The class of cases described under the term Paranoia have long been recognized in England, though, perhaps, they have not been studied to such an extent as on the Continent, and have, no doubt, been looked at from a different point of view. The word in Greek literally means “madness;” we find it employed by authors synonymously with the terms Wahnsinn and Verrücktheit, and on account of the confusion existing between these, Mendel, in 1881, and Werner, in 1889, proposed to substitute “paranoia” for them. In this sense it may be taken to mean “systematized insanity,” a definition which covers all classes of paranoia.