The Lancet: You do, in fact, know something, John Snow

The editors of The Lancet (the long-running British journal of medicine) issued a correction this week for several rude statements and a rather terse obituary that it published in the 1850s. All of these relate to John Snow, the epidemiologist famous for figuring out that cholera was spread by contaminated water. The trouble with this: Snow's evidence-based arguments stepped on the toes of a former Lancet editor who believed strongly that such diseases were caused by bad air — and who had, as a consequence, led an initiative to ban tanners, soap makers, and other smelly professions from the city of London. Snow had testified before Parliament that bad air could not possibly cause disease. A feud ensued.


  1. I was of course hooked by this expecting some Game of Thrones insight. Great story anyway.

    1. I wonder if his testimony before Parliament included the plea “I want to fight for the side that fights for the living.”

  2. So actually, it sounds like  Dr. Snow was in the wrong in the area that made the previous editor of The Lancet upset, although for reasons separate from his thesis. He testified that tanneries didn’t cause disease, which is certainly true for cholera but considerably less so for cancer and nervous system problems associated with chromium, mercury, hydrogen sulfide, etc.

    Or, to put it another way, just because you know something doesn’t cause one disease doesn’t mean that it’s necessarily perfectly fine.

    1. “Snow told Members of Parliament that the foul smells from processes such as tanning and soap boiling were not capable of producing acute fever or epidemic disease in an individual.”

      To be precise, the other things you mentioned aren’t exactly caused by the smells of tanneries.  Pointing out that one aspect of a bunch of professions doesn’t indicate their danger doesn’t necessarily mean all of those professions are perfectly fine, either.

      1.  I think you’re being overly pedantic. I don’t think anyone was suggesting that the literal smells are bad, but that, the “noxious gases and vapours” are. And that’s true, and it was good for public health to control them. It’s a shame that it was seen as a zero sum game rather than a case where both bad air and bad water could be unhealthy in different ways.

        1. Best as I can tell from the linked article, that’s is *exactly* what they were suggesting. “miasma, or the stench from decaying vegetable and animal matter, was widely held responsible for epidemic disease.”

          Oh, and hey, look, here’s a quote from sanitary reformer Sir Edwin Chadwick, testifying to Parliament in 1846: “All smell is, if it be intense, immediate acute disease; and eventually we may say that, by depressing the system and rendering it susceptible to the action of other causes, all smell is disease.” That didn’t take too long to look up.

          1. I think you’re basically suffering from wording issues and pedantry (and ontological persnicktyness) over smell vs. thing-which-smells. H₂S smells very bad and is indeed poisonous.

          2. Have you been sniffing toad farts?  Look up the miasma theory of disease and how it was used to suppress the germ theory of disease for decades, fueling public health crises and killing millions.

          3. You keep accusing people of “pedantry” when it’s more accurate to say that they’re being factually correct. 

        2.  EvilSpirit covered it, but I’d point out that the professions that were in danger were being lumped together precisely because they all smelled bad, and that part of what triggered the feud was Snow pointing out that the people who worked in those professions weren’t coming down with illnesses that were being blamed on these smells.

          You also claimed that “Dr. Snow was in the wrong in the area that made the previous editor of The Lancet upset,” but the area in question was specifically “acute fever and epidemic disease” being caused by these smelly professions.  There may have been other health risks associated with some of these professions (I’m sure soap-makers were well aware of many of the dangers of what they worked with), but that doesn’t make him any less correct.

          1. What’s more, his study had at its geographic heart a brewery which was also suspected of foul smells and vapors.  But few of the brewers got sick.  Only ones who lived nearby and drank from the infected wells outside of the brewery.  The brewery drew its water from a different source, unaffected by the waste stream.  So the workers there had no exposure.  His study was brilliant on so many levels.  For anyone looking to make a takedown of Snow, you are a bunch of friggin’ idiots.  Seriously.  Without what Snow did, we wouldn’t have the robust epidemiology we have today.

          2. @mattdm:disqus “That can all be perfectly true, while it is still also true that industrial pollution is toxic.”

            No one (including Snow) has said anything to the contrary.

            The smelliness of an industry is not necessarily an indicator of whether it will cause illness.  And even if it was a solid indicator, Snow wouldn’t be wrong about it because the toxicity of industrial pollution, and the medical problems it causes, were not what was being investigated.  At the time, epidemic disease was a much higher risk to life, and banning soap-makers certainly wouldn’t have done anything to help matters in that regard.

            The editor of The Lancet certainly wasn’t correct in claiming that soap-making and tanning were causing epidemics of communicable diseases, was he?  So how can you say Snow was wrong?

    2.  By that logic, we are ALL wrong, because 100 years hence, everything we take for granted will be considered wrong.  This is similar to lex retro non agit

        1. The logic of your “other reasons” theory.

          Your tannery/cancer theory was unknowable then.  It would be another 100 years before a tannery/cancer link could be established.  So you can’t look back in history and say, “John Snow, you wrong-headed idiot, you might have been right about the cholera, but good gawd you were WRONG about the cancer and cns diseases, you fool! The Lancet had a good point to criticise you, but not for the reasons they thought!”  &c.

          …Cavemen, you stupid idiots, you didn’t know that cuts get infected?  Didn’t you have antibiotics?  Didn’t you know?  You stupid heads.

          1. He _was not_ wrong.  With the available scientific knowledge at the time, he was well within the right territory.

          2.  So, awjt, your thesis here is that the “cavemen” were perfectly right to ignore infection because they didn’t know the science behind it, or that the people ignoring water sanitation “were not wrong” because they didn’t have the available scientific knowledge?

            That’s silly.

          3. How can you ignore something that nobody knows about, including yourself? It’s silly to suggest that ignorance is the same thing as ignoring.

    3. You’re missing a big point here, which is that, thanks to diseases like cholera, diseases like cancer weren’t as big of a deal back then because people didn’t live long enough to get them as often. 

    4. In addition to all the other reasons you’re wrong, the process of using chromium in leather tanning wasn’t even invented, much less popularized, until well after Snow had published his treatise. So even if 19th-century Londoners had been avoiding death from other causes long enough to worry about cancer, their leather wouldn’t have been tanned using carcinogens in the first place.

  3. The Lancet has a history of acting too late.
    I’m thinking of the MMR vaccine, of course, and Wakefield.

  4. Steven Johnson’s book “The Ghost Map” is recommended reading for anyone interested in the subject. Its a fabulous and entertaining book.

    Mr Miller, you’re being obtuse simply for the joy of being contrary. Modern understanding of industrial pollution in no way vindicates the beliefs of the Miasmatists of Snow’s era, they were as wrong as flat earthers.

    1. I must second that book recommendation.  I think it would make a fantastic mini-series.

      Unless I’m mistaken, Snow also developed different types of general anesthesia and administered some to Queen Victoria for at least one of her births.  He would sit at his desk with his various concoctions, inhale one, black out, and then start writing notes when he awoke.  That would make a great scene.

      It’s impossible to overstate the benefits of his detective work in discovering the source of cholera.

Comments are closed.