So what links farting, mythical beasts and religious miracles?

Our Microbial Overlords were an occult phenomenon for almost the entirety of the 250,000 years we’ve been around.

We remained blissfully ignorant of the true origin of the largesse they granted us – beer, wine, bread cheese, salami, kimchee, even Cupriavidus metallidurans which excretes solid gold – until very recently.

Yes, we were painfully aware of the odd plague here and there but we blamed those on demons, tainted blood, humours and all sorts until quite some time after Janssen (not Leeuwenhoek!) invented the microscope.

The impact Our Microbial Overlords have had on us – and their interwoven-ness with our lives – never ceases to astound me, but there are some amazingly cool jokes they’ve played on us in the past.

Forget the pestilence for a moment and draw up a chair…

Farting and Dragons

For any small (or large) boy, the humble fart has to be one of the most brilliant manifestations of Our Microbial Overlords; it’s free, it never ceases to entertain, and is clearly intended to be shared.

Its aetiology is everso simple; there are many simple sugars (oligosaccharides) we cannot digest so the bacteria in our gut (principally in the colon) do it for us. And yes, beans are a great source of these oligosaccharides. The bugs ferment the oligosaccharides into molecules such as acetic, propionic and butyric acid, providing energy and helping the absorption of essential dietary minerals such as calcium, magnesium and iron.

But a key by-product of this fermentation is hydrogen gas. Lots and lots and lots of it. About a third of us produce methane as well (due to archaea such as Methanobrevibacter).

And 99% of flatus is odourless – it’s the 1% methylmercaptans and sulphides that whiff.

It’s extremely unlucky to be superstitious for the simple reason that it is always unlucky to be colossally stupid. – Stephen Fry

Anyway, we each produce 0.5 – 1.5 litres of flatus every day, the vast majority of which is hydrogen. As the flatus escapes the repeated and rapid opening and shutting of the anal sphincter forms the round of applause that gives the outburst its characteristic sound.
But what’s this got to do with dragons? Or superstition?

Rather a lot, apparently.

Bear with me here. It’s soooooo worth it.

Dragon myths exist in many, many cultures. There are two distinct traditions: the European version is more akin to a winged lizard but the original Asian one is a fire-breathing serpent.

And Asia, unlike Europe, is home to some pretty humongous snakes. The Burmese python, for example, will snack on rats or the Fluffy Vermin but given half a chance can and will eat crocodile – or deer and other ruminants.

Which all will decompose and swell with precisely the same fermentation gases my six-year-old generates in prodigious volume.

Studies on pythons and rats have shown that a few days after having been eaten, the rat will burst (euwww!) under the pressure of the gas generated as its gut flora fart hydrogen like billy-o.

The point at which a snack rat explodes has been measured with gas chromatography in some truly demented scholarship.

Let’s go Paleo for a moment. I’ve written about Paleo myths before but forget all this hunter / gatherer romantic bollocks – we were and still are lazy scavengers at heart and will happily have a go at prey something else has killed.

Even a dozy snake replete with some poor mammal it scoffed earlier and is sleepily digesting. Bash it on the head and drag it back to camp. Result.

Chemistry time. You need ~>5% hydrogen in air for it to ignite. (As I’ve said, farts are mostly hydrogen but a 50-100ml average fart will be diluted so rapidly that to ignite it you need to hold a match right up close to your Chocolate Starfish – and no, that’s not a recommendation).

Back to our ex-snake. Bear with me, FFS. The fermentation gases which would be bloating it from its last meal will comprise far in excess of 5% hydrogen / methane. Just picture chucking that on the ‘barbie and the size of the plume of flame that would inevitably spew forth from its gob.

One can only imagine our ancestors’ reaction: you’ve spent all day foraging, you score some really ace protein (I’ve eaten snake and can recommend it highly) you’re chillin’ by the campfire, looking at the stars, nice gourd of wine, and all of a sudden your quietly-searing supper pukes an epic plume of fire – and most likely makes a hell of a noise too.

So, the leap from that to folklore of fire-breathing serpents isn’t really a leap at all. And this is probably how we discovered adrenalin is brown (that’s epinephrine for my colonial readers)…

So now you know how Our Microbial Overlords scared the living shit out of us and gave rise to the dragon myth.

But it gets better.


You can check the Wiki for this one, but according to the Catholic Church, bread and wine are not symbolic, they

become, in a way surpassing understanding, the Body and Blood of Christ”.

At a church near you, every Sunday.

Surpassing understanding”. Couldn’t have put it better myself. Anyway, actual, physical proof of the conversion of bread to bleeding flesh has been witnessed many times, most notably at a Mass at Bolsena in 1263, led by a priest who had doubts concerning transubstantiation. So he was sent a sign.

During the Mass, the Eucharist appeared to bleed and each time the priest wiped away the blood, more would appear. This event is celebrated in a fresco painted by Raphael you can see in Vatican City and led to Pope Urban IV instituting the Feast of Corpus Christi in 1264.

 Doubts about the Invisible Man In The Sky Who Despite Being Omnipotent Still Needs Your Flock’s Cash? Silly boy. Say six Hail Marys and bugger a few more kids and let that be the end of such nonsense.

This is also the reason Serratia marcescens is my favourite bug ever and why no other will ever replace it in my affections.

Serratia is the bug that causes that pinky sort of guck you get growing on the tile grout in your shower. But when it grows on bread it produces copious amounts of a blood-red pigment called prodigiosin. You get the namby-pamby pink version in showers etc because of all the phosphates in soap scum etc – but deprive it of phosphate and the pigment-producing strains go nuts.

So leave it on bread (or communion wafers) for a week and guess what happens?

It appears to be weeping blood.

There are other blood myths but all have been debunked.

But what happens when pigmented strains of Serratia marcescens grow on bread offers a neat explanation of Medieval transubstantiation miracles – where bread is converted into the body of Christ in front of your very eyes…