Recent research on the professionalization of psychology at the end of the nineteenth century shows how objects of knowledge which appear illegitimate to us today shaped the institutionalization of disciplines. The veridical or telepathic hallucination was one of these objects, constituting a field both of division and exchange between nascent psychology and disciplines known as 'psychic sciences' in France, and 'psychical research' in the Anglo-American context. In France, Leon Marillier (1862-1901) was the main protagonist in discussions concerning the concept of the veridical hallucination, which gave rise to criticisms by mental specialists and psychopathologists. After all, not only were these hallucinations supposed to occur in healthy subjects, but they also failed to correspond to the Esquirolian definition of hallucinations through being corroborated by their representation of external, objective events.