Sir Humphry Davy used the first anaesthetic in 1799: nitrous oxide (laughing gas).
William T. G. Morton's demonstration of ether as an anaesthetic in 1846 was initially dismissed because it irritated the lungs of the patients.
Chloroform had been invented in 1831, but its uses had not been greatly investigated.
Dr Robert Mortimer Glover had first described the anaesthetic properties of chloroform upon animals in 1842 in a thesis which won the Harveian Society's Gold Medal that year, but had not thought to use it on humans (fearing its safety).

In 1847, Simpson first demonstrated the properties of chloroform upon humans, during an experiment with friends in which he learnt that it could be used to put one to sleep.
Dr Simpson and two of his assistants, Dr George Skene Keith (1819-1910) and James Matthews Duncan (1826-1890), used to sit every evening in Dr Simpson's dining room to try new chemicals to see if they had any anaesthetic effect.
On 4 November 1847, they decided to try chloroform.
On inhaling the chemical they found that a general mood of cheer and humour had set in.
But suddenly all of them collapsed only to regain consciousness the next morning.
Simpson knew, as soon as he woke up, that he had found something that could be used as an anaesthetic.
They soon had Miss Petrie, Simpson's niece, try it.
She fell asleep soon after inhaling it while singing the words, "I am an angel!".
There is a prevalent myth that the mother of the first child delivered under chloroform christened her child "Anaesthesia"; the story is retailed in Simpson's biography as written by his daughter Eve.
However, the son of the first baby delivered by chloroform explained that Simpson's parturient had been one Jane Carstairs, and her child was baptised Wilhelmina. "
Anaesthesia" was a nickname Simpson had given the baby.

It was much by chance that Simpson survived the chloroform dosage he administered to himself.
If he had inhaled too much and died, chloroform would have been seen as a dangerous substance, which in fact it is.
Conversely, if Simpson had inhaled slightly less it would not have put him to sleep.
It was his willingness to explore the possibilities of the substance that set him on the road to a career as a pioneer in the field of medicine.

An account of some of Simpson's early uses of ether in childbirth are related by Manchester-based doctor Edmund Lund who visited him in 1847 and can be found in a manuscript held by special collections at the University of Manchester with the reference MMM/12/2.
Sir Humphry Davy used the first anaesthetic in 1799: nitrous oxide (laughing gas). William T. G. Morton's demonstration of ether as an anaesthetic in 1846 was initially dismissed because it irritated the lungs of the patients. Chloroform had been invented in 1831, but its uses had not been greatly investigated. Dr Robert Mortimer Glover had first described the anaesthetic properties of chloroform upon animals in 1842 in a thesis which won the Harveian Society's Gold Medal that year, but had not thought to use it on humans (fearing its safety).
In 1847, Simpson first demonstrated the properties of chloroform upon humans, during an experiment with friends in which he learnt that it could be used to put one to sleep. Dr Simpson and two of his assistants, Dr George Skene Keith (1819-1910) and James Matthews Duncan (1826-1890), used to sit every evening in Dr Simpson's dining room to try new chemicals to see if they had any anaesthetic effect. On 4 November 1847, they decided to try chloroform. On inhaling the chemical they found that a general mood of cheer and humour had set in. But suddenly all of them collapsed only to regain consciousness the next morning. Simpson knew, as soon as he woke up, that he had found something that could be used as an anaesthetic. They soon had Miss Petrie, Simpson's niece, try it. She fell asleep soon after inhaling it while singing the words, "I am an angel!". There is a prevalent myth that the mother of the first child delivered under chloroform christened her child "Anaesthesia"; the story is retailed in Simpson's biography as written by his daughter Eve. However, the son of the first baby delivered by chloroform explained that Simpson's parturient had been one Jane Carstairs, and her child was baptised Wilhelmina. "Anaesthesia" was a nickname Simpson had given the baby.
It was much by chance that Simpson survived the chloroform dosage he administered to himself. If he had inhaled too much and died, chloroform would have been seen as a dangerous substance, which in fact it is. Conversely, if Simpson had inhaled slightly less it would not have put him to sleep. It was his willingness to explore the possibilities of the substance that set him on the road to a career as a pioneer in the field of medicine.
An account of some of Simpson's early uses of ether in childbirth are related by Manchester-based doctor Edmund Lund who visited him in 1847 and can be found in a manuscript held by special collections at the University of Manchester with the reference MMM/12/2.
James Young Simpson