In the interlude, Foster reaffirms the practice of intertextuality in literature. He addresses the question as to why and how works inevitably contain references to other texts. One of the reasons, discussed before, is the comfort of familiarity and recognition of elements seen during our prior reading - a quality that, if lacking, would make for quite an unnerving experience for readers. Foster also explains that writers, while they have to "forget" the materials they have read as they sit down to write, and incorporate the great tradition of literature and poetry unconsciously. Whether or not writers acknowledge these influences is another issue, but there is little doubt that the themes, stories, characters and images that have been retained in their subconscious guide their work. A distinguishing feature of intertextuality is also the concept of archetype which is a pattern that develops out of mythic original and which, because of its relatable nature and appeal, keeps recurring in works of literature, becoming stronger and more effective as they appear in increasing number of texts. Archetypes can include any component of stories, a quest, the knight character, a certain sacrifice etc. Foster concludes by stating that there has only really been one story that has been going on forever around us and which has enabled writers and readers to make use of literary structure, symbolic logic and shared knowledge.
In Chapter 21 Foster discusses the symbolic importance that physical marks or deformities take on in literature. Physical imperfections go beyond the body - they tell us something about the character's uniqueness or even of the prevailing social and political thought of the time. The Puritans and Shakespeare for instance wrote during a period where one's closeness or favor with God was manifested outwardly in the self or in their worldly lives. While scars or other shortcomings are by and large no longer considered as moral shortcomings or proof of divine displeasure, they nonetheless continue to mean various things in literature. The practice of marking characters goes back to the Folktales of the Slavs and persists to modern works of fiction such as Harry Potter. Individual markings each tell their own unique tale but all ultimately point to character differentiation.
The famed Greek mythological figure, Oedipus blinds himself - an impairment that suggests atonement, guilt, and grief - but he is in fact a marked man from the very beginning as his name suggests. Oedipus literally means wounded foot. His distinction as a public figure is well known through the narration of his fate and story. Frankenstein's menacing and damaged face is representative on some level of the darker side of science, forbidden quests, and a pact with the devil. Marked-ness need not imply something negative, as for instance in the case of the Hunchback of Notre-Dame, who has a beautiful soul but an unappealing exterior. Yet even his deformity can be a foreboding sign if we consider his eventual fate at the hands of death. Not all scars or disfigurements have to mean something, but if the writer chooses to single out a character due to a particular physical feature it is worth wondering why.
In chapter 22 Foster considers the implications of blindness as a literary feature. He notes that in introducing blindness, writers wish to emphasize other levels of sight or characteristics beyond the physical. A blind character requires a shift in perspective not only from his/her own position, but also requires change in behavior by others, even if these changes are subtle. Oedipus' physical blinding of his own self actually turns out to be an explicit manifestation of his inner blindness or inability to grasp the truth. Foster also states that when blindness and sight appear as themes in a work of literature, then related images and phrases increasingly emerge in the text. Most literary works deal with issues of darkness and light, seeing and blindness, even if there isn't a specifically blind character in the story. Those that do feature such figures possibly wish to cast even greater light on this subject, placing it in the forefront of their plot. In most such cases, Foster points out, writers tend to introduce the blind character fairly early on in the novel and readers who recognize this trope should keep a look out for related imagery and allusions.
Chapter 23 continues the discussion on health maladies by considering literary situations of heart diseases. Like blindness, which suggests meanings that go beyond the external, heart diseases usher in themes that guide the plot or the character. For Foster, heart disease is the most convenient and lyrical literary tool for writers largely because of the clear symbolism associated with it. As a symbolic repository of feeling and emotion, the heart says a great deal about the character - a heart of iron, heartbroken, a heart full to bursting - these are just some of the many heart references used to describe strong human emotions. Because this is a universally recognized meaning, writers are able to use heart ailments as indicative of their characters, their characters' humanity, or even a society's general ills. Heart disease can indicate bad love, cruelty, loneliness, pederasty, shock, cowardice, weakness of character and so forth. Heart ailments can be described even without recourse to an actual heart disease - Nathaniel Hawthorne's The Man of Adamant is about a misanthrope who secludes himself in a cave because he believes everyone else is a sinner. Yet because his limestone cave has drips of water that contains calcium, eventually the toxic liquid seems into his body causing his heart to turn into stone. The irony is clear, and indeed descriptions or references to physical ailments such as that of the heart make great use of irony in achieving some of their effects.
