HEALTH AND BUSINESS 35 



weight to each. The one may be regarded as representing mental 

 alertness; the other as representing strength of will. Combined 

 they represent mental power. Such power, especially when united 

 with physical vigor, gives a nation the ability to do the things 

 that cause progress and promote civilization. Of course such 

 ability may be exerted in the wrong direction, but our present 

 concern is merely to find out what causes it and how it is modified. 

 Above the curve of mental power in Figure 3, I have again placed 

 the curve of health. The two curves agree even more closely than 

 do the curves of Figure 2. Without exception each upward or 

 downward movement of one is reflected in the other. The dotted 

 lines connecting the maxima bring this out clearly. With one 

 exception the maxima of mental power lag a year behind the 

 maxima of health. In the exceptional case the lag is two years. 

 From the early nineties to the first few years of the twentieth 

 century the general health of the United States improved about 

 20 per cent more than would be expected on the basis of the 

 improvement in medical practice and hygiene. During the same 

 period mental power apparently increased in almost equal ratio, 

 I know that it sounds unreasonable to place these two things in 

 such close connection, but the facts are stubborn. What can they 

 mean except that man's power of achievement is closely dependent 

 upon his health? 



Here is the apparent sequence of events. This year the death- 

 rate is low; people have relatively few serious illnesses; they are 

 comparatively free from anaemia, colds, and other minor ills that 

 constantly prevent us from doing our best. As a result the young 

 people who are going to take the Civil Service Examinations study 

 unusually well; the young men who have begun to drink a little 

 swear off; those who have not yet begun to drink do not yield 

 to temptation so easily as they would if they did not feel so strong 

 and vigorous. Hence the community is in a fit condition to make 

 progress, and a year later the effect is evident in the Civil Service 

 Examinations and in the drink bill. 



