In 1919, the post-war period in which all institutions began to resurface, new reflections on man and madness were coming to the fore. They took up the 1905 propositions of the Chaumié 1 circular on criminal responsibility and in particular the responsibility of the mentally ill. Seeking a middle ground between the criminal non-responsibility of the insane and their full responsibility, this circular of the Minister of Justice made it a requirement that an ‘expert witness be summoned to indicate with the greatest possible clarity the extent to which the accused was, at the time of the offence, responsible for the act that has been imputed to him’. 2 This question would arise for the Landru case.