We consider, therefore, that child-protection is necessary, although, notwithstanding great pains and great sacrifices, it often results in the survival of individuals who are useless to society. The view that only the children of the inferior and poorer classes of the population are suitable for the application of the methods of child-protection, is erroneous, if only for the reason that the well-to-do to-day bring forth offspring utterly regardless whether these are strong or weak; and also because capitalism interferes in other ways with the effective operation of natural selection. These various evils can be obviated to-day only by means of child-protection. In the case of infants, there is no question of the struggle for existence. For their death-rate depends upon two factors--first, upon their inborn capacity; secondly, upon the conditions in which they are reared. The former factor is of far less importance in relation to infant mortality than it is in relation to child mortality. Only in an extremely limited sense is it possible, with regard to infants, to speak of a struggle for existence, in virtue of which the fittest survive. The infant is exposed to numerous dangers, in coping with which its inborn capacity hardly counts at all. When certain external influences come into play, the infant is quite incapable of making an advantageous use of its inborn physiological capacities. Such external influences destroy quite indifferently infants well-equipped and ill-equipped at birth. There is no doubt of the fact that a strong infant could better resist most of the diseases of infancy than a weakly infant; but the differences in power of resistance in infants are far less extensive than is generally believed. It is certainly wrong to maintain that a strong infant is able successfully to resist all diseases. For the very reason that certain diseases--for example, certain affections of the stomach and intestines--will destroy even the strongest infant, the prevention of these diseases becomes a matter of the first importance. It is unquestionable that such diseases can be more effectively prevented in proportion as the circumstances are favourable in which the infant is reared.