At the First Race Betterment Conference held at Battle Creek, Mich., many methods were suggested by which it was believed that the people of America might be made, on the average, healthier, happier, and more efficient. One afternoon the discussion turned to the children of the slums. Their condition was pictured in dark colors. A number of eugenists remarked that they were in many cases handicapped by a poor heredity. Then Jacob Riis--a man for whom every American must feel a profound admiration--strode upon the platform, filled with indignation. "We have heard friends here talk about heredity," he exclaimed. "The word has rung in my ears until I am sick of it. Heredity! Heredity! There is just one heredity in all the world that is ours--we are children of God, and there is nothing in the whole big world that we cannot do in His service with it." It is probably not beyond the truth to say that in this statement Jacob Riis voiced the opinion of a majority of the social workers of this country, and likewise a majority of the people who are faithfully and with much self-sacrifice supporting charities, uplift movements, reform legislation, and philanthropic attempts at social betterment in many directions. They suppose that they are at the same time making the race better by making the conditions better in which people live. It is widely supposed that, although nature may have distributed some handicaps at birth, they can be removed if the body is properly warmed and fed and the mind properly exercised. It is further widely supposed that this improvement in the condition of the individual will result in his production of better infants, and that thus the race, gaining a little momentum in each generation, will gradually move on toward ultimate perfection. There is no lack of efforts to improve the race, by this method of direct change of the environment. It involves two assumptions, which are sometimes made explicitly, sometimes merely taken for granted. These are: 1. That changes in a man's surroundings, or, to use the more technical biological term, in his nurture, will change the nature that he has inherited. 2. That such changes will further be transmitted to his children. Any one who proposes methods of race betterment, as we do in the present book, must meet these two popular beliefs. We shall therefore examine the first of them in this chapter, and the second in Chapter II.