There is no entirely satisfactory discussion of the general problem of frontiers. T. L. Holdich, _Political Frontiers and Boundary Making_ (London, 1916), is concerned chiefly with ‘natural’ frontiers outside of Europe. For the facts of race, see W. Z. Ripley, _The Races of Europe_ (New York, 1899). Leon Dominian, _Frontiers of Language and Nationality in Europe_ (New York, 1917), is convenient. A more authoritative work on the linguistic side is A. Meillet, _Les langues dans l’Europe nouvelle_ (Paris, 1918). Experience with plebiscites is brought together in Miss Sarah Wambaugh’s elaborate _Monograph on Plebiscites_ (New York, 1920). A. Toynbee, _Nationality and the War_ (London, 1915), is an attempt to state the territorial problems in the early months of the war; L. Stoddard and G. Frank, _Stakes of the War_ (New York, 1918), seeks to sum them up at its close. The relation of certain of these problems to a league of nations is discussed in _The League of Nations_, edited by Stephen P. Duggan, with references (Boston, 1919); and by Lord Eustace Percy, _The Responsibilities of Peace_ (London and New York, 1920). FOOTNOTES: [2] Webster, _The Congress of Vienna_, p. 93. [3] _Was von der Entente übrig bliebe wenn sie Ernst machte mit dem “Selbstbestimmungsrecht”_ (Berlin, D. Reimer). [4] _Atlantic Monthly_, xc, pp. 728, 731 (1902). [5] Keynes, _Economic Consequences of the Peace_, p. 265. [6] Dillon, _The Inside History of the Peace Conference_, p. 151. [7] Keynes, _The Economic Consequences of the Peace_, pp. 30-32. M. Mantoux asserts that Mr. Keynes never attended a regular session of the Council of Four. _London Times_, February 14, 1920. II BELGIUM AND DENMARK Our examination of the specific territorial problems of the Conference may most conveniently begin with the simplest, the frontier between Germany and Denmark. This had been established by force of arms when Schleswig was taken from Denmark in 1864, while a promise made in 1866 to consult the population had never been fulfilled. Only at the close of the World War did an opportunity come to fix the boundary in accordance with the will of the inhabitants. The duty of the Conference was to provide the means of giving effect to their desires.