tion, if not absolutely necessary, at least conduces to acuteness of sense; and that where abundantly present it is often an index of vitality.[1] This eminent naturalist even ventures to connect the aggressiveness of the male sex among the lower animals with its brilliancy of coloring.
Applying these considerations to man, evidence is not entirely wanting to support De Candolle's (1887) thesis that "pigmentation is an index of force." Disease often produces a change in the direction of blondness, as Dr. Beddoe has observed; asserting, as he does, that this trait in general is due to a defect of secretion. The case of the negro, cited by Ogle, whose depigmentation was accompanied by a loss of the sense of smell, is a pertinent one. The phenomenon of light-haired childhood and of gray-haired senility points to the same conclusion. A million soldiers observed during our civil war afforded data for Baxter's[2] assertion that the brunette type, on the whole, opposed a greater resistance to disease, and offered more hope of recovery from injuries in the field. Dr. Beddoe finds in Bristol that the dark-haired children are more tenacious of life, and asserts a distinct superiority of the brunette type in the severe competitions induced by urban life.[3] It is not for us to settle the matter here and now. The solution belongs to the physiologist. As statisticians it behooves us to note facts, leaving choice of explanations to others more competent to judge. It must be said in conclusion, however, that present tendencies certainly point in the direction of some relation between pigmentation and general physiological and mental vigor. If this be established, it will go far to explain some of these curious differences between country and city which we have noted.
From the preceding formidable array of testimony it appears that the tendency of urban populations is certainly not toward the pure blond, long-headed, and tall Teutonic type. The phenomenon of urban selection is something more complex than a mere migration of a single racial element in the population toward the cities. The physical characteristics of townsmen are too contradictory for ethnic explanations alone. A process of physiological and social rather than of ethnic selection seems to be at work in addition. To be sure, the tendencies are slight; we are not even certain of their universal existence at all. We are merely watching for their verification or disproof. There is, however, nothing improbable in the phenomena we have noted. Naturalists have always turned
