THE CHART OF EVOLUTION 23 



point of the physician. Instead we shall view it from the stand- 

 point of the geographer and evolutionist. First we shall examine 

 the astonishing relationship between health and business In the 

 United States. We shall see that conditions of health not only 

 cause great differences In man's activity from region to region but 

 from decade to decade. Incredible as It may seem, health seems to 

 play a predominating part In the ebb and flow of the stock market, 

 In the rise and fall of prices, and In the fluctuations of prosperity 

 and of immigration. A realization of this will lead us to Inquire 

 minutely into the causes of fluctuations in health from year to 

 year and from day to day. We shall discover that far and away 

 the most important cause of fluctuation Is variations in tempera- 

 ture and In other climatic elements. Then we shall take a back- 

 ward look into geological times to see how man acquired his 

 wonderfully delicate adjustment to climate. That will lead us to 

 the most far-reaching of all our conclusions, namely, that brief 

 extremes of weather are among the most potent causes of biological 

 mutations and thus may lead to the origin of new species. Coming 

 down to historic times we shall study Rome as an example of the 

 effect of health upon the greatest of ancient empires. Next 

 Turkey will occupy our attention as a modern example of the way 

 in which unfavorable conditions of health retard a nation and 

 cause untold trouble to the rest of the world. Finally the dilemma 

 of Germany will make clear the way in which mere strength of 

 body and mind without the safeguards that come from the right 

 kind of training may turn the world upside down. 



Germany furnishes an example of nervous energy like that 

 which is both the pride and the danger of the United States. It 

 also furnishes an example of the aggressiveness which caused 

 Rome to wield so wide an empire. Both the nervousness and the 

 aggressiveness appear to be largely matters of climate, not only 

 in Germany, but In the United States and Rome. A nation with 

 the German inheritance, the German climate, and the German 

 geographical position is bound to expand. We shall find that 



