The mapped head, such as that in Fowler’s Practical Phrenology (1847), was essential in a non-expert examination; it allowed even the lay reader to “project upon the living body a whole network of anatomo-pathological mappings: to draw the dotted outline of the future autopsy” in order “to bring to the surface that which is layered in depth” (M. Foucault, The Birth of the Clinic 200).