John Snow’s credentials as the first English Anaesthetist have long been established. It was described in a previous blog, how his clinical evaluation and experiments helped establish an understanding of the safe use of ether and chloroform. The use of the new agents quickly spread more widely, until the fateful day of 28 January 1848.

On this day, a 15-year-old girl from Newcastle, Hannah Greener, was supposed to have an operation to treat an ingrown toenail. Thomas Meggison, the surgeon, and his assistant, Mr. Lloyd, arrived at her parents’ house, after it had been decided that she would not go back to the Newcastle Infirmary, where the initial operation had taken place on October of the previous year.

 Meggison had poured a teaspoon of chloroform onto what was recorded as ‘tablecloths’ and held it in front of her nose. Hannah Greener pulled his hand down after two breaths but was told to keep her hands on her knees and continue inhaling. She became rigid and the operation began. With the first incision, Hannah jerked, and it was decided to administer more chloroform from the tablecloth.

 When checking the depth of her anaesthesia by pulling up an eyelid, the eye stayed open. She also turned pale and didn’t respond to water dashed in her face or a measure of brandy that was administered before she was laid down on the floor for bleeding. The time between administering chloroform and her eventual death had taken no more than 2 or 3 minutes.

During the post mortem examination on the following day, the coroner decided that ‘congestion of the lungs’ caused by the inhalation of the chloroform was the reason for Hannah’s death and that Meggison could not be given any responsibility for this. ‘No human foresight, no human knowledge, no degree of science could have forewarned any man against the use of chloroform in this case.’

An exchange in the Lancet followed, in which many eminent medical men looked into this recent death. Many agreed that Hannah Greener must have died from ‘the shock of the surgical operation’ and not the efforts to revive her, which were common at the time. James Young Simpson became especially defensive and argued that proper use of the substances was essential. While looking at Greener’s case, he agreed that the administration of chloroform and brandy had been to blame for the choking of the patient. He too defended his colleague Meggison, as these were the traditional ways to deal with the given situation.

 Other correspondents disagreed with Simpson and rather connected the fatal outcome with the potency of the agent. They thought that the effects of an overdose might have destroyed the nervous system.

John Snow, with all his clinical research firstly into ether and then chloroform, followed up the investigation into the death during chloroform administration. He disagreed with the coroner’s and Simpson’s suggestion of asphyxiation and went on to say that the attempts to revive the patient by using water and brandy had not been wise in this particular case.

 He was quite adamant that Simpson gave his support to Chloroform too freely:

“It will be remembered that Dr. Simpson recommended the general use of undiluted chloroform very quickly after its existence was made known to him by Mr. Waldie, and that amongst the advantages which he stated that chloroform possessed over sulphuric ether was this, that it requires no particular apparatus on its administration. There can be no doubt that this was a great error. Chloroform being more powerful, when inhaled, than any other agent which has been used in a similar manner […] particularly requires mechanical means for its regulation.”

 He believed strongly that the administration of chloroform by means of a handkerchief had been one of the main reason for the fatal outcome. As with this method, the rapid action of chloroform had produced a much deeper uncontrolled degree of anaesthesia than had been intended, and this had occurred too far and too fast finally resulting in Hannah Greener’s respiration to stop.

The following statement opens the subsequent paper On the Cause and Prevention of Death from Chloroform in 1852: 

‘Chloroform, like other medicine which relieve or prevent pain, is capable of causing death, if it’s action be carried out too far.’

 Snow had experimented with a number of warm and cold-blooded animals in his possession. These had been administered various strength of chloroform enriched air. The fatalities, which had been exposed to higher concentrations of chloroform, all showed a reflex of gasping for air once the agent had been removed. Not all efforts of revival were successful, and the post mortem all showed the right cavities of the heart being filled with blood. His conclusion was that a concentration of 4-5% of chloroform to air was safe, whilst 10% invariably proved fatal.

He also meticulously listed all human fatalities that were proven to be caused by chloroform. There were 21 cases in total, ranging in age from from children, with the youngest age recorded as 15, to 48 and covering a wide range of treatments intended. He excluded three or four fatalities, because these happened to people inhaling chloroform outed on a handkerchief with nobody present and no medical indication, which made them irrelevant for his current paper.

The youngest patient on the list was Hannah Greener at 15 years. There were also international fatalities from America, India, France, Germany and Mauritius. In London, there were also 2 cases for the United Hospitals of the Borough. Fatality number 12 was 48-year-old John Shorter, who had died at St. Thomas’ Hospital on 10 October 1849 after a toe nail operation. A year later case number 16, 34-year-old Alex Scott, died on 16 June 1850 after a partial removal of his hand.

 Following this first paper, he continued with the publication Further Remarks on the Cause of Death from Chloroform, 1856. In this work he stated that after establishing further fatalities in the meantime: 

 “In all the cases of death from chloroform, in which the state of the pulse at the time of the accident is described, it was found to cease suddenly and abruptly, and in only two of the cases was there the slightest indication of returning pulsation, for a brief interval. In several cases, indeed, it was observed that the very last pulsation was equal in strength to the ordinary ones. This is entirely different from what takes place in asphyxia. Under a total privation of air, the pulse retains its usual strength for a minute or two, and then gradually diminishes in frequency and force during two or three minutes, till it finally ceases.”

 Snow’s findings were also recorded by Dr Sibson, a colleague, who had stated in 1848 that the concentration of chloroform was highest in the coronary arteries and the lungs. Gas left on the lungs from the last inhalation was still absorbed even after the chloroform had been removed and pure air was given. Both concluded that this point was of no consequence, but only if the administration of the drug was in a ‘gradual and uniform manner’ though. Only if the dose was too high in the beginning, as shown in the observed fatalities, was there the possibility these organs could get overloaded.

 To sum up his findings, Snow concluded that the safest method of giving chloroform is by using an apparatus as described in On Chloroform and and Other Anaesthetics, 1848, his chloroform inhaler. This device would make sure that the recommended safe dose would not exceeded. But if a handkerchief or cloth were the only option left to a practitioner, Snow referred to the tables in the same publication, which gave an overview of the saturation of chloroform in air at different temperatures.


Snow, John. February, 1848.  The fatal chloroform Case at NewcastleLancet 1. 

Snow, John. June 1852. “On the Cause and Prevention of Death from Chloroform.” London Journal of Medicine 4.

Snow, John. February 1856. “Further Remarks on the Cause and Prevention of Death from Chloroform.” Lancet 1.

To cite this post : Iris Millis, “John Snow, the first English Anaesthetist. Part 7-John Snow and the Pump Handle”, Museum Highlights (blog on, April 4th, 2018. 

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Iris Millis is currently a museum officer at the Old Operating Theatre Museum and Herb Garret. She has previously worked for the Anaesthesia Museum and Bodyworlds. She is member of the History of Anaesthesia Society and the John Snow Society. Follow her on Twitter, @historical_iris.

John Snow, the First English Anaesthetist, Part 7: Chloroform, Death and Explanations
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