However great, for example, be the influence which the soil exerts on men, this influence will always vary according to the race in which it produces its effect. Dearth of soil may stimulate one race to the most strenuous efforts and highest achievement; while, for another race, the poverty of the soil may be the cause of misery and finally of undernourishment, with all its consequences. The internal characteristics of a people are always the causes which determine the nature of the effect that outer circumstances have on them. What reduces one race to starvation trains another race to harder work.

All the great civilizations of the past became decadent because the originally creative race died out, as a result of contamination of the blood.