I have a question that has perplexed me for some time: When I visit the “powder room” and drop anchor for 30 minutes or more I am rarely inconvenienced by any malodorous airs. My closest associates, however, make no polite attempt to hide their gagging and retching and claim that I am most foul. (Alas, I live among Philistines.) No doubt I am the victim of wanton hyperbole but the question remains: why can they smell what I cannot?
My first hypothesis, made long ago, was that one couldn’t detect one’s own emanations. This can be easily disproved: When I momentarily leave my penetralian sanctuary for 15 or 20 seconds—say, to retrieve the latest issue of some prestigious journal—I am confronted upon my return with direct evidence that I am, indeed, most foul. Apparently leaving the scene of the crime clears the nasal palette, so to speak, and leaves us helpless. (When I first discovered this as a young lad I was crushed to learn that my shit did stink.)
My next hypothesis was that we are immune to the stench because it is introduced to us slowly. I cover most of the throne, after all, and only a relatively small amount of gas can escape at any time, giving one’s nose a chance to brace itself. This, too, does not hold up to experimental evidence. Anybody who has shared a communal commode with men (e.g. a locker room or dorm hall) knows that being in the room when the deed is done is no protection.
So I am left to ponder. Is there some symbiosis between sphincter and sinus that warns our olfactory nerves that “now!” would be a good time to take a holiday? What evolutionary pressures were on my paleolithic forebears that allow me to read in peace?