The term cold refers to the abstraction of heat, to the substance by means of which such abstraction is effected, and to the sensation created by such abstraction. The sensation of cold is evoked when the temperature of the substance is lower than that of the body area to which it is applied. It is possible to develop the paradoxical situation in which the same substance will feel cold to one hand and warm to the other when one hand has been previously immersed in warm water and the other in cold water. The temperature of the skin surface of the torso can be regarded as the neutral point and is usually about 93 F (33.9 C). When water is used as a therapeutic agent it is called tepid if its temperature is between 80 and 93 F (26.7 and 33.9 C); cool, between 65 and 80 F (18.3 and