Gulliver affects a certain delicacy about his frequent references to excrement, urine, dirt, and disease. However, it quickly becomes clear that Swift is obsessed with this aspect of human existence. The second part of the book gives him a particular opportunity to enlarge on this theme, since Gulliver is observing creatures so much larger than himself and is therefore able to examine their defects in lurid detail. He describes a woman with breast cancer, which has produced holes large enough for him to creep inside, and talks about the coarse, uneven complexions of the court ladies “with a mole here and there as broad as a trencher, and hairs hanging from it thicker than packthreads.”

In part 4, the Yahoos pelt Gulliver with excrement almost as soon as he arrives in the country of the Houyhnhnms, and one of their children whom he later holds in his arms covers him with “its filthy excrements of a yellow liquid substance.” He also notes that when a pack of Yahoos decides to elect a new leader, they “come in a body, and discharge their excrements upon him from head to foot.” Swift’s particular association of the Yahoos with physical filth, and particularly with a stench so repulsive that Gulliver has to plug his nose with tobacco or herbs to be able to endure their proximity, gives the reader a clear indication of his intention in addressing this theme. It is closely related to his excoriation of folly and evil, in the attempt to strike directly at humanity’s sense of its own dignity. Swift wants to remind his readers of the corrupt nature of their own bodies. Even a healthy body produces waste which looks and smells disgusting, and an unhealthy one can be described in all manner of humiliating ways. Despite being a clergyman, Swift was far from being a conventional Christian, but he does have a strong sense of original sin, and he expresses this through physical disgust. Even if a person manages to be wise and virtuous (which he thinks they will not), their excrement will continue to stink, and this is a mark of the fallen nature of humanity. As George Orwell remarks in “Politics vs. Literature,” it is probably not a coincidence that Swift’s ideal beings, the Houyhnhnms, are horses, an animal which produces the least offensive dung of practically any animal. Even so, it is striking, given the number of times Swift mentions excrement and foul smells in part 4, that never once are these themes associated with the Houyhnhnms.