ECONOMIC FACTORS 251 



the proportion of adults to the whole population. 1 Now, on the 

 whole, the greater the average age of a given population, the greater 

 will be the per capita consumption of foodstuffs ; and this is especi- 

 ally the case with meat and some other animal foodstuffs, which 

 are consumed in but small quantities by infants and young children. 

 Among animal foodstuffs milk is the only striking exception, though 

 the extra quantities of milk consumed by children under 7 or 8 

 years of age does not suffice to bring their normal consumption of 

 animal foodstuffs as a whole to anything approaching the level of 

 the average working adult in the same population. It may be said 

 that older people beyond the prime of life consume less foodstuffs 

 than younger and more active people, though it is probably also 

 true that the quantities of concentrated foodstuffs consisting 

 mainly of meat and dairy produce consumed per capita, do not 

 diminish perceptibly in the diet of most people as they grow older. 

 Again, a decline in the birth-rate may have this important conse- 

 quence that it increases the income available for the purchase of 

 foodstuffs per unit of the family, and thereby lead to an increase 

 in the quantities of animal foodstuffs consumed by all members of 

 the family. This is especially true wherever the family food budget 

 is limited by considerations of incomings, as in the case of the 

 working classes, which, after all, form the great bulk of European 

 populations. Clearly among the working classes, where family 

 incomes tend to a more or less uniform level, the per capita con- 

 sumption of animal foodstuffs, that is, of the more cost!} 7 forms of 

 nourishment, is likely to be greater in those families in which there 

 are no children, or only one or two, to be provided for, than in those 

 where the number of dependent children is numerous. 



It follows that calculations concerning the per capita consumption 

 of animal foodstuffs, which are consumed in greater per capita 

 quantities by adults and by those of greater relative means, are not 

 comparable for different periods in the same countries, nor for dif- 

 ferent countries at the same time, unless some account is taken of 

 changes or differences in the age- constitution. Changes in the age- 

 constitution are most noticeable among the more advanced coun- 

 tries of white population, and one of the more striking social effects 

 of the European War is a further marked decline in the birth-rate 

 of the countries closely involved in the conflict. Apart, therefore, 

 from army casualties, it will be found that the proportion of adults 

 in the near future in these countries will be higher than ever before. 



1 A decline in the birth-rate, even if the rate of infant mortality is at the 

 same time somewhat lowered, raises the average age, while a decline in the 

 death-rate, unless confined to infants and children which in actual experience 

 is not the case, also raises the average by sparing to older years those who 

 would otherwise have disappeared from the population. 



