Abstract
The apparatus and technique used in the preparation and observation of explants of brain tissue capable of producing spontaneous potentials in vitro are described. The magnitude and pattern of spontaneous potentials from explants of telencephalon of 15 day chick embryos (measured using external bare platinum electrodes) and some aspects of their "normal" behavior during 12 days in vitro are also described. No change was noted in these potentials with change of amplifiers, recorders, or electrodes. The response of the potentials to change in temperature and proportionate composition of the atmosphere around the explant was such as to suggest that the potentials arise as a result of a living process. The changes brought about by the administration of anesthetics, strychnine, brucine, and barbiturates were those that might be anticipated in a normal functional activity of the central nervous system. It is concluded that these potentials are a true physiological phenomenon and arise from living cells of the central nervous system.