London has always been at the forefront of medical science. As slowly we vaccinate our population against this new pandemic, a modern plague it reminds us that we have been here before. This time we have the wonder of modern science to protect us against this virus and its rapid mutating variants. Medicine is often called the “imperfect science” with many of the discoveries made by accident. We often find ourselves battling an invisible enemy. However, these discoveries have led to saving thousands of lives, arguably more than any war in human history.
Let’s take a look at some of these discoveries, and into the work of three men who did huge contributions to medicine and to the fight against diseases.
Tackling the source of epidemics: John Snow
In the mid- 19th century, the big killer in London was cholera. However, people did not know where this disease is coming from. Dr John Snow thought he might have an answer: he challenged the popular belief that cholera was caused by breathing vapours or a “miasma”. Dr Snow had long believed that water contaminated by sewage was the cause of cholera. Cholera is an intestinal disease that can cause death within hours after the first symptoms of vomiting or diarrhoea. Dr Snow published his article in 1849 outlining his theory, which was widely criticized by the scientific community. Dr Snow needed to find the evidence. This came from his own neighbourhood Soho in London’s West End.

Left: Portrait of John Snow (Public Domain). Center: pump at Broad Street, London (Creative Commons). Right: Blue plaque erected by the Royal Society of Chemistry (Photo by Tony Hisgett, license CC BY 2.0)
Within 250 yards of the spot where Cambridge Street joins Broad Street, there were upwards of 500 fatal attacks of cholera in 10 days. Dr Snow wrote, “As soon as I became acquainted with the situation and extent of this irruption of cholera, I suspected some contamination of the water of the much-frequented street-pump in Broad Street.” Now on the corner of Broadwick and Lexington Street, the pump that is now called “John Snow Water Pump” and now stands in front of the present John Stow pub. Dr Snow had suspected that those who lived or worked near the pump were the most likely to contract cholera. Using a geographical grid (now kept at the Hunterian Museum, at the Royal College of surgeons) to chart deaths from the outbreak and investigating each case to determine access to the pump water, Snow developed what he considered positive proof the pump was the source of the epidemic. He had the handle of the pump removed, and cases of cholera immediately began to diminish. However, Snow’s germ theory of disease was not widely accepted until the 1860s.
The development of vaccines: Edward Jenner
Cholera is spread by bacteria, however, one of the greatest challenges to medicine is battle against viruses. Humans have only successfully eradicated two viruses in human history, and Smallpox was contained using vaccination. One of the most trending topics today, the COVID vaccines has been developed by the Jenner Institute at the University of Oxford, named after Dr Edward Jenner. Born in the small town of Berkeley, Gloucestershire, Jenner became an apprentice to the father of modern surgery Dr John Hunter at St George’s Hospital, at Hyde Park Corner (Now the Lanesborough Hotel, one of London’s most expensive luxury hotels).

Statue of Edward Jenner at Kensington Gardens (Creative Commons)
The Hunters were not just known for their medical knowledge but there interested in anatomy and natural history, something that John passed onto Edward. Returning to his native town in 1773, Jenner became a successful family doctor and surgeon. He had a very handsome house in the middle of the town. Jenner was not only a practising medicine; he was observing the natural world around him. He noticed that the local milkmaids appeared to be immune to smallpox. Edward hypothesised that the less virulent cowpox could be protecting them from smallpox. He then made the brave decision in 1796 to scrape pus from cowpox blisters on the hands of Sarah Nelmes, a milkmaid who had caught cowpox from a cow called Blossom (whose hide now hangs on the wall of the St. George’s Medical School Library now in Tooting, south London) and deliberately infect James Phipps an 8-year-old boy with first cowpox and shortly afterwards smallpox.

Dr Jenner performing his first vaccination on James Phipps, a boy of age 8. 14 May 1796. (Public Domain)
James Phipps was successfully vaccinated. The lancets or blades he used are preserved at the Wellcome Gallery at London’s Science Museum. Today Jenner’s name is immortalised in statues across London such as Kensington Gardens and on the front of the London School of Hygiene & Tropical Medicine.
Antibiotics, from discovery to large scale production: Alexander Fleming and Howard Florey
By the early 20th century mankind had started to win the battle against both viruses and bacterial disease. Sadly, we were still losing the battle against infection. In the crypt of St Pauls Cathedral, the burial place of military heroes, Nelson and Wellington, on the floor is a single tile marked with the letters AF. It marks the simple grave of a man who saved more lives than any military hero: Alexander Fleming. And all because he had a slightly untidy lab in St Mary’s Hospital, Paddington, now preserved in its 1928 condition as the Alexander Fleming Laboratory Museum. Before leaving for his holiday, he coated a series of bacteria culture plates and left them on a bench in a corner of his laboratory. On his return, Fleming noticed that one culture was contaminated with a fungus and that the colonies of bacteria culture immediately surrounding the fungus had been destroyed. Fleming had just discovered the mould penicillin; samples of the mould can be seen in the Making of the Modern World Gallery of London’s, Science Museum.

Sample of penicillin mould presented by Alexander Fleming to Douglas Macleod, 1935. Front three-quarter view, grey background (Creative Commons)
It took many years for the significance to be realised. In 1939 Ernst Boris Chain and the Australian Howard Florey at the University of Oxford were impressed by Fleming’s 1929 paper and realised its potential as a lifesaving drug. Its development during the Second World War saved countless lives, and due to his work, Howard Florey may not be a household name but he is honoured by a memorial in our “nations parish church” Westminster Abbey.
Featured image: Creative Commons
About the Author:
Dr Aaron Hunter is a scientist with the University of Cambridge and a qualified Blue Badge Tourist Guide for London. He is a Palaeontologist who gained his PhD from the University of London on the Jurassic rocks and fossils of Bath, the Cotswolds and the Jurassic Coast. He very much likes guiding all ages but especially families and specializes in guiding the Natural History Museum, the British Museum, and the Crystal Palace Dinosaurs. You can check his London tour around scientific discoveries here.