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Ismar Boas

Photo: Ismar Boas um 1925 | © Privatsammlung Harro Jenss

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Portrait-Bild von Ismar Boas um 1925
Ismar Boas um 1925 | © Privatsammlung Harro Jenss

A bold step: