NATURAL SELECTION IN MAN 191 



this figure can be considered only as a rough approximation to 

 the truth. 



It is a remarkable fact that while the death rate of most civi- 

 lized countries has been falling for the past hundred years the 

 infant death rate in general should have suffered little improve- 

 ment and in some countries actually increased up to the beginning 

 of the 20th century. During the past few years much greater 

 attention has been devoted to the subject, and a variety of organ- 

 izations have been active in checking the inexcusable loss of infant 

 life which has been so long suffered to go on, and as a consequence 

 infant mortality in many localities has very rapidly fallen. In 

 the same country enormous differences in the infant death rate 

 still exist in different towns and sections not far removed from 

 each other, as may be illustrated by the infant mortality rates of 

 the following towns of Massachusetts in 191 2: 



Chicopee 177 



North Adams 1 13 • i 



Waltham 86.8 



Brookline 55 



These conditions are usually associated with the economic 

 status of the inhabitants. The death rate is higher in urban 

 than in rural districts, and it increases in cities with the greater 

 density of the population. 



In all places infant mortality is very much higher among the 

 poor. In fact Mr. Ashby states that ''poverty is perhaps the first 

 and greatest predisposing factor in infant mortaUty." Duncan 

 and Duke in their valuable survey of the infant mortality of 

 Manchester, N. H., find that the rate of infant deaths rapidly 

 falls as the income of the father rises. Where the annual earnings 

 of the fathers are less than $450, the infant mortality rate was 

 found to be 242.9. Fathers earning from $650 to $850 lose 

 162.6 per thousand of their children, while those earning $1,250 

 and over, lose only 58.3. Among the foreign born mothers of 

 Manchester the death rate was 183.5, while among the native 



