Johann Georg Sulzer (1720-1779) [Wikipedia]
Taste of Electricity "Battery Tongue Test"
Johann Georg Sulzer tasted pieces of lead and silver together. He stated, "a pungent sensation that reminds me of the taste of green vitriol (Iron (II) sulfate, FeSO4-7H2O) when I placed my tongue between these metals." Sulzer thought that the cause is a “vibratory motion” of the metal atoms, which make some interactions with the nerves of the tongue. He had found this phenomenon before Volta but did not connect the phenomenon with electricity.

Johann Georg Sulzer
Recherches sur l’origine des sentimens agréables et désagréables. Troisième partie. Des plaisirs des sens
Histoire de l’Académie Royale des Sciences et des Belles-Lettres de Berlin, Anné MDCCLII
(Haude et Spenner, Berlin, 1752) pp. 350-372. (in page 356)
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