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SS G@ALVANISM. 
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Gatvanism is a branch of natural philosophy, which 
_ has originated within the last twenty-five years, and 
derives its name from Galvani, professor of anatomy at 
Bologna. He had the good fortune to make some ob- 
servations on the electricity of the muscles of frogs, 
that appeared to him to depend upon a new power in 
the animal body ; and although it is now generally ad- 
mitted, that he drew an erroneous inference from his’ 
they led to'a train of experiments, 
which have A ockaned | his name with some: of the most 
brilliant discoveries of modern science. To the sup- 
posed new power he gave the name of animal electricity, 
conceiving it to depend upon something inherent in the 
animal body itself; but we now re, na these effects as 
produced by minute quantities of the electric fluid, set 
. Part I. 
Secr, I. Experiments before the Discovery of the Pile. 
Tue original discovery, to which we have already 
alluded, took place from a singular accident. The wife 
of the philosopher, being in a declining state of health, 
employed as a restorative, according to the custom of 
the country, a soup made of frogs. A number of these 
animals, ready skinned for the purpose of cookery, 
chanced to lie in Galvani’s laboratory, on a table near 
the electrical machine. While the machine was in ac- 
tion, an attendant happened to touch, with the point of 
a scalpel, the crural nerve of one of the frogs, that was 
not far from the prime conductor, when it was obser- 
ved, that the muscles of the limb were instantly thrown 
into strong convulsions. This experiment was perform- 
ed in the absence of the Professor, but it was noticed 
- by his lady, who was much struck with the appear- 
ance; and communicated it to her husband. He re- 
peated the experiment, varied it in different ways, and 
perceived that the convulsions only took place when a 
at liberty by a certain agency of substances upon each. In 
other, 
Galvanism may be defined, a series of electrical phe- 
nomena, in which the electricity is developed without 
the aid of friction, and where we perceive a chemical 
action to take place between some of the bodies em- 
ployed. ; 
Nn treating upon this subject, we shall arrange our Plan of the 
We shall erring, am article. 
materials into two divisions. 
historical detail of the discoveries that have been suc- 
cessively made, ‘from the time of Galvani’s first obser« 
vation, to the present period ; and, in the second place, 
we shall give an account of the theories and hypotheses 
that have been formed to explain the phenomena of 
galvanism. 
HISTORY. 
ly so called. ‘Having suspended a number of fro 
y metallic hooks to an iron railing, he found that the 
limbs were frequently thrown into convulsions, when 
it did not appear that there was any ates in the 
atmosphere. Having duly considered this phenome- 
non, he discovered that it did not originate from an 
extraneous electricity, but that it depended upon the 
position of the animal, with respect to certain metallic 
bodies. 
It appeared, that when the muscle and nerve of a Action of 
frog were each in contact with metallic bodies, and these two metals. 
were also connected by a metal, the contractions were 
always produced. The effect was considerably increased 
by arming the nerve with a metallic coating, by which 
means a larger portion of it was brought into contact 
with the metal. But the most important of Galvani’s 
discoveries was the effect produced by the combination 
of two metals. Of these combinations the most power- 
ful was that of zine and silver, and the most violent 
convulsions ensued when the nerve was coated with one 
PLaTe 
spark was drawn from the prime conductor, while the 
I of these metals, the muscle placed in contact with the o¢p xy, 
nerve was, at the same time, touched with a substance 
other, and the two metals connected by a conductor of Fig. 19. 
which was a conductor of electricity. At the time that 
this accidental discovery was made, Galvani was en- 
gaged in a set of experiments, the object of which was 
to prove, that muscular motion depends upon electri- 
city ; and it appeared, in a very remarkable manner, 
to confirm his hypothesis ; so that he was induced to 
te the inquiry with redoubled diligence. See 
de Galvani, par Alibert. 
1en a frog was so placed as to form part of’ the 
electric circuit, it was found that an extremely minute 
quantity of electricity produced contractions in the 
* muscles, If the hind legs were dissected from the body, 
the connection being kept up by the crural nerves only, 
and the electric fluid was passed through it in this state, 
a still more minute quantity ruacesdaved visible ; so 
that a frog, ed in this manner, was. capable of 
exhibiting very decisive marks of electricity, where none 
could be detected by Bennet’s gold-leaf electrometer. | 
After employing the electric fluid, as disengaged from 
the common machine, he next tried the atmospherical 
electricity ; and it was in pursuance of this object, that 
he was first Jed to observe the effects of galvanism pro- 
electricity. 
Galvani’s general conclusion from his experiments 
was, that the animal body possesses an inherent elec- General 
tricity of a specific kind, which is connected with the conclusions, 
nervous system, and conveyed by means of the metals 
into the muscles, so as to throw them into: convulsions. 
He deduced a theory of muscular motion from his dis- 
coveries, according to which the body contains an ap- 
paratus analogous to the Leyden phial, the muscles and 
nerves being in different states of electricity, and the 
metals forming a connection between them, by: which 
the electricity is equalized. In this raiser? of the 
new phenomena, Galvani went beyon 
correct deduction ; yet he deserves much commendation 
for the perseverance and ingenuity which he exhibited 
in prosecuting the inquiry.. Although the discovery 
originated, in.a considerable degree, from accident) still 
it must be remembered, that it is only men of ability 
who take advantage of such accidents. In the year 
1792, he published an account of his discoveries and 
theories, under the title of A Commentary on the Powers 
of Electricity in Muscular Motion. 
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