Medieval dung, argues Martha Bayless, is theologically meaningful, and that makes the culture of the western Middle Ages systematically different from modernity. Theoretically underpinned by the work of George Lakoff and Mark Johnson, which argues for the groundedness of all metaphors in bodily, lived experience, she claims that in filth the material and symbolic merge.  Her analysis is also informed by the work of psychologist Paul Rozin, whereby she identifies our disgust at excrement as fear of carnality and thus of our own mortality.  Ranging widely across a millennium's worth and more of medieval texts, she cites mostly exegetical and homiletic works, keeping her focus for the greater part on the serious rather than the comic mode of writing.
Chapter one elaborates the theoretical structure of her thesis. She draws from Mary Douglas's structural anthropology to argue that the disgust filth arouses has symbolic valence in allowing a society to create systems with boundaries of taboo and hence insiders and outsiders, right and wrong.  The rule of law, as it were, arises out of such necessity for boundary. She finds this cultural universal of boundary-making fundamentally different from the ideas propounded in the scholarship of filth influenced by Mikhail Bakhtin's study of François Rabelais, which ultimately interprets excrement in dialectical terms to embody its own contradiction; filth and fecundity entail each other. She also distinguishes her position from Sigmund Freud, dispatching the association between money and shit as anachronistic in an era when the economy was less money-dependent than now (see my final paragraph). Briefly considering the work of Julia Kristeva, Bayless notes her leanings toward the early modern rather than medieval period, for which reason abjection also is placed to one side. Bayless also disclaims gender as a path of study through this topic, arguing that excrement is ungendered; while this observation seems indisputable at one level, the possibility that the female bowel might be perceived to be more susceptible to looseness than that of the male as a sign of both intestinal and moral incontinence (thinking, for example, of Gautier le Leu's De deus Vilains) is not considered. Finally, Bayless analyzes disgust at dirt, arguing that it arises not simply from matter being out of place (to cite Douglas's famous characterization), but ultimately from fear of one's own mortality (here Rozin's work is particularly relevant).
Chapter two deals extensively with sewage management and the architectural details of latrines, and there is laudable effort here spent in tracking the various uses to which dung could be put: making saltpeter, soil fertilizer, or turf for fuel; and as a cleaning agent, fermenter, and fabric softener. Although latrines were always enjoyed by the privileged, the norm for most common folk, at least until the fifteenth century when domestic privies were more common, was to make do with the great outdoors or the most makeshift of toilet structures. The cultural and fiscal value of dung differed greatly between town and country: in urban environments, effective and hygienic sewage disposal was critical and around the constant need for its regulation grew a large body of nuisance law that prescribed the time and place of disposal; in agricultural environments, on the other hand, dung, especially stable dung, was valuable and never sufficiently abundant, for farmers were always caught in the dilemma between needing sufficient grain to feed cattle and not having enough cattle to manure the fields to grow sufficient amounts of grain (to feed the cattle to manure the fields...).
Chapter three treats of the symbolic significance of bodily orientation and, by consequence, of dung. Bayless invokes a well-known cosmological paradigm of hierarchies founded not only upon an up/down, right/left, and front/back axis but also upon correspondences between the heavens and the human head on the one hand and on the other between hell and the body's nether regions (of which similar paradigms have been in place at least since Plato's Timaeus). The human body is a microcosm of these larger hierarchies. "Uprightness" and "backwardness" denote morally as much as they do posturally, and Bayless teases out the literalness of these so-called figures of speech very well here. It follows then that "down there" at the back of the body where excrement is produced constitutes the site of the unholy. "The Christian struggle was the struggle to keep the head paramount; to sin was to give way to the lower body" (75). In the chapter's later sections she considers instances of the body inverted, contra naturam, in particular the mouth/anus inversion deployed widely in medieval comic tales, ludic marginalia, demonic iconography, and heretical rituals such as the osculum infame. In both narrative and iconography, sinners are associated with and defined in terms of the anal and excremental.
In chapter four, in a consideration of a number of exegetical discussions, Bayless then addresses some of the most ticklish of posers: whether our Lord pooped; whether Adam and Eve pooped before the fall; whether our bowels will be included in the resurrection of the body; and what Noah did about all the poop in the ark for over a month. The fact that the Bible should not bring up such questions did not hold back medieval exegetes from doing so, for they recognized that answers were needed in the interests of systematic theology despite the dangers of sacrilege, even heresy, in explicitly addressing these matters. It is here, rather late into the book, that she begins to develop a more nuanced position on purity, entertaining the possibility of a fully incarnate, defecating body, albeit without shame or stink. "Purity is material as well as moral" (154).
In her conclusion, she returns to some of the theoretical issues raised in the first chapter. In her reading of received critical opinion on the matter of medieval shit, she finds in disparate arguments a general agreement about its double nature: excrement is both offensive and life-giving, both abject and fruitful. Placing Bakhtin at the center of this tradition, she characterizes it as essentially dialectical. A central claim is that the secularization of thought epitomized by Enlightenment culture has emptied excrement of all its theological and symbolic significance, reducing it to a substance that is as distasteful as it is trivial. The cost of Enlightenment progress is that dung has "lost its power to instruct" (181).
Bayless's book is admirable for the range and extent of its primary references, and anyone working in this area will want to avail themselves of her archive of sources. That said, the proliferation of citations sometimes undercut the deepening of an argument. I felt this particularly in chapter three, where the many examples of polarities between up/down, right/left, and front/back in the cosmic order cried out for some mitigating consideration of medieval equilibrium as in, for example, dietary and humoural balance or Aristotle's golden mean between excess and defect. Mediating nuance would also have been welcome in characterization of historical periods. Although there is no dispute with the claim that the secularization of thought has robbed feces of its theological resonance, it does not follow that its significance nowadays is banal. Indeed, it is modernity rather than shit that gets trivialized here: "modern snickering attention to medieval hygiene" (29); "by modern standards this narrative is tasteless" (136); "the modern sensibility that regards dung as insignificantly repulsive" (176). It is difficult to agree with these comments at anything other than a superficial level, especially since Freud, whose theories about the role feces plays in psychosexual formation are prematurely discounted from consideration on grounds that the Middle Ages was less money-dependent than the nineteenth century. This objection can be countered merely by the fact that the association at issue is less between excrement and fiduciary coin than it is between excrement and gold (that is, treasure), in an ancient pairing that connects the corruptible with the incorruptible. Freud's analysis is fully engaged with the fear of and desire for death as a motive for the psychic investment in excrement. While there is no requirement to consider his theories in what is properly a study of the medieval, let him be discounted for better reasons than a straw man.
Of greater concern is the tendency to dispatch medieval comedy for its lack of instructiveness on the topic of excrement. My point is less that this or that comic narrative should have been discussed than that such ones she does consider are generally underinterpreted as amoral, ultimately offering only the insight: "Aren't the things of the body ridiculous?" (31, 167). But as Roy Pearcy has long argued, the fabliaux are profoundly implicated in the linguistic and ontological relations between literal and figurative, between the material and the symbolic. And in the context of religion, confusing the two--as the fabliaux regularly do--can border on sacrilege.  Bayless does not entertain the possibility that in desecration one might encounter the holy, that comic defacement can make the transcendent immanent.  This doubleness constitutes more than an "interesting paradox" brought about merely by using comedy as a neutral instrument to achieve the contradictory ends of profanity or sacredness (165-66). It inhabits medieval comedy as a condition of possibility, complicating conceptual polarities that themselves are not in dispute yet are far from simplistic or single. It is in many ways refreshing to read a work that does not capitulate to the "pervasive modern view" (165) of the double nature of excrement and that takes seriously the overarching categories that shape mainstream medieval thinking, yet it is not clear, at least to this reader, that this modern view has been effectively debated and, consequently, superseded.
1. George Lakoff and Mark Johnson, Metaphors We Live By (Chicago: University of Chicago Press, 1980); Philosophy in the Flesh: The Embodied Mind and its Challenge to Western Thought (New York: Basic Books, 1999).
2. Paul Rozin, Jonathan Haidt, and Clark R. McCauley, "Disgust: The Body and the Soul Emotion," in Tim Dalgleish and Mick J. Power, Handbook of Cognition and Emotion (Chichester and New York: Wiley, 1999), 429-45.
3. Mary Douglas, Purity and Danger: An Analysis of Concepts of Pollution and Taboo (London and New York: Routledge, 1966).
4. Compare Joel Kaye's consideration of the neutral state between contraries in A History of Balance 1250-1375: The Emergence of a New Model of Equilibrium and its Impact on Thought (Cambridge: Cambridge University Press, 2014).
5. See Sheila J. Nayar's analysis of Eucharistic allusion in La Crote [The Turd], in "Coprus [sic] Christi," in Holly Crocker, ed. Comic Provocations: Exposing the Corpus of the Old French Fabliaux (New York: Palgrave, 2006), 63-81. Roy J. Pearcy has written extensively on language and the fabliaux, for example: "Modes of Signification and the Humor of Obscene Diction in the Fabliaux," in Thomas D. Cooke and Benjamin L. Honeycutt (eds), The Humor of the Fabliaux: A Collection of Critical Essays (Columbia, MO: University of Missouri Press, 1974), 163-96.
6. See Michael Taussig, Defacement: Public Secrecy and the Labor of the Negative (Stanford: Stanford University Press, 1999); and Valerie Allen, On Farting: Language and Laughter in the Middle Ages (New York: Palgrave, 2010): "The tired contrariety between sacredness and profanity we call the hallmark of medieval art is better understood as a higher order of synthesis in which profanity becomes a kind of devotion" (45).