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 areolæ of the nipples (_Obstetric Works_, vol. i, p. 345). Engelmann discussed the subject and gave cases, "The Hystero-Neuroses," pp. 124-139, in _Gynæcological Transactions_, vol. xii, 1887; and a summary of a memoir by Fouquet on this subject in _La Gynécologie_, 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 girl with rudimentary uterus and ovaries who had little or no axillary and pubic hair, although the hair of the head was long and strong.[167]