504 
fpark to be taken from the machine, the 
fame phenomenon appeared again. On 
repeating the experiment with the fame 
knife, the motions were /ometimes ftronger, 
fometimes weaker, and fometimes difap- 
peared entirely, which was found to arife 
from the manner in which he happened to 
hold the knife, becaule, when he held the 
handle, which .was of bone, the animal 
remained motionlefs, but as foon as he 
touched the metallic part, the contractions 
were immediately produced. In order to 
determine whether this phenomenon did - 
depend on the idioeleGtric nature of the 
dry bone, or on the conducting property 
of the metal, Mr! Galvani changed the 
knife for a clean glais tube, and for an 
iron cylinder, but the above phenomenon 
never appeared on applying the glafs 
tube to the nerve, even when very ftrong 
{parks were drawn, whereas it was imme- 
diately produced by the leaft {park on ap- 
plying the iron cylinder. Thus Mr. Gal- 
vani found it confirmed, that for pro- 
ducing the above phenomenon the contact 
of a conduéting body with the nerve was 
requifite. When the iron cylinder was 
applied to the nerve, without being held 
by the hand of any body, the drawn {park 
occafioned ne motion, whereas the con- 
traction came on when, inftead of the cy- 
linder, he took a long iron wire, fo that 
a certain length and extenfion of the con- 
ducting body fcemed to be required for 
effecting the above phenomenon. Thefe 
conduéting bodies were called by Mr, 
Galvani nervous conduétors. ‘The expe- 
yiment likewife lucceeded at a difiance, by 
very long infulated conductors, in animals 
prepared for that purpoie, particularly 
when a condu€ling tube was hung at the 
feet of che frog, communicating with the 
floor; “thefe conductors he diltinguifhed 
by the name of mufcular conductors.— 
After having made a great number of ex- 
periments in a different manner, viz. by 
interrupting the free courfe of eleCtricity, 
by coating the nervous conductors to their 
ends, with an eleétric fubftance, and b 
applying negative electricity, the electro- 
pnor, &c. the effegt of atmofpherical 
electricity’on mulcplar motion remained 
to be examined. To this end he raifed a 
long and proper conductor, which was 
infulated, on the roof of a houfe, from 
which frogs, or the legs of warm-blooded 
animals, were hung by the nerves; an- 
other conduétor being attached to their 
feet went into the water of a well. As 
foon as it began to lighten, the mufcles 
were leized with violent and repeated con- 
- traétions, which, like the lightning, pre- 
Hiftorical Account of Galvanifins 
[Jan 1, 
_ceded the thunder; thefe contractions did 
even enfue when no muicular conductor 
had been applied, and the nervous con- 
duétor was not infalated. They were even 
obferved when the conductor was railed 
on lower places, and in gloomy weatter. 
The experiments fucceeded with dead 
animals as well as with living, but the 
mere lightning, without thunder, pro 
duced no movements. ei 
Thefe curious experiments happened to 
give rife to the proper Galvanic difcovery. 
Mr. Galvani being curious to know what 
effe& atmofpherical electricity might have 
in quiet and clear weather, He fulpended 
fome frogs on metal hooks, fixed in the 
{pine of the back, from the iron-rails of 
his garden, and he obferved thofe contrace 
tions, not only when it lightened, but 
alfo in clear and quiet weather. At firft 
he thought that the caufes of thefe con~ 
traGtions might arife from changes in the 
electricity of the atmof{phere, but upon a 
more minute examination he found, that 
on bending the hook with which the {pinals 
marrow was perforated, towards the iron- 
rails, in order to fee whether mufcular- 
motion might be thus produced, and 
whether any difference or change in the 
ftate of atmofpherical electricity would | 
manifeft itfelf, he began to conceive, that 
the contractions did not relate to this ftate 
of the atmofphere. Having, however, 
only feen thefe contractions take place*in 
open air, he was, notwithfanding, in- 
clined to afcribe them to the atmofpheri- 
cal eJe&tricity, which running over into 
the animal, may there be accumulated, 
and he imagined, that hence it might be 
vehemently difeharged at the conta& of 
the hook with the iron-rail, but he was 
foon undeceived. Having placed a frog 
upon an iron-plate in his room, he hap- 
pened to prefs it againft the plate with his 
diffeCiing forceps, whereon immediately 
the contraétions took place. The experi- 
ment fucceeded with all metals, but never 
on employing non condutting fubftances, 
Indaced by thefe experiments, our author 
began to fufpeét the animal to poffefs an 
electricity of its own, a conjecture which 
appeared to him to be confirmed by the 
phenomena of a circulation from che nerves 
to the mufcles, fimilar to that taking place 
in the Leyden phial. For on holding a 
frog that had been previoufly prepared for - 
the experiment, by a hock fixed in the 
{pine of the back, with one hand, fo as to 
Jet the feet reach a {mall filver cup, and 
on touching the cup with the other-hand, 
by means of a metallic body, the animal 
fell into violent convulfions. If one Hes 
cn 
