IN 1791, a German doctor called Eberhardt Gmelin reported a bizarre case: one of his patients regularly transformed from a middle-class German woman into a French aristocrat. She would suddenly “exchange” her personality for the manners and ways of a French-born lady, speaking French perfectly but German as a Frenchwoman might. As her French self, she could remember everything she had said or done during her previous French “episodes”. As a German woman, she knew nothing of her French personality.
Gmelin’s French aristo was followed by other similarly odd cases. Felida X, for example, had three different personalities, each with their own illnesses. One of them…
