Snow and the pump handle on in London Broad Street.
John Snow was born in 1813 and his father was a coal miner. His talent was very good and very hard, in the school's performance is very good. Snow wanted to be a doctor, at the age of 14, went to Newcastle to follow the Dr.Hardcastle as an apprentice. In 1831, the outbreak of cholera in Europe, claimed hundreds of thousands of lives. In the summer of this year, cholera began to wreak havoc and spreader quickly to the north, and in October, Newcastle began cholera.
In the short term infected patients was too much, Dr.Hardcastle completely to see, apprentice Snow to help deal with these critically ill patients, and at that time that time, treatment and completely unsuccessful, abdominal pain, diarrhea, vomiting caused by severe dehydration of patients. It is still bleeding this kind of worse treatment. In February of the second year, the overwhelming chunks were suddenly stopped, and twenty thousand people in England were killed by cholera in this plague.
After more than a decade, cholera hit London again. In September 1848, the German steamer called Elbe from Hamburg, after several days of sailing in London. There was a hotel named John Harold who was admitted to a hotel in Horsley town. On September 22 he died of cholera. A few days later, a man named Blenkinsopp lived in his room, and on September 30 he died of cholera. Within a week, nearby residents began to report a lot of cholera deaths.
This cholera epidemic eventually extended to the whole of England. The epidemic of the cholera has been repeated for a long time, and in the same area it is often broke out, paused, then exploded, and then paused, and after two years of cholera popular in the UK, 50,000 people died in the plague.
For the spread of cholera, the prevailing theory at that time was poisonous. To control the epidemic of infectious diseases, the most important issue is to know the spread of the plague. Gas poisoning theory under the guidance of people on the prevalence of cholera or helpless, nothing more than to avoid contact, disinfection of the room, the most effective way is to take advantage of the disease has not yet quickly escape.
Facing the panic brought about by cholera, only the spirit of reason can support calm thinking. As a doctor, Snow is always calm and grim in front of the patient. Snow is certainly not an indifferent person, it is because, Snow through the immediate pain and horror, in thinking and looking for disease and the reasons behind the popular. We need a rational mind when mankind knows nothing about cholera and is full of misunderstanding. And sooner or later cholera will meet people like Snow.
1831 Apprentice's Snow had noticed that some coal miners are sick and die, and he has considered that these patients may have pathogenic substances in their hands because there is no water to wash their hands. Perhaps the thought of cholera has never left Snow's mind. Now, in the summer of 1848, 35-year-old Snow began to formally challenge the traditional gas miasma theory. If the spread of cholera is achieved through the gas miasma, then
1) Why those who have not been to the hotel room also have infected?
2) Why the same doctor twice to the room twice to see the two unfortunate patients and patients were spent together for several hours without being infected?
3) Gas through the breathing into the body, why the symptoms only in the digestive tract?
4) It is staggering that, in the weeks leading up to the outbreak, cholera can actually skip several blocks to infect?
By the summer of 1849, cholera continued, and after nearly a year of observation and investigation, Snow undertook his own theory that cholera was caused by the ingestion of a substance that was not yet clear, This substance is present in the excrement of other diseased patients, either by direct contact with the substance or by (more likely) the drinking of water contaminated with the substance. Cholera is contagious, but not through air-like any other infectious disease. Cholera is swallowed, not sucked in.
Snow's evidence comes from two groups of studies. The first study was the community study. In July 1849, 12 people died in an outbreak in Thomas Street, where they lived in the same building House (S floor), sharing the front of a well. Domestic sewage, septic tank water, often spread to wells. A person's excretion once the pollution wells, all the water will appear cholera. The street map of the community provided great help to Snow's research.
Snow found the building behind a circle of houses, formed a yard, living is also close to life is almost poor people, other environments and S floor exactly the same, on a difference: the yard without wells, their water from different the place. Within two weeks of the death of 12 people in the S building, only one person in the yard infected the cholera. S and the yard constitute a large square courtyard, if it is a gas miasma spread of cholera, then in such a small range, will lead to two aspects of the same conditions in the same population of the case more than 10 times the difference?
Snow's research in modern epidemiology is called a controlled study, and his research is fully in line with the standards of modern epidemiological research, and more accurately, modern epidemiology continues with Snow's research standards: reviewing a specific period, Match the conditions of the control, observe the frequency and distribution of the disease, infer and determine the event of the decision and the influencing factors.
At the same time, Snow's focus on the source of water from the investigation of the courtyard rose to the analysis of the entire administrative region and even the whole of London, which is Snow's second group of research. Formake it clear.First, we needknow a person. In 1838, Office of the Registrar-General appointed William Farr, 1807-1883 to record the birth, marriage and death of the city, and report regularly to the authorities. He is a very serious and serious person who has used the registered data to study the relationship between life and marriage. Snow's second group of research was to use his study of the June 1848 - 1849 cholera deaths to develop a study of the relationship between water supply companies and the incidence of cholera.
Fall reported that the total number of cholera deaths in London was 7466. Of these, 4001 were on the south side of the Thames River. Use this data to calculate the partition mortality rate. Southern cholera mortality rate is eight thousandths, three times the city, and one thousandth of the northwest suburbs. The worst living conditions in the Eastern District, the crowded population, the dirtiest streets, the most pungent odor, according to the gas miasma, the highest incidence of cholera, but their cholera mortality rate is only half of the Southern District.
Snow made these summary data into the London health department, pointing out that different water supply companies in the Thames River in different sections of the water to the residents of different districts to provide domestic water is the root cause of the different incidence of cholera in various regions. The authorities did not accept Snow's theory of water transmission in cholera and did not listen to the views of Snow's investigation and clean water.
In the second half of 1849, when cholera continued to prevail, Snow's own money printed a pamphlet (39 pages in total) to share the idea of cholera water communication with his peers, and then wrote a paper in London Medical journal "published, hoping to have more people to see. Judging from the newspaper's point of view, the medical community's efforts to Snow are positive, but the conclusions are still very skeptical. The fundamental reason is, of course, because the mainstream of the gas miasma theory is difficult to shake Snow's water communication theory but immediate evidence is needed.
The main question from the London Medical Journal is that there is no conclusive evidence of the causal relationship between the contaminated water and the epidemic of cholera: Snow needs a decisive ideal experiment to keep the contaminated water Sent to a distant place without cholera, the people who used the water disease, not used without disease.
Of course no one can artificially carry out this ideal experiment.
In 1849, for the spread of cholera, Snow's study indirectly proved the way of survival and epidemic of cholera, the way of cholera has come to the conclusion of the absolute correct, but the challenge of fighting the gas is still far from victory The
How will the rationality of the cholera period disperse the fog of knowledge?
Probably in the period of the epidemic of cholera, there was a police officer named Thomas Lewis and his wife, Sarah, moved into the 40th Broad Street in London's West End. The house was originally designed for a family, plus a few servants living, a total of 11 rooms. Lewis lived in the living room after the converted room. Soon they had a boy born. The child is born very weak, 10 months to die. A few years later, in March 1854, their second child was born. The child looks a lot stronger than the previous brother to death, Sarah is also very bother to take care of her, because she has her own health reasons and cannot give the child feeding, relying on rice noodles and milk, the child's development and health to the summer It is still very good.
Now cannot figure out in August 1854, the child is less than 6 months old, in the end is how to come into contact with cholera. Although a few years ago, from August 1853 onwards, the southern part of London has a lot of cholera reports, but they live in this place is for several years did not happen cholera cases.
18:00 on August 28, 1854 (Monday) at six in the morning, people are still in bed, the poor children suddenly began to vomit diarrhea, green water stool has a pungent taste. While waiting for a doctor, Sarah washed the child's stool in the bucket and washed it in the bucket, taking the child asleep, putting the water downstairs and pouring it into the sewage pool at the door.
