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 machine.

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. Fig 347
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.

Fig 349 - The poliscope, the forerunner of modern endoscope.
Galvanism and Galvanometer. Fig 348
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.