From Asimov to Zelazny, nearly every work of science fiction squeezes in its own often subtle (and, often, not-so-subtle) breed of excretory metaphors.
An example of toilet imagery plain to even the dullest mind is present throughout Larry Niven's award-winning novel Ringworld. On the most fundamental level, even the setting of the story stinks of the water closet. Specifically, the Ringworld itself is a hundred million mile diameter "ring" of material, on which various species live out their regimented lives.
Surely, the Ringworld is the most transparent kind of metaphor -- clearly representing a galactic-sized toilet seat (or, "ass-toroid", as any ass-trophysicist might conjecture). The various species living out their miniature lives are intended to represent the various intestinal flora that live and breed on your own toilet seats. The metaphor could not be clearer.
As an exercise, I leave it up to the gentle reader to log other fecal imagery throughout the plot, setting, and characters in this important work. Any reasonable person will admit that Niven's usage of such imagery was intentional, and adds particular punch to the force of his story.
In fact, one of the two sequels to this famous novel is entitled The Ringworld Throne -- providing incontrovertible validation of this observation. Mr. Niven maintains the parallel of the Ringworld to the toilet throughout, going so far as to name the book after a euphemism for a commode.
Examples of subtler variations on this theme may be found in Isaac Asimov's work, for Asimov always appreciated decorum and cleverness -- he'd never leave a steamy pile in plain view.
For instance, in his celebrated and Hugo award-winning novel Foundation's Edge (note: edge), one of the two strong female characters is named Harla Branno. Harla Branno is a cunning, portentous, quasi-masculine firebrand who is able to smoothly manipulate her underling (Golan Trevize) into undertaking a dangerous journey.
The suspense and tension are maintained until the very last moment, when all is released in a sudden and surprising way. And that completes the picture. From the title, to the character names (Branno = bran, Golan = Colon), to the sudden-release structure of the plot, all is feces. Bravo, Isaac!
Also lost on many of today's readers is the constipation imagery in The Moon is a Harsh Mistress, by Robert Heinlein. Once the title itself is considered in the context of bathroom ritual, the previously elusive interpretation is brightly revealed. Possibly the "moon" is in one sense Earth's satellite -- but the literary analyst with sufficient acumen will surely appreciate the simultaneity in interpreting this as meaning "ass".
That the "moon" is a "harsh mistress" means, in the former sense, that man's invasion of the Moon as a home for humanity, complete with its unique social, political, and economic ramifications provides a rich and nearly insurmountable physical and mental challenge. In the latter sense, however, surely Heinlein intends to liken this sociological struggle to the physiological battle of defecation with bowels slightly obstructed. In fact, the parallels are irresistible, once brought into the light of day.
Some authors confine their fecal imagery to the title alone, as L. Sprague de Camp with the obvious Lest Darkness Fall, and Robin Hobb's much more subtle Assassin's Quest. Some manage to split it among a book and its sequel, as was done with Conflict and Resolution by Hamilton. Yet others have apparently toilet-free titles, and restrict their coprophilic allusions to character names, as with "Jonnie" in Battlefield Earth by L. Ron Hubbard. In any case, a sufficiently probing search will reveal the offending mass of bathroom-based alchemy subliminally inserted into our consciousness by American science fiction authors.
Surely a fecal conspiracy is afloat in the sea of science fiction, and try as we might, never can we flush all traces of such imagery away. We are left little choice but to wipe it out of our minds as we read, enjoying the yarn itself without succumbing to its darker tendency.
-- Kyle K.