From the temperature dependence of the impedance dispersion in dipalmitoylphosphatidylcholine liposomes, we reported that halothane decreased the apparent activation energy of the lateral surface conductance of phospholipid vesicles (Yoshida et al. Biochim. Biophys. Acta 1990, 1028, 95; Yoshino et al. Biochim. Biophys. Acta 1992, 1107, 55). However, the presence of proton flow within the electrical double layer at the lipid-water interface has been a matter of controversy. The difference in interpretation on two-dimensional proton flow is focused on imperfection in the experimental procedure, in particular, change of the meniscus of water surface at the electrode and the trough caused by monolayer formation, which changes the effective surface area of the electrode, pH instability due to local CO2 concentrations, polarization by the accumulation of ions on the electrode surface, and temperature instability. We designed a novel horizontal-plate electrode, totally immersed in water, to eliminate formation of meniscus. Together with elimination of CO2 in a completely enclosed measuring system and careful temperature control, we obtained conclusive results on the existence of lateral surface electric conductance. Alcohols (ethanol, I-propanol, and l-butanol) increased the surface electrical conductance at low concentrations and decreased it at high concentrations that induce anesthesia. Similar electrical conductance may exist at protein surfaces among charged amino acid side chains.