Von Ziemssen in 1892, on the basis of clinical observations, was perhaps the first to note that in shock and hemorrhage "salt infusion was of benefit only for a short time as compared with blood transfusion." Blalock1sums up the present day view based on both clinical and experimental observations: "There is no doubt but that the intravascular volume can be temporarily increased by the direct introduction of salt solutions into the vascular system. Prompt temporary response of most patients with depleted blood volume to such treatment is well known. It is equally well known that this favorable response is often disappointingly transient, and the blood stream again becomes dehydrated and the circulatory impairment progresses in spite of the continued introduction of fluid. The introduction of aqueous solutions dilutes the plasma colloids in the blood stream. Tissue edema develops while the blood stream remains dehydrated. If there is extensive