This topic crosses certain boundaries. It is a topic of physiological interest but not one discussed in polite company. As such, it serves as a lesson in not allowing politeness to encumber academic investigation.
That the bowel produces gas is well known to everybody. Nobody alive has even not produced bowel gas. In the healthy individual, this gas is a natural byproduct of the activity of the symbiotic bacteria living in our large intestines. When teaching the large intestine, the production of this gas may be commented upon (in passing, pun intended), but this is not always the case. That this gas is often wilfully vented inevitably goes unremarked. This is despite the interesting fact that even when suffering from diarrhoea, we are often able to vent gas (albeit carefully) while successfully containing the liquid faeces. This suggests that the anal sphincter possesses a certain dexterity—for want of a better word. It is a pity that this dexterity is not more widely appreciated and discussed in lectures.
I remember a rather uncouth boy at school who deliberately broke wind in class one day and remarked to those sitting around him how nice he found its smell and how nice they ought to find it too! They did not; quite the opposite, of course. This does raise the question of why he liked it and the others did not.
I do not know why, but I do think it to be a reasonable question to pose. That we find some of the smells produced by others unpleasant may have something to do with the 'Yuk factor' or, to put it more scientifically, 'the wisdom of repugnance'. This is the notion that certain things that we find inherently unpleasant are also potentially harmful to us. In turn, the reaction to the unpleasantness prevents us from incurring any harm. Avoiding contact with faeces is obviously to our benefit. This may perhaps extend to the smells associated with them. Their smells may alert us to potential harm.
At the same time, being able to smell one’s own bowel gas when passed does provide us with a feedback mechanism of sorts. It does allow aspects of the chemistry of the bowel to be scrutinised consciously and, perhaps more importantly, subconsciously. Does bowel chemistry in terms of the gas smelt influence subsequent dietary choice?
That bowel gas has an odour, and the differing reactions to that odour are something socially unconscionable even in the lecture theatre. It is my contention that there are no barriers to what is allowed in the lecture theatre or indeed any forum of academic discourse. All academic discourse seeks to explore ideas, often rigorously interrogating their flaws and weaknesses. However, promoting and trying to inculcate ideologies and doctrines is another matter. That and ordinary academic discourse should not be confused.
To that end, I did once have a professor who discussed defecation and its... (left us call them for politeness) concomitants. There is a lot of feedback to be had from the act of defecation. What this tells us about the state of our bowels is important to recognise and should not be ignored out of mere politeness. Bowel cancer has become a prominent topic in the UK in recent years. Now is clearly a time to relax certain inhibitions on what is discussed.
NB As the length of the Wikipedia entry on flatulence demonstrates, there is much more to bowel gas than one realises. I was surprised; it is worth a look.
