The worst condition with regard to the fertility prevails among those with the highest mental endowment. Evidence of this is given in Figure C 123, "+Insufficient Fertility of the Highly Endowed in Holland+," after J. R. Steinmetz. It shows the rapidity with which the number of children decreases. In order to estimate the significance of these statistics, it must be noted that after taking into account the mortality among children and young persons, and the unfitness for parenthood of an appreciable fraction of the adults, a fully capable couple would have to produce at least four children to assure the necessary moderate increase in the population which is required to prevent a people from sinking into stagnation and deterioration.
The dying out of highly gifted families is shown to be more accentuated in Figure 255, after Bertillon, "+Progeny of the Highly Gifted in France+." Four hundred and forty-five of the best known Frenchmen, with their wives, have not even reproduced that number of individuals, and this in spite of the fact that repeated marriages of the same individuals have not been taken into account.
Even if one has been able, up to the present, to live in the hope that the number of persons of more than average ability produced by the mass of the people is always sufficient to replace those that are used up, at the present time anxiety about the "heads" is replaced by anxiety about the "hands." The knowledge of means of preventing fertilization spreads incessantly, and is recklessly promulgated by the neomalthusians and by a shameless industry. We point to Figure C 125, "+Want of Fertility in French Towns+," after Jayle, and to Figure C 126, "+Fertility in Prussia+." In Berlin fertility is decreasing most rapidly; at the end of the sixties it still amounted to 200 in every 1,000 women of child-bearing age. In the five years, 1905-1910, only to 84; in the year 1910 only to 74. This state of things is shown also in the relative increase in numbers of the first born.
Figure C 127, "+Decrease of Legitimate Fertility in Berlin--the two-children system+." The other German towns follow the example of Berlin. Berlin to-day produces 20% less children than are required to maintain its own population without immigration, and the same conditions will soon prevail in other towns. Up to now the country districts in general maintain their fertility (West Prussia on Figure C 128), but there, too, modern practices begin to make themselves felt. The town and industrial population increases so rapidly that the conditions prevailing among them have an ever increasing effect on the people as a whole. Thus we see, even at the present time, a serious decline in fertility among an overwhelming majority of European States: Figure C 129, "+Decrease of Fertility in Some European States+."