The next and the greatest concern of race-hygiene—much greater than the relative increase of inferiority—is, to-day, neomalthusianism, the intentional restriction of the number of births in varying degrees up to complete unproductiveness. Though conscious regulation of the production of children is absolutely necessary, it becomes fatal to a nation if under no control but the egotism of the individual. For its permanent prosperity a nation requires, in order merely to hold its own, a sufficient number of "hands" and a sufficient number of "heads" to guide those "hands." We referred to this when mention was made of sterility as a phenomenon of degeneration, but this cause of sterility during the last decades only takes a second place compared to deliberate intention. The wealthy and higher social classes were first attacked by neomalthusianism. Their progeny is becoming more and more utterly insufficient, so that under our present social conditions, particularly which give mind and talent better openings, and thereby more and more take out of the mass of the people the better elements, make the strongest demand for them and use them up, the danger of an increasing deterioration of the average quality of its progeny grows greater and greater. The baneful influence of wealth on fertility is shown by several tables. Figure C 118 "Fertility and Wealth," after Goldstein and Tallquist, gives the condition in the French Departments; Figure C 119, "Number of Children and Wealth," after Bertillon, for the Arrondissements of Paris; Figure C 120, "Fertility and Wealth," after Mombert, for Münich, 1901, Table C 121, "The Number of Children in Families of Different Classes in Denmark, 1901," after Westergaard; Table C 122, "Fertility of Marriages, Occupation, and Wealth for Copenhagen, and Dutch Conditions," after Rubin, Westergaard, and Verrijn Stuart.
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.