IN MANY types of shock the use of blood transfusions is a time-honored method of attempting to correct the presumed disparity between the volume of circulating blood and the capacity of the vascular bed. Although considerable work has been done studying the effects of blood transfusions and other intravenously administered fluids in the treatment of shock, there is an incomplete understanding of what happens when a blood transfusion is given to a normal person or animal. Boycott and Oakley1 stated that after a transfusion of whole blood in dogs the plasma volume returns to normal in two to three days and the blood volume is increased for at least two days in proportion to the volume of red cells added. They also reported that the injected protein disappears from the blood stream within the same period. Krumbhaar and Chanutin2 have reported similar results. According to Sibley and Lundy,