John Snow’s life
In 1813, John Snow was born in Yorkshire, northern England, his father was a coal miner, Snow has 8 siblings. Snow’s family lives on North Street by the Ouse River, which is often hit by flooding from the Ouse River, making it one of the worst drained areas. Although the family was not wealthy, when Snow was 6 years old, his mother sent him to a private school with a small inheritance. Snow was an inquisitive, intelligent and hard-working student. During his 8 years at school, he studied all subjects, of which mathematics and natural history were his favourite subjects.
Snow completed his early education at the age of 14 before being sent to the suburban town of Langton, Newcastle upon Tyne, to apprentice with general practitioner William Hardcastle. Snow’s six-year apprenticeship was an important stage in his life. Hardcastle was a well-known local doctor. Under his earnest teaching, Snow received medical training seriously during his apprenticeship and participated in medical practice, which laid a solid foundation for his future formal medical education.
Snow was able to receive a formal medical education thanks to funding from his uncle, Charles Empson. Charles is Snow’s mother’s older brother. Snow has had a close relationship with Uncle Charles since he was a child. Charles left Yorkshire at an early age and eventually became a well-known museum manager and art dealer in London. After Charles learned of his nephew’s love for medicine, he grew up. Appreciate and encourage, and make every effort to support. In October 1836, John Snow entered Hunter College, Great Windermere Street, London, to begin formal medical education. Snow began clinical work at Westminster Hospital in October 1837, expecting to gain practical experience in a hospital setting. In 1838, Snow, who was only 25 years old, passed the examination successively, became a member of the Royal Society of Surgeons, and obtained a practicing certificate from the Association of Pharmacists, becoming a licensed general practitioner. But Snow didn’t stop there, eager to gain more academic medical education and be able to diagnose more patients. Eventually, Snow continued his studies at the University of London, where he received a Bachelor of Medicine in 1843 and a Doctor of Medicine from the University of London in 1844. In June 1850, Snow passed the examination and obtained the practice qualification of the Royal Society of Physicians.
John Snow was the first anaesthetist in England. In 1846, ether was introduced into the United Kingdom as an anesthetic. He immediately conducted experiments and invented a corresponding device for the clinical use of this drug. After the successful clinical demonstration, it was popularized and applied. In 1847, Snow developed new equipment for the use of chloroform anesthetics. Snow was Queen Victoria’s personal physician, and when the queen gave birth to her last two children, Prince Leopold and Princess Beatrice, in 1853 and 1857, Snow used chloroform on the queen to ease her labor pains , The Queen expressed deep gratitude to him, and the public gradually recognized the use of anesthetics.
John Snow was a vegan and ardent alcoholic who abstained from tobacco and alcohol—drinking boiled water. He loves sports and is a famous swimmer. Although Snow loves children, he never married. At the age of 45, Snow suffered a stroke while he was at his desk writing his last book, Chloroform and Other Narcotics, when he wrote the word “exit” when the stroke came on suddenly, and since then After that, he never woke up again. At 3:00 pm on June 16, 1858, Snow was euthanized, fell asleep peacefully, and was buried in Brompton Cemetery after his death.
John Snow’s Preliminary Research on Cholera
In 1831, cholera first struck England, and Longton, Newcastle, where Snow was an apprentice, was not spared. The fear of cholera engulfed the UK and killed thousands in a short period of time. The initial symptoms of cholera were nausea, stomach pain, vomiting, diarrhoea, and patients eventually died of dehydration. Dr. Hardcastle was so busy that he sent Snow to the Killingworth Coal Mine to treat sick coal miners. Snow tried various conventional remedies for the disease: bloodletting, laxatives, opium, peppermint, brandy, but none of these methods and medicines were ineffective in curing cholera. Observe and record carefully. The medical community at the time had no clue about the origin and spread of cholera. It was this outbreak of cholera that Snow began to pay attention to the epidemic and hoped to find out the cause of the disease.
The popular explanation for the outbreak of cholera in the British medical community at the time was the “miasma theory”. Most doctors believed that cholera was caused by “miasma”, which was sewage, swamps, rubbish pits, open graves and other decaying things. The cholera virus floats and reproduces in the air. Once people inhale this gas, they will get sick, and the spread of cholera will intensify. But Snow was skeptical of the miasma theory, which he believed could not explain the spread of cholera. Because during his treatment in 1831, he had noticed that the sick coal miners spent most of their time deep underground, where there were no sewers or swamps, and there was no so-called “miasma”, and he speculated that cholera was transmitted by invisible bacteria. , Miners often do not wash their hands because of the water shortage, the bacteria on the hands will enter the body when eating and drinking, causing illness.
In 1848, cholera struck London again, and this time Snow decided to follow the development of the epidemic and explore the transmission route of cholera. The first fatality in London was a merchant seaman named John Harold. On September 22, Harold arrived in London from Hamburg. After a long and tiring sea voyage, he decided to rent a room in the London parish of Horslipton, but that night he suddenly suffered from cholera. Onset of death. A few days later, another Mr. Blenkinthorpe was admitted to the same room, and the unfortunate thing happened again, he was infected with cholera the next day, and died after eight days after treatment failed. John Snow then inspected the rental, suspecting that Mr Blenkinthorpe had been killed by cholera germs left on the sheets because the owner had not cleaned the room where Harold had stayed.
As more cases emerged in London, Snow began to study the symptoms of the patients. He found that the first symptom in most patients was nausea and vomiting, a problem with the digestive tract. Snow concluded that cholera must have been acquired after eating contaminated food or water, because if, according to the miasma, the patient had inhaled air contaminated with cholera toxins, their first symptoms should have appeared in The nose or lungs, not the digestive tract. In August 1849, Snow published a pamphlet “On the Mode of Transmission of Cholera” at his own expense, in which Snow mentioned that cholera was a contagious disease caused by a toxin, and he believed that the The main route is water contaminated with this toxin. The pamphlet didn’t get much traction when it was published, because Snow’s new argument was seen as just one of many theories put forward as the cholera epidemic raged.
Drawing of the “Map of Cholera”
In the summer of 1854, London was again shrouded in a haze of cholera. Snow knew that the epidemic would continue to spread until the source of cholera was found. He decided to challenge this problem and find the source of cholera. Snow began to investigate the sources of drinking water for London residents, suspecting that the spread of cholera was caused by the contamination of their drinking water by the Thames. At that time, London’s residential water was connected to the Thames River, and the Thames River flowed through central London from west to east. Most of the water companies supplying water for London residents took water from the Thames River, but the sewage used by residents would eventually be injected into the river. Snow checked municipal records and found that there are two private water companies in South London that draw water from the Thames to provide water to local residents: one is Southwark-Vauxhall Water, which draws water from the lower Thames: the other It was Lambeth Water, which drew water from the upper Thames, and Snow decided to conduct a comparative study of morbidity and mortality among consumers of the two water companies. Snow personally visited and asked about the owner’s residence. Through a large number of sample statistics, Snow came to the data conclusion: within a period of four weeks, those families who took water from Southwark-Vauxhall Water Company suffered from the disease. The mortality rate is 14 times higher than that of Lambeth Water consumer households. Snow was excited by the conclusion, convinced he had found strong evidence for a link between drinking sewage and the spread of cholera. But Snow’s findings were still attacked by miasmaists, who claimed that the Thames was full of water enough to dilute the sewage sufficiently that the water taken from the Thames would not be toxic to humans.
In late August 1854, there was a sudden outbreak of cholera in Soho, west London, and the epidemic spread rapidly. The two streets in the area, Broad Street and Cambridge Street, became the hardest hit area. More than 500 people died in just 10 days. people. Snow, who lived near Broad Street at the time, copied the cholera death records from the London Registry and marked the exact location of all the dead on a map. He found that most of the cholera dead lived in Broad Street. Within 250 yards of the pump (one yard is equal to three feet), this discovery became an important clue for Snow to explore the cause of cholera, and he believed that water pollution was the key to the transmission of cholera. Snow carried out microscope and chemical analysis on the water in the pump, and found a large number of unusual white flocculent particles in the water. Snow believed that these small particles were pathogenic substances, but he still could not make a conclusion on what the pathogenic substances were. . Snow decided to continue to collect information to further improve the “cholera map” drawing.
Snow noticed that some of the residents had no deaths, and through further investigation, he found that these people were working in the pub at 7 Cambridge Street, and the pub provided them with free beer, so they did not drink water from the pump. Snow also found that there were more than 530 poor people in the Polish Street Workhouse, not far from the Broad Street Pump, but only five cholera deaths. The reason is that the workhouse has its own well, and drinking water does not need to be drawn from the pump. Snow also found evidence of cholera deaths in other parts of London: after a woman named Susannah Ellie moved out of Broad Street, she was accustomed to drinking water from the Broad Street pump, and sent people from the Broad Street pump every day. The pump brought water to the house, and after drinking the water from the pump, she and her niece contracted cholera and died. Based on various signs and evidence, John Snow blamed the cholera epidemic in this area on the Broad Street water pump, which was the source of cholera to all who drank from the water pump.
On the evening of September 7, 1854, at a meeting of the St. James Parish Council to investigate the causes of cholera, John Snow briefly explained his theory of cholera contagion and presented the evidence he had found (Broad Street Pumps). cholera map nearby), identified the water pump as the source of cholera, and made a suggestion to “remove the handle of the water pump”. The parish commissioners did not believe Snow’s theory and judgment, but ultimately had to follow the recommendation to “remove the handle of the pump.” To the surprise of the parish commissioner, the cholera outbreak on Broad Street quickly subsided as residents could no longer draw water from the pump since the handle was removed. Later, Snow put forward other preventive measures based on the theory of sewage transmission of cholera, such as recommending to boil water before using it, washing dirty clothes, advocating the use of filtration facilities by water companies, and prohibiting the sale of contaminated water from the Thames. Promoted the “clean water movement” of the reformers at that time, the clean water for residents was guaranteed, and the spread of cholera was naturally blocked.
John Snow’s work on the transmission of cholera through water was a major advance in understanding cholera at the time. Until Snow’s death in 1858, he did not come to a conclusion as to what the “toxin” in the water was, a question that was finally resolved by the German bacteriologist Robert Koch, who discovered this toxin in 1884. The virion is Bacillus cholerae. Although John Snow’s cholera research did not find the pathogen that causes cholera, he creatively used spatial statistics to find the source of infection, and thus proved the value of this method. Today, the map represented by “cholera map” is drawn. The method has also become a basic research method in medical geography and epidemiology.
There is now a water pump on Browick Street (the original site of the Broad Street Pump) near Gold Square, London, with its handle removed, and a monument to John Snow’s cholera research.