[2] A full list of these occurs in the bibliographical section of this essay.
[3] Chapin, F. S., Introduction to the Study of Human Evolution, pp. 30-31.
[4] This law, of course, does not fully operate among men in a highly civilized state of living, for in this state its force is much diminished by various uplift, or counter-selective, agencies.
[5] Gregory, Keller, and Bishop, Physical and Commercial Geography, pt. II, p. 126.
[6] Gregory, Keller, and Bishop, Physical and Commercial Geography, pt. II, p. 126.
[7] Keller, A. G., Societal Evolution, pp. 24-37.
[8] What is said here, and also in the remaining pages of this chapter, are for the most part reproductions of parts of Chapter I of Immigration, by H. P. Fairchild. In some cases quotations and paraphrases from this source are also given. The acknowledgment here, however, is once and for all.