[ 25 ] 
force. It is proper to obferve, that I 
could not obtain from any of thefe three 
frogs the fmalleft mark of eledtricity, 
when I touched the coating of the fpine, 
or any part of the nerves, anterior to their 
infertion into the mufcles ; but by put¬ 
ting the coating lower down, the move¬ 
ments took place in a manner fufficiently 
evident. I have not met with any that' 
have retained this power longer than 
twenty-four hours, nor any in which it 
has difappeared in lefs than four. If pre¬ 
pared frogs be left in water, their mufcles 
become impregnated with it, and lofe 
their irritability in lefs than four hours. 
Animals with warm blood are not proper 
for this kind of experiment. I have often 
left the wings of fowls prepared for a quar¬ 
ter of an hour, and they have only given 
a few flight tremblings, and fometimes 
none at all. If, however, their eledtricity 
he excited immediately after they are pre¬ 
pared, 
