St. John, as Jesse Gellrich has discussed, is sometimes pictured eating books. Gellrich argues that such illustrations underscore the primary status of speaking in the medieval world--we would expect writing to have priority. It was because of such expressions as that in Psalm 39.11, in which God says that he is "the food of strong men," that what was said and heard continued to be seen as the primary mode for conveying truth, even as the book made its enormous influence felt.
What is behind such images (the word as food) is the problem of the status of knowledge. Gellrich argues that eating is a figure for consuming the word and dealing with words orally; hearing and speaking are opposed to reading and understanding. Gellrich argues that early medieval culture were accustomed to hearing the word (the law, not only divine law) and to speaking it and that they were suspicious of reading, especially silent reading. Images of hearing (the dove speaking into John's ear) or eating words conveyed the reality of those acts in a concrete way; reading, on the other hand, seemed less real, less authentic. Anthropologists have shown that primitive cultures regard writing as a sign of weak memory and a threat to the older, orally-transmitted body of truth sacred to the culture. Our orientation today is, of course, the opposite: we believe what we read, we verify things by checking them against texts, and we dismiss "hearsay" evidence as insubstantial, second-hand, and unreliable.
Among the books in Link 00 to consult in regard to this question are Gellrich, The Idea of the Book (pp . 37-39 for starters), and M. T. Clanchy, From Memory to Written Record (see index on oral skills and orality in the Index, and see Chapter 8, Hearing and Seeing).
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