[Mongolism: an encephalopathy "not like others"].

Considering ancient and new aspects to Langdon Down's disease, the author points out: the varieties of evolution, due to associate physical and sensorial defects and peculiarly to the differences of intellectual level and ego structuration. They are under dependence of social and familial factors. A demonstration is given in Lyon by a sheltered workshop where mongolian adults have found good possibilities. Sexual and sentimental life is a problem of great difficulties connected with conscient and inconscient reactions of normal adult (parents and "educateurs").