From the volume of Church and Peterson on _Nervous and Mental Diseases_ a further confirmatory opinion may be cited: "In determining the factor of heredity we must not be content with ascertaining the existence of psychoses in the ascendants, but must seek, by careful interrogation of various members of the family, for some of the hereditary equivalents, such as epilepsy, chorea, hysteria, neurasthenia, somnambulism, migraine, organic diseases of the central nervous system, criminal tendencies, eccentricities of character, drunkenness, etc., for these equivalents are interchangeable from one generation to another, and are simply evidence of instability of the nervous system. It is the unstable nervous organization that is inherited, not a particular neurosis or psychosis, and it must be our aim in the investigation of the progenitors to discover the evidence of this." =Certain Forms of Insanity, But Not All, Seem to Behave as Mendelian Recessives.--=A number of psychiatrists and investigators of the inheritance of insanities (Rudin, Lunborg, Davenport, Rosanoff, Jolly), although working independently and in different countries, concur in the opinion that manic-depressive insanity, dementia precox and allied psychopathic conditions tend to occur after the manner of a Mendelian recessive. On the other hand such maladies as Huntington's chorea are transmitted as a dominant and in all probability at least half of the children of an afflicted individual will inherit and manifest the defect. As to inheritance of various other psychoses we have too few accurately charted pedigrees for most types to make very positive statements about their degree or manner of inheritance. Little can be said beyond the statement that there is a decided tendency for various forms to recur in offspring. Where more than one case of insanity occurs in a given family or stock it is strong presumptive evidence that a hereditary defect is at the bottom of it. As Doctor Wilmarth says, "Mental accident may occur in any family, but it is rarely a second case occurs unless there is a tendency to nerve degeneracy." For example, of 818 insane at the Wisconsin State Hospital for the Insane during the biennium 1909-10, 187, or practically one-fourth were positively known to have insane relatives. Of these, 24 had insane fathers, 31 insane mothers, 30 insane brothers, 23 insane sisters, 25 insane uncles, 21 insane aunts, and 21 insane cousins. Where definite information could be obtained it was found that of the 5,700 admissions of insane patients to the New York state hospitals during the year ending September 30, 1911, 27.7 per cent. of the cases showed a history of insanity in the family and an additional 22.9 per cent. showed a history of alcoholism, nervous diseases and the like.