Funk and Wagnall's Dictionary offers the following definition: "Very extraordinary gifts or native powers, especially as displayed in original creation, discovery, expression, or achievement." Webster's New International Dictionary defines "genius" as "Extraordinary mental superiority; esp. unusual power of invention or origination of any kind; as, a man of _genius_." The Dictionary of Psychology defines "genius" in part in terms of IQ, but at the same time denies the word any special meaning as a recognized scientific term: "Genius--a very superior mental ability, especially a superior power of invention or origination of any kind, or of execution of some special form, such as music, painting, or mathematics. . . . It has no special technical meaning, but has occasionally been defined as equivalent to an intelligence quotient (IQ) of 140 or above." Generally speaking, then, dictionaries define genius as a superior or superlative degree of intellectual capacity, and avoid claiming it for any concept of an added, different, or abnormal element in human faculty. CONCEPTS OF GENIUS _As a manifestation of abnormal psychology_. A number of thinkers in fields allied to psychology have laid emphasis upon a supposed connection between genius and nervous instability or insanity. This idea is embodied in the statement by Pascal: "L'extrême esprit est voisin de l'extrême folie." Lamartine refers to "la maladie mentale qu'on appelle génie." Lombroso (10) is perhaps the most widely quoted among those who have held or who hold this point of view. _As constituting a different species_. The idea has been expressed by thinkers other than professed psychologists--and at times by psychologists themselves--that men of genius are a separate species, partaking of qualities not shared in any degree by persons at large. This concept is at one with that which would regard the idiot and the imbecile as distinct in kind, not in degree only, from the mass of mankind. Genius would thus be not merely more of the same but a different sort altogether. Thus Hirsch (7) specifically declares: The genius differs in _kind_ from the species, man. Genius can be defined only in terms of its own unique mental and temperamental processes, traits, qualities, and products. Genius is another psychobiological species, differing as much from man, in his mental and temperamental processes, as man differs from the ape. _As a hypertrophied and highly specialized aptitude for specific performance_. The thought has been advanced that intellectual genius is a matter of specialization; that the mind of a genius will not, typically, work on all data with superior results, but that it is adapted only or primarily to certain kinds of intellectual performance. In other words, the genius is thought to lack general ability. A recent statement by Carrel (2) seems to express in part at least this theory: