“Eels” of South America: Mid-18th-Century Dutch Contributions to the Theory of Animal Electricity

During the mid-18th century, when electricity was coming into its own, natural philosophers began to entertain the possibility that electricity is the mysterious nerve force. Their attention was first drawn to several species of strongly electric fish, namely torpedoes, a type of African catfish, and a South American “eels.” This was because their effects felt like those of discharging Leyden jars and could be transmitted along known conductors of electricity. Moreover, their actions could not be adequately explained by popular mechanical theories. Many of the early documents supportive of the hypothesis of animal electricity were associated with the Dutch colonies in South America. This article presents and examines those documents, and shows how Dutch scientists on both sides of the Atlantic conducted experiments and communicated with each other in the 1750s and 1760s. It reveals the important roles played by inquisitive physicians and lovers of nature in South America, and by natural philosophers and collectors of exotic specimens in the Netherlands—learned men who began to make a credible case for animal electricity in some exciting places at a pivotal moment in time.