In the preceding chapters, various agents of nerve action were put forward to account for the rapidity with which nerves conduct sensations and produce motor responses as occurs in a reflex such as that in the example given by Descartes (Chapter 5), where a foot is burned and rapidly withdrawn even before the pain is sensed. The various new physical principles and chemical entities discovered in the Renaissance were advanced to serve this function, but failed to fit all the properties of nerve action. Electricity had properties that suggested that it might be the long sought-for agent of nerve action. It was invisible and imponderable; acting with lightning speed and having profound excitatory actions on the nerves and muscles. How electricity came to be accepted as the agent of nerve conduction is the theme of this chapter. Its history can be divided into three periods. The first period extended from ancient times to that of Galvani at the turn of the eighteenth century when electricity was generated as a static discharge and its potent effects on the body experienced. The second period extends from the introduction of the battery by Volta after the turn of the nineteenth century, when the flow of current in body tissues was investigated, though not differentiated from electrical conduction in metals.