sufficient to cause lasting displacement of the bones or dislocation.