352 HUMAN BIOLOGY 



ences cannot be explained satisfactorily on any basis of 

 selective race, age, sex, occupational or economic differences 

 among the 11,318,734 people dealt with in this study. As 

 Dr. DePorte well says: "Among the several important causes 

 of death, the element of residence is perhaps of greatest 

 weight in mortahty from tuberculosis." 



Turning now to the death rates of the registration area of 

 the United States in 19 10 and 1920 we find not only in the 

 rate for all causes combined, but for a goodly number of 

 the more common causes of death, higher rates among the 

 city people than among the rural. The following table gives 

 not only the differences between urban and rural rates, 

 but the trend and the consistency of the differences over that 

 decade during which the shift of population to the cities took 

 on the highest speed, to be exceeded in all probability, 

 however, by the period since 1920. No similar period of 

 time has been characterized in this country by a greater 

 improvement in general health conditions in both city and 

 rural regions. At no previous period have the services of 

 science and of the medical profession and public health 

 workers been more nearly similar in value for the great 

 majority of rural communities as well as for the cities. 



Various parts of the country, notably in the states of 

 New England and in northern New York where extreme 

 changes have occurred in the age grouping and rural pro- 

 portion of the populations concerned, there has been observed 

 during the past fifty years an increasing inadequacy in 

 the number and distribution of physicians to meet the 

 desires or necessities of small and widely scattered village 

 and farm groups. Physicians distribute themselves very 

 much as other people do, on the basis of more advantageous 

 economic and social conditions for themselves and their 

 families. They too, therefore, have gravitated to city 

 centers where hospitals, laboratories, libraries and schools 

 are available. While one physician to seven hundred people 

 was a reasonable ratio in the era of the horse and buggy 

 and dirt roads, today with no more effort or time, a physician 

 can readily serve a thousand people as well or better, even 

 if they are as scattered and distant, as were their ancestors. 

 There would seem to be no evidence that health protection or 



