||P.5 bottom paragraph: "Extracellular Fluid Volume (ECV) and Exchangeable Amount of Sodium. (Na[ex]). These parameters have been measured in selected species. Ruch and Hughes (1975) determined the ECV as the Br82 space. This ion is, like the CI ion, largely distributed in the ECV. The authors investigated domestic ducks maintained on either fresh water (FW) or salt-water (SW), and both glaucous-winged gulls (Larus glaucescens) and roosters offered FW. The following values of ECV were found: Ducks (FW), 24.9% of body weight ducks (SW), 26.4%, gulls, 38.2% and roosters, 28.8%. The values for roosters and ducks are similar to those observed in mammals. The high value in glaucous-winged gulls is in agreement with the unusually high value of TBW (Total Body Water) obtained in this species (Table 1.2)."