This article discusses the electrical properties of biological membranes, including potential, impedance, and rectification. It explores how these properties are influenced by the composition of the external medium, the physiological state of the cell, and the movement of ions. The study uses both direct and alternating current measurements to determine the conductance and capacitance of membranes, which are modeled as parallel resistance-capacitance combinations. The article also describes the phenomenon of rectification, where the conductance of a membrane may vary depending on the direction of the current. This has been observed in various biological systems, including the squid giant axon and frog muscle. The article also discusses the structural properties of biological membranes, noting that they are likely composed of protein and phospholipid, with possible organized arrangements of these elements. The study of these properties has been complicated by the difficulty of analyzing biological membranes, but some progress has been made using artificial membranes, such as collodion membranes. The article describes the preparation and testing of these membranes, including the use of a bridge circuit to measure impedance over a wide frequency range. The results show that the capacitance of membranes is relatively constant and independent of physiological state, while the conductance and potential depend on ion mobility and concentration. The rectification observed in these membranes under moderate concentration gradients was found to be small, indicating the need for more sensitive measurement techniques. The study also discusses the theoretical basis for these findings, including the use of kinetic theory to explain the behavior of ions in membranes. The article concludes that while the data obtained from these studies are not yet sufficient to fully explain the electrical properties of biological membranes, they provide valuable insights into the behavior of these systems. The results suggest that the electrical properties of membranes can be understood in terms of physical factors rather than purely metabolic ones. The study also highlights the importance of further research into the properties of artificial membranes and the potential for developing materials that can more accurately mimic the behavior of biological membranes.This article discusses the electrical properties of biological membranes, including potential, impedance, and rectification. It explores how these properties are influenced by the composition of the external medium, the physiological state of the cell, and the movement of ions. The study uses both direct and alternating current measurements to determine the conductance and capacitance of membranes, which are modeled as parallel resistance-capacitance combinations. The article also describes the phenomenon of rectification, where the conductance of a membrane may vary depending on the direction of the current. This has been observed in various biological systems, including the squid giant axon and frog muscle. The article also discusses the structural properties of biological membranes, noting that they are likely composed of protein and phospholipid, with possible organized arrangements of these elements. The study of these properties has been complicated by the difficulty of analyzing biological membranes, but some progress has been made using artificial membranes, such as collodion membranes. The article describes the preparation and testing of these membranes, including the use of a bridge circuit to measure impedance over a wide frequency range. The results show that the capacitance of membranes is relatively constant and independent of physiological state, while the conductance and potential depend on ion mobility and concentration. The rectification observed in these membranes under moderate concentration gradients was found to be small, indicating the need for more sensitive measurement techniques. The study also discusses the theoretical basis for these findings, including the use of kinetic theory to explain the behavior of ions in membranes. The article concludes that while the data obtained from these studies are not yet sufficient to fully explain the electrical properties of biological membranes, they provide valuable insights into the behavior of these systems. The results suggest that the electrical properties of membranes can be understood in terms of physical factors rather than purely metabolic ones. The study also highlights the importance of further research into the properties of artificial membranes and the potential for developing materials that can more accurately mimic the behavior of biological membranes.