THE INCREASING interest in the auto-immune state has refocused the medical view on the patient who is sensitive to cold. This is the individual who reacts to his own tissue upon cooling. A drop in skin temperature, whether it be produced by a breeze, contact with a cool object, or entering an air-conditioned room, may be followed by erythema, pruritus, and even urticaria. Such cold urticaria, because of its obviousness, is a diagnostic hallmark of the cold hypersensitive state, but it is still only one of a galaxy (Table 1)1-4 of signs and symptoms which may occur. Such patients experience frightening dysphagia after ingesting ice water or chilled foods. Moreover, cold showers, a chilling rain, and the winter wind are particular hazards that they soon learn to avoid also. But as Horton, Brown, and Roth 1 pointed up 25 years ago, swimming in cold water poses the ultimate