The study refers to Eugen Bleuler's first systematic publications on "the natural born criminal" (1896) and his subsequent forensic-psychiatric expertise, written by Bleuler as Director of the psychiatric Department of Psychiatry of the University of Zurich ("Burghölzli"). It could be clearly shown that Bleuler was influenced by a deterministic understanding of human behaviour. He referred to the Anglo-American concept of "moral insanity" as a circumscribed defect of altruistic feelings despite other psychic functions being normal and tended to include this psychopathic deviation in psychiatry. Although this theoretic position remained unchanged, the elderly E. Beuler--under pragmatic points of view--accepted the traditional differentiation between mental illness in a narrower sense and "moral insanity" as a personality feature of most delinquents, falling under the responsibility of law and penal institutions. In his publications as emeritus (after 1927). Bleuler was influenced by the natural philosophic and vitalistic concept of the so-called "Minemism", which, however, still made him reject the postulate of "freedom of will".