“Dr. Heidegger’s Experiment” is generally considered to be a work of Gothic fiction, a genre with a particular emphasis on themes and images considered dark, morbid, or shocking and an atmosphere that evokes fear and dread. Gothic literature developed alongside Romanticism in Britain, and it is sometimes considered a sub-genre of Romantic literature. In this story, Hawthorne employs a number of conventions that are typical of Gothic literature, several of which can be seen in the description of a book found in Dr. Heidegger’s study.
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 had peeped forth from the mirror; while the brazen head of Hippocrates frowned, and said,—"Forbear!"
In just a few sentences, Hawthorne presents an index of Gothic clichés: ghostly apparitions, ancient tomes, magical artifacts, rattling skeletons, and mad scientists. As is often the case in Gothic literature, the lines between reality and fiction are unclear, and the narrator presents local rumors and superstitions as fact (the book, for example, is “well known” to be magical.) This mysterious and otherworldly atmosphere highlights the ambiguous or “dual” nature of Dr. Heidegger, a man of science whose tools and methods seem to be drawn primarily from the realm of the supernatural.