CHAP. I. GALVANI. 3 



of the electric organ to that of a Leyden jar. 

 "The electricity of the Torpedo," he says, "is 

 entirely due to the batteries ; their upper and under 

 surfaces are capable, from a state of electric equi- 

 librium, of being instantly thrown, by a mere energy, 

 into a plus and minus state, like that of a charged 

 phial, and the current results from a conducting 

 medium between their opposite surfaces being sup- 

 plied naturally or artificially." 



Since that period, several philosophers have under- 

 taken the examination of the electric power of the 

 fish, and the identity between these two powers, 

 that of the fish and of ordinary electricity, has been 

 satisfactorily proved ; attraction and repulsion have 

 been obtained, the galvanometer has been affected, 

 chemical decomposition produced, and magnets made ; 

 but even at this early period, some of the most 

 important facts connected with animal electricity 

 were well known; and, without intending to de- 

 preciate the labours of Galvani, men's minds were 

 well prepared at his time to seize upon any new fact 

 that might arise. 



In 1791, Galvani published his celebrated Com- 

 mentary, entitled, De Yiribus Electricitatis in motu 

 muscvlari Commentarius ; but prior to that he was 

 evidently well acquainted with the circumstance, 

 that the discharge from an electrical machine would 

 produce convulsions in a frog. This discovery has 

 been attributed to chance ; to the circumstance, that 

 some frogs had been prepared for making broth for 



