Blood Volume and its Regulation

emphasized a primary interest of investiga­ tors in development of adequate methods for determination of blood volume and for establishment of ranges of values in healthy and in diseased states. By 1960, there was fairly general agreement that the available methods gave a reasonable measure of the blood volume; Reeve, Allen & Roberts (3), work­ ing on this assumption, devoted their review to an elegant mathematically oriented discussion, based on a simplified model, of the factors controlling plasma volume. They were concerned chiefly with factors affecting the steady state distribution of water, prot ein, and soluble fluxes through the organism, regulation of total erythrocyte volume, and interactions between red cell and plasma volume. Their concluding paragraph on "Integration of Factors Controlling Blood Volume" indicated various possibilities for the interaction of reflex and humoral factors, a discussion which presaged the later more de­ tailed review by Farrell & Taylor (4). These authors emphasized the neuro­ endocrine aspects of blood volume regulation and "the emergence of a unify­ ing concept that certain elements of blood volume regulation (the control of water and electrolyte balance) may be by systems analogous to those for the maintenance of arterial