having begun by attempting to ameliorate the conditions of life, has gradually begun to realize that it is necessary to go deeper and to ameliorate life itself.  For while it is undoubtedly true that much may be done by acting systematically on the conditions of life, the more searching analysis of evil environmental conditions only serves to show that in large parts they are based in the human organism itself and were not only pre-natal, but pre-conceptional, being involved in the quality of the parental or ancestral organisms.

Putting aside, however, all humanitarian considerations, the serious error of attempting to stem the progress of civilization in the direction of procreative control could never have occurred if the general tendencies of zooelogical evolution had been understood, even in their elements.  All zooelogical progress is from the more prolific to the less prolific; the higher the species the less fruitful are its individual members.  The same tendency is found within the limits of the human species, though not in an invariable straight line; the growth of civilization involves a diminution in fertility.  This is by no means a new phenomenon; ancient Rome and later Geneva, “the Protestant Rome,” bear witness to it; no doubt it has occurred in every high centre of moral and intellectual culture, although the data for measuring the tendency no longer exist.  When we take a sufficiently wide and intelligent survey, we realize that the tendency of a community to slacken its natural rate of increase is an essential phenomenon of all advanced civilization.  The more intelligent nations have manifested the tendency first, and in each nation the more educated classes have taken the lead, but it is only a matter of time to bring all civilized nations, and all social classes in each nation, into line.[429] This movement, we have to remember—­in opposition to the ignorant outcry of certain would-be moralists and politicians—­is a beneficent movement.  It means a greater regard to the quality than to the quantity of the increase; it involves the possibility of combating successfully the evils of high mortality, disease, overcrowding, and all the manifold misfortunes which inevitably accompany a too exuberant birthrate.  For it is only in a community which increases slowly that it is possible to secure the adequate economic adjustment and environmental modifications necessary for a sane and wholesome civic and personal life.[430] If those persons who raise the cry of “race suicide” in face of the decline of the birthrate really had the knowledge and intelligence to realize the manifold evils which they are invoking they would deserve to be treated as criminals.