It seems wierd that in a time when mathematics, chemistry,physics, even biology was developing at high speeds, the connection between washing your hands before performing surgery and less chance of infection was completely unknown.
The only reason why you think that handwashing is a 'good' thing to do between surgery is because you've had 150 years-worth of medical evidence to support that idea. You know about germs, germ theory, proper experimentation, so it's natural to you because there is no other paradigm to give an alternative explanation. Things make sense to us because they fit our expectations, and handwashing didn't fit the paradigm. You need several things to come together - a model, evidence, and critical mass. Marco Varro said in the first century BC that living in marshy areas put you in reach of tiny minute animals which would get into your nostrils and give rise 'to stubborn distempers', but the notion of invisible creatures you can't see wouldn't have gained any currency - no microscopes until the 1600s- and alternative disease theories are floating around (imbalances in the four humours).
So we have to go back a bit to understand where the ideas stem from. In the 16th century, An Italian, Lancisi suggested (alongside Varro), that animalcula floated around in the atmosphere, and that these could cause and irritate wounds. Importantly, he notes that inorganic matter can't be the cause of disease. So we're on our way to some sort of organic theory of disease, but it's one thing to identify a disease, it's another to understand how it's transmitted. That's a problem.
A pamphlet in 1721, written by Mr Place, suggested that chemical compounds could not in themselves cause disease, so we shouldn't be looking for miasma and infections in chemicals, it's organic. Benjamin Marten in 1720, said that diseases are caused byanimaculae, not by spontaneous generation. By 1762, Marcus Plenciz said that disease is carried by infectious living agents, but that they also multiply in the body and are carried in the air. In the late 1700s to early 1800s, Agostino Bassi, an Italian, said that a number of diseases such as syphilis and gonorrhoea are caused by animal parasites -an astounding proposition that unfortunately was published later in 1835. There's plenty more before 1850 that bring out the idea that disease is transmitted by germs, but how things are transmitted is the issue. So while we have people with a correct concept of what disease is, we need a model of transmission, we need enough evidence to make it certain, and then we need critical mass to make it happen.
This is where Semmelweiz normally pops into the discussion. He's normally flagged as the poster-child for handwashing and how he discovered that women with puerperal fever died because the hospital assistants and doctors didn't wash their hands. Semmelweiz is a good example of good propaganda, because the story is a lot more complicated than that, and stories love an underdog and Semmelweiz suits (or suited) the bill. But the truth is a bit more complicated and contrary.
In 1815, 30 years before Semmelweiz started his work, the English surgeon William Hay said, regarding puerperal fever:
It was an invariable rule with me never to attend a patient in childbirth, in any article of clothing which had been in the presence of one affected with the puerperal fever, nor without washing repeatedly such parts of my person as could be exposed to infection.
But he wasn't the first either. Charles White found in the late 1700s, that childbirth fever could be reduced by isolation and cleanliness. Alexander Gordon, in Scotland discovered that it was doctors who were transmitting the disease. Over in America in 1843, Oliver Holmes wrote in the New England Journal of Medicine about a young doctor who in 1835 had discovered that changing his clothes and washing his hands in chlorinated lime reduced childbed fever rates. Holmes recommended that physicians should never attend autopsies prior to attending birthing women, change clothes after attending a delivery, and leave gaps in attending infectious women in childbirth, and that this information should be passed on to nurses and assistents. Holmes was ridiculed for this.
But now lets go to Semmelweiz, working in hospitals that had actually adopted Charles White's principles but then had abandoned them. Death rates started to rise, and Semmelweiz suggested that puerperal fever was caused by
cadaverous tissue causing childbed fever,
alive people producing cadaverous tissue causing childbed fever (he didn't know how) and
dead animal flesh producing childbed fever.
It was fairly obvious to anyone at the time that what Semmelweis was saying through all 3 theories was contradicted by findings elsewhere, specifically
women had been catching childbed fever before autopsies had been around
he didn't provide examples for this theory although he dogmatically said that it was the answer
his examples for alive people producing cadaverous tissue made no sense as the women involved did not catch the disease themselves (one woman with cancer of the uterus, one with a rotten knee).
So Semmelweiz has made a transmission theory error, even though his solution (washing hands etc.,) is actually correct. He published his work in 1849, quite some time after all these ideas had already been floating around. In fact, the famed surgeon James Young Simpson wrote letters to various medical journals pointing out that Semmelweiz wasn't the first one to suggest this.
I'm moving into an anti-Semmelweiz rant now, so let's try to bring this together. Handwashing had been around for some time and had been correlated to healthier patients. Why, wasn't known properly, it just 'worked'. Semmelweiz's problem was that he was a thoroughly unpleasant man, who despite the pleadings of various scientific establishments, refused to publish his work or engage in experimentation that would have proved his research. He said that doctors were the cause, which annoyed all the doctors. He said that the disease was monocausal when everybody knew it wasn't. It was his friends who had to push out his theories while he was still alive: Joseph Skoda (1805–1881), pathologist Carl von Rokitansky (1804–1878), dermatologist Ferdinand von Hebra (1816–1880), and surgeon Ludwig von Markusovszky (1815–1893).
We need to understand germs and how to kill them to complete the circle. Louis Pasteur, as tagged by Wikipedia, is responsible for vaccination, microbial fermentation, and er, pasteurization,, which would have come as a surprise to Benjamin Jesty, a farmer who vaccinated his family in 1774, (followed by Jenner 20 years later), Antoine Bechamp on microbes and germs, at least 20 years earlier than Pasteur - aaand I'm going off on a rant again. Anyway, Pasteur and others bring up germs and how they work and how they're responsible for bad things, providing some substantiation for what Semmelweiz thought he saw. Sometimes there's a distance between discovery and knowledge- cholera was 'discovered' well before it was understood that it caused cholera. How do you kill them? Handwashing is a good start as Semmelweiz said, but people still die. The disease is still there even though you wash your hands.
Joseph Lister, some years after Semmelweiz died, is credited with the discovery that carbolic was good for killing germs (1867) despite that it was mentioned in the medical journal, The Lancet in 1863, and had been previously used in America although without much success, and a French surgeon, Dr Lemaire, had been using it since 1865. Nevermind, the point was that carbolic, in varying quantities, was good for killing germs. Washing your hands with carbolic soap is very good for killing germs. Spraying it around your operating theatre like Lister did, is good for killing germs, but also good for killing surgeon's lungs. This practice is modified by William Arbuthnot Lane, who rather than using carbolic spray, soaked his clothes in lysol, and his medical instruments in carbolic. Later on, he introduce steam sterilization and boiling his instruments between surgery, and thus the circle of life is complete.
There could be something to say about other fields developing at high speeds, but that's another post.
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