The historical route to present-day patch clamping started with the scientific recognition that electrical phenomena are part of animal physiology. This bioelectricity was demonstrated in the nineteenth century in frogs, where muscle movements could be evoked by applying electrical stimuli to the animal. The recording of inherent electrical activity can be charted by the development of increasingly sophisticated electrodes. Long before anything was known about ion channels, membrane potentials were recorded using crude glass electrodes in the few preparations where this is possible, most famously the squid giant axon (Hodgkin and Huxley, 1952). To measure membrane potential in other preparations, much finer electrodes were needed. Graham and Gerard (1946) produced.
