In the 19th century and the fin de siècle period, tuberculosis and syphilis were frequently constructed as signs of creativity in literary fiction and as illnesses of the character by the psychiatry of degeneration. With the paradigm shift of germ theory and the discovery of tuberculosis and syphilis bacilli by German researchers in 1882 and 1905, both diseases were linked to an external cause. German novels then became a medium for harmonizing old and new knowledge, the metaphysics of disease and experimental medicine, and thus demonstrate how cultural constructions of disease emerge from the cross-fertilisation of literary and medical discourses.