[7] Report on National Vitality, Irving Fisher, Washington Government Print., 1909, pp. 76-77.
[8] The Problem of Individualizing Instruction, W. F. Andrew, Education, Vol. 26, p. 135 (1905).
[9] Evolution and Ethics, T. H. Huxley, New York, D. Appleton & Co., 1902, p. 220.
[10] Growth and Education, J. M. Tyler, Houghton Mifflin Co., New York, 1907, p. 21.
[11] Education, H. Spencer, New York, D. Appleton & Co., 1861, p. 162.
[12] Supra, p. 63.
[13] Annual Report, U. S. Commissioner of Education, 1911; Washington Government Print., 1912, Vol. I, pp. 12-13.
[14] Conserving Childhood, Andrew S. Draper; The Child Workers of the Nation, Proceedings of the Fifth Annual Conference on Child Labor, Chicago, Ill., Jan. 21-23, 1909; New York, 1909, pp. 9-10.
[15] Report U. S. Commissioner of Education, 1911, Vol. I, p. 12.