"A mother who suckles her children gives herself directly, gives her own body to nourish the children, who are unable to live without it. This is love. So, the workman, who for the welfare of others, wears out his body by toil, and thus brings himself to the verge of death, also gives himself, his body, to nourish others. And such love is possible only to the man for whom, between the possibility of the sacrifice of himself and those beings whom he loves, no obstacle to sacrifice exists. The mother who trusts her child to a foster-mother cannot love it; the man occupied in acquiring and keeping riches cannot love."