||P.778 right column bottom: "The ability of methylamine to raise intracellular pH in the Xenopus embryo was tested in six batches of eggs. Measurements with pH-sensitive microelectrodes
in control embryos gave a mean intracellular pH of 7.81±0.018 (±1 standard error, n = 55), closely similar to that observed by Turin & Warner (1980). As found previously, there was considerable variation from embryo to embryo and batch to batch (lowest batch average: pH7.67, highest batch average: pH7.94)." The authors found that batches of embryos varied extensively in intracellular pH - the range is the lowest and highest averages from 6 batches of embryos.