Their home upstairs, also with the wide street 40, lived a tailor, record the name of the tailor is not all, and we call him Mr. G. Summer London climate damp heat intolerable, his wife to help the door of the wells to fight cold water to quench their thirst. August 30, 1854 (Wednesday) afternoon, Mr. G began to feel uncomfortable stomach, August 31 began to vomit diarrhea, September 1 Mr. G two eyes depression, lips purple, 1 pm, Mr. G was Cholera takes life.
This was the first cholera deaths in the area after the last cholera epidemic stopped five years later. Less than 24 hours, September 2 at 11 am, downstairs little baby stopped breathing. In the small area of this neighborhood, cholera has killed nearly a hundred people this day.
Cholera broke out again in London. Snow's home (clinic) from the wide street only 15 blocks, walking will be about 5 minutes. On Sunday, September 3, when Snow came to the cholera outbreak center, the yellow flag of the plague was hung on the high building on Berwick Street, which intersects Broad Street. On the evening of the day, Snow took samples from the wide-street wells, as most of the deaths occurred in the neighborhood, and also in several nearby wells.
Snow's previous study of the water company shows that the water in this area is from the Thames River relatively clean urban sewer exports upstream, but the wells are polluted by residents of the possibility of sewage is still there. Snow was disappointed with the results of the comparison, the four different samples are very clear; do not see any suspicious material under the microscope. Snow decided to start investigating the relationship between the population of cholera and their water intake.
The next day he went to the Registrar's address of 83 cholera cases that had been copied from September 2 (the first week of the outbreak), returned to the wide street, measured the distance between their address and the wide street wells, and found that 73 cases from the wells of the distance than any other nearby wells are close, 73 cases inside, there are 61 is to drink a wide well water. Visited the other ten families, Snow knows one of the eight people drank wide wells of water, there are two students, every day school to go through this well to drink water.
On September 6, Snow went to the government to report his findings and asked the government to order the removal of the wide-street wells. The authorities did not accept the theory of water pollution, but the handle of the wells was immediately removed.
Shortly after the handle was removed, the local cholera stopped. City health department in order to figure out the reasons for the outbreak of the popular sent to investigate the residents of the area living environment. This is a research report based on the theory of gas mallet. On September 11, the report said that most cases of home were unexpectedly clean.
1854 Broad Street in the cholera incident in the water pump
Snow continued to investigate in this district, he found the distance to the wide well as the center within 3 minutes of walking, the number of deaths in the first week of the week was 197, and many people were sick after going to other places outside the hospital died was not recorded. Surprisingly, some distant cases are also directly linked to wide wells.
On the 10th floor of Cross Street, 100 feet west, a tailor and five children live in a room. Every time the middle of the night to wake up, called adult boss or second run long way to the wide street of the wells to play a bucket of cold water to drink. There was a more well in their house, but the taste was not good. Snow saw the record from the report of fall, but when he found the address, it was too late, the tailor and five children died in four days.
There was a brewery in a place not far from the wide well, and no one had cholera, and Snow found that they had their own wells, not only that, but also those who were mainly bitten by beer.
Snow tries to understand people's lifestyle and eating habits. He's investigation found that the wide street of the wells is very popular people; some visitors to the wide street must drink well water. There is a family has been using the wide street of well water, but the watering daughter just a few days sick, the whole family to escape cholera. There is a man named Gould to drink this water adult, but that day he smelled no smell and did not drink it, it was not infected.
Lewis is the baby girl's father, who stayed upstairs and did not like the water in the well. He never drank the water of the well. He did not have any symptoms when the child was ill, but he did not escape the bad luck. It has been questioned that the removal of wells in the control of cholera epidemic in the process of no significance, because in the removal of the handle, the incidence of cases has begun to decline. In fact, Lewis's symptoms are in the hands of the demolition after the emergence of the poor Sarah in the bereavement of the pain, but also to take care of the sick husband, it is difficult to say that she would not as usual, the same excrement of Lewis, Pour the contaminated water into the sump. If the handle is not removed, then Lewis is likely to be like his daughter as a source of pollution of well water.
