From Hamburg to medicine
Richard Lewisohn was born in Hamburg on July 12, 1875, to German Jewish parents. Hamburg was then one of the great trading ports of Europe and home to a large and prosperous Jewish community. He was educated at the local gymnasium, the academic secondary school, and in 1893 entered medical school at Kiel.
Like most German medical students of the time, he moved between several universities during his training. He received his doctorate from the University of Freiburg in 1899 with a thesis on malignant tumours of the kidney. He then spent two years as an assistant to the pathologist Karl Weigert at the Senckenberg Institute in Frankfurt, and in 1904 became an assistant to the surgeon Vincenz Czerny in Heidelberg, one of the leading surgical clinics in Germany. The combination of laboratory pathology and surgery shaped the rest of his career: he was a surgeon who, unusually for the time, also did research.
A new life in New York
In 1906 Lewisohn emigrated to New York, where he joined Mount Sinai Hospital, the hospital founded by the city’s Jewish community, and worked as a gastroenterologist and surgeon. In 1911 he married Constance Strauss. They had three children, two of whom survived to adulthood.
He became a fellow of the American College of Surgeons in 1916 and rose through the surgical staff at Mount Sinai, serving as chief of its general surgical service from 1928 to 1936, in succession to the surgeon Alexis Moschcowitz. In that role he was responsible for the hospital’s general surgery and for the younger surgeons training under him. But the work for which he is remembered began in the hospital’s laboratory, with a problem that had defeated doctors for centuries.
Why blood transfusion was so hard
By the early twentieth century, doctors understood that a patient losing blood from an injury, an operation or childbirth could be saved by receiving blood from someone else. Karl Landsteiner’s discovery of the blood groups in 1901 had shown how to match donors to patients. But one problem remained: blood begins to clot within minutes of leaving the body.
The only reliable way around it was direct transfusion, in which a surgeon connected an artery of the donor to a vein of the patient. The technique, demonstrated by Alexis Carrel at the Rockefeller Institute in 1908, required great skill, so only the most accomplished surgeons could do it. Donor and patient had to lie side by side, and it was hard to know how much blood had passed. Doctors had long wondered whether a chemical could keep blood liquid, but anticoagulants tried in animals were often too toxic for people. As a result transfusion remained a rare and difficult procedure, available to few of the patients who needed it.
The right amount of citrate
Sodium citrate, a salt of citric acid, prevents clotting by binding the calcium that blood needs to clot. In April 1914 the Belgian physician Albert Hustin used it to keep donated blood from clotting during a transfusion, and in November 1914 Luis Agote used a citrate method in Buenos Aires. Working independently at Mount Sinai, Lewisohn tackled the decisive practical question: how much citrate could safely be given? Too little would let the blood clot; too much would poison the patient.
Through careful experiments he found the optimal concentration, sodium citrate at about 0.2 percent of the blood, with no more than about 5 grams of citrate in a transfusion. At that level the blood stayed liquid and the patient was not harmed. He announced the method in New York on January 23, 1915, and published it in full in the journal Surgery, Gynecology and Obstetrics in July 1915. His Mount Sinai colleague Howard Lilienthal gave citrated blood prepared by Lewisohn’s method to a patient, among the first such transfusions in the United States. With citrate, a doctor could collect blood into a flask, mix it, and give it later, without connecting donor and patient at all.
The change mattered as much for who could give a transfusion as for when. In the citrate procedure, a small amount of the solution was placed in a glass flask and the donor’s blood was drawn into it, then run into the patient’s vein. That was a procedure an ordinary hospital doctor could learn, not a feat of vascular surgery reserved for a handful of experts. Transfusion could now move out of a few elite operating theatres and into general hospitals, and the donor no longer had to lie on the next table.
From a flask to the blood bank
Lewisohn’s method allowed blood to be kept safely for up to about two days. Within a year others had improved on it, adding substances that extended the storage time to around two weeks. The citrate method was used during the First World War, and in 1917 the Canadian surgeon Oswald Robertson introduced it to the British army’s medical services, where stored blood was given to wounded soldiers.
