[BIBLIOGRAPHICAL NOTE XVIII.--Materials for a more extended study of the questions touched upon in this chapter are set forth in Part IV of the Bibliographical Index. Wright's _Report on Marriage and Divorce_ is, of course, indispensable. It may be supplemented from the _Eleventh Census, U. S._, I; the _Census of Massachusetts_, 1875, 1885, 1895; the _Registration Reports_ of the New England states, of which the forty-first for Massachusetts is most important; and from those of Indiana, Illinois, Michigan, and Ohio. Useful summaries of statistics may also be found in Secretary Dike's _Reports of the National Divorce Reform League_, and its successor, the _National League for the Protection of the Family_ (Montpelier and Boston, 1886-1903). An important statistical monograph is Willcox's _Divorce Problem_ (2d ed., New York, 1897). This should be read in connection with his "Study in Vital Statistics," in _Pol. Science Quarterly_, VIII (New York, 1893); his "Marriage Rate in Michigan," in _Pub. of Am. Stat. Association_, IV (Boston, 1895); Crum's "Marriage Rate in Massachusetts," in the same volume; and Kuczynski's article in _Quart. Jour. of Economics_, XVI (Boston, 1902). See also Dike, "Statistics of Marriage and Divorce," in _Pol. Science Quarterly_, IV (New York, 1889), a study of the government report; _idem_, "Facts as to Divorce in New England," in _Christ and Modern Thought_ (Boston, 1881); Wells, _Divorce in Mass._, extract from the _41st Registration Report_ (Boston, 1882); Abbott, "Vital Statistics," in _28th Rep. Mass. State Board of Health_ (Boston, 1897); Wright, _Practical Sociology_ (New York and London, 1899); Mayo-Smith, _Statistics and Sociology_ (New York and London, 1895); Loomis, "Divorce Legislation in Conn.," in _New Englander_, XXV (New Haven, 1866); and Allen, "Divorces in New England," in _North Am. Rev._, CXXX (New York, 1880). Important foreign statistical works are Bertillon, "Note pour l'étude stat. de divorce," in _Annales de démographie internat._, IV (Paris, 1880); _idem_, _Étude démographique du divorce_ (Paris, 1883); _idem_, "Du sort des divorcés," in _Jour. de la soc. de statistique_ (Paris, 1884); Oettingen, _Die Moralstatistik_ (2d ed., Erlangen, 1874); Rubin and Westergaard, _Statistik der Ehen_ (Jena, 1890); Bertheau, _Lois de la population_ (Paris, 1892); Molinari, "Decline of the French Population," in _Jour. of Royal Stat. Soc._, L (London, 1887); Ogle, "Marriage-Rates and Marriage-Ages," _ibid._, LIII (London, 1890); Farr, "Influence of Marriage on the Mortality of the French People," in _Trans. Nat. Assoc. for Promotion of Soc. Science_, LVIII (London, 1859); _idem_, _Vital Statistics_, Parts I, II (London, 1885); Newsholme, _Vital Statistics_ (3d ed., London, 1892);