It must be the most unmodern doctor's office in the United States," John Eustace Denmark, 90, says of the 125-year-old farmhouse where his wife, the pediatrician Dr. Leila Denmark, 91, has her practice. The floors are bare dark wood (rugs would be too germ-ridden). The equipment is astonishingly simple: a scale for weighing infants, her original 1928 stethoscope, a few basics. On the desk and tacked to a screen are three generations of children's photographs.