Foster's discussion on physical and health concerns continues in chapter 24 to encompass all illnesses in general. Health afflictions can be frustrating, even startling, in real life, but in literature we are less concerned with the bodily condition itself and more interested in what the disease tell us about the suffering character and the story at large (and perhaps even about the writer's intent). Diseases up until the twentieth century were by and large a mystery causing illnesses to take on a certain superstitious and fearful quality. Foster identifies four main governing principles for descriptions of illnesses in literature; firstly, illnesses are not given equal treatment, that is to say, some diseases tend to be favored in literature over others even if they occurred in great frequency primarily because of associated public perception (cholera, because of its rather unpleasant debilitating effects had a bad reputation whilst syphilis, evidence of sex beyond marriage, was taboo in its moral corruption implication); secondly, the illness used should be picturesque so that the physical alteration is dramatic in effect; third, they should be mysterious in origin, again for dramatic effect and to undermine expectations; and finally they should have strong symbolic or metaphoric interpretations (e.g. Tuberculosis, the wasting disease, could be used as a commentary on individual lives wasted away).
Foster points out that TB and cancer largely dominated the literary scene of illnesses throughout the nineteenth and early twentieth century whilst the plague has been a historic favorite. In our contemporary age, AIDS seems to have become a prominent feature of literary texts that contain reference to disease - its compelling allure can be attributed to the political and social commentary it offers and while it is particular to its time, it nonetheless conveys a universality of suffering, despair, self-control and loss that we can all relate to. For Foster, the ideal illness is one that is made up, or not clearly identified. Fevers fall under this category for their generic yet nonetheless health related implications - a writer is less restricted when the disease in unspecified for it doesn't require adherence to formalities such as its known causes, symptoms etc. The fever can represent the randomness of fate, the difficulty of life, the unpredictability of God's decree, and so forth. Admittedly in the modern age of medicine when diseases are more easily identified, the use of the generic fever is harder to pull off in literature.
References to intertextuality are interspersed throughout the book, and the chapter on intertextuality should be seen as a synthesis, or clearer exposition on this subject. However it is also important to note that "intertextuality" is not as separate or neat a category as the chapter might suggest - it is closely woven with another theme Foster discusses, that is, the idea that there is ultimately only one story in literature, which is about the human experience. How intertextuality functions also brings in other literary conventions such as archetypes, universal meanings, historic traditions or myth, and so forth. Rather than identifying it as a distinct component of literature, the reader would perhaps fare better in viewing intertextuality as woven into the complex web of literature, emerging often but in different ways.
Foster's discussion of physical marks rightly points out how writers differentiate certain characters from the rest. It is perhaps just as telling when there are no distinguishable marks on a prominent character or characters. A classic example would be the portrayal of identical twins in literature - at times one is distinguished from another by a tiny, seemingly innocuous mark such as a freckle on the finger, but when there are no such distinctions then internal characteristics or features become much more important. Similarly, characters described as perfectly fashioned should also be a cause for closer study. Foster largely discusses physical shortcomings in terms of dis-figuration but characters can also be marked by external elements such as tattoos or piercings.
In early Western culture the eyes were often prized as the most superior of sense organs and thus associated with notions of knowledge, man's superiority, and so forth. In light of this, then, blindness in literature takes on all the more significance. Maren Tova Linnett, who focuses on blindness and intimacy in early twentieth century literature, also looks at the ways in which writers used these themes over the centuries. She agrees with Foster's analysis of blindness symbolizing either lack of knowledge or profound insight, related to themes of light and darkness, but also states that perceptions of blindness have evolved over time. In pre-modern literature blindness couldn't lead to a completely fulfilling or happy life no matter its other benefits (the tradition of ocular-centrism - privileging of vision over other senses) but with changing beliefs, twentieth century and modernist literature have valued blindness over the ability to see. Blind characters are often presented as exuding a sense of calm or contentment, having been shielded from the anxieties that others are exposed to. More important is Linnett's argument that literary blindness is often associated with intimacy - where blind characters are better able to connect and communicate with people.
Foster's discussion of heart disease and illnesses in literature is another instance of how literature is a reflection of the human experience - for better and for worst. This also implies that the way in which such themes are presented in texts is affected in part by the prevailing socio-historic conditions. For instance, in the book Victorian Poetry and the Culture of the Heart, Kirstie Blair focuses on ways in which Victorian advances in medicine, and changing perceptions of the heart, affected the literary heart that poets and writers presented in their writing. For the Victorians the heart was seen as distinct and separate from mind and will, which accorded it a special place of significance. Blair argues that there was increasing suspicion on validity of feelings/emotions as well as rise in medical literature regarding the pathological heart, which led to a general sense of concern over its health. This general concern, experienced by poets and writers as well, ultimately made its way into Victorian poetry and text.
Blair's analysis offers a more practical perspective with which to read illnesses (heart and others) in literature. Whereas Foster focuses on the symbolism and possible implications of such themes, one can also engage more deeply with the text by understanding some of the broader factors that prevailed during the time the text was written. Knowing these conditions and the context in which the author wrote might enable readers to have a deeper insight into why the author chose the trope he did, and how it was likely to be received by the audience.