314 THE TREND OF THE RACE 
dimensions is simply due to the fact that the greater the age of 
the mother the greater is the number of previous deliveries, and it 
follows that if the women married as soon as they were capable 
of bearing children we should expect, with a rise in the fertility, 
an increase in these dimensions in the foetuses.” (Problems in 
Eugenics, II, 117-18.) 
With advancing age of parents there is in general a higher death 
rate of children in the first year of life. There is, however, a 
preliminary descent from the earlier ages due probably to the 
high death rate of the first born. The statistics studied by 
Ewart show that the infant mortality falls “until the twenty- 
fourth year is reached and then slowly rises again,” reaching 
its maximum in mothers of over 4o years of age. This is indi- 
cated in the following table: 
Infant Mortality According to Maternal Age 
Age of Mother | No. of Births | Deaths in rst Year \Per 1,000 Births 
Under I9...... 152 26 171 
20-24 Inc...... 536 66 132 
O58) eas 396 66 166 
BORR A Swine 316 74 170 
B5=36°% Lead 150 34 220 
Over 4o Inc.... 36 12 330 
After the initial fall the rise in the infant death rate with in- 
creasing years of the parents is very striking. Data from New 
South Wales from 1893 to 1900 dealing with 277,799 confinements 
show a similar fall to the 2zoth year of the mother’s life, and a 
gradual rise with later years, the infant mortality of mothers 
above 40 being over four times as heavy as in mothers of 20. 
When first births alone are tabulated there is a similar fall until 
the 2oth year is reached, after which there is a rise, as is indi- 
cated by the following table based on 56,247 first births: 