In order to better display their own research materials, more deeply to persuade the authorities, Snow painted a wide area of the map, marking the location of the wells, each address (house) in the case of bar code display, bar code is obvious Concentrated in the vicinity of the wide street wells. This is the famous ghost figure.
Snow's investigation is a rational interpretation of this natural disaster, in the course of this interpretation; Snow saw a huge experiment on cholera, a huge experiment done by nature. Five years ago, the London Medical Journal hypothesis of the decisive experiment, actually in 1854 this residential area of the cholera outbreak naturally formed.
In the wide street there is a detonator factory, the boss died after the child to take over, his wife Susanna also moved far to Hampstead to live, but she drank decades of wide well water habits do not change. Although there are several miles away from here, the child is still regularly to her car to push the water, the last water is August 31. The detonator factory workers also used the well water, and when they appeared in the case, Suzanne had symptoms, and she was the only case of cholera deaths in the area. When Suzanne fell ill, her niece came to see her, and drank the water of her home, and the niece died after she died in cholera.
On September 25, the health department finally sent an ombudsman to investigate the wide-street wells, but the report was unfavorable to Snow. The well structure is complete, the surface is smooth, the bricks are free from cracks, the sewer is deeper than the bottom of the well, and the well is 10 feet away. In mid-October, after confirming the complete control of the cholera, the handle of the well was fitted. At the end of October, people fleeing home. In November, a priest named Henry Whitehead invited Snow to participate in the investigation of the cause of the outbreak of cholera, he did not accept the beginning of the theory of Snow, but particularly admire the spirit of Snow, but also highly praised Snow's research methods The
The handle of the well pump was later a symbol of modern epidemiology, and when we faced the prevalence of a new disease, scientists and public health policy makers would lament that where was the handle?
At the end of 1854, Snow's "On the mode of cholera transmission" second edition. In the same year, Pasini, a medical scientist in Italy, found the bacteria on the small intestine wall of the dead patient and published an article. But the article did not pay attention, nor translated into English.
Snow's reason to see the cholera, but unfortunately Snow's eyes did not see the cholera bacteria look.
Snow's theory of cholera water transmission began to be accepted after 1860. In front of the system to complete the evidence, the gas miasma theory is so hard to shake. Cholera is terrible, and some inherent doctrine occupies a lifetime of souls that are terrible. Cholera frantically captured the lives of people, but from the start of the Snow, where again and again the cholera raging slowly shook the absurd theory of people's minds. Since cholera is so powerful, is it also to infect our meridians, vent your anger?
On the day of March 1855, the priest Whitehead, at the time of the report of the cholera death, noticed that a report had such a text: 40th Street, a five-month-old baby girl died on September 2 after four days of vomiting and diarrhea. The priest calculated that the baby's symptoms were earlier than Mr. G, that is, Mr. G was the first to die but not the earliest case. The priest immediately rushed to the home of Lewis, to Sarah to understand the child's situation. The priest surprised to listen to Sarah said before the house there are sewage pools: not all changed into a sewer it?
April 23, after inspection found that the sewage pool is aging, pool wall corruption, structural loosening,and sewage accumulation; the most frightening is that the pool to leave the wells only 2 feet 8 inches. Ordinary sewage permeates the well, once the rain, the sewage spread directly in the past.
Infant's excreta were first poured into the sump on August 28th. Cholera suddenly begins.
In September 2nd, after the death of the baby, No new excreta are allowed into the pool. Cholera suddenly stops.
The health department did not accept the conclusion of the Snow and Whitehead reports. June 16, 1858, Snow died young. The theory of water transmission in cholera is still not recognized by the authorities. The newspaper also did not mention his contribution to the understanding of mankind and ultimately victory over cholera. Of course, one hundred and fifty years ago people could not understand that Snow's study of cholera created a strong discipline that made him the father of modern epidemiology.