70 



without mechanical confinement. Will 

 not a wire when electrified continue to 

 be so, if surrounded by non-conductors ? 

 Experiments made on the limbs of ani- 

 mals with electricity, produced in the 

 manner first explained by Volta, shew 

 that different parts of the body have dif- 

 ferent conducting powers. Skin and mem- 

 brane being very bad conductors, and 

 brain, muscle, and blood being remarkably 

 good ones. 



The celerity with which motions are 

 transmitted from the tangible extremities 

 of nerves most distant from the brain, 

 and the celerity with which volition is 

 transmitted to the muscles, in consequence 

 of sensations thus induced, are sufficient 

 to convince us that such effects must be 

 produced by the motions of a very mo- 

 bile substance. It is not necessary to 

 suppose that when such motions are trans- 



