ANIMAL ELEC?RICI?r. 233 



convulfions were much lefs obfervable, when lead, iron or cop-- 

 per were fubftituted inftead of thefe. 



Experiment II. 



I next tried all the above mentioned experiments with one 

 half-crown piece only, placed oppofite to the tinfoil ; and on 

 preffing the tinfoil againft the filver-piece, by means of a brafs- 

 wire which I held in my hand, I found, that the mufcles were 

 convulfed exactly in the fame manner as where two pieces of 

 the filver were employed in the manner before mentioned. 



Experiment III. 



I found likewife, that the experiment fucceeded equally well, 

 although the filver-piece did not touch the body of the animal, 

 but was merely brought into contact with the tinfoil put around 

 the nerve, by prefTure with a brafs-wire held in the hand. 



Experiment IV. 



After inclofing the Upper part of the fciatic nerve in tinfoil, 

 I tied a linen-thread around it, where it is about to pafs from 

 the trunk into the thigh, fo tight as to deprive the mufcles of 

 their power of acting by the ordinary exertions of the animal, 

 and the fkin and toes of their feeling, yet when, with a brafs- 

 wire held in my hand, I prefTed the tinfoil againft the iilver- 

 piece, the mufcles of the limb were violently convulfed* 



Vol, III. Gg Expb^ 



