Severe bruises should be treated promptly by applying very cold water to the part, if it can be obtained. A cloth wrung out in very hot water will accomplish the same purpose, which is to limit swelling, prevent discoloration, and reduce pain. "It always seems strange that the two opposites—cold and heat—should have the same effect on the blood-vessels, but this is actually the case. . . . Every one knows how shrunken the hands look after they have been in hot water for some time".