The greatest curiosity of the study remains to be mentioned; it was a ponderous folio volume, bound in black leather, with massive silver clasps. There were no letters on the back, and nobody could tell the title of the book. But it was well known to be a book of magic; and once, when a chambermaid had lifted it, merely to brush away the dust, the skeleton had rattled in its closet, the picture of the young lady had stepped one foot upon the floor, and several ghastly faces peeped forth from the mirror; while the brazen head of Hippocrates frowned, and said – "Forbear!" (3)
Well, that sounds important. This description of the black book jacks up the story's suspense and raises the supernatural stakes (as if dead spirits and skeletons were not enough, right?). We want to know what's in it, and we fully expect it to play a role in the story's plotline.
Sure enough, Dr. Heidegger soon opens the mysterious black book. Except he doesn't read from it, and we never get to know what's written on its "black-letter pages." Instead, he takes out from it a rose, which his dead fiancée had given him.
As with most of "Dr. Heidegger's Experiment," there are different ways to deal with this. The supernatural interpretation is that the book really is magic – perhaps even beyond the realm of our understanding – and that the rose held on its pages is similarly mystical. It could also be that this is part of Dr. Heidegger's grand scheme to dupe his guests (and for the narrator to dupe his reader). All this theatricality – the skeleton, the magic mirror, the spooky black book – may be just that: a conjurer's show. The fanfare and spectacle distract and deceive so that we misconstrue a rather ordinary reality.