It’s a common trope in fiction – press a handkerchief soaked in chloroform over a victim’s mouth and nose, and almost instantly, they lose consciousness and go limp. But does chloroform really work that quickly? What even is chloroform exactly, and how does it work?
I’ll begin by defining the properties and background of chloroform. Chloroform, also known as trichloromethane, formula CHC13, is a colorless, nonflammable liquid with a pleasant smell and taste. It occurs naturally in seaweed and fungi, but is most commonly man-made. In the past it was used as an anesthetic and refrigerant, though today it is used in pesticides, cleaners, dyes, resins, plastics, propellants, and solvents.
Chloroform is the result of chlorinated lime combined with ethanol, chlorine bleach combined with ethanol and acetone, or heating chlorine with either methyl chloride or methane. Chloroform’s empirical formula was discovered by the French chemist Jean-Baptiste Dumas in 1834, but it did not see medical use for several more decades. At the time, ether – ethanol and sulfuric acid – was the preferred anesthetic. William Morton, an American dentist and physician, used inhaled ether gas as an anesthetic in 1846, performing a tooth extraction on a patient without pain. Shortly thereafter, a dispute rose over who had truly discovered ether, as two others, Dr. Charles T. Jackson and Horace Wells, immediately stepped forward to claim that they had made the real find. As well, the same year, physician Crawford Long used ether to remove a tumor from a patient’s neck, but didn’t publish his findings until after Morton had already gained fame. Despite the debate and Morton’s less-than-credible character, he was ascribed with the groundbreaking discovery. But there were still flaws with ether. It required fourteen minutes to take effect, and was also flammable. Chloroform was first used as an anesthetic by Sir James Simpson in 1847. It worked much faster than ether and was easier to produce, but was also more dangerous. It was easy to overdose and cause lung paralysis, resulting in death. Regardless, it was preferred by both surgeons and their patients, many of whom were soldiers during the Civil and Crimean Wars, and famously, in 1853, Queen Victoria used it during the birth of her eighth child. As it was eventually suspected to be carcinogenic – cancer-causing – chloroform faded out of use after the early 1900s, but has regardless remained a common trope in literature and cinema.
So how does chloroform work?
Scientists have discovered that general anesthetics, including chloroform, induce loss of consciousness through the disrupting of the organization of lipid rafts in cellular membranes. The cellular membrane denotes the walls or skin that surround a cell. A lipid raft is an assembly or cluster of proteins and lipids in the bilayer, which is a fluid double layer of lipids in a cellular membrane. Some scientists have also discovered evidence that points towards anesthetics disrupting the proteins in the rafts, rather than, or in addition to, the lipids. Anesthetics inhibit the cholesterol already in the rafts and prevent phospholipase – a type of protein – from reaching those rafts. Cholesterol is a key component of lipid rafts, and determines how fluid and how rigid the cell membrane is. Phospholipases are enzymes. They break ester bonds in phospholipids, and these resulting reactions create lipid products, which in turn affect cellular signaling: how the cell grows, works, and interacts with other substances and cells around it. Abnormal cell signaling can lead to cancer. It is also thought that the hydrophobic molecules in chloroform and other inhaled anesthetics activate TWIK-related potassium channels or TREK-1 channels, through the release of the signaling lipid phosphatidic acid. Phosphatidic acid is the byproduct result of phospholipase being unable to reach the lipid rafts. The potassium released from these channels causes hyperpolarized neurons, meaning that the neurons can’t fire well or at all. Scientists think that when this happens to neurons in the thalamus, a part of the brain near the center, unconsciousness results. The thalamus regulates consciousness and relays sensory and motor signals, and is made almost entirely of gray matter, that is, cell bodies of neurons. Therefore, the inhaled anesthetic sets off a chain reaction through rafts, cells, channels, and neurons, eventually leading to full-body insensibility.
In the movies, knocking a victim out with chloroform is as simple as dipping a handkerchief in a bottle, pressing it over the mouth and nose of the victim, and waiting for a second or less. In real life, however, chloroform works nothing like that. It is believed to take about five minutes of steady inhalation to knock someone out with chloroform. Five minutes is an estimate, as no experiments to test this have been conducted. Furthermore, the victims in film and novels often wake up some time later with nothing worse than perhaps a headache, but in reality, chloroform is easy to accidentally overdose with, and has more side effects than shown in entertainment. Chloroform administration causes skin irritation short-term, and longer-term exposure results in nausea, flatulence, and vomiting, then ataxia, dizziness, and drowsiness. (Yes, flatulence.)
However, more exposure or a high concentration causes coma, convulsions, and even respiratory failure or irregular heartbeat, both of which will lead to death. There is also the risk of long-term liver or kidney failure, and possibly cancer. Additionally, when chloroform is exposed to air and UV rays, which are present in sunlight, it can create a toxic gas known as phosgene. Chloroform requires a concentration of 24 to 73 grams per cubic meter and about five minutes of inhalation to induce anesthesia, though there is no research available on how much is required to cause death – but due to recorded deaths and a history of its use in crime, we know that too much inhaled chloroform will indeed be fatal. Anesthesia will last anywhere from 20 minutes to two hours. Applied orally, as little as 14.8 grams can be enough to inflict respiratory failure or cardiac arrest, with the average lethal dose being 45 grams. Chloroform, then, doesn’t work the way it is portrayed to, neither in the time it requires to take effect nor in the results. So if you’re trying to find a way to conveniently knock out your character, chloroform is unfortunately not the answer.
We’ve seen chloroform used in everything from movies to TV shows to novels as a quick and easy method of inducing unconsciousness, but in reality it is far less predictable, far less speedy, and far more dangerous. As it takes about five minutes of inhalation to knock someone out, in reality it is not a very effective tool. Furthermore, it is illegal to own without a license, and is not as easy to acquire as fiction would make it seem. This is important for writers, filmmakers, and screenwriters to know, as this can mean that crucial parts of their stories and plots can be inaccurate. They should instead consider researching other types of anesthetics or drugs, such as Benzodiazepines or Ketamine. Another option is reworking their writing to include accurate details. In conclusion, chloroform is volatile, slow, and dangerous, and as a result does not operate the way popular culture claims it does.
I will also warn you right now — after having read this article it will drive you crazy every time you see someone use chloroform in their writing. Sorry.
Alright, have a lovely week. Bye!
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