226 WORLD-POWER AND EVOLUTION 



discovered the causes of malaria and the measures to prevent it. 

 We have also found that hitherto unrecognized disorders such as 

 pellagra and the hookworm disease are responsible for no end 

 of ignorance and inefficiency. All of these diseases seem to be 

 closely dependent upon climate. Further investigation will 

 doubtless disclose many other ailments whose effects are so mild 

 that we have not hitherto called them diseases. Yet their com- 

 bined effects may account for a large part of the contrast in health 

 and energy in different parts of the world. When they are eradi- 

 cated we perhaps should not expect the people of unfavorable 

 climates to work as steadily and energetically as thos^ of the best 

 parts of the world. Yet we may reasonably expect that much of 

 the seeming stupidity, and much of the indifference, vice, and 

 crime will disappear. The medical rebirth of countries like 

 Turkey is as important as their political and economic rebirth. 

 The first great step toward medical rebirth is an exhaustive study 

 of the causes of the present inertia. It is good to think that 

 science, through the study of biology and evolution, offers such 

 hope for the regeneration of backward nations. 



