Figure 1.

A semilogarithmic graph of the disappearance of ¹²C¹⁸O¹⁶O, mass 46, with time, in the presence of intact human red blood cells at 37°C and pH 7.4, from the Philadelphia experiments. At time zero, dry NaHCO₃ 2% enriched with ¹⁸O to produce 25 mM was added to 125 mM saline and at the arrow, an aliquot of the red cell suspension producing a v of 0.0013 in the control (open circles) and 0.00121 in the DIDS (solid circles) experiment. For the control graph (experiment 25, run 8) and DIDS graph (experiment 25, run 3), the SRs were 3.1 and 3.2 and n’s for the regressions were 0.014 and 007 sec⁻¹, respectively.