Although ancient writers have given short descriptions of mental diseases affecting children, it was not until the commencement of this century that the subject began to attract attention. Since then Esquirol, Guislain, Delasiauve, and others have written on the matter, and in 1856 Le Paulmier, in a thesis, gave the most complete description of the affection which had previously been published. Numerous authors in England, Germany, and France have since 1856 written on the subject, but still there seems to be a good deal of want of knowledge regarding the mental affections of children.