"Ja, she'll be fine. But you can call me tomorrow morning – seven o'clock is okay – if you are worried."

For the mother of a sick child the time between dawn and when one can call the doctor seems interminable. Dr. Reyersbach, unmarried, older than most of her patients' mothers, knew this. And she knew that being available, calm, realistic, reassuring was more important than having a tidy office and fancy equipment. Her patients and their parents, who represented the whole social, economic, racial, religious spectrum of Boston, picked their way anxiously into her old-fashioned office littered with toys, and emerged feeling better. One grateful mother wrote, "I knew I was in the presence of an extraordinary human being – very opinionated, fiercely dedicated, stubbornly protective of your patient's well-being, and all this bound together with humor and compassion." If a patient required special treatment she fought and conquered the bureaucracy of hospitals, the arrogance of specialists, the misinformation that is itself a disease.

She was a fighter from the start and came by this trait naturally. Her great-grandfather and his family moved from Bavaria to Oldenburg, Germany, at the start of the nineteenth century and prospered, integrating themselves fully, they thought, into their small city. Her mother's parents had a small farm where the family gathered in the summer time; Gertrud remembered eating too many strawberries, and being frightened by the geese. Her father and his brother had a dispute with the local rabbi (too intolerant, they decided) and after that the Reyersbachs, though they never forgot they were Jews, went their own way. They had an English nanny for Gertrud and her brother, whom they sent to the best school in Oldenburg; they were so sure of themselves that when Gertrud decided she wanted to go to medical school no one discouraged her.

Gertrud did well. She was tough, bright, independent, and clearly attractive (Berthold Brecht, whom she met in Berlin, wrote a sentimental message for her in one of his books). Her professors admired her; in 1933 one of them wrote, "I would be very happy if Miss Reyersbach would succeed in completing her studies despite the different regulations." The different regulations were the anti-Semitic laws of Nazi Germany. In 1937 she went to England where cousins had established themselves, to investigate opportunities there. Then she heard that her uncle had been arrested by the Nazis and had died in prison. (Forty-eight years later Oldenburg named one of its streets for him.) She returned to Germany and managed to bring her widowed mother to England where she would be safe. Her brother escaped to South America. Gertrud realized that there would be little opportunity for her to practice medicine in England, and in May 1937 sailed to the United States.

She was thirty years old, five feet four inches tall, fine-boned and elegant, a fully qualified pediatrician with special training in endocrinology and rheumatic diseases. In the course of the next three years she had to be recertified as a physician; she had to persuade the American immigration authorities that she was not a threat to the nation; she had to decide where to work. She rejected an appointment in Cincinnati – too German, she said; she was considering New York City or Philadelphia when in 1942 Boston's Massachusetts General Hospital, desperate for physicians as more and more men were being drafted into the military, had an opening. She came and lived in the hospital for eight years (she was one of the first women residents there). "No, it wasn't difficult. I had a room to myself. And of course I was always there for the really interesting cases."

Her first paper to be published in the United States, on rheumatic fever in children, appeared in 1941. She followed this with papers on persistent infectious diarrhea in infants (1948); on brain damage in juvenile diabetes (1951); on a link between excessive vitamin A intake and bone deformation (1952); on inherited kidney disease (1966). In 1957 The Boston Globe ran a front page article on her research into the relationship between estrogen and height in young girls; the photo shows her at an uncharacteristically tidy desk. She taught Harvard medical students, some of whom impolitely called her "Auntie Gedda" behind her back and went on to greater fame. She moved into a one-room apartment near the hospital so that she could get to her patients no matter what the weather. When I first met her she charged $10 for an office visit, and answered the phone or returned messages around the clock. One mother of a croupy child remembered that she made a night-time house call on a cold January evening (Dr. Reyersbach was a terrible driver) simply because "I know it's very scary." Another panicky mother telephoned: "My son has eaten some berries and I think they might be poisonous. I'm off to the hospital – please please call." At nine-thirty that night, her telephone rang. "Mrs. Jones, are you the person whose child ate some strange berries?" "Yes," said Mrs. Jones, "and I know I forgot to leave my name. How did you find me?" "I just called the families of all the two-year-old boys in my practice till I found you…."

She was a master of common sense. "Let him do it," she said when an asthmatic boy wanted to try out for the lacrosse team. "He has to live, you know. He'll stop if he can't succeed." A dyslexic child? "Ach, don't worry, she's very bright. When she grows up she'll have a secretary who can spell." One father who brought his frightened young son for a vaccination heard her say, "Now I want you to yell as loudly as you can. No, louder than that, please." After a horrific yell, the boy said, "When will you give me the shot?" "Oh," said Dr. Reyersbach, "I've already done that." "I was scared," said the boy, "but since you're so good I couldn't feel anything."

When Dr. Reyersbach retired at the age of 80, her patients, who sometimes included three generations of the same family, gave her a party. The album they compiled for her bulges with photos, notes in the straggling letters of first-grade students, doggerel, drawings, tributes to a woman who was responsible for saving their lives and their sanity. The lad who had not felt a single shot wrote, "I liked all the toys in your office but actually my favorite thing was you." No one was too poor, too cranky or too old to be welcomed into her office, advised, healed, and encouraged. One man confessed, "I didn't propose to my wife until after Dr. Reyersbach had told me she approved." For years after her retirement former patients would call with "just one question…."

Our children were her patients. So was I, turning to her for advice about matters far removed from runny noses or childhood diseases. She helped me choose a bathing suit: "Not the black one, the one with flowers. I'm all for color." As time went on, we became close friends, in part because we recognized that we had the same love of chocolate, the same sense of humor, the same outlook on life. As close as we were, we maintained the formal conventions with which we had both been brought up: I was Mrs. Steiner, she was Dr. Reyersbach, no matter what experiences we shared or subjects we discussed. "I suppose I should know more about being Jewish," she once said. "Nonsense," said I. "After all, you know everything that is important for being human." Indeed, if being Jewish means keeping to the high moral ground, remembering that each person is made in the image of God, doing justice and loving mercy, Dr. Gertrud Reyersbach, daughter of a rebellious Jewish family in Oldenburg, was the kind of Jew and the kind of physician whom Maimonides would have recognized and saluted.