The idea that social work necessarily concerns the poor is wholly wrong. It concerns the sick; it concerns the tuberculous; some of the sick and some of the tuberculous are poor. Others are not. The State provides dispensaries for tuberculosis, and the people pay for them out of the taxes. Hence all the people feel that they have the right to go there and that they are not in any sense accepting charity in going there. But social work is done in all these dispensaries. Thus the connection between medical and social studies is tending to upset the old idea that social work is necessarily concerned with poverty, and that economic studies are the main part of it. In America our leading ideas about social work (formerly called charity), came originally from England and from the studies of English economists. Hence to a considerable extent economic considerations have governed the history and evolution of social work even up to the present day. Economists and people interested especially in political economy have studied, practised, and spoken and written upon these subjects, and all who are governed by the traditions inherited from England are still obsessed by the idea that money and money troubles are the gist of social work. Nobody should turn up his nose at economics. Anybody who is careless in money matters is sure to come to grief. But in my medical-social work, which has included a large number of cases where poverty existed, I have almost never found the economic trouble to be the essential one. Economics is everywhere present, everywhere subordinate. That is an adaptation of a saying of the German philosopher Lotze: "Mechanism everywhere present, everywhere subordinate." The idea applies also to economics which has many qualities in common with mechanics. I shall therefore lay especial stress in this book, not upon economic but mental deficiencies, which in most cases seem to me more fundamental than economic need or physical weakness. A considerable portion of all social diagnoses should contain the word _ignorance_. I wish to distinguish ignorance from moral fault. It is true that somebody's sin, somebody's evil-doing is the fundamental thing in the social diagnosis of many cases. I have never yet studied carefully a case involving social work without finding some moral weakness as an important element in the trouble. Moral elements always enter into the study of a case of social work, but they are often not the main element, often subordinate.