[ 42 ] 
ments, one fhould at leaft have the con¬ 
ductor of a different metal ; I fay at leaft, 
for that is not always fufficient. Amongft 
the different metals, there are fome more 
proper for the experiment than others. 
There are others, like wife, that are very 
improper, when the animal is feeble, and 
its vitality about to difappear. 
That I may convey a more precife idea 
of this matter, I flaall make a recital of 
the fet of experiments I had the honour to 
make before the CommilTaries of the 
Academy of Sciences at Paris, or rather 
of thofe we made together. 
Experiment XXII. 
The crural nerves of a frog were placed 
upon a piece of gold, and the thighs put 
in contaCl with a piece of filver. A cop¬ 
per conductor produced flight movements. 
Two coatings of filver did the fame, by 
means of the fame conductor. 
When 
