801 
171)1, a very remarkable discovery made by 
Dr. Gal vani of Bologna was announced to 
the scientific world in a publication entitled, 
Aloysii Galvani de Viribus El ectricitatis in 
motu musculariCommentarius. Bononia;l79l. 
1 he discoveries of Galvani were made 
principally with dead frogs. He in the first 
place discovered that, a frog dead and skin- 
ned, is capable of having its muscles brought 
into action by means of electricity, even in 
exceedingly small quantities. 
Secondly, that independant of any appa- 
rent electricity, the same motions may be 
produced in the dead animal, or even in a 
detached limb, merely by making a commu- 
nication between the nerves and the muscles, 
with substances that are conductors of elec- 
tricity. If the circuit of communication 
consists of non-conductors of electricity, as 
glass, sealing-wax, and the like, no motion 
will take place. Similar experiments were 
also successfully instituted upon other ani- 
mals ; qnd as the power seemed to he inher- 
ent in the animal parts, those experiments, 
of the power which produces the motion of 
the muscles in those experiments, were deno- 
minated animal electricity. But it being now 
fully ascertained, that by the mere contact 
of metallic and other conducting substances, 
some ^electricity is generated, it is evident 
that the muscular motions in the above-men- 
tioned experiments are produced by that 
electricity ; hence we have confined the 
name of animal electricity to denote the 
power of the fishes which give the shock, 
&c. as described in a preceding article. (See 
Electricity.) And, at least for the pre- 
sent, we shall examine the electricity which 
is produced by the contact, or by the’ action, 
of metallic and other conducting substances 
upon each other, under the title of galvan- 
ism ; though in truth Galvani’s discoveries 
go no farther than what relates to certain 
effects of the contact of animal parts princi- 
pally with metallic. We shall briefly de- 
scribe the several facts which relate to the 
above-mentioned sort of muscular motion, 
and shall then proceed to those which refer 
to the wonderful effects of the mere contact 
or action of one conducting substance upon 
another, amongst which the metallic are the 
most conspicuous. 
The action of electricity on a frog, recent- 
ly dead and skinned, (and indeed on other 
animals more or less) occasions a tremulous 
motion of the muscles, and generally an ex- 
tension of the limbs. 
Dr. Galvani used to skin the legs of a frog 
recently dead, and to leave them attached to 
a small part of the spine, but separated from 
the rest of the body. Any other limb may 
be prepared in a similar manner ; viz. the 
limb is deprived of its integuments, and the 
nerve which belongs to it is partly laid 
bare. 
If the limbs thus prepared, for instance 
the legs of a frog, are situated so that a little 
electricity may pass through them, be it by 
the immediate contact of an electrified body, 
or by the action of electric atmospheres (as 
when the preparation is placed within a cer- 
tain distance of an electrical machine, and a 
spark is taken from the prime conductor) ; 
the prepared legs will be instantly affected 
with a kind of spasmodic contraction, some- 
times so strong as to jump a considerable wav. 
VOL. I. 
GALVANISM. 
[ When the electricity is caused to pass 
through t’ne prepared frog by the immediate 
contact of the electrified body, a much small- 
er quantity -of it is sufficient to occasion the 
movements, than when it is made to pass 
from one conductor to another, at a certain 
distance from the prepared animal. 
The movements are much stronger when 
the electricity is caused to pass through a 
nerve to the muscle or muscles, than through 
any other part. 
The sensibility of the prepared animal is 
greatest at first, but it diminishes by degrees 
tid it vanishes entirely. Animals with cold 
blood, and especially frogs, retain that sen- 
sibility for several hours, sometimes even 
tor a day or two. With other animals the 
sensibility does not last long after death, and 
sometimes not above a few minutes. 
The like movements may be produced in 
the prepared animal without the aid of any 
apparent electricity. In an animal recently 
dead, detach one end of a nerve from the 
surrounding parts, taking care to cut it not 
too near its insertion into the muscle ; re- 
move the integuments from over the muscles 
which depend on that nerve ; take a piece 
of metal, as a wire, and touch the nerve 
with one extremity of it, and the muscles 
with its other extremity ; on doing which you 
will find that the prepared limbs move in the 
same manner as when some electricity is 
passed through them. This, however, is not 
the most effectual way of forming the com- 
munication ; yet it will generally succeed, 
and the experiment will answer whether the 
preparation is laid upon conductors or upon 
electrics. 
If the communication between the nerve 
and the muscle is formed by the interposition 
of non-conductors of electricity, such as 
glass, sealing-wax, &c.' then no movements 
will take place. 
When the application of the metal or me- 
tals is continued upon the parts, the contrac- 
tions will cease after a certain time, and on 
removing the metal, seldom, if ever, any 
contraction is observed. 
The conducting communication between 
the muscle and the nerve may consist of one 
or more pieces, and of the same or, much 
better, of different bodies connected toge- 
ther, as metals, water, a number of persons, 
and even wood. But it must be observed, 
that the various bodies, which form tills cir- 
cuit, must be placed in full and perfect con- 
tact with each other, which is done by pres- 
sure, or by the interposition of water, &c. 
The less perfect conductors will answer only 
at first, when the prepared animal is vigor- 
ous ; but when the power begins to diminish, 
then the more perfect conductors only will 
answer, and even these will produce various 
effects. 
The most effectual way of producing those 
movements in prepared animal parts is by 
the application of two metals, of which sil- 
ver and zinc seem upon the whole to be 
best, though silver and tin, or copper and 
zinc, and other combinations, are not much 
inferior. If part of tire nerve proceeding 
from a prepared limb is wrapped up in a bit 
of tin foil, or only laid upon zinc, and a 
piece of silver laid with one end upon the 
bare muscle, and with the other upon the 
above-mentioned tin or zinc, the motion of 
the prepared limb will be very vigorous. The 
5 I 
two metals may he placed not in contact 
with the preparation, but in any other part 
of the circuit, which may be completed by 
means of other conductors, as water, &c. 
The best preparation for this experiment 
is made in the following manner: 
Separate with a pair of scissars the head 
and upper extremities of a frog from the rest 
of the body. Open the integuments and 
muscles of the abdomen, and remove the 
entrails, by which means you will lay bare 
the crural nerves. Then pass one blade of 
the scissars under the nerve, and cut off - the 
spine with the flesh close to the thighs, by 
which means the legs will remain attached 
to the spine by the nerves alone. This done, 
leave a small bit only of the spine attached 
to the crural nerves, and cut off all the rest. 
Thus you will have the lower limbs G, II, 
(fig. 1, Plate Galvanism) of the frog adhering 
to the bite of spine A B, by means of the 
crural nerves C, D. These legs must be 
flayed in order to lay bare the muscles ; and 
a bit of tin foil should be wrapped round the 
spine A B. With this preparation the ex- 
periment may be performed in various ways, 
but the two which follow are the best. 
Hold the preparation by the extremity 
of one leg, the other leg hanging down, with 
the armed bundle of nerves and spine ly- 
ing upon it. In this situation interpose a 
piece of silver, as a half-crown, between 
the lower thigh and the nerves, so that it 
may touch the former with one surface, and 
the metallic coating of the latter with the 
other surface, or with its edge ; and you 
will find that the hanging leg will vibrate 
very powerfully, sometimes so far as to 
strike against the hand of the operator, 
which holds the other leg. 
Otherwise, place two wine-glasses, both 
full of water, contiguous to each other, but 
not actually touching. Put the thighs and 
legs of the preparation in the water of one 
glass, and laying the nerves over the edges 
of the two glasses, let the bit of spine with 
its armour (viz. tin foil) touch the water of 
the other glass. Things being thus' pre- 
pared, if you form the communication be- 
tween the waters of the two glasses, by 
means of silver, or put the fingers of one 
hand into the water of the glass that contains 
the legs, and holding a piece of silver in 
the other, you touch the coating of the 
nerves with it, you will find that the pre- 
pared legs, move so powerfully as sometimes 
to jump fairly out of the glass. ■ 
Fig. 2 represents a prepared frog sus- 
pended on a metallic wire, and parallel to the 
animal, a metallic chain. When the receiver 
x is exhausted, on pushing down th erod so 
that the nerve of the frog and the chain 
may touch the metallic plate z at the bot- 
tom, the frog is convulsed as in the open air. 
By the application of armours of different 
metallic substances, and forming a commu- 
nication between them, the motions may be 
excited even in an entire living frog, as also 
in some other living animals, particularly 
eels and flounders. The living frog is placecl 
upon a piece of zinc, with a slip of tin foil 
pasted upon its back. This done, whenever 
the communication is formed between that 
zinc and the tin foil, especially if silver is used, 
the spasmodic convulsions are excited, not 
only in the muscles which touch the metallic 
substances, but likewise in the neighbouring 
