In the single page discussing farts in Constance Classen, David Howe and Anthony Synott's book, Aroma: the Cultural History of Smell, they note that in Morocco, "it is traditionally held that breaking wind inside a mosque will blind, or even kill, the angels therein." They go onto observe that farting is so closely associated with harmful spirits that a spot where one occurred may be marked by a small pile of stones, as if to trap the evil spirit inside. Citing an early anthropological study by Edward Westermarck, they suggest that the taboo against farting in public is so strong amongst the Berber tribes in Morocco, people have reportedly committed suicide for succumbing to an ill-timed fart.

Beyond such passing (and vaguely dubious) references, a more detailed examination of the meaning of farts is found in the work of Anthony Seeger and Jon Crocker, who work amongst related Indian tribes in Brazil: the Suya and Bororo, respectively. According to their accounts, in both groups, farts are classified under the category of "rotten smells" and are perceived to be dangerous and powerful–crucial to avoid at all costs. When faced with the olfactory invasion of the fart, both the Suya and the Bororo respond by spitting; when anyone farts in public the whole group must go through an elaborate ritual of hacking, spitting and coughing to expel the polluting odour from their bodies.

Common in these accounts is the damage a public fart causes to the prestige of the unfortunate farter. Such fears are somewhat comprehensible to the average North American, as the thought of releasing an audible fart during a speech, presentation, or meeting is enough to make most people break into a cold sweat. Silent or virtually soundless farts are certainly the best option in this context, although if they are accompanied by a strong smell the conditions must be such that anonymity can be preserved.[3]

Indeed, the desire of the French writer Honoré de Balzac to one day be "so well known, so popular, so celebrated, so famous, that it would… permit me to break wind in society and society would think it a most natural thing" has the ring of a utopian dream. Nobody gets to fart with impunity.

Or do they? Personally, I'm not convinced that all farts are equal – in other words, who farter is and whom they fart around seem to be important factors.

Certainly, in a North American context, some farts appear to be judged less harshly than others, with the farts of the infirm, the elderly, and small children evoking relatively little response.[4] Female farts (barring those emitted by the aforementioned categories), on the other hand, seem to fall at the opposite end of the spectrum. Indeed, I have seen t-shirts proclaiming "girls don't fart." Whether taken as a statement of fact or a plea for anal rectitude, the meaning is clear: "ladies" are not supposed to fart. This leads women to attempt to become virtually fartless at best and "silent but deadly" farters at worst.

Even a fart in a public toilet booth can be a source of considerable embarrassment for females–leading to elaborate tactics to avoid attribution, such as a series of coughs to cover up the sound or waiting in the toilet stall until all the women in the remaining booths have left.[5]

Obviously, farts contain several sensory dimensions that might help to explain the hostile reactions they are liable to receive: many of them are accompanied by noise, they are associated with faecal matter, and can be lit to rather startling effect.

However, the odour of farts appears to be the source of their offensiveness. As Benjamin Franklin once wrote, "Were it not for the odiously offensive smell accompanying such escapes, polite people would probably be under no more restraint in discharging such wind in company than they are in spitting or blowing their noses."

Benjamin Franklin appears to be onto something. The anthropologist Mary Douglas has famously argued that bodily refuse (such as mucous, spittle, blood and nail clippings) is universally seen to be a symbol of power and danger because it traverses the boundaries of the body.

The feminist philosopher Julia Kristeva similarly argues that this matter expelled from the body is "abject" –it simultaneously revolts and fascinates us because it "disturbs identity, system, order." The abject distorts the boundaries between what is "me" and what is "not me" because it escapes the boundaries of one body and attacks the boundaries of others.

Farts may very well be the ultimate bodily emission. They are likely to be perceived as far more polluting than other bodily excretions such as faeces, because they are for all intents and purposes invisible. We cannot actively avoid them. While we can generally side-step faeces, blood and urine, or complain to the waiter if we find a hair in our soup, little can be done to protect ourselves from the sensory invasion of the fart.

Thus, the spitting and hacking response of the Suya and Bororo Indians to the fart makes perfect sense when its invasive capacities are made explicit. The tendency to hold one's breath upon stepping into a lift and registering that its previous occupant has left a parting gift represents a similar attempt to stave off invasion by this nameless, faceless, yet fragrant stranger. However, in both cases, the attempt is unsuccessful–like death itself, the fart will not be denied entry.

So the next time you fart, whether it be alone in an elevator, or surreptitiously during a meeting (phantom farters, you know who you are), or when you have just settled into bed and your partner lifts the covers to climb in and is greeted by an unwanted surprise, pause for a moment to contemplate the abject power of the fart.

In one quite literally foul swoop, the fart momentarily[6] destroys our allusions regarding the integrity and autonomy of the human body–our certainty and security regarding the boundaries between what is "me" and what is "not me" –and reveals both its fragility and vulnerability.