36 



WORLD-POWER AND EVOLUTION 



If health is so potent in controlling man's mental power, has it 

 any effect upon his other activities ? The answer is found in Fig- 

 ure 4. There the upper line is the curve of health — the founda- 

 tion, so to speak, of our present discussion. Below it comes the 

 curve of mental power in the United States. These two curves 

 are identical with those of Figure 3 except that the line represent- 

 ing mental power has been pushed one year to the left. If the 

 dotted lines of Figure 3 were inserted in Figure 4 they would 



- Mental Power 

 — 10% —1 year 



School Attendance 

 +40% —1 year 



New York Bank 

 Clearings 



— S years 



General Prices 

 +15% —4 years 



National Bank 



Deposits 

 —15% — i years 



Immigration 



—5 years 



Prosperity (Average 



of Curves C to G> 

 -10% 



Health (Smoothed) 

 +10% 



Yield per Acre of 9 

 Crops (Smoothed) 

 - -10% 



1870 1880 1800 1900 1910 



Figure 4. Health and Business in the United States 



