These characters must, however, have begun as individual variations, and there is no reason to doubt that if systematic breeding experiments were kept up for a sufficiently long period, with albinoes or leucoderms, or if these characters came into play in natural or sexual selection, races of albinoes or leucoderms in the human species could be established.
Source: wiktionary
It is also admitted that these gradations in colour have a protective value; in the case of the melanoderms against the actinic rays of the sun and in that of the leucoderms against cold, since white is the best colour for keeping in the heat of the body.
Source: wiktionary
[…]I adopted the following terms for every anthropological group: (a) Leucoderms—men of white skin, rather brownish (no. 10-19 of von Luschen’s scale) black hair and wavy, (kymatotrichs) brown or black eyes, medium height, brachycephalian, leptorrhinian. The Brazilian leucoderms present two types of height: 1 ᵐ,63 and 1 ᵐ,69.
Source: wiktionary
Dark-skinned peoples (melanoderms) are, as a rule, more resistant to this parasite than the fair-skinned peoples (leucoderms).[…]In the case of malaria, we have already noted the differentiation between the leucoderms and melanoderms.
Source: wiktionary