An Account of the Late Improvements in Galvanism: With a Series of Curious and Interesting Experiments Performed Before the Commissioners of the French National Institute, and Repeated Lately in the Anatomical Theatres of LondonAldini, Giovanni
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An Account of the Late Improvements in Galvanism: With a Series of Curious and Interesting Experiments Performed Before the Commissioners of the French National Institute, and Repeated Lately in the Anatomical Theatres of London
Aldini, Giovanni
Electricity -- Early works to 1850
1st, In arming the spinal marrow by means of a cylinder of lead
introduced into the canal of the cervical vertebræ, and then conveying
one extremity of a silver arc over the surface of the heart, and the
other to the arming of the spinal marrow. The heart of the first
individual subjected to our experiments immediately exhibited very
visible and very strong contractions. These experiments were made
without the intervention of any kind of pile, and without any armature
applied to the heart. It is very remarkable, that when the former is
touched first, and then the arming and spinal marrow, the contractions
of the heart which follow are more instantaneous, and stronger, than
when the arming of the spinal marrow is first touched, and then the
heart. In a memoir on Galvanism, read in the last public sitting of
the academy, I gave an account of a great number of experiments, made
especially on frogs, which exhibited a similar phænomenon. In these
animals I observed, a great number of times, that when the arming of
the crural nerves was touched first, and then the muscles of the
thigh, there were no contractions, or the contractions were
exceedingly weak; and, on the other hand, that when the muscles of the
thighs were first touched, and then the arming of the crural nerves,
as long as the least vitality remained in the organs, the contractions
of the muscles were constant and violent. In the memoir already
mentioned I have endeavoured to account for this phænomenon, to which
I shall recur, when it has been ascertained by a sufficient number of
trials, that it is as general in men as I found it in frogs and other
cold-blooded animals.
The second manner in which we tried the influence of Galvanism on the
heart was by arming the par vagum and the great sympathetic nerve. The
object of these experiments will be readily comprehended by anatomists
acquainted with the details of neurology. In these, as well as in the
first and other experiments where we armed the cardiac nerves
themselves, we obtained contractions in the heart. In this, as in the
former case, the contractions took place when the heart was first
touched, and then the arming of the nerves, were much stronger than
when the arming of the nerves was touched first, and then the heart.
In this method we even observed that the Galvanic experiments
sometimes failed.
The third kind of experiments on the heart were performed by means of
the pile. The pile employed on the 10th of August, for the experiments
on the first decapitated criminal, was composed of fifty plates of
silver and as many of zinc, with pasteboard moistened by a strong
solution of muriate of soda. The silver was mixed with a tenth part of
copper. This is the proportion which we found most favourable to the
intensity of the signs of Galvanism:
Metre.
The diameter of the silver plates was 0·036
Their thickness 0·0015
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