In the country districts, the age-class of the children and the age-class of the old both contain proportionately larger numbers than the same age-classes in the towns. In the large towns and the manufacturing districts, there is an especially large proportion of persons of about 20 years of age. There are three reasons for this: first, the birth-rate is higher in the country districts; secondly, there is a drift from the country to the towns of persons of an age to earn a living; and, thirdly, a proportion of those who have grown old in the towns find their way back to the country. _The Excess of Women._--All the civilised countries of twentieth-century Europe contain more women than men. For every 1000 males there are invariably more than 1000 females. The excess of females is not usually greater than 5 per cent. Only in certain uncivilised countries of Europe do we find no excess of females. Whether we compare the total female population with the total male population, or compare only males and females of a marriageable age, the result is the same; the females are always in excess. Even in those countries in which women are comparatively less numerous, we still find an excess of women of a marriageable age. This excess of women depends upon the following causes:--In civilised countries more boys are born than girls. The average excess of male births over females is 106:100. (In the case of illegitimate children, the excess of male births is not so great as in the case of legitimate children.) But in males the death-rate is much higher than it is in females. Especially high is the death-rate among male infants (in the first year of life), and among males during the ages at which they are competent to earn a livelihood. The reason given for the higher mortality of male infants is that their powers of resistance are inferior to those of female infants; during the productive years of life the death-rate of males is higher because, on the one hand, they have a far greater mortality than women from diseases of occupation, and, on the other hand, during this period of life males suffer far more than females from the effects of alcoholism, of criminality, and of various other factors exercising an unfavourable influence upon their death-rate.