While numerous historiographical works have been written to shed light on Freud's early theoretical education in biology, physiology, and medicine and on the influence of that education on psychoanalysis, this paper approaches Freud's basic comprehension of science and methodology by focusing on his early research practice in physiology and neuranatomy. This practice, taking place in the specific context of Ernst Brücke's physiological laboratory in Vienna, was deeply concerned with problems of visuality and the revelation of hidden organic structures by use of proper preparation techniques and optical instruments. The paper explores the connection between such visualizing practices, shaped by a physiological context as they were, and Freud's later convictions of the scientific status of psychoanalysis and the function of its method as means to unveil the concealed structure of the “psychical apparatus”.