INFLUENCES OF ENVIRONMENT 145 



or mischief, as the case may be. On very dry days in 

 Denver the amount of crime among adults and of mis- 

 conduct among school children increases largely. The 

 nerves seem to become unstrung by reason of the high 

 state of electric or magnetic tension, by the dryness and 

 the wind. When the wind dies down and the air becomes 

 moist, the nerves return to their normal condition, but 

 the system has been through an experience which reduces 

 the power to control emotional impulses. We find that 

 people in extremely hot, dry countries, like Persia and 

 Chinese Turkestan, are highly emotional and seriously 

 lacking in self-control. 



Each kind of climate and the geographical character- 

 istics of every inhabited region exert more or less influ- 

 ence upon the industrial life and the social organization 

 of the people. If the plain is waterless in summer and 

 the plateau deeply buried in snow in the winter, the ani- 

 mals must migrate. Man finds the region too dry in 

 one part and too cold in another part for agriculture. 

 Therefore he must live upon animals, either as a hunter, 

 or, after he has partially domesticated some species of 

 animal, as a shepherd. This leads to a nomadic life, 

 which in turn induces habits of cleanliness in eating, 

 traveling, sleeping, working, and resting. Such habits 

 becoming mass phenomena or usages of the group, de- 

 velop moral standards of abstemiousness, hardihood un- 

 der physical difficulties, laziness, hospitality, and the like. 

 Thus the physical features mold the people. Geograph- 

 ical environment has an important influence upon the 

 forms of invention. Protection against exposure is at- 

 tained in accordance with the available materials; for 

 example, the snow house of the Eskimo, the bark wigwam 

 of the Indian, and the cave dwelling of the tribes of the 



