The large families of the proletariat provide a greater supply of labour, and this leads to a fall in wages. Because wages are lower, there results, in turn, an increase in the birth-rate. The great number of conceptions among the proletariat interferes with the effective working of selective forces--an evil which every unprejudiced thinker must deplore, and must endeavour to remedy to the utmost of his ability. The most important means available for this purpose are: first, a rise in wages, and, secondly, the use by the proletariat of positive methods to restrict or prevent procreation. Parents should procreate so many children only as they are in a position to maintain and educate in a suitable manner; it is obvious, therefore, that working-class families should be comparatively small. Yet to-day we see the exact opposite. Only among the well-to-do and the more intelligent sections of the population do we find that these principles are carried into effect. The tragic consequence is that the more prosperous and the comparatively intelligent procreate very few children, the very reverse of what is desirable. Rich people are in a position to have many children, and have but few; working-class parents, on the other hand, ought to have but few children, and they have a great many. If the weekly wage-earners were more prosperous and more intelligent, they would be in a position to have more children, but they would, in fact, have fewer in that case. _The Tendency of Evolution._--During the last quarter of the nineteenth century, a decline in the birth-rate set in in every civilised country in Europe, notwithstanding the fact that in all these countries the proletariat constitutes an ever-increasing proportion of the total population. The probable causes of this decline are: first, women’s dread of pregnancy, of childbirth, and of rearing children, and, secondly, pelvic contraction(?). The death-rate is harder to control than the birth-rate. For the birth-rate is influenced to a far greater extent by factors which are under individual control; whereas, in the case of the death-rate, great natural forces are the chief determinants. Death comes to every one, whether his parents and other relatives desire it or not, but those only are born whose parents desire it. In this matter of the population problem, well-considered action will be directed where a result may be obtained with comparative ease. By this it is not meant to imply that the campaign against excessive mortality is to be altogether neglected; but rather that the campaign against an excessively high birth-rate demands more attention than it has hitherto received.