My earlier experiments1 and those of Parsons and Phemister2 showed that severe trauma to an extremity causes a sufficient loss of red blood cells and of blood plasma into the injured tissues to account for the associated decline in blood pressure. These studies were performed at room temperature on animals which had not been deprived of food and water. The present experiments were carried out to determine the effects of cold and of the deprivation of food and water on the minimum loss of blood necessary to produce death. Loss of blood was produced in some instances by the removal of blood through a cannula that had been placed in the femoral artery and in others by injury to the muscles.
All of the animals were anesthetized and exhibited no evidence of pain. A cannula that was connected to a mercury manometer was introduced into the femoral