ficant fact that the eyes and hair darken _pari passu_
with sexual development. In women, during menstruation, there is a general
tendency to pigmentation; this is especially obvious around the eyes, and
in some cases black rings of true pigment form in this position. Even the
skin of the negro women of Loango sometimes becomes a few shades darker
during menstruation.[163] During pregnancy this tendency to pigmentation
reaches its climax. Pregnancy constantly gives rise to pigmentation of the
face, the neck, the nipples, the abdomen, and this is especially marked in
brunettes.

This association of pigmentation and sexual aptitudes has been recognized
in the popular lore of some peoples. Thus the Sicilians, who admire brown
skin and have no liking either for a fair skin or light hair, believe that
a white woman is incapable of responding to love. It is the brown woman
who feels love; as it is said in Sicilian dialect: "Fimmina scura, fimmina
amurusa."[164]

The dependence of pigmentation upon the sexual system is shown by
the fact that irritation of the genital organs by disease will
frequently suffice to produce a high degree of pigmentation. This
may the neck, the trunk, the hands. Simpson long since noted that
uterine irritation apart from pregnancy may produce pigmentation
of the areolae of the nipples (_Obstetric Works_, vol. i, p. 345).
Engelmann discussed the subject and gave cases, "The
Hystero-Neuroses," pp. 124-139, in _Gynaecological Transactions_,
vol. xii, 1887; and a summary of a memoir by Fouquet on this
subject in _La Gynecologie_, February, 1903, will be found in
_British Medical Journal_, March 28, 1903,

Of all physical traits vigor of the hairy system has most frequently
perhaps been regarded as the index of vigorous sexuality. In this matter
modern medical observations are at one with popular belief and ancient
physiognomical assertions.[165] The negative test of castration and the
positive test of puberty point in the same direction.

It is at puberty that all the hair on the body, except that on the head,
begins to develop; indeed, the very word "puberty" has reference to this
growth as the most obvious sign of the whole process. When castration
takes place at an early age all this development of pubescent hair is
arrested. When the primary sexual organs are undeveloped the sexual hair
is also undeveloped, as in a case, recorded by Plant,[166] of a gir