How recently medical knowledge on this important subject has developed along strictly scientific lines may perhaps best be appreciated from the fact that Professor Mendel of Berlin, to whom we owe the term _paranoia_, the recognised scientific designation for crankism, is yet alive and continuing his lectures on neurology at the great German university. The term, from the Greek word [Greek text], meaning alongside of, and {284} [Greek text], mind, expresses the fact that the mental faculties of individuals designated by it are beside themselves, that is, the mental powers are not entirely under the control of the individual, so that they only come near voluntary intellection in its highest sense. In a word, the term contains a series of expressive innuendos by its etymological derivation. Professor Berkley of Johns Hopkins University says that the word paranoia was first adapted by Mendel from the writings of Plato, to indicate an especial form of mental disease occurring in individuals capable of considerable education, at times of brilliant acquirements, yet possessing a mental twist that makes them a class apart from the great mass of humanity. Professor Peterson, the President of the New York State Commission of Lunacy, gives a very good definition of the condition which, though couched in somewhat technical terms, furnishes the most definite idea of the essential properties of paranoia. He says: "Paranoia may be defined as a progressive psychosis founded on a hereditary basis, characterised by an early hypochondriacal stage, followed by a stage of systematisation of delusions of persecution, which are later transformed into systematised illusions of grandeur." He continues: "Though hallucinations, especially of hearing, are often present, the cardinal symptom is the elabourate system of fixed delusion." In a word, the paranoiac is a crank usually descended from more or less cranky ancestors, with an overweening interest in his health to begin with, who later develops the idea that many people are trying to do him harm, or at least to prevent his rise in the world, and who finally becomes possessed of the notion that he is "somebody," even though those around him refuse to acknowledge it and pay very little attention to the claim. Such people not infrequently hear things that are not said. That is, not only do they hear the voices of the dead, of spirits good and evil, but also the voices of living persons, who are at a distance from them and sometimes even when those living persons are present, but have said absolutely nothing. These delusions of hearing, however, are not so important as the self-deception forced upon them by their {285} mental state with regard to their importance in the world and their relations to other people.