18 August 2012

Scicurious | Beans, Rectal Tubes, Mylar Pants, And Duct Tape

Scicurious at Friday Weird Science | Neurotic Physiology:

We humans have always been interested in farts, above and beyond many bodily functions. Because, well, farts sound funny. And they stink. So, hilarious, is what I’m saying. Guaranteed to make any social situation immediately more awkward.

And of course, you do wonder, what MAKES the smell? The sound is easy enough, passing air through a tight tube like your anus is going to produce some sound at the right angles. But the smell? What causes that? And because it’s a gas, it’s extra hard to tell. I mean, you see vomit and you know what’s in it. Urine and feces can be easily collected and studied. But gas? Gas is so ... volatile (you see what I did there.)

This is why you need the rectal tube. And the duct tape.

The authors of this study were interested not only in the chemical content of farts (specifically the chemicals that produce the smell), they were also interested in how to CONTAIN the fart, how to reduce it and control its odor, to save us all from humiliation at various points in our lives. The authors of this study are not the first to attempt such a feat. Benjamin Franklin famously noted that we should be looking for things to eat to make farts smell more pleasant (whether he tested them scientifically is lost to history.)

But these authors were going to do it, and going to do it in a scientifically controlled fashion. They took 16 volunteers, and fed them an extra 200g of pinto beans (one of the best beans for producing some good gas) the night before and the morning of the experiment. They added some lactulose two hours before specimen collection as well, to ensure maximal gas output.

Now, we’re just going to put this tube in your rectum to create an airtight seal … wait, where are you going? Once the tube was in, the participants let it fly, and each fart was collected in a syringe and analyzed with a gas chromatograph (how appropriate!). The gas was also rated by two independent judges for the … Intensity … of the smell.

What did they find? Well, the major odor producing compounds were, rather unsurprisingly, the sulfides, hydrogen sulfide and dimethyl sulfide, with an extra dose of methanethiol. The more of these you had, the more intense the smell. In fact, the scientists worked out the EXACT concentration: 0.9 mmol/L hydrogen sulfide, 0.36 mmol/L methanethiol, and 0.18 mmol/L dimethyl sulfide. You can now make your own joke fart odor in the lab! You’re welcome. Women had higher concentrations of hydrogen sulfide and a greater odor intensity than men, but men passed way more gas, resulting in equal amounts of “malodorous” material. Quantity vs quality, I suppose.

But of course, we all know that the smell is bad. The question is is, how to stop the smell? To find this out, the authors mixed the farts with different things, zinc acetate or activated charcoal, to try and rid of the smell. Activated charcoal worked best.

But now, you have to get the farts mixed with activated charcoal before they hit the outside world. Enter the mylar pants and the duct tape. The participants (lucky people!) put on pairs of Mylar briefs.

These were made skintight by liberal application of duct tape, and checked by immersing the people in a tub of water while they farted (taco, burrito, what’s comin’ out of your Speedo?) Half of the participants got Mylar pants filled with control substance, while the other half got activated charcoal cushions (the Toot Trapper, tm). Then they measured the volume of the gar escaping the gas tight pants.

And it worked pretty well, if you’re willing to wear Mylar pants with activated charcoal in them to save you from embarrassment. So if you’re worried about farting on your date, all you need to do is bring along (or make, I suppose) a pair of Mylar pants, stuff in some activated charcoal, create a gas tight seal, and fart with confidence! Me, I’d just stay away from the pinto beans.

F L Suarez, J Springfield,M D Levitt (1998). Identification of gases responsible for the odour of human flatus and evaluation of a device purported to reduce this odour Gut DOI: 10.1136/gut.43.1.100 

You can buy the Toot Trapper at GasBGon.

For tomB

No comments: