According to legend, Aesculapius bore two daughters, Panacea and Hyegeia, who gave rise to dynasties of healers and hygienists. The schism (分离)remains today, in clinical training and in practice and, because of the imperative nature of medical care and the subtlety of health care, the former, has tended to dominate. Preventive medicine has as its primary objective the maintenance and promotion of health. It accomplishes this by controlling or manipulating environmental factors that affect health and disease. For example, in California presently there is serious suffering and substantial economic loss because of the failure to introduce controlled fluoridation(加氟作用)of public water supplies. Additionally, preventive medicine applies prophylactic(预防性的) measures against disease by such actions as immunization and specific nutritional measures. Third, it attempts to motivate people to adopt healthful lifestyles through education. For the most part, curative medicine has as its primary objective the removal of disease from the patient. It provides diagnostic techniques to identify the presence and nature of the disease process. While these may be applied on a mass basis in an attempt to 'screen' out persons with preclinical disease, they are usually applied after the patient appears with a complaint. Second, it applies treatment to the sick patient. In every case, this is, or should be, individualized according to the particular need of each patient. Third, it utilizes rehabilitation methodologies to return the treated patient to the best possible level of functioning. While it is true that both preventive medicine and curative medicine require cadres of similarly trained personnel such as planners, administrators, and educators, the underlying delivery systems depend on quite distinctive professional personnel. The requirements for curative medicine call for clinically trained individuals who deal with patients on a one-to-one basis and whose training is based primarily on an understanding of the biological, pathological, and psychological processes that determine an individual's health and disease status. The locus (地点)for this training is the laboratory and clinic. Preventive medicine, on the other hand, calls for a very broad spectrum of professional personnel, few of whom require clinical expertise. Since their actions apply either to environmental situations or to population groups, their training takes place in a different type of laboratory or in a community not necessarily associated with the clinical locus. The economic differences between preventive medicine and curative medicine have been extensively discussed, perhaps most convincingly by Winslow in the monograph The Cost of Sickness and the Price of Hearth. Sickness is almost always a negative, nonproductive and harmful state. All resources expended to deal with sickness are therefore fundamentally economically unproductive. Health, on the other hand, has a very high value in our culture. To the extent that healthy members of the population are replaced by sick members, the economy is doubly burdened. Nevertheless, the per capita cost of preventive measures for: specific diseases is generally far lower than the per capita cost of curative medicine applied to treatment of the same disease. Prominent examples are dental caries(蛀牙), poliomyelitis(脊髓灰质炎) and phenylketonuria(苯丙酮尿). There is an imperative need to provide care for the sick person within a single medical care system, but there is no overriding reason why a linkage is necessary between the two components of a health care system, prevention and treatment. A national health and medical care program composed of semiautonomous systems for personal health care and medical care would have the advantage of clarifying objectives and strategies and of permitting a more equitable division of resources between prevention and cure. The author's primary concern is