It should be among the medical duties of the visitor to investigate the hygienic aspects of the home in order to explain them to the doctor, who can then include them among the facts on which his diagnosis, prognosis, and treatment are based. The social worker may then try to carry out such improvements in housing as the combined judgment of the doctor and the social worker suggests. More important than medicines, often, is the provision for proper warmth and proper ventilation of the patient's rooms during the day and especially at night. Darkness, dirt, poor ventilation, favor the growth of germs, vermin, parasites of all sorts. They also depress the vigor and power of the human organism to resist disease. Doctors and social workers cannot hold Utopian views in matters of housing, but must content themselves with trying to secure something a little better than they find in the worst of the patient's lodgings, especially when these lodgings represent conditions below the family's own standard of living at some previous time. People adapt themselves wonderfully to bad hygienic conditions, and once so adapted, they may be able to preserve their health for a long period. But if then a family is suddenly forced to crowd itself into smaller, darker, dirtier, noisier quarters than it has been used to, or if a family group increases its numbers within the same quarters, the adaptive powers of the human organism may be overstrained and break down. It is against these conditions especially that the social worker and the doctor should labor. Housing problems are among the most difficult of all that confront society. Yet we should pledge ourselves to attempt some improvement, not disdaining slight gains because we are enamored of distant Utopias. Sometimes people are living beyond their means, are accepting bad quarters at high prices when they could get as good or better quarters for less money in some less crowded and popular district. Human beings have a strong tendency to stay wherever they find themselves, to settle down by chance and resent any suggestion of change even for their own greater comfort. After a few months any place soon comes to have the attractions of home merely because we have been there. Hence we stick in the same place, though we may know that it is chance and not choice or necessity that has put us there. Under these conditions a social worker may do real service by her greater knowledge of other lodgings at lower prices, or (what is essentially the same thing) better lodgings for the same price now paid. If the social worker is familiar, as she should be, with the lodging conditions in the neighborhood in which she works, she may be able to give a patient facts about lodgings which were either unknown to him, or more probably unrealized, because he has never seen them. Our mental horizon becomes restricted. Any one who enlarges it by presenting new and helpful possibilities serves us well.