Note 9 — SECTION I. Are the Phenomena, exhibited by the Application of certain different Metals to Animals, referrible to Electricity?

Since what I had before written upon this subject went to the press, I have been informed by a friend, that Dr Lind of Windsor has found, that contractions may be excited in a frog by touching it with iron alone. In a frog very recently killed, I have myself, sometimes, excited contractions, by touching its nerves with iron and steel in conjunction. But I can by no means consider this as a satisfactory proof, that contractions may be excited by the contact of one metal alone; since I have never been able to excite contractions with a piece of iron, of the same quality throughout, applied to a frog which had been so long dead as to leave no suspicion that the contractions were occasioned by mechanical irritation. In Dr Valli’s experiment, with scissars of bad steel, upon a frog recently killed, these circumstances do not appear to have been sufficiently attended to.