Ignaz Semmelweis and Handwashing
Childbed Fever, Chlorinated Lime, and a Rejected Discovery
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Semmelweis introduced chlorinated lime handwashing in 1847, reducing deaths to less than 2 percent. He had to prove his theory after a colleague died from a scalpel wound, which he believed was caused by the same infectious agent he'd identified. His ideas were rejected by the medical establishment, and he spent his final years in an asylum.
This book explains how Semmelweis's work laid groundwork for modern infection control. Readers will find this essential who want to understand the origins of hand hygiene in medicine.
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Overview
Ignaz Semmelweis was a Hungarian doctor of German descent who became known as the “saviour of mothers” for his work with childbed fever in the 19th century. In 1847, at Vienna General Hospital’s First Obstetrical Clinic, he introduced handwashing with chlorinated lime solutions and reduced maternal mortality from 18% to less than 2%. He published his findings in a book titled Etiology, Concept and Prophylaxis of Childbed Fever in 1861. Though his methods worked, many doctors rejected his ideas because he couldn’t explain them scientifically, and some were insulted by the suggestion they needed to wash their hands. In 1865, Semmelweis suffered a nervous breakdown and was committed to an asylum, where he was beaten. He died from a gangrenous wound on his right hand. His discoveries only gained acceptance years after his death, when Joseph Lister applied antiseptic techniques with success.
Family and early life
Ignaz Semmelweis arrived on 1 July 1818 in Buda, then part of the Austrian Empire, in the Tabán neighbourhood. He was the fifth of ten children in a well-off family; his father, József Semmelweis, had become a citizen of Buda in 1806 and opened a spice and consumer goods business named Zum weißen Elefanten. His mother, Teréz Müller, was from Buda, and her father, Fülöp Müller, was a coachbuilder. Semmelweis started his studies in law at the University of Vienna in the autumn of 1837 before switching to medicine. He graduated in 1844 and, after not securing a position in internal medicine, focused on obstetrics, training under Carl von Rokitansky, Joseph Škoda, and Ferdinand von Hebra.
Position at Vienna General Hospital
Ignaz Semmelweis started working as assistant to Professor Johann Klein in the First Obstetrical Clinic at Vienna General Hospital on 1 July 1846. The clinic had a maternal death rate of around 10% from puerperal fever, while the Second Clinic’s rate was under 4%. Women were so afraid of the First Clinic that they begged to be sent there, even preferring to give birth in the streets rather than face the risk. Semmelweis saw women kneeling in desperation, pleading not to be admitted to the first clinic. Some pretended to have given birth on the way to the hospital just to avoid it. The low rate of infection among street births puzzled him and led him to wonder what protected those who delivered outside the clinic.
Theory of cadaverous poisoning
In 1847, Ignaz Semmelweis made a breakthrough after his friend Jakob Kolletschka died from an infection likely caused by being poked during an autopsy. Semmelweis noticed that the symptoms resembled those of women dying from childbed fever, and he theorized that "cadaverous particles" carried on hands from autopsies to patients were spreading the disease. He observed that the student midwives in the Second Clinic, who didn’t do autopsies, had much lower death rates. To combat this, he introduced a hand-washing policy using chlorinated lime, a solution that worked best at removing the smell of infected tissue and possibly destroying the invisible "cadaverous" agent. The mortality rate in the First Clinic dropped from 18.3% to as low as 1.2% within months, and for the first time since anatomical studies began, there were no deaths in that clinic.
Efforts to reduce childbed fever
Ignaz Semmelweis believed firmly that childbed fever could be prevented by simple cleanliness, and his idea that poor hygiene was responsible was considered extreme and largely ignored or ridiculed. He was dismissed from his Vienna hospital for political reasons and faced intense harassment from the medical community, eventually moving to Budapest. Outraged by the profession's indifference, he wrote angry open letters to leading European obstetricians, sometimes calling them irresponsible murderers. His contemporaries, including his wife, thought he had lost his mind. In 1865, nearly twenty years after his breakthrough, he was committed to the Landesirrenanstalt Döbling, a provincial lunatic asylum. He died there of septic shock just fourteen days later, possibly after being severely beaten by guards. His practices were not widely accepted until years after his death, when Louis Pasteur developed the germ theory of disease, offering a scientific explanation for Semmelweis's findings. He is now recognized as a pioneer of antiseptic procedures.
Conflict with established medical opinion
Semmelweis's findings challenged medical beliefs based on the outdated theory of dyscrasia—the idea that illness came from an imbalance of the four humours. At the time, doctors believed each disease was unique and treated patients individually, without understanding that puerperal fever might be one condition with a common cause. Autopsies showed varied symptoms, reinforcing the belief that there were many unknown diseases rather than one identifiable one. His ideas were rejected because they lacked scientific explanation then and because some doctors felt insulted by the suggestion that their hands could be unclean. As a result, Semmelweis's washing protocol, introduced in 1848, was met with resistance. It wasn't until the 1860s and 1870s that scientists like Louis Pasteur and Robert Koch developed the germ theory, which finally explained his success in reducing mortality rates to nearly zero in his hospital ward.
Hesitant publication of results and first signs of trouble
By late 1847, reports of Semmelweis's work—along with similar findings by Oliver Wendell Holmes Sr.—began spreading across Europe. His students wrote letters to directors of major maternity clinics, and Ferdinand von Hebra announced Semmelweis's discovery in Austria's leading medical journal, comparing its impact to Edward Jenner's smallpox vaccine. In late 1848, one of Semmelweis's former students gave a lecture in London, reviewed in The Lancet, followed by another essay in a French periodical. As news of the dramatic drop in Vienna's mortality rates spread, Semmelweis likely expected chlorine washings to be widely adopted, saving countless lives. But early responses showed trouble ahead: some physicians misunderstood his claims, and others dismissed his work as unoriginal, arguing that he'd merely repeated ideas from Holmes's 1843 paper. In fact, Semmelweis warned against all decaying organic matter, not just contagion from infected patients. These misinterpretations persisted because Semmelweis had published nothing himself, relying instead on secondhand accounts from colleagues and students. Some say he never intended to officially share his method with Vienna's medical circles or write it down.
Political turmoil and dismissal from the Vienna hospital
In 1848, political upheaval across Europe affected Ignaz Semmelweis's career. On 13 March, medical students and faculty in Vienna joined workers in demonstrations for civil rights. Two days later, Hungary rose up in revolution against the Habsburgs, sparking months of unrest. Though Semmelweis wasn't personally involved, some of his brothers were punished for supporting Hungarian independence, and he likely sympathized. His superior, Professor Johann Klein, was conservative and probably mistrusted him. When Semmelweis's term ended March 20, 1849, Klein chose Carl Braun over him for the assistant position in the First Clinic. Semmelweis petitioned to become a docent of obstetrics, but was denied at first. He reapplied and was finally appointed October 10, 1850, though he was barred from using cadavers and had to teach with leather mannequins. Shortly after, he left Vienna abruptly for Pest, reportedly unable to endure further frustration with the medical establishment.
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Overview
Postpartum infections, also called childbed fever or puerperal fever, are bacterial infections of the female reproductive tract after childbirth or miscarriage. They typically cause a fever over 38°C, chills, abdominal pain, and foul-smelling discharge, appearing after the first 24 hours and within ten days. The most common type is puerperal sepsis, often linked to C-sections, group B streptococcus, or prolonged labor. In 1847, Hungarian physician Ignaz Semmelweis reduced deaths in Vienna’s First Obstetrical Clinic from nearly 20% to 2% by introducing handwashing with calcium hypochlorite. These infections were a major cause of maternal death from at least the 18th century until the 1930s, when antibiotics became available. In 2015, about 11.8 million cases occurred worldwide, resulting in 17,900 deaths.
Causes
After childbirth, a woman’s genital tract has a large open surface that's vulnerable to infection. These infections can stay in the uterus or spread, leading to sepsis or other serious conditions, especially if labor was long or there was heavy bleeding. The most common infections happen after the placenta separates, but they can also come from cuts anywhere in the genital area. Germs can enter the bloodstream and cause inflammation in the connective tissue, abdominal lining, or other areas. The severity depends on the strength of the bacteria, how well the body resists, and the woman’s overall health. Common causes include Streptococcus pyogenes, staphylococci found on skin, anaerobic streptococci that grow in damaged tissue, E. coli and Clostridium perfringens from the bowel, and Clostridium tetani.
Management
Postpartum infections were managed with a range of treatments depending on the condition. Atelectasis required pulmonary exercises and ambulation, while urinary tract infections were treated with antibiotics based on culture results. Endometritis demanded intravenous antibiotics like clindamycin, gentamicin, and sometimes ampicillin if there was no response. Wound infections needed drainage, saline packing, and antibiotics for cellulitis. Septic pelvic thrombophlebitis was addressed with IV heparin for seven to ten days. Mastitis was managed with antibiotics and drainage of abscesses when present. Antibiotics were key in preventing and treating these infections, but misuse posed a serious global health threat, making proper guidelines essential for their use.
Epidemiology
Puerperal sepsis, or childbed fever, was a leading cause of maternal death for centuries. In the 18th and 19th centuries, it affected about six to nine women per 1,000 births, killing two to three, making it the single most common cause of maternal mortality and second only to tuberculosis in killing women of childbearing age. In England and Wales alone, an estimated 250,000 to 500,000 women died from it during that time. The rate of puerperal infections varied widely in medical literature, possibly due to different definitions or recording methods. In the United States, such infections were believed to occur between one and eight percent of all births, with about three deaths per 100,000 births. Caesarean section was identified as the most important risk factor. In the UK from 1985 to 2005, genital tract sepsis caused 0.40–0.85 direct maternal deaths per 100,000 pregnancies, and by 2003–2005, it accounted for 14% of direct causes of maternal death. Globally, bacterial infections are responsible for ten percent of maternal deaths, a figure higher in low-income countries but also present in high-income nations.
History
For centuries, women in childbed had been known to suffer fatal fevers, though the specific term "puerperal fever" only showed up in records during the early 1700s. By the 20th century, deaths among women giving birth had dropped in developed nations, thanks to better hygiene, improved medical care, and antibiotics. Scientists also believe the bacterium *Streptococcus pyogenes*—which causes puerperal fever—became less dangerous over time. This same germ is responsible for scarlet fever, which followed a similar trend of decline but has recently resurged, especially in Asia, with smaller cases reported in the US and Canada. In the UK alone, 12,906 cases were recorded between September 2015 and April 2016—a spike since 1969.
"The Doctor's Plague"
From the 17th century through the mid-19th century, most childbed fever cases were caused by doctors lacking germ knowledge who saw no need for handwashing. Hospitals crowded women, performed frequent vaginal exams, and used contaminated tools, with doctors delivering multiple babies without washing hands or changing clothes. The first recorded epidemic struck Hôtel-Dieu de Paris in 1646, with European and American maternity wards consistently reaching 20-25% death rates, sometimes killing all women in a ward. In the early 19th century, Ignaz Semmelweis discovered that washing hands before delivery with calcium hypochlorite solution reduced deaths by 90%. His findings were rejected by the medical establishment, leading to his move from Vienna, breakdown, and death in a mental asylum. Alexander Gordon had warned in 1795 that doctors transmitted the disease, admitting he carried infection to many women. In 1842, Thomas Watson, professor at King's College Hospital in London, wrote that practitioners should use "most diligent ablution" and recommended handwashing with chlorine solution and changing clothes to prevent infection transmission between patients.
Hygienic measures
In 1844, Ignaz Semmelweis began working at Vienna's General Hospital, where he noticed a much higher death rate from puerperal fever in the ward where doctors worked, compared to the midwifery ward. He observed that doctors performed autopsies daily while midwives did not, and after a colleague died from sepsis following an autopsy, Semmelweis connected the two. Starting in May 1847, he made doctors wash their hands in chlorinated lime solution before seeing patients, reducing the fever rate from 18% to less than 3%. His findings were ignored, even as he repeated them in Pest, Hungary, and published in 1860. Meanwhile, in 1843, Oliver Wendell Holmes Sr. had published The Contagiousness of Puerperal Fever, claiming doctors and nurses spread the disease, and suggested clean clothing and avoiding autopsies could prevent it. His views were mocked, especially by Charles Delucena Meigs, who said, "Doctors are gentlemen, and gentlemen's hands are clean."
Notable cases
Postpartum infections touched lives across the social spectrum, as witnessed by several prominent deaths. Elizabeth of York, Henry VII's queen consort, died of puerperal fever a week after giving birth to her daughter, who also died. Her son Henry VIII lost two wives to the same illness: Jane Seymour and Catherine Parr. Suzanne Barnard, mother of Jean-Jacques Rousseau, fell ill after childbirth and died nine days later; Rousseau recalled, "I came into the world with so few signs of life that little hope was entertained of preserving me." Mary Wollstonecraft, author of Vindication of the Rights of Woman, died ten days after giving birth to her second daughter, who grew up to write Frankenstein. Other notable victims include Phillis Wheatley (1784), Isabella Beeton (1865), and Jean Webster (1916). In A Christmas Carol, Charles Dickens implies that Scrooge's mother and sister both died from the disease, shaping his difficult relationships with family.
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Overview
Ferdinand Karl Franz Schwarzmann, Ritter von Hebra was an Austrian doctor and dermatologist who lived from 1816 to 1880. He founded the New Vienna School of Dermatology, which became a major force in shaping modern dermatology. This group of physicians laid important groundwork for the field, and von Hebra’s work helped define how skin diseases would be understood and treated in the years to come.
Life
Ferdinand Ritter von Hebra was born in Brno, Moravia, to a military officer and studied in Graz and Vienna, graduating in 1841. Influenced by Carl Freiherr von Rokitansky, he advanced understanding of scabies in 1844, establishing it as a specific disease caused by the itch mite. He introduced chemical peels using agents like phenol and nitric acid for skin treatments. His work influenced Carl Mayrhofer, who later continued Semmelweis's research on puerperal fever. In 1856, he published the first edition of Atlas der Hautkrankheiten, which by 1876 reached its tenth edition. He began writing Lehrbuch der Hautkrankheiten, completed after his death by student Moritz Kaposi. He became president of the College of Physicians in Vienna following Rokitansky's death in 1878, but died in August 1880 of pulmonary emphysema before chairing a meeting. Colleague Heinrich von Bamberger eulogized him, saying his death meant "one more name adorns the pantheon of Austrian scholars."
Semmelweis and Hebra
Ferdinand Ritter von Hebra, an early supporter and editor of a leading Austrian medical journal, announced Ignaz Semmelweis's handwashing discovery in December 1847 and April 1848. Hebra compared Semmelweis's work to Edward Jenner's cowpox inoculations and was the only friend who stayed in touch after Semmelweis's Vienna departure. Due to Semmelweis's mental health struggles, János Balassa signed commitment papers sending him to a mental institution. On 30 July 1865, Hebra arranged what was supposed to be a trip to a new water-cure hospital but instead took Semmelweis to the Viennese asylum in Lazarettgasse. Semmelweis realized what had happened, tried to escape, was restrained, and died two weeks later from a gangrenous wound possibly caused by the struggle. Hebra did not attend Semmelweis's funeral, made no further mention of him during his lifetime, and no references to Semmelweis appear in any of Hebra's papers, though a full biography of Hebra has yet to be written.
Legacy
Ferdinand Ritter von Hebra was so influential in his time that his clinic became the center of dermatology, shifting focus from England and France to Austria, according to medical historians Walter B. Shelley and John T. Crissey, who called him "by far the most important" dermatologist of the 19th century. Victor Robinson, a medical historian in the early 20th century, described Hebra as "the undisputed potentate of Hautkrankheiten [skin diseases]" during his lifetime. Known for his engaging teaching and speaking style, combining sympathy with satire, he trained students who would go on to become prominent dermatologists themselves, including Kaposi, Auspitz, and Neumann.
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Overview
Iatrogenesis refers to harm caused by medical practices, including mistakes, treatments, or even well-intentioned but flawed interventions. The term first appeared in 1924, and later, in 1976, Ivan Illich brought it into sociology, arguing that modern society often overmedicalizes life, leading to more harm than good. This can include mental distress caused by medical beliefs or statements made by doctors. Some iatrogenic effects are clear, like operating on the wrong body part, while others, such as dangerous drug interactions, may go unnoticed. In 2013, it was estimated that around 20 million people suffered negative consequences from medical care worldwide. That same year, about 142,000 people died directly due to harmful effects of treatment, a number higher than the 94,000 who died in 1990 from similar causes.
Risk associated with medical interventions
Medical interventions, even when well-intentioned, can carry serious risks. Sometimes, the treatments themselves cause harm—like adverse effects from prescription drugs or vaccines. Overuse of medications, especially antibiotics, can lead to resistance in bacteria, making infections harder to treat. Drug interactions can also be dangerous, and some therapies, such as those using immunosuppressants, may weaken the immune system on purpose to treat conditions like autoimmune disorders or prevent organ rejection. But this suppression can leave patients more vulnerable, possibly impairing their ability to fight infections or even recover from cancer. These unintended consequences highlight how deeply intertwined healing and risk can be in medicine.
Medical error and negligence
Iatrogenic conditions aren’t always the result of medical mistakes like wrong surgeries or incorrect drugs. Sometimes, the treatments themselves cause harm, such as radiation therapy or chemotherapy leading to side effects like hair loss, anemia, or infertility. Removing a diseased organ can also cause iatrogenic problems, like diabetes after part of the pancreas is taken out. The risk of death from a ruptured aortic aneurysm is under 25%, so even if a patient dies during treatment, the procedure might still be better than no treatment at all. In other cases, negligence occurs—like when pharmacists write prescriptions by hand or when providers ignore patients due to prejudice, causing mistrust and fewer people seeking care, which leads to more deaths.
Adverse effects
Adverse effects from medical treatment, known as iatrogenic harm, include unexpected allergic reactions to drugs and the growing problem of antibiotic resistance in bacteria, which has developed due to overuse. Some medications cause damage even at therapeutic doses: alkylating agents, for example, harm DNA more in cancer cells but also lead to serious side effects and secondary tumors. Arsenic-based treatments like melarsoprol used for trypanosomiasis can cause poisoning, while aminoglycoside antibiotics may harm the kidneys. Surgical tools designed decades ago can also cause unintended injury, such as tissue trauma, because their risks haven’t been fully understood.
Psychiatry
In psychiatry, iatrogenesis occurs when doctors misdiagnose patients, like with hystero-epilepsy or bipolar disorder, especially in children. Conditions such as somatoform disorder are thought to have both sociocultural and iatrogenic causes. Chronic Fatigue Syndrome was once seen as psychiatric, and Graded Exercise Therapy, an outdated treatment, caused harm. Multiple sclerosis is often mistaken for functional neurologic disorder, leading to stigma and dismissal of real symptoms. PTSD treatments may also cause iatrogenic issues, particularly with certain antipsychotics that reduce brain volume over time. Some groups, like those labeled with substance abuse disorders, are at risk of misdiagnosis. Dissociative identity disorder is debated as possibly entirely iatrogenic, with most cases coming from a small group of practitioners. The link between diagnosis and harm remains unclear and controversial, especially since psychiatric labels often rely on subjective criteria. Many former patients believe their struggles stemmed from power dynamics in treatment, fueling the anti-psychiatry movement.
Iatrogenic poverty
Meessen et al. introduced the term "iatrogenic poverty" to describe how medical care can push households into financial ruin. When people face catastrophic health expenses or are forced to borrow money for treatment, they often end up poorer because of the very care they needed. Worldwide, more than 100,000 families fall into poverty each year due to health costs. In the United States, illness and medical debt were behind half of all personal bankruptcies in 2001. As countries transition economically, people want better health services, and providers respond quickly, but safeguards and regulations often don’t keep up. This leaves patients vulnerable to cycles of illness, poor treatment, spending their savings, going into debt, selling what they own, and eventually becoming impoverished.
Epidemiology
In 2013, around 142,000 people died worldwide because of harm caused by medical care, a rise from 94,000 in 1990. In the United States, hospital errors and infections contribute to tens of thousands of deaths each year. An estimated 12,000 people die from unnecessary surgery, 7,000 from medication mistakes, and 20,000 from other hospital errors. Another 80,000 die from infections acquired in hospitals, while 106,000 more die from harmful side effects of drugs that aren’t errors. Altogether, iatrogenesis—illness or death caused by medical treatment—may be responsible for as many as 225,000 deaths a year in the U.S., not including clear mistakes. An earlier report put the number even higher, between 230,000 and 284,000.
History
The term iatrogenesis comes from Greek, meaning “brought forth by a healer,” and in earlier uses could describe either good or harmful effects of medical care. Since Hippocrates, people have known that treatments might cause harm, a principle captured in the modern ethical rule “First do no harm.” By the 19th century, the spread of infection from autopsy rooms to maternity wards led to devastating childbed fever rates, a major iatrogenic disaster. Ignaz Semmelweis identified how this transmission occurred. Though scientific advances like antiseptics and antibiotics were expected to reduce such harm in the 20th century, iatrogenic illness still posed serious risks.
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Origins and historical context
Ignaz Semmelweis was an Austrian-Hungarian physician who in 1847 discovered that childbed fever deaths dropped tenfold when doctors washed their hands with a chlorine solution before seeing patients or after performing autopsies. At one hospital where he worked, physicians conducted autopsies on every patient who died. Semmelweis believed the fever was spread by "cadaverous particles" and saved many lives twenty years before germ theory was accepted. His fellow doctors rejected his findings, sometimes for reasons unrelated to medicine—like refusing to believe that a gentleman's hands could carry disease. The term "Semmelweis reflex" comes from author Robert Anton Wilson, who described it as "mob behavior found among primates and larval hominids on undeveloped planets, in which a discovery of important scientific fact is punished." Thomas Szasz said Semmelweis's story gave him a deep sense of how false truths can hold powerful social influence.
Confirmation bias
When Semmelweis proposed that handwashing could prevent childbed fever, he faced resistance because doctors at the time believed diseases spread through "bad air," a theory known as miasma theory. They also thought the illness was caused by patients’ own weakness rather than unclean hands. His idea contradicted these deeply held beliefs, leading many to dismiss his evidence even though studies showed handwashing reduced maternal deaths from 18 percent to less than three percent. This bias against new ideas, despite clear data, is what we now call the Semmelweis reflex.
Authority bias
People tend to trust authority figures more than evidence, and this bias played a major role in how Ignaz Semmelweis was treated. In the days before doctors understood germs, senior physicians like his professor Johann Klein dismissed Semmelweis’s idea that infections could be prevented through antimicrobial methods. The leading obstetrician, Charles Meigs, opposed him too, saying “doctors are gentlemen, and gentlemen’s hands are clean.” Even though Semmelweis was right, the medical community believed their respected elders instead. As a professor assistant at the time, he had little power to change their minds. This pattern of deferring to authority, even when wrong, is what we now call the Semmelweis reflex.
Semmelweis reflex as belief perseverance
The Semmelweis reflex shows how people hold onto their first beliefs even when faced with clear evidence that contradicts them. This pattern of thinking is linked to the way our brains work, especially the cerebral cortex and prefrontal cortex, which help us resist change and stick to what we already know. Because of this, belief perseverance can feel like a natural response, a way the mind avoids discomfort and resists shifting from familiar ideas. It’s not just about being stubborn—it's a deep-rooted human tendency that makes it hard to accept new truths when they challenge long-held views.
Semmelweis reflex as groupthink
In the 19th century, Semmelweis’s idea faced total resistance from the medical world, a clear case of groupthink stifling progress. When new concepts clash with widely held beliefs, individuals often shut them out to preserve their shared worldview. In response, Semmelweis wrote an open letter calling his colleagues “ignorant murderers,” a move that deepened his isolation. Studies show that when fresh ideas appear to come from outside or threaten group pride, they are harder to accept—even when they’re correct.
Semmelweis reflex as theory-induced blindness
In the book Thinking, Fast and Slow, Daniel Kahneman describes a phenomenon called “theory-induced blindness,” which helps explain why some false ideas persist. When people fully accept a theory, their minds—System 1—internalize it as a thinking tool, making it hard to see its flaws. Even when evidence contradicts the theory, System 1 assumes there must be a way to reconcile it, without digging deeper. Getting rid of such an entrenched idea requires conscious effort from System 2, which is why old theories can linger long past their usefulness.
Freud's methodology
Sigmund Freud developed his theory of psychological illness in Vienna from the 1890s to the 1930s, much like Semmelweis, the Viennese medical establishment rejected his ideas. Even after Freud became internationally known and respected, he never achieved the rank of ordinary professor in Vienna. He remained an hourly-paid Privatdozent, giving his one lecture on Saturdays from 8 to 10 am—a time slot that some modern lecturers still use for introducing psychoanalytical methods, keeping the tradition alive.
Albert Einstein's "Teutonic" critics
Albert Einstein’s work on relativity was attacked by nearly all major German physicists between 1900 and 1945, who dismissed it as "Jewish physics." Only Max Planck supported Einstein publicly, defending his theories when others refused to publish or accept them. Because of this opposition, Einstein could not work as a scientist in Europe, and instead had to take a job as a patent-office clerk while continuing his research. Without Planck’s help, Einstein might never have been able to share his groundbreaking ideas with the world.
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Overview
Hand washing, or hand hygiene, is the practice of cleaning hands with soap and water to remove harmful bacteria, viruses, and other substances. Drying hands is just as important because wet hands pick up germs more easily. When soap and water aren’t available, a hand sanitizer with at least 60% alcohol can work, unless hands are visibly dirty or greasy. The World Health Organization recommends washing for at least twenty seconds before and after certain activities, especially after using the toilet, changing diapers, and before eating or preparing food. In situations where neither soap nor sanitizer is possible, clean water and ash may be used, though their effectiveness is unclear. Regular hand washing can dry out skin, which increases infection risk, so moisturizing is often advised.
When it is recommended
Washing hands with soap is vital at five key times to stop the spread of disease via fecal-oral contact: after using the toilet, after cleaning a child’s bottom, before feeding a child, and before eating or preparing food. The World Health Organization outlines additional moments for hand hygiene in healthcare settings, recommending practice before and after touching patient surroundings, after patient contact, after exposure to body fluids, and before aseptic tasks. Other important times include before and after treating cuts or wounds, after sneezing or coughing, after handling animal waste or animals, and after touching garbage. These steps help reduce infection rates in both daily life and medical environments.
Health benefits
Hand washing with soap is the most effective and affordable way to prevent diarrhea and acute respiratory infections, which together kill nearly 3.5 million children under five each year. A 2013 study found that better hand hygiene can improve child growth, while research shows people touch their faces over 20 times an hour, spreading germs easily. In developing nations, simple changes like washing hands can cut childhood deaths from these diseases by almost half. Interventions promoting handwashing reduce diarrhea episodes by about a third and pneumonia-related deaths by one-quarter. UNICEF says making handwashing before eating and after using the toilet a habit could save more lives than any single vaccine or medical treatment, and this practice is often part of water, sanitation, and hygiene programs.
Adverse effects
A small downside to handwashing is that it can damage the skin, especially when done too often. A study from 2012 in Denmark found that washing hands too much can cause a dry, flaky skin condition called contact dermatitis. This problem is common among health-care workers. Using alcohol-based hand sanitizers frequently can also irritate the skin and make it dry. However, some formulations include moisturizers that may help reduce this effect.
Behavior change
In many places around the world, people don’t wash their hands with soap very often. A 2015 study looked at 54 countries and found that, on average, just under 40% of households washed hands with soap. Saudi Arabia had the highest rate, at 97%, while the United States was around the middle with 77%, and China had the lowest at 23%. To help change this behavior, programs now exist to encourage hand washing at key moments. One approach is group hand washing for school children at set times during the day. The “Essential Health Care Program” in the Philippines is one example of such a large-scale effort. It includes deworming twice a year and daily hand washing with soap, along with brushing teeth with fluoride, and has also been successfully carried out in Indonesia.
Recent Global Initiatives (2020-present)
In recent years, hand hygiene has stayed at the center of global efforts to prevent infections, especially after the COVID-19 pandemic. The World Health Organization reported in 2023 that fewer than 60% of health-care facilities in low- and middle-income countries have the basic resources needed for proper hand hygiene. To help fix this, the WHO and UNICEF started the Hand Hygiene for All initiative in 2020 to push hand hygiene into national health policies. In 2025, the WHO released new hand-hygiene recommendations that highlight the need for reliable access to water, soap, and alcohol-based rubs, along with safe grey-water disposal. These guidelines also stress clear instructions on when, why, and how to wash hands, as well as creating a physical and social environment that makes hand hygiene easy and accessible.
Soap and detergents
The act of washing hands with soap or detergents helps remove germs from the skin. These substances, known as surfactants, work by breaking down the protective layer of fats in microbial membranes and changing the shape of their proteins. They also mix with oils on the skin, making it easier for dirt and microbes to be rinsed away with water. This process is key to preventing the spread of infection, especially in medical settings where cleanliness can mean the difference between life and death.
Solid soap
Studies have found that bacteria on solid soap—due to its repeated use—can potentially transfer to others, though some research suggests the risk is low because the foam rinses most contaminants away. Despite this, the Centers for Disease Control and Prevention continues to recommend liquid soap, especially when hands-free dispensing systems are available.
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Overview
The history of medicine examines how practices have evolved over time using sociology, politics, and health sciences to understand the bigger picture. It traces human approaches to health and illness from ancient times to today, including when written records are missing, relying on archaeology instead. Early traditions came from Babylon, Egypt, China, and India. The microscope was invented during the Renaissance, helping improve understanding. Before the 1800s, people believed disease was caused by an imbalance of body fluids, but this idea gave way to the germ theory. Military doctors advanced surgery and trauma care. In the 19th century, public health grew as cities expanded. By the early 1900s, research centers opened, often tied to hospitals. Antibiotics appeared in the mid-1900s, along with progress in chemistry, genetics, and radiography. Medicine became more professionalized in the 20th century, especially for women, who entered nursing in the 1870s and medical school after 1970.
Prehistoric medicine
Prehistoric medicine looks at how early humans cared for illness and injury before writing existed, from around 3.3 million years ago until about 5000 BCE. Since there were no written records, researchers study bones, plant remains, and tools to understand what healing practices were used. Evidence shows that Neanderthals and other early humans used plants and minerals for medicine, like psilocybin mushrooms found in the Sahara around 6000 BCE or dental care from 11,900 BCE in Italy. One well-known example is Ötzi the Iceman, who lived around 3230 BCE and carried a small medical kit including birch polypore fungus, poppy seeds, sloe berries, and sphagnum moss—each for specific ailments. These findings show that even thousands of years ago, people were experimenting with self-treatment and healing.
Ancient medicine
Ancient history spans from around 3000 BCE to 500 CE, marking the era when writing first developed and ending with the classical period. During this time, societies across the world created their own ideas about healing, often mixing nature, religion, and beliefs about energy and fluids. Though some texts and scholars offered detailed medical knowledge, that understanding was often lost or changed as it moved from place to place. Communication broke down, and practices became inconsistent, leaving real-world applications of ancient medicine unclear and unreliable.
Ancient Mesopotamian medicine
In present-day Iraq, Kuwait, Syria, Iran, and Turkey, early civilizations like the Sumerians, Akkadians, Assyrians, and Babylonians formed healing practices blending science, magic, and religion. The Sumerians developed one of the first writing systems around the 3rd millennium BCE, leaving cuneiform tablets with drug prescriptions, operations, and exorcisms performed by professionals like bârû (seers), âs[h]ipu (exorcists), and asû (physician-priests). A prescription-like medicine from the Third Dynasty of Ur dates to around 2112–2004 BCE. After Sumerian conquest by the Akkadian Empire, Babylonian culture took over, and in the middle of the 11th century BCE, a major medical text called the Diagnostic Handbook was composed by Esagil-kin-apli, chief scholar of Borsippa. It focused on diagnosis, prognosis, physical examination, and remedies, using logical rules to connect symptoms with treatments based on theories involving natural causes, supernatural magic, and religious explanations. Most recovered artifacts come from later periods ruled by native Mesopotamian leaders, including many medical clay tablets, although damage limits our understanding of their full practices. These civilizations also showed awareness of disease prevention, stroke, and mental illness.
Ancient Egyptian medicine
Ancient Egypt, lasting from around 3150 BCE until Alexander the Great's conquest in 332 BCE, developed one of the world's earliest and most complex medical traditions. Surviving documents like the Edwin Smith Papyrus, possibly dating back to 3000 BCE, contain detailed surgical knowledge with no trace of magic, and are considered among the oldest surgical texts ever written. The Kahun Gynaecological Papyrus, from around 1800 BCE, deals with women's health issues, while the Ebers Papyrus mentions enemas and names specialists like the Iri, or "Shepherd of the Anus." Imhotep, a figure from the Third Dynasty, is sometimes credited as the founder of Egyptian medicine and possibly the original author of the Edwin Smith Papyrus. The earliest known physician was Hesy-Ra, who served King Djoser in the 27th century BCE, and Peseshet, a woman titled "Lady Overseer of the Lady Physicians," practiced during the Fourth Dynasty. Medical institutions called Houses of Life were established as early as 2200 BCE. Herodotus noted that Egyptians were among the healthiest people on Earth, partly due to their advanced public health system and highly specialized doctors.
Ancient Chinese medicine
Medical practices in early China were shaped by traditional Chinese medicine, with roots dating back to the Zhou dynasty and reflected in ancient texts like the Classic of Changes and the Classic of Poetry. The foundational text, the Huangdi Neijing, was written between the 5th and 3rd centuries BCE. Later, during the Han dynasty, Zhang Zhongjing referenced it in his Treatise on Cold Damage around the end of the 2nd century CE. In the Jin dynasty, Huangfu Mi quoted the Yellow Emperor in his Jiayi jing around 265 CE. By the Tang dynasty, the Suwen had been expanded and revised, becoming the best surviving version of core principles including herbal treatments, acupuncture, and massage. Critics argue that TCM lacks scientific foundation, with a 2007 Nature editorial calling it "fraught with pseudoscience" and a 2008 review stating scientists still cannot find evidence supporting key concepts like qi, meridians, or acupuncture points.
Ancient Indian medicine
The Atharvaveda, a sacred Hindu text from around 1200 to 900 BCE, is among the earliest Indian medical writings, blending spells and herbal remedies. Later, around 600 BCE, Ayurveda emerged as a full medical system, built on earlier practices and theories. Charaka and Sushruta were two key figures whose texts, the Charakasamhitā and Sushruta Samhita, shaped this tradition. These works covered diagnosis, treatment, and surgery, including detailed descriptions of over 125 surgical instruments and procedures like rhinoplasty and cataract surgery. The medical system recognized eight branches, from internal medicine to toxicology, and required students to learn not just medicine but also metallurgy, pharmacy, and distillation.
Humors
The theory of humors, dominant in Western medicine until the 19th century, originated with Greek philosopher and surgeon Galen of Pergamon (129-216 CE). This system linked four bodily fluids—blood, phlegm, yellow bile, and black bile—to illness and personality. Hippocrates, around 400 BCE, connected these humors to seasons and life stages: spring with blood, summer with yellow bile, autumn with black bile, and winter with phlegm. Galen associated temperaments with humor imbalances, describing phlegmatic traits as calm and introverted, melancholic as moody and depressed, sanguine as extroverted and cheerful, and choleric as aggressive and impulsive. Treatment involved restoring balance through methods like bloodletting, purging, or expectorating, while considering factors such as climate, diet, sleep, and emotions. Galen identified three faculties—natural, vital, and psychic—related to growth, emotion, and thought, with the liver producing the natural faculty, the heart the vital, and the brain the psychic. Blood was believed to be formed in the liver and carried through veins, while arterial blood resulted from air mixing with blood in the lungs. Half of the bile produced went into the blood, and half to organs like the gallbladder or spleen.
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Overview
Puerperal fever was a deadly illness that struck women in the first few days after giving birth, bringing sudden and severe symptoms like intense abdominal pain, high fever, and weakness. It was often caused by contaminated medical tools or unclean hands during delivery, spreading infection from the genital tract. Though it's rare today thanks to better hygiene and antibiotics, this disease once devastated mothers and their families.
The work of Dr. Ignaz Semmelweis
At the Vienna General Hospital, Dr. Ignaz Semmelweis served on a three-year contract beginning in 1846, working in the maternity clinic where puerperal fever was killing nearly forty percent of patients. The high death rate troubled him deeply, leading him to theorize that infection spread through decaying matter on doctors’ hands after performing autopsies. He proposed using chlorinated lime for handwashing—a disinfectant known to kill germs. His ideas contradicted the medical beliefs of the time, before germ theory had been accepted. His theory was rejected and ridiculed, and his contract was not renewed. He was effectively banished from the medical community in Vienna. Semmelweis died alone, in a mental institution.
Puerperal fever – a modern disease
An 1841 account describes childbed fever as a modern disease, noting that historical documents offer limited evidence to judge its presence in earlier times. The cases reported by Hippocrates, often thought to be puerperal fever, were actually bilious fever — a condition common among maternity patients that was no different from its occurrence in non-maternity patients or men. Hippocrates himself never recognized it as a distinct disease.
Hospital Hôtel-Dieu de Paris
In 1664, at the Hôtel-Dieu in Paris, Phillipe Peu documented a severe outbreak of what would later be known as childbed fever, noting that mortality among newly delivered women was exceptionally high, with certain seasons proving more deadly than others. The infection, described as la fièvre puerpérale, became a recurring winter threat at the same hospital starting in 1774, with records showing that as many as seven out of twelve maternity patients were struck down each year.
The maternity clinic at Würzburg
At the small maternity clinic in Würzburg, Franz Kiwisch von Rotterau reported 27 deaths among 102 patients in one year, a rate of 26.5%. That was much higher than what Semmelweis had seen in Vienna. He explained the difference by pointing out that in smaller hospitals like Würzburg, every patient was often used for teaching purposes. In contrast, "in Vienna there is such an excess of teaching material that hundreds of individuals are not used for teaching and thus are not infected."
Inconsistencies in data
There are inconsistencies in the data that Semmelweis collected and published, especially when comparing yearly and monthly figures. He noted that actual death rates were often higher than recorded because women who died during childbed fever outbreaks were sometimes moved to the general hospital, where they weren't counted in maternity ward records. Some patients were even released from the maternity ward and later readmitted to the general hospital after symptoms appeared. A similar issue occurred at the Charité hospital in Berlin, according to Joseph Hermann Schmidt. Semmelweis worked at the Vienna General Hospital, which had two maternity clinics, but he didn't always clarify whether his numbers included both or just one. The figures come from the 1861 work translated by Carter in 1983. There were also small math errors in some calculations, so all rates on this page have been recalculated.
Explanatory power of his theory of cadaverous poisoning
From his theory that decaying matter on doctors' hands caused childbed fever, Semmelweis could explain why winter mortality was so much higher than summer. In winter, students returned from vacation and flooded the maternity hospital while also visiting the morgue and surgical wards more frequently. The assistant of obstetrics held cadaver exercises before afternoon rounds in winter, but not in December 1846 and January, February, and March 1847—when the first clinic saw lower death rates. Semmelweis had Carl von Rokitansky's permission to examine all female corpses, and on 20 March 1847, after conducting gynecological studies in the morgue, he began examining patients. His contaminated hands then came into contact with many women in labor, leading to 57 deaths out of 312 in April—18.3 percent. He also explained why women with extended dilation often died: infection usually occurred during manual examination, before chlorine washings were used.
Yearly patient mortality rates at the Dublin Maternity Hospital 1784–1849
Semmelweis looked at death rates in Vienna and compared them with those in the United Kingdom, where they were lower. He chose the Dublin Maternity Hospital as an example, noting it was like the Viennese hospital in being a large teaching institution for physicians. He argued that German and French maternity hospitals often shared buildings with general hospitals, meaning students worked in morgues and surgical wards, becoming carriers of disease. In contrast, maternity hospitals in the UK were separate from general hospitals, so students focused only on obstetrics and did not perform autopsies.
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