That is actually quite a clever idea. I wonder what factors would lead to one location having higher microbe density than others? Probably things like nearby sewers, meat / fish markets, etc.
Edit: since the chosen location was besides the Tigris river, maybe the river fauna acted as a natural pest control. Less flies and mosquitoes absolutely would help hygiene.
To quote the wikipedia source: "hanging a piece of meat in several places for a few days and deciding in favor of the place where meat was found to be least infected." Infected definition = "contaminated with an infective agent (such as a bacterium or virus)."
I think they could likely see some infective agents such as flies, maggots, and spoilage in meat, and translate this to their own flesh as analogous to meat. In terms of theory, my best guess is simply one of "meat goes bad when it is infected by parasites (i.e. maggots as well as perhaps stuff we do not/cannot see)"
Note that per  "Basic forms of germ theory were proposed in the late Middle Ages by physicians including Ibn Sina in 1025"
Whereas, from OP's source: "The Al-Adudi Hospital was founded in 981 by the then ruler of Baghdad, Adud al-Dawlah, and was also named after him"
Given the proximity of those dates (981 vs 1025)-- the proposal of Germ Theory by Middle Eastern (specifically, Persian in the case of Ibn Sina) doctors, and the hospital's founding in the near Middle Eastern region of Turkey a few years decades earlier, and the prolific nature of science in the Medieval Islamic-sphere of influence/Middle Eastern world, I think it's a decently strong argument that the basis is very early germ theory.
Note that also per  germ theory was stated pretty well in the first century BC:
> The Roman statesman Marcus Terentius Varro (116–27 BC) wrote, in his Rerum rusticarum libri III (Three Books on Agriculture, 36 BC): "Precautions must also be taken in the neighborhood of swamps […] because there are bred certain minute creatures which cannot be seen by the eyes, which float in the air and enter the body through the mouth and nose and there cause serious diseases."
This doesn't really differ from the germ theory of disease as we understand it today.
But when the microscope was discovered in the 17th century people looked at microorganisms and found that the grosser the sample the more microorganisms you could find. That was material to work with, and the germ theory followed in due course.
That's true, but it doesn't stop people from doing things that are "correct" based on the theory.
> But the Greeks had no way of detecting atoms.
There's an experiment in which you pour oil over water with a movable constraint on one side. As you enlarge the area available to the oil, it will eventually become unable to cover the water, suggesting that it is not infinitely divisible. This is well within the means of the Ancient Greeks.
Oil molecules are gargantuan monstrosities, not atoms, but I think it's similar enough to count.
More compelling would be Brownian motion. Glass was known in the Hellenistic era, and the Romans were expert stonecutters. The principles of optics were known to the Ancient Greeks, and some guy could have made lenses and assembled them into a microscope. Unfortunately that path was not taken until the 1600s, but the technology was all there.
I disagree. Germ theory also covers stuff like non-airborne transmission (food/water/bodily fluids). The only thing that it got right is "you can get infected by invisible things in the air", but even then it's not that accurate. Do people really get sick from the air near swamps, or is it the mosquitoes?
First, that's not correct; the germ theory of disease is simply the statement that diseases are caused by germs as opposed to being caused in some other way. Transmission is not a part of it.
Second, if you believe that small creatures too small to see can make you sick if you inhale them, it's not really a stretch to think that those creatures can make you sick if they get into your body by any other means.
(Note that not all apparent diseases are caused by germs; some are caused by genetic conditions, some are caused by dietary deficiencies, some are caused by inorganic poisons, and some are caused by creatures which are easily large enough to see with the naked eye. Does this make the "germ theory of disease" incorrect?)
“The miasma theory (also called the miasmatic theory) is an obsolete medical theory that held that diseases—such as cholera, chlamydia, or the Black Death—were caused by a miasma (μίασμα, Ancient Greek for "pollution"), a noxious form of "bad air", also known as night air. The theory held that epidemics were caused by miasma, emanating from rotting organic matter. Though miasma theory is typically associated with the spread of contagious diseases, some academics in the early nineteenth century suggested that the theory extended to other conditions as well, e.g. one could become obese by inhaling the odor of food.”
I think that’s an educated guess in the basis that this was a wide-spread theory, and fits the experiment performed.
Not far from the truth either, quite impressive for 1000 years ago.
By air alone? How far can it possibly spread? Can you get measles if you walked within 100ft of a mass grave? miasma theory would say yes, but I doubt that's actually the case.
If you include other forms of transmission (eg. insects, animals, food/water), then it can definitely spread miles away, but this goes back to my original point of only being correct about disease being (loosely) correlated by distance. But even then it gets a bunch of stuff wrong. A rat with the bubonic plague stowed away on a ship can infect people hundreds of miles away, for instance. You could also live next to a mass grave and be fine as long as you have mesh windows and boiled your drinking water.
What would be the limiting factor on how far it can spread? Do the particles deactivate after a while in the air? Or is it that the concentration is not high enough? Latter case, wind patterns would matter a lot.
Surely, when authorities talk about diseases being able to spread x many feet, it ignores many factors and is meant to be an actionable simplification that works in a statistical sense.
> For corruption of understanding is much more a plague than such a distemper and change of this environing atmosphere; for this is a plague to animals, as animate beings, that is a plague to men, as human beings.
I know my response is glib, but no "theory of" is needed to do useful work. Humans can build intuitive understanding through personal experience, observation, and thinking. And they can pass some forms of this understanding via apprenticeship, laws, rules, organizational structures and cultural norms among other things.
+ the causes of disease are the same as the causes of meat rotting
+ that cause is localised in space, and stays there over time
The healthcare may have been primitive but the policy goes further than what a lot of countries offer today.
But I still wondered if my (and your) surmised interpretation would hold true. I think it is well understood (certainly is within the medical community) that hospitals are a dangerous place to be, though clearly if you’re seriously ill it’s worth the risk. But do hospitals pose a risk to their neighbours?
I don’t understand this side comment. What are you referring to? The supposed source (bats) came from an infested market in China, not the US