The relation of pigmentation to cli

The relation of pigmentation to climate has long interestedgeographers as a question of environment; but their speculations on the subject have been barren, because the preliminaryinvestigations of the physiologist, physicist and chemist arestill incomplete. The general fact of increasing nigrescencefrom temperate towards equatorial regions is conspicuousenough, despite some irregularity of the. shading. Thisfact points strongly to some direct relation between climateand pigmentation, but gives no hint how the pigmentalprocesses are affected. The physiologist finds that in the caseof the negro, the dark skin is associated with a dense cuticle,diminished perspiration, smaller chests and less respiratorypower, a lower temperature and more rapid pulse,31 all whichvariations may enter into the problem of the negro's coloring.Hie question is therefore by no means simple.