358 HUMAN BIOLOGY 



By comparison of the life expectancy tables of 1901 with 

 those of 19 10 it appears that by this criterion there 

 has been a gradual reduction of the disadvantage of the 

 city dweller. While the rural population still (1910) enjoyed 

 a substantially longer hfe expectancy at every decade of 

 from four to eight years, than did his city friend, the gains 

 of the city man and woman have been a little greater; thus 

 the difference has been reduced. There is good reason to 

 believe that there has been a continued reduction in the 

 handicap of the urban population since 19 10, but the life 

 expectancy tables have not yet been officially issued since then. 



A white male born and continuing to live in the country 

 had an expectation of hfe at birth, in 1901, 10 years greater 

 than that of a similar male child in the city. At the age of 

 fifty this advantage had decreased to 4.2 years. Similar 

 values for white females are 7.5 years and 3.2 years. 



In 19 10 the actual expectancy of a male child had increased 

 in the city by 3.3 years and in the country by i.i years so 

 the advantage in favor of the country had been reduced 

 2.2 years, that is from ten years to 7.8 years. At the age of 

 fifty the expectation was unchanged in the city and 0.4 

 years less in the country, reducing the country advantage 

 from 4.2 to 3.8 years. 



Turning now from the quite convincing evidence that, 

 taken as a population group, city people die earfier and at a 

 higher rate from the principal causes than do country 

 people, we have many elements, entirely apart from those 

 of heredity, race, age, sex and a possible social selection, 

 any one of which may have a share in causing the disadvan- 

 tages, and which are worthy and possible of analysis. 



In the environment of the city dweller, compared with 

 that of the rural family, we appreciate difi"erences of atmos- 

 phere, water, food, clothing, fighting, insects and personal 

 contacts, each a possible factor in modifying the safety of 

 life. 



While there seems to be almost no fimit to the adaptations 

 of fife to diff'erences of environment in permitting these to 

 occur without sacrifice of the individual, there is some reason 

 to befieve that we have not caught up with the rapid changes 

 which have accompanied the artificial environment we 



