Thus the excess of women is closely associated with that peculiarity of the modern system of production in virtue of which far more men than women are engaged in the work of production. This is obvious from the consideration that the death-rate of wage-earning women is higher than that of other women, and from the consideration that in great towns the ratio between the death-rates of the respective sexes is very different from what it is in the country districts. The excess of women is one of the causes of the failure of so many women to marry, of the birth of so many illegitimate children, of the wide diffusion of prostitution, &c. But it would be quite erroneous to attribute these various phenomena of our sexual life exclusively to the prevalent excess of women. If in any country we desire to diminish the excess of women, it is necessary not merely to lessen the emigration of males, but also to diminish the death-rate of male children. This may be effected by reducing infant and child mortality in general, for measures that accomplish this reduction will lower the death-rate of boys to a greater extent than the death-rate of girls; for the higher the death-rate the greater the effect we can produce by measures effecting its diminution. Hence child-protection, the principal means for the diminution of infant and child mortality, is not only an important part of our campaign against the excessive mortality of male children, but will tend to redress the existing numerical inequality between the sexes, and thus to ameliorate the conditions of our social life. The regulation of the birth of boys and girls (the determination of sex) would be an important means for the restoration of a proper numerical balance between the sexes, and would therefore be of value, not merely to interested individuals, but also to society at large. Unfortunately, contemporary science is not even in a position to ascertain the sex of the infant before birth; and still less are we in possession of such a knowledge of the determinants of sex as might enable us to procreate boys or girls at will. Should the astounding advance in medical science eventuate in the solution of this problem, it will then be in our power to restore the proper numerical balance of the sexes. _Marriage._--In the civilised countries of modern Europe the number of marriages per 1000 inhabitants of all ages is from 6 to 8; whilst for every 1000 inhabitants of a marriageable age the annual marriage rate is 50. Of 1000 men over 15 years of age from 400 to 700 are married, whilst of 1000 women over 15 years of age from 440 to 640 are married. A high marriage-rate is not _per se_ either a favourable or an unfavourable manifestation; it is dependent upon economic conditions, and transient variations in the marriage-rate arise from the favourable or unfavourable economic conditions of the year in which these variations occur.