VOL. LXXXV.J PHILOSOPHICAL TRANSACTION^, 551 



made, were the fat and essential oils. Ether, from its similarity to alcohol, I 

 expected would also have concurred in the excitement of the influence, but it 

 did not; neither would it conduct the influence when excited by any other 

 means. I may remark however, that the ether I employed had been prepared 

 with great care; other ether therefore, less accurately made, may possibly be 

 found to contribute to the excitement of the influence, either from the unde- 

 composed alcohol, or naked acid, it may contain. 



Having thus given an answer to the first question, I proceed to the discussion 

 of the 2d. It has hitherto been maintained by every author, whose works I have 

 read on the subject of Galvani's experiments, and by every person with whom I 

 have conversed respecting it, that metals are the only substances capable, by 

 their application to parts of animals, of exciting the influence, which in those 

 experiments occasions the muscles to contract. But it appears rather extraor- 

 dinary, that none of those, who contend for the identity of this influence and 

 the electric fluid, have ever suspected, that the only very good dry conductor of 

 the latter which we know, besides the metals, possesses like them the property 

 of exciting the former. I confess however that it was not this consideration, 

 but accident, which led me to discover that charcoal is endowed with this pro- 

 perty, and in such a degree that, along with zinc, it excites at least as strongly 

 as gold with zinc, the most powerful combination, I believe, which can in this 

 way be formed of the metals. But to prevent disappointments I must mention, 

 that all charcoal is not equally fit for this purpose, and that long keeping seems 

 to diminish its power. 



It being shown that charcoal is also to be ranked among the exciters of this 

 influence, I shall now speak of the circumstances in which both it and the 

 metals must be placed, to fit them for the exercise of their power. With respect 

 to metals, Mr. Volta maintains, that to this end it is only necessary that 2 dif- 

 ferent species be applied to any other body which is a good conductor of elec- 

 tricity, and that a communication be established between the 2 metallic coatings. 

 But charcoal is a much better conductor of electricity than water, and yet metals 

 in contact with it alone will not excite. Again, Mr. Volta says, that the simple 

 application of 2 metals to 2 parts of an animal, disturbs the equilibrium of the 

 electric fluid, and disposes it to pass from one of the parts to the other, which 

 passage actually takes place as soon as a conductor is applied between the metals. 

 But what should prevent the passage of the fluid before the application of a new 

 conductor, since the metals were already connected by means of the moisture of 

 the animal? Further, a consequence of this opinion is, that if the under sur- 

 faces of 2 different metals be placed in moisture, and their upper surfaces be af- 

 terwards connected by means of a nerve, still attached to its muscle, contractions 

 ought then to be produced ; since the whole quantity of the electric fluid neces- 



