RELATION OF PRIMITIVE PEOPLES TO ENVIRONMENT. 627 



and instead of the environment affecting him he changes the environ- 

 ment. The whole process is reversed. The environment now becomes 

 the creature of the man. He dresses in skins or in feathers, or in 

 some other manner protects himself from cold. He builds his house 

 and warms it, and that leads him to a multiplicity of other inventions. 

 The whole effect of environment is to develop him intellectually, not 

 physically. 



Now, let us see the effect of environment in another region, another 

 climate, and under other conditions. In temperate climes there are 

 trees ; he can not build of ice, for ice melts ; so he builds homes of trees, 

 of the slabs of trees, of young trees and of boughs ; he weaves mats 

 with which to cover his house, or he covers it with earth or leaves, as 

 the environment suggests. He exercises his ingenuity in the devising 

 of a habitation, and all the utensils of his home and the implements 

 useful in his domestic life; thus he controls and becomes the creator of 

 his environment instead of permitting his environment to change his 

 physical constitution. He uses his intellect, and instead of merely 

 developing as an animal would develop under those circumstances — 

 herding on the plain, wandering in the forest — and changing his 

 environment from one condition to another, he modifies and changes 

 it. Human evolution thus, in so far as it is affected by environment in 

 middle latitudes, is evolution of mind ; it is not evolution of kinds of 

 men, but of grades of mind. 



A little farther south we come to an arid land where trees and other 

 vegetation is scant, and where the rocks lie in profusion over the sur- 

 face of the earth. Here man is thrown under another environment. 

 The plant in an arid climate develops a bark or a skin which is covered 

 with glaze, so that the water does not evaporate; then it provides 

 organs by which water when it comes is stored within the plant, and a 

 method by which this can be utilized when rain does not come. Life 

 may be held in abeyance; the plant may sleep or partially sleep during 

 the arid time, living only on stored water. It provides itself also with 

 protecting organs to preserve it from destruction. In all of the arid 

 lands plants are found to have a singular armature of spines and 

 thorns and serrate edges, with which to save themselves from being 

 devoured by animals. The animals also develop in a peculiar way. 

 They not only have horns and spines, but several of them develop 

 poisons, like that of the rattlesnake and of other reptiles and insects 

 found in arid lands. But the^ effect upon man is altogether different; 

 man does not develop poisons or horns, or a skin which can not per- 

 spire. He is not physically changed by reason of the arid climate; his 

 organs as such are not greatly modified; there is no differential evolu- 

 tion in the man. The man now invents a house. Let us see how he 

 does it. He takes these rocks that he finds scattered all over the land 

 and builds him a house, perhaps under the cliffs where it will be 

 shaded. He develops a great variety of houses, all adapted to the 



