The purpose of this study is to provide a conceptual and social history of hallucinations. In historical research, hallucinations have already been treated as a specific object of study. The subject of this research is thus not a new object. But, previously, the history of halluci-nation was studied from the point of view of the history of theories on hallucinations. This history of theories of hallucination encompasses different disciplines, according to the his-torical context. These disciplines include in particular theology, philosophy, physiology, neurology, psychiatry and psychology. This list is not exhaustive. These disciplines have contributed to the development of diverse theories on hallucination. The history of these disciplines also makes it possible to trace back the constructions, the points of reference and the limits specific to the explanations given on the subject of hallucination.
This historical study also looks at hallucination over a defined period: 1915-1932. The period is situated between the First World War and the Second World War. During this period, it was mainly the medical discipline that took up the question of hallucination. Med-icine was at that time the discipline that made the most attempts to explain hallucinations. Hallucination has been the subject of debate and discussion, articles, monographs and con-ferences.The historical issue is the following one: why did doctors feel they were in charge to provide an answer to the question of hallucination? How did they address this issue ?
From a methodological point of view, this study completes the history of theories of hallucination with other forms of historical analysis. It even exploits biographical material, with one author in particular: Raoul Mourgue (1886-1950). Mourgue was a French doctor who worked in a number of different places and psychiatric institutions. He worked in par-ticular in Bordeaux, Villejuif, Mulhouse and Zürich. His socio-professional career was unique at this time and among his fellowship. In relation to his professional career, it is ana-lyzed how he worked on the subject of hallucination. The different places where he worked are thus also taken into account in terms of resource and historical material in order to un-derstand how he worked on the subject of hallucination. This research began by compiling an inventory of the doctor's research, in addition to the two publications in French that are still little known: L'introduction biologique à l'étude de la neurologie et de la psychopathol-ogie (1928), in collaboration with the Zürich neuroanatomist Constantin von Monakow (1853-1930); and Neurobiologie de l'hallucination (1932). Archives were consulted - much correspondence - which are currently available in Paris (Mourgue collection). Mourgue was a doctor who corresponded a great deal with scientists of his time.
In terms of the history of science and the methodological approach, this study looks at the medical observation methods and laboratory techniques that Raoul Mourgue used to address the hallucinatory phenomenon. It shows how Mourgue collaborated with patients in laboratory experiments. In this new context, the patient is no longer just a patient. But the patient becomes a kind of collaborator with the doctor. This historical study also shows the complex relationship between observation and hallucination, but also between observational writing and hallucination. The question of writing is an important one. What status did Ra-oul Mourgue and the doctors of his time give to medical writing on hallucinations? Raoul Mourgue summed up his entire method by calling it ‘neurobiology’. What does it mean? These complex questions develop the first question formulated above. With Raoul Mourgue in particular, the historical working hypothesis is that hallucination becomes something oth-er than a symptom. Hallucination becomes a means of questioning psychiatric practice it-self. As we saw above, in order to develop and better grasp these socio-historical issues, the study proceeds, at the methodological level, with alternative and successive focuses and de-centering.