Where is Gilles? Or, the little mistake in a copy of Brouillet's painting: "A clinical lesson at the Salpêtrière"

Professor Jean-Martin Charcot is considered the most important professor of Neurology and also the head of the Salpêtrière School of Neurology. In a famous picture painted by André Brouillet and presented at the Salon of 1887, under the title "A clinical lesson at the Salpêtrière", Professor Charcot presents a case of hysteria to a large audience of physicians and renowned intellectuals. Copies of this guided picture are also available for sale at the shop of the Museum of the School of Medicine of Paris and are frequently used in lectures by neurologists worldwide. However, in these reproductions, Gilles de la Tourette's and Charles Féré's positions are inverted. This historical note sheds some light on this little mistake in some of the reproductions of Brouillet's famous painting, so that further confusion can be avoided.