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Let there be two glasses of Water; in one of them let a thin plate of Silver
be plunged, and in the other a plate of Tin, which plates must touch each
other without the Glasses, or be made to communicate by the interposition
of another metal. Into the Water into which the Tin is plunged let the tip only
of the tongue be dipped; as yet no sensation of Taste will be perceived, but
as soon as the water in the other glass, which contains the Silver, is touched
with a finger, you will begin to perceive the usual acid taste; which will go on
increasing in proportion as you dip that finger more deeply into the water,
and afterwards the others, and then the whole hand, and will continue until
the circuit is interrupted in some part; either by taking the hand, or the tongue
out of the Water, or by taking away the metals. Either of these interruptions
is sufficient to make it cease; and the re-establishment of the contacts is also
sufficient to make it return.

Experiments of this kind succeed equally well with two, or three, or a
greater number of Persons, who make a circular chain; only the effects become
more weak in proportion as the circuit through which the electric fluid must
pass is longer; and that the contacts between these bodies are made either
in a few points, or in parts not very wet. In order to form such a continued
chain, therefore, let some of the Persons hold each other tightly by the Hands,
which should be wet; let another put the tip of his tongue into the water;
between two others let a prepared fro, g etc. make a link of communication;
finally let the two extreme persons, one of them grasping a flat piece of Silver,
the other a piece of Tin, bring these pieces to touch each other., At that instant,
the limbs of the frog, or frogs, if there should be more than one in the chain,
will be convulsed; and the tip of the tongue will perceive the acid taste if the
tongue is turned towards the tin, that is, towards the current which comes
from it. [4]

Let the experiment be repeated in such a manner that, between two
Persons a part only of the crural nerve of a Frog, or of the ischiatic nerve of
a Lamb (still united to the leg, and only laid bare, and separated from all
surrounding adherences) make a link of communication. That is to say, let one
Person hold firmly between two fingers, the end of this nerve, where it happens
to be cut off; and let the other person, in like manner lay hold of it with two
fingers, a little lower, before its insertion into the thigh; then, upon bringing
together the other two hands, one of them grasping a thin plate of silver,
the other a plate of tin, every time the two metals are made to touch each
other, the muscles of the frog or of the lamb, etc. are convulsed, and the leg
starts.