DESPITE the large number of studies on hemorrhage, there is little exact information in regard to the phenomenon of hemodilution, this term being used to describe a decrease in the red cell concentration in the blood, as measured by the hematocrit reading, by the erythrocyte count or by the concentration of hemoglobin. While most observers agree that hemodilution (i.e., anemia) ordinarily follows severe hemorrhage, it is generally believed to occur only after the lapse of time. For example, in two textbooks on hematology the hemodilution following a severe hemorrhage is described as follows: "The red cell count, hemoglobin, and volume of packed red cells, at first misleadingly high as the result of vasoconstriction and of liberation of corpuscles from storehouses such as the spleen, decrease and may continue to fall for several days even though hemorrhage has ceased."1 "There will be little or no deviation from normal if an