The emergence of a modern public-health system in the United States began in the last quarter of the nineteenth century. During the first half of the century most doctors were poorly trained, and—like most Americans at the time—they lived in rural areas of the country. Because the population was widely scattered most people could not afford the indirect costs of arranging a doctor's visit: first a messenger would have to be sent to the doctor, who would then have to travel to the patient's home. Until the mid nineteenth century these indirect costs of medical service outweighed direct costs such as the doctor's fee or the price of medicine.

Medicine and the Technological Revolution.

With the beginning of the great movement of the American population from the countryside to the city, more doctors moved than people with other callings. The building of...