178.
"While it is improbable that _all_ the difference of the sexes with
regard to physical strength can be attributed to persistent difference
in training, it is certain that a large part of the difference is
explicable on this ground. The great strength of savage women and
the rapid increase in strength of civilized women wherever systematic
physical training has been introduced both show the importance of this
factor."--Ibid., p. 178.]

[Footnote 45: "Physical and Mental Deviations from the Normal among
Children in Public Elementary and Other Schools," _Report of the
Sixty-fourth Meeting of the British Association for the Advancement of
Science_, 1894. pp. 434ff.]

[Footnote 46: A. Mitchell, "Some Statistics of Idiocy," _Edinburgh
Medical Journal_, Vol. XI, p. 639.]

[Footnote 47: "Koch's Statistics of Insanity," _Journal of Mental
Science_, Vol. XXVI, p. 435.]

[Footnote 48: Mayr, _Die Verbreitung der Blindheit, der Taubstummheit,
des Bloedsinns und des Irrsinns in Baiern_, p. 100.]

[Footnote 49: Cf. Campbell, _loc. cit._, pp. 146ff.]

[Footnote 50: Ibid., pp. 132-40.]

[Footnote 51: J.H. Manley, "Harelip," _International Medical Journal_,
Vol. II, pp. 209ff.]

[Footnote 52: _Communications of the Massachusetts Medical Society_,
Vol. II, No. 3, p. 9.]

[Footnote 53: Of the 3,956 individuals examined, 1,645 were males, and
of these 47 (2.857 per cent.) presented supernumerary nipples. Of
the 3,956 individuals 2,311 were females, and of these 14 (0.605
per cent.) presented supernumerary mammae or nipples. That is, this
anomaly was found to occur more than four times as frequently in
men as in women.--J. Mitchell Bruce, "On Supernumerary Nipples and
Mammae," _Journal of Anatomy and Physiology_, Vol. XIII, p. 432.

Leichtenstern, however, whose investigations were of earlier date than
those of Bruce, says that supernumerary mammae occur with about equal
frequency in the two sexes.--Leichtenstern, "Ueber das Vorkommen
und die Bedeutung supernumeraerer Brueste und Brustwarzen," Virchow's
_Archiv fuer pathologische Anatomie_, Vol. LXXIII, p. 238.]

[Footnote 54: Ellis, _loc. cit._ (4th ed.), pp. 413ff.]

[Footnote 55: Lombroso e Ferrero, _La donna delinquente_, chap. 12.]

[Footnote 56: Hyrtl, of Vienna, however, examined thirty subjects,
and found the anomaly in question only three times, and exclusively
in females. He attributed it to tight lacing. D.J. Cunningham,
"The Occasional Eighth True Rib in Ma