Prospects for prevention.

All will agree that the health of the nation may be improved in many ways, not only by the activities of our profession as we strive to prevent and treat disease, but also by the social and economic changes that result in better nutrition, smaller families, less overcrowding, and better education. I doubt, however, if anyone has a clear idea of the relative returns to be expected from investment in each of these fields, and it cannot be easy for those who are seeking to improve health on the national scale to know how to allocate available funds. Understandably, therefore, allocation tends to be made on the basis of the existing pattern, modified by a judicious response to competing pressures. In recent years these pressures have shifted, and it is now commonly argued that the burden of disease and the cost of services could both be reduced by redistributing funds in favour of prevention1 ; while some add that such action would have the additional attraction of reducing the dependence of society on the medical profession.2 3 This shift in public opinion is due to many factors. One is the very success of curative medicine, which has been so great that cures are taken for granted and clinical medicine is now blamed for its remaining failures. Another is the increasing scope, complexity, and, particularly, cost of the services that aim to cure, which has been so great that four Secretaries of State were led to write, in 1976, that ''curative medicine may be increasingly subject to the law of diminishing returns.4 Opinion has been changed, too, by the experience of iatrogenic illness that has sometimes accompanied the use of effective drugs and of the environmental hazards that have sometimes resulted from industrial growth and the introduction of new and potentially noxious materials. Most