The fact that heat is brought to the extremities by the flow of blood is generally recognized. The temperature of the part has come to be accepted as indicative of the state of circulation to the tissues. When the hands or feet are cold, it is natural to believe that the blood supply is reduced. Similarly, warmth of the parts indicates adequate blood flow.
It has long been established that the circulation to the extremities is increased by the application of heat and decreased when cold is applied. Quantitative studies1 have demonstrated the relationship between elevated temperature and increased flow of blood. Since warmth of the extremities is closely related to the circulation and since it is recognized that the blood flow may be increased by the application of heat it is natural to attempt to correct the cold due to inadequate circulation by applying heat.
Patients with impaired