Notes

See Woods, Frederick Adams, "Laws of Diminishing Environmental Influences," Popular Science Monthly, April, 1910, pp. 313-336; Huxley, J. S., The Individual in the Animal Kingdom, Cambridge and New York, 1912. Pike, F. H., and Scott, E. L., "The Significance of Certain Internal Conditions of the Organism in Organic Evolution," American Naturalist, Vol. XLIX, pp. 321-359, June, 1915.

There is one line of experiment which is simple and striking enough to deserve mention—namely, ovarian transplantation. A description of this is given in Appendix A.

Galton, Francis, Inquiries into Human Faculty, 1907 edition, pp. 153-173. This volume of Galton's, which was first published in 1883, has been reissued in Everyman's Library, and should be read by all eugenists.

What is said here refers to positive correlations, which are the only kind involved in this problem. Correlations may also be negative, lying between 0 and -1; for instance, if we measured the correlation between a man's lack of appetite and the time that had elapsed since his last meal, we would have to express it by a negative fraction, the minus sign showing that the greater his satiety, the less would be the time since his repast. The best introduction to correlations is Elderton's Primer of Statistics (London, 1912).