“…Therefore, in the studies here described all determinations were carried out simultaneously, and were repeated serially at given intervals. Furthermore, the reliability of the substances used in this study to measure the various fluid compartments, viz., deuterium oxide, inulin and I1,1-tagged human serum albumin has been confirmed by many workers (13,15,16,(23)(24)(25)(26)(27)(28)(29). The use of the volume of distribution of the thiosulfate ion as a measure of extracellular fluid volume has been suggested by Cardoza and Edelman (19) and in the present study there was excellent experimental agreement between the thiosulfate and inulin spaces whenever these two measurements were carried out simultaneously.…”