Possibly the emotional element is in part accountable for the glycosuria observed after painful stimulation, but conditions causing pain alone will reasonably explain it. As we have already seen, strong stimulation of sensory fibres causes the discharge of impulses along the splanchnic nerves, and incidentally calls forth an increased secretion of the adrenal glands. In glycosuria resulting from painful stimulation, as well as in emotional glycosuria, the adrenal glands may be essential factors. Later the evidence will be given that sugar is the optimum source of muscular energy. In passing, we may note that the liberation of sugar at a time when great muscular exertion is likely to be demanded of the organism may be interpreted as a highly interesting instance of biological adaptation. REFERENCES [Footnote 47: Kleen: On Diabetes Mellitus and Glycosuria, Philadelphia, 1900, pp. 22, 37-39.] [Footnote 48: Naunyn: Der Diabetes Mellitus, Vienna, 1898, p. 72.] [Footnote 49: Schultze: Verhandlungen der Gesellschaft deutscher Naturforscher und Aerzte, Cologne, 1908, ii, p. 358.] [Footnote 50: Zeitschrift für Heilkunde, 1902, xxiii, Abtheilung iii, pp. 14, 19.] [Footnote 51: Mita: Monatshefte für Psychiatrie und Neurologie, 1912, xxxii, p. 159.] [Footnote 52: Folin, Denis and Smillie: Journal of Biological Chemistry, 1914, xvii, p. 519.] [Footnote 53: Arndt: Zeitschrift für Nervenheilkunde, 1897, x, p. 436.] [Footnote 54: Naunyn: _Loc. cit._, p. 73; Hirschfeld: Die Zuckerkrankheit, Leipzig, 1902, p. 45.] [Footnote 55: Waterman and Smit: Archiv für die gesammte Physiologie, 1908, cxxiv, p. 205.] [Footnote 56: Henderson and Underhill: American Journal of Physiology, 1911, xxviii, p. 276.] [Footnote 57: Böhm and Hoffmann: Archiv für experimentelle Pathologie und Pharmakologie, 1878, viii, p. 295.] [Footnote 58: Eckhard: Zeitschrift für Biologie, 1903, xliv, p. 408.] [Footnote 59: Loewy and Rosenberg: Biochemische Zeitschrift, 1913, lvi, p. 114.] [Footnote 60: See Abderhalden: Handbuch der biochemischen Arbeitsmethoden, Berlin, 1910, ii, p. 181.] [Footnote 61: Scott: American Journal of Physiology, 1914, xxxiv, p. 283.] [Footnote 62: Cited by Scott: _Loc. cit._, p. 296.] [Footnote 63: Rolly and Oppermann: Biochemische Zeitschrift, 1913, xlix, p. 201. Jacobsen: _Ibid._, 1913, li, p. 449. Hirsch and Reinbach: Zeitschrift für physiologische Chemie, 1913, lxxxvii, p. 122.] [Footnote 64: Cited by Kleen: _Loc. cit._, p. 37.] [Footnote 65: Folin, Denis and Smillie: _Loc. cit._, p. 520.] [Footnote 66: See Macleod: American Journal of Physiology, 1907, xix, p. 405, also for other references to literature.] [Footnote 67: See Meyer: Comptes rendus de la Société de Biologie, 1906, lviii, p. 1123; Nishi: Archiv für experimentelle Pathologie und Pharmakologie, 1909, lxi, p. 416.]