First separate edition in English; there appears to have been an earlier appearance with other of Ribot’s Diseases; first published in French in 1885. A study of mental illnesses including double personality (‘double monsters’, and twins), insanity, sexual characteristics such as ‘opposite sexuality’, hallucinations and insanity. The three principal types of mental illness are categorized by Ribot as ‘alienation, alternation and substitution’. The morality of mental illnesses was still of importance, Ribot distinguishing between ‘superficial’ problems originating with the brain (substitution) and those from ‘the depths’ of the conscience or ego (alienation).