[ 99 ] 
tnufcles are occafionally in a flate^of ftiff* 
nefs and tenlion, at which time the move¬ 
ments are languid and tranfient. At other 
times, the movements occur as in the moil 
animated frogs. 
Four of thefe frogs prefented a lingular 
phenomenon. At the firff contact of the 
exciter they were much agitated, but be¬ 
came motionlefs after three or four fhocks. 
For a few minutes they were left to 
themfelves. I afterwards endeavoured ta 
excite them, but without fuccefs. Not* 
withftanding in frogs, and in general in 
all animals, the movements ceafe gradually 
by little and little. 
It is impoffible that the nerves Ihould 
lofe their conducting power all at once 
without any evident caufe, and the mufcles 
their vis infita. 
There exilts in the animal economy a 
principle of life which prevents the equi¬ 
librium of the electricity to be eftabli£hed, 
H 2 and 
