The early twentieth century was a period of tremendous advancements in medicine and technology and as a result experienced a revolutionary change in the delivery of healthcare in America. Modern medicine which encompassed specialized knowledge, technical procedures, and rules of behavior, changed the way medical care was provided in the United States during this period. In addition, the development of advanced diagnostic tools changed the interactions between doctor and patient. In many respects, the evolution of medicine in New Jersey mirrored the culture of medicine as it was developing in America. Sandwiched between the dominating medical centers of Philadelphia and New York, New Jersey practitioners drew upon the knowledge and expertise of their metropolitan colleagues. As the New Jersey practitioners accepted and integrated new techniques and therapeutics into their practices, the relationship between doctor and patient changed. This project focuses on medicine in Middlesex County during the early twentieth century, in particular, the two cities of New Brunswick and Perth Amboy. This geographic setting and the timeframe of the early 1900s represents an era and location in which modern medicine began to evolve in central New Jersey and technology became a part of routine medical care. Although much has been written about medical events and medical organizations in other New Jersey counties, such as Essex and Camden, Middlesex County received little attention. The intent of this study is to rectify the lack of attention to the history of medicine in Middlesex County. Middlesex County medical practitioners were in tune with how illnesses were being addressed and how innovative medical techniques were being practiced nationally. The introduction of new diagnostic test procedures and technology changed the way they interacted with their patients. The establishment of social and professional medical organizations and institutions; the passing of legislation; and the application of modem approaches to medical practice, helped to change the landscape of medicine in the county. This project presents a historical and social context for the practice of medicine in the county and the research contributes to New Jersey's medical history. The process that occurs during the doctor and patient interaction is central in the practice of medicine. This relationship evolved alongside the practice of medicine and its institutions during the early twentieth century and is a common thread among all of the chapters in the study. The organization of medical institutions to care for the sick and the development of new medical technology, which gave physicians authoritative decision- making powers, transformed patient and doctor relationships in the county, as it did in other counties and cities across the country. This dissertation presents a history of medicine and the establishment of medical institutions in Middlesex County, New Jersey that transformed doctor and patient relationships during the early twentieth century. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]