This overview has been adapted from Dean Jenkins's and Stephen Gerred's ECGlibary.com. for which they are gratefully acknowledged.
The history of the ECG goes back more than one and a half centuries.
1600 - 1800
1600. William Gilbert, Physician to Queen Elizabeth I, President of the Royal College of Physicians and creator of the 'magnetic philosophy', introduces the term 'electrica' for objects (insulators) that hold static electricity. He derives the word from the Greek for amber (electra). It has been known from ancient times that amber when rubbed could lift light materials. Gilbert adds other examples such as sulphur and describes what will later be known as 'static electricity' to distinguish it from the more noble magnetic force. He sees his ideas as part of a philosophy to replace forever the prevailing Aristotlean view of matter. [1 ]
1649. Sir Thomas Browne, Physician, while writing to dispel popular ignorance in many subjects, is the first to use the word 'electricity'. Browne calls the attractive force "Electricity, that is, a power to attract strawes or light bodies, and convert the needle freely placed". (He is also the first to use the word 'computer' - referring to people who compute calendars.) [2 ]
1662. The work of Rene Descartes, French Philosopher, is published (posthumously) and explains human movement in terms of a complex mechanical interaction of threads, pores, passages and 'animal spirits'. He has worked on his ideas in the 1630s but did not publish because of the persecution of other radical thinkers such as Galileo. William Harvey developed similar ideas but they were never published. [3 ]
1664. Jan Swammerdam, a Dutchman, disproves Descartes' mechanistic theory of animal motion by removing the heart of a living frog and showing that the frog is still able to swim. When the brain is removed all movement stops (which could be in keeping with Descarte's theory) but then, when the frog is dissected and a severed nerve end stimulated with a scalpel, the muscles twitch. This proves that movement of a muscle can occur without any connection to the brain.Therefore the transmission of 'animal spirits' is not necessary.
Swammerdam's ideas are not widely known and his work is not published until after his death. However, he writes many letters and his friend, Nicolaus Steno, attacks Cartesian ideas in a lecture in Paris in 1665. Boerhaave publishes Swammerdam's 'Book of Nature' in the 1730s.It is translated into English in 1758.
1729 Stephen Gray, English scientist, distinguishes between conductors and insulators of electricity. He demonstrates the transfer of static electrical charge to a cork ball across 150 meters of wet hemp thread. Later he finds that the transfer can be achieved over greater distances through brass wire.
A Leyden Jar
1745 Dutch physicist Pieter van Musschenbroek discovers that a partly filled jar with a nail projecting from a cork in its neck can store an electrical charge. The jar is named the 'Leyden Jar' after the place of its discovery. Ewald Georg von Kliest of Pomerania invents the same device independently.
Using a Leyden jar in 1746, Jean-Antoine Nollet, French physicist and tutor to the royal family of France, sends an electrical current through 180 Royal Guards during a demonstration for King Louis XV.
1769 Edward Bancroft, an American scientist, suggests that the 'shock' from the torpedo fish is electrical rather than mechanical in nature. He shows that the properties of the shock are similar to those from a Leyden jar in that it can be conducted or insulated with appropriate materials. The torpedo fish and other species are widely known to deliver shocks and are often used for therapeutic
reasons. However, electrical theory at this time dictates that electricity will always flow through conductors and diffuse away from areas of high charge to areas of low charge. Since living tissues are known to be conductors, it is impossible to imagine how an imbalance of charge can exist within an animal. Therefore animals can not use electricity for nerve conduction - or to deliver shocks. Furthermore, 'water and electricity do not mix' so the idea of an 'electric fish' is generally not accepted. [4 ]
1773 John Walsh, Fellow of the Royal Society and Member of Parliament, obtains a visible spark from the electric eel Electrophorus electricus. The eel is out of water, as it is not possible to produce the spark otherwise. Walsh uses thin strips of tin foil to demonstrate his technique to many colleagues and visitors at his house in London. Unfortunately, he never publishes his eel experiment, though he does win the Copley medal in 1774 and 1783 for his work. Walshes observations. and those of Bancroft before him, adds to the argument that some form of animal electricity. [5 ]
1774 The Rev. Mr Sowdon and Mr Hawes, apothecary, report on the surprising effects of electricity in a case report of recovery from sudden death published in the annual report of the newly founded Humane Society (now the Royal Humane Society). The Society develops from 'The Institution for Affording Immediate Relief to Persons Apparently Dead from Drowning'. It is "instituted in the year 1774, to protect the industrious from the fatal consequences of unforseen accidents; the young and inexperienced from being sacrificed to their recreations; and the unhappy victims of desponding melancholy and deliberate suicide from the miserable consequences of self-destruction."
A Mr Squires, of Wardour Street, Soho, lives opposite the house from which a three year old girl, Catherine Sophia Greenhill falls from a window on 16th July 1774. After the attending apothecary declares that nothing could be done for the child, Mr Squires, "with the consent of the parents very humanely tried the effects of electricity. At least twenty minutes had elapsed before he could apply the shock, which he gave to various parts of the body without any apparent success; but at length, upon transmitting a few shocks through the thorax, he perceived a small pulsation: soon after the child began to sigh, and to breathe, though with great difficulty. In about ten minutes she vomited: a kind of stupor, occasioned by the depression of the cranium, remained for some days, but proper means being used, the child was restored to perfect health and spirits in about a week.
"Mr. Squires gave this astonishing case of recovery to the above gentlemen, from no other motive than a desire of promoting the good of mankind; and hopes for the future that no person will be given up for dead, till various means have been used for their recovery."
Since it is clear she sustained a head injury, the electricity probably stimulated the child out of deep coma rather than providing cardiac defibrillation (see also 1788, Charles Kite). Annual Report 1774: Humane Society, London. pp 31-32
1775 Abildgaard shows that hens can be made lifeless with electrical impulses and he can restore a pulse with electrical shocks across the chest. "With a shock to the head, the animal was rendered lifeless, and arose with a second shock to the chest; however, after the experiment was repeated rather often, the hen was completely stunned, walked with some difficulty, and did not eat for a day and night; then later it was very well and even laid an egg." [6 ]
Italian Anatomist Luigi Galvani