INFLUENCE OF ORDER OF BIRTH, ETC. 
313 
Table Showing the Influence of the Age of the Mother on Birth Mortality, 
Eliminating and not Eliminating the Effect of Order of Birth 
Saxe-Meinungen (1878-89) Luxemburg (1901-03) Berlin (1893-97) 
Taking birth mortality Taking birth mortality when | Taking birth mortality for 
when mother is 35-49 at 100,| mother is 35 and up al 100 all births at roo, the 
birth mortality at other birth mortality at other |birth mortality according to 
Age of Mother ages is ages ts the age of the mother is 
Eliminating Eliminating Eliminating 
Not eliminating| order of Not eliminating] order of Not eliminating| order of 
order of birth birth order of birth birth order of birth birth 
Under 20....... 66 32 60 42 57 61 
20-26: sts se 68 42 50 38 73 80 
Lak |: See 68 54 54 44 83 94 
30-35 80 77 69 63 97 102 
BSHAQ iiss sisi 100 100 88 87 120 114 
40-45 123 127 157 128 
45 and 210 119 
upwards 150 157 227 165 
When the effect of order of birth is eliminated there remains a 
very considerable correlation between the age of the mother and 
the percentage of stillbirths. On the other hand, when the 
influence of maternal age is eliminated there is after the first 
birth little relationship between birth order and ante-natal 
mortality. 
There is no reason to suppose that these effects of age depend 
upon influences which may be properly described as hereditary. 
They may be expressive of changes in the maternal organization 
rather than any primary differences among the offspring. The 
same may be said for the relation between age of parents and 
height and weight of their children. The younger mothers tend 
to bear the smallest children. When we deal with large numbers 
of cases it is found that there is a slight increase of height and 
weight as the age of mothers increases. A part of this is due to 
the very evident increase of giant births (over 4ooo gr.) with 
increasing age of the mothers. (See Prinzing, Med. Statistik, 
p. 52.) As Gini has shown, the apparent influence of age on the 
size of offspring is really due mostly to order of birth. ‘The age 
of the mother,” he says, ‘‘has no decisive influence of its own on 
the dimensions of the foetus; the increase which is found in these 
