Taking a cognitive approach to Huysmans's 1887 novel En rade, this article studies the writer's aesthetic transmutation of the theories of Wilhelm Wundt (1832–1920)—a figure widely known as one of the founders of modern psychology. The protagonist, Jacques Marles, invokes Wundt's claim that an extended foot during sleep may prompt the experience of falling in a dream. This explanation has led critics to cast Wundt as a foil for psychoanalytic readings, dismissing wholesale his writings despite their pertinence to the author's portrayal of Jacques's errant thought. Considering Wundt's perspectives on the mediating work of consciousness, I examine Huysmans's use of the scientist's ideas on the physiological unconscious, reaction times, and apperception to portray the struggle of the conscious mind when confronted with its unconscious other. In so doing, I argue that ennui functions as the conscious register of unconscious activity to become an agent of psychic change over time.