t 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