In addition to the oscillation of limits, we should also study in any given population the geographic distribution of a definite anthropological datum. This must also be done in the case of the pigments. Among Livi's splendid charts, there is one regarding the distribution of the brunette type in Italy. From this it appears that the greatest prevalence of the brunette type is in Sardinia and Calabria, and that in general there is a prevalence of the dark types in the southern districts; while the lowest percentage of brunettes is found in Piedmont, Lombardy and Venetia, and in general the number of brunettes is less in northern and central Italy.
The relative distribution of other ethnical data should be noted, such as the stature and the cephalic index, in the corresponding charts.
By combining these results, we find that in the north of Italy the prevalent type is blond, brachycephalic, and of tall stature; while in the south it is a dark, dolichocephalic type, of low stature. This is what I succeeded in showing in my work upon the women of Latium, in which I sought to complete the details of these two ethnic types. In Latium there is a prevalence of the dark, dolichocephalic type of low stature, a type that is still almost pure at Castelli Romani; this type is fine, slender and delicate in formation, and corresponds to Sergi's Mediterranean stock, to which are due the great Egyptian and Græco-Roman civilisations. The other race is blond, tall and brachycephalic, and has only a scanty representation in southern Latium, but is prevalent in an almost pure form in the neighborhood of Orte. This type is much coarser and more massive in its formation, with a euriplastic skeleton, and corresponds to Sergi's Eurasian race that immigrated from the continent.
In general, we may say that it is foreordained in our biological destiny not only what form, but also what colouring we ought to attain in the course of our individual evolution, when we finally arrive at mature development.
The Pigments during Growth.—In the course of individual evolution, it is not only the form that becomes modified, but the pigments as well. We know, for example, that children are more blond than adults. Transformations in regard to the pigments occur, however, more especially at the period of puberty.
Pigmentation of the Hair.—The colour of the hair becomes darker in the course of growth, changing from light chestnut to dark, from blond to light chestnut, from dark to black, from light auburn to fiery red. Sometimes this darkening of the hair is accompanied by a change in tone (from blond to chestnut); at other times it consists in an intensification of the original colour through an increase of pigment, which fixes and defines a colour that was previously indefinite.
In children who were ill or ailing during their early years, in other words, weakly children (through denutrition, exhausting illnesses, overexertion), this phenomenon is imperfectly achieved, just as their growth as a whole is imperfectly achieved. The consequence is that these weaklings retain a paler and less decided pigmentation, which explains the fact that statistics show a greater proportion of frail, rachitic, tuberculous and mentally deficient persons among the blonds than among the brunettes; but it is among that class of blonds whose light colour represents an arrest of development (suppressed brunettes).
Social conditions also exert an influence upon the colour of the hair; a larger number of blonds and of lighter and more indefinite blonds are to be found in the schools for the poor than in those for the rich; also a larger number in country schools, where the poverty is greater, than in city schools. Consequently we may conclude that there are two classes of blonds: that which is associated with a racial type, and that which is the consequence of arrested development. The first type has a vivid, uniform and decisive colour tone, accompanied by physiological robustness; the second is indefinite in colour tone and lacks uniformity—for example, the more exposed parts of the body are paler, and the hair varies in tone, some locks showing greater intensity of colour than others. This is especially noticeable in frail young girls from the country, where the sun discolours the surface layer of hair. In this connection it should be remembered that in those geographical regions where the rays of the sun are most nearly perpendicular, the pigments are, on the contrary, darker and that the skin becomes bronzed under the ardent kiss of the sun. But while the sun intensifies the tints that are strong with life, it destroys those that are weak and moribund, just as it does in the case of lifeless fabrics, which become bleached out by the action of the solar light.
Accordingly the pigments give us an important test for judging the robustness of the body; the blonds who are the product of arrested development of brown tones that have not been attained because of weakness, are frail in health and physical resistance, which is the basis of the popular belief that vigorous wet-nurses must be brunettes.