27,6 EXPERIMENT'S relating to 



" and as the circulation of the Leyden phial fuppofes two con- 

 " trary electricities, the one more condenied or pofitive, and 

 " the other lefs fo or negative, fo Profeifor Galvani concludes, 

 " that a limilar diftinction takes place in the bodies of animals, 

 " and that one of thefe electricities, to wit, the condenfed or 

 '* pofitive, is feated in the nerves, and the other in the mufcles *." 



Hence both of them have conceived it neceffary, to eftablifh 

 a communication between the nerve and the mufcle, by means 

 of metalline coating of the nerve and pieces of metal and me- 

 talline conductors ; or by coating the nerve with lead or tin v 

 then laying one piece of filver in contact with the tin, and ano- 

 ther in contact with the mufcle ; and, in the laft place, efta- 

 blilhing a communication between the two pieces of metal, or 

 between the nerve and the mufcle, by means of a brafs-wire, 

 which they term a conductor' f. 



But, inftead of this complex apparatus, I have found, from 

 the above experiments, that the mufcle is thrown into action, 

 although no metal is directly in contact with it, or when the 

 communication between the metals and the mufcle is made by 

 the nerve alone. 



It appears therefore, that ProfefTor Galvani and Dr Valli 

 have allowed preconceived theory to conduct their experiments, 

 inftead of allowing their experiments to conduct their theory; 

 in confequence of which, feveral of their experiments have 

 been performed with lefs accuracy than might have been ex- 

 pected. Thus, they tell us. that if the conductor is firft applied 

 to the mufcle, the convulfions are ftronger than when it is 

 firft applied to the nerve ; that the ihocks are ftronger when the 

 feet communicated with the earth, i$c. whereas the application 

 of the conductor to the mufcles, or of the feet to the earth, are 

 quite out of the queftion. 



2. Wfi 



* See Medical Fads and Obfervations, Lend. 1792. p. 187, 188. 



f Ditto, p. 187. 191. 211. 



