Though famous for its visual effects, the most important feature of Ann Radcliffe’s gothic fiction is its use of mysterious music and indistinct sounds. According to late eighteenth-century vitalist physicians, the nerves vibrated in response to external impressions like the strings on a musical instrument. Alternately pampered and overstimulated by modern conveniences, the nerves lost the ‘tone’ necessary for physical and mental health. With the rise of a new ‘expressive’ aesthetics that emphasized literature’s power, like music, to stimulate affective responses rather than ideas, novels soon became implicated in this discourse. Like ‘ethereal’ instruments such as the Aeolian harp and the glass harmonica, Radcliffe’s narrative machinery was to administer therapeutic vibrations and excite imaginative reveries that reconnected the body to nature’s vital resources. In The Mysteries of Udolpho, however, Radcliffe warns that this machinery, if administered to an already debilitated body, could cause nervous pathologies and excite uncanny hallucinations.