In 600 BC, the Greek phylosopher, Thales of Miletus noted
when rubbing along a piece of fabric on the surface of the
fossil resin, the amber, the same acquired the property to
attract light bodies. In the reality amber is a Greek word-meaning
“electron” where the term Electricity came from.
However, the amber’s attraction properties became unknown
for almost 2000 years.
|Fig 347 - An early type of electric
In the beginning of XV century, the Queen Elizabeth’s
private physician, William Gilbert discovered that when rubbing
along some kind of materials they presented a similar behavior
like the amber. Gilbert describe his experiments in a Latin
treatise under the title “De Magnete”, where these
substances he called as “electries”; and the force
itself as “vis electrica”.
In the beginning of XVII century the European physicians used
electric machines as a therapy for pain and circulatory diseases.
Therefore the development of the methods for measuring and
recording the electrical causes generated by the biologial
processes were possible with the improvement in the science
of Eletrology only. In this way in 1726, the Italian physician
and professor of Anatomy, Luigi Galvani upon severing frog’s
legs noted when the scalp touched by accident in the animal’s
nerves the muscles suddenly contracted. Since during the experiment
the frog laid on a table, nearby an electric machine in use,
Galvani though that the apparatus might have induced the kicks.
Further on he did another experiment by lay down the frog’s
leg nearby an electric machine and noted the same phenomenon
of nerve contractions. Galvani found that the frog’s
nerves were an extremely sensitive charge’s measurers.
He was so interested in this nerve response to electricity,
that he conducted another experiment in a place far way from
any electrical interference. During the same he touched the
frog’s leg with two metals bar, respectively zinc and
copper duly interconnected and again he observed the same
muscle kick. In 1791 he succeeded in publishing his theory
of “animal electricity”. However, in an important
sense, Galvani was intuitively right. There are indeed tiny
electric nerves impulses and they are vital to animal life.
In those days of the triumph of reason it did not seem too
much to expect a final explanation of life itself. However,
among the scientists who rushed to confirm Galvani’s
theory was professor Alessandro Volta, inventor of the first
electric pile that after several experiments clearly pointed
in another direction.
In the reality through his experiments with the frog’s
leg Galani discovered the flow of electricity related with
the current generated by the contact of two kinds of metals.
In spite of the erroneous concept of his theory Galvani became
famous through his electrical experiment and in this way his
name is deeply related with several terms often use in electricity
such as: Galvanic current,
Fig 348 – Galvani’s experiment.
Galvanism and Galvanometer. Fig 348
Fig 349 - The poliscope, the forerunner of modern endoscope.
In XVIII century due to new discoveries in the electromagnetism,
it gave birth to the first practical applications of electricity
in the field of medicine.
Thus, in 1851, John Marshal, launched one of the first type
of electric cautery for surgical purpose.
In 1871, in France it was introduce an advanced surgical technique
to cauterize the lachrymal gladule by means of a battery-operated
apparatus developed by M.G. Planté.
The poliscope, forerunner of the modern endoscope was invented
in France by M. Trouvé. Basically the instrument consists
of a battery provided with a rheostat connected to Platinum
filament. It could be used either as a surgical lamp when
provided with special kind of concave, parabolic or spherical
reflectors as well as an electric cautery. Fig 349
In 1876, Dr. Duchenne, in Boulogne developed an electric apparatus
used for muscles stimulation. Further to these new inventions,
in 1881, M. Hughes developed a type of electric stethoscope
originally designed to locate fragments of metals in wounds.
However, the discovery of the X-Rays was the first great contribution
of the electric phenomenons for the medical sciences.