Separating donor from patient in time and place was the step that made blood banks possible. In 1937 Bernard Fantus opened a blood bank at Cook County Hospital in Chicago, storing citrated blood donated in advance so that it was ready when patients needed it. In 1924 Lewisohn looked back on the change in a paper titled The Citrate Method of Blood Transfusion after Ten Years. The principle he helped establish, an anticoagulant at a safe dose, is still used: modern blood bags contain citrate-based solutions so that donated blood can be stored and given to patients who need it.
How patients benefit today
Every day hospitals around the world give blood to accident victims, to mothers who bleed after childbirth, to patients undergoing surgery and to people with cancer, sickle cell disease and other conditions. Almost all of it is collected from volunteers, stored, and transfused hours or days later, often far from where it was given. None of that would be possible if blood could not be kept from clotting outside the body.
The credit for this transformation is shared. Landsteiner made safe matching possible; Hustin and Agote first used citrate in human transfusion; others extended storage times and built the first blood banks. Lewisohn’s particular contribution was to find a dose that was both effective and safe, the practical step that turned a laboratory idea into a routine treatment. The American Association of Blood Banks recognized this in 1955 when it gave him its Karl Landsteiner Memorial Award.
Surgeon and researcher
Lewisohn’s work did not stop with blood. He travelled to Innsbruck to see the surgeon Hans von Haberer, who removed part of the stomach to treat peptic ulcers, and in 1922 he persuaded his Mount Sinai colleague Albert Berg to perform the first subtotal gastrectomy for peptic ulcer in the United States. The operation spread across the country for ulcers that resisted other treatment. Lewisohn reported that it changed the acidity of the stomach in a way that simpler operations did not, and he suggested that infection might play a part in causing ulcers, long before the bacterium Helicobacter pylori was identified.
In 1937 he retired from active surgery and became a consulting surgeon, turning to cancer research. According to a history of Mount Sinai published in the Rambam Maimonides Medical Journal, he was the first to define the significance of folic acid in the biology of cancer and among the first to use drugs that block folic acid in patients, an approach that later led to some of the first effective cancer chemotherapies.
A German Jewish émigré
Lewisohn belonged to the generation of German Jewish doctors who brought the scientific medicine of German universities to America. He was born to a Jewish family in Hamburg and trained in German clinics and laboratories, then made his career at Mount Sinai, the hospital founded and supported by New York’s Jewish community.
He emigrated in 1906, long before the Nazi era, by choice rather than as a refugee. The sources consulted say little about his religious life; his public identity was that of a surgeon and scientist, and his life’s work was carried out within one of the great Jewish medical institutions of the United States.
Later years and legacy
Lewisohn did not fully retire. In 1954, in his late seventies, he returned to research to oversee a new cell research laboratory at Mount Sinai, created with the help of a large donation. In January 1959 he was made an honorary fellow of the Royal College of Surgeons of England. He was also a fellow of the American Gastroenterological Association and served on the American Board of Surgery. He died in New York on August 11, 1961, at the age of 86. Nine years earlier, in 1952, the American Journal of Medicine had reprinted his original 1915 article on blood transfusion by the citrate method, a sign of how completely his once novel technique had become part of everyday practice.
His name is less familiar than those of the surgeons who performed famous operations, but his contribution touches more lives than almost any single operation. Each unit of stored blood waiting in a hospital refrigerator depends on keeping blood liquid without harming the patient who receives it, the problem Richard Lewisohn solved in a Mount Sinai laboratory in 1915.
Sources & further reading
Richard Lewisohn, Wikipedia · Heroes of Progress, Pt. 4: Landsteiner and Lewisohn, HumanProgress · New Blood, circa 1914, The Scientist · History of Medicine: Mount Sinai, Rambam Maimonides Medical Journal · Researched from the sources above and checked against them. Spotted an error? Tell us.
A life of tikkun olam. This is part of tikkun olam, the Jewish idea of repairing the world, and every one of us can add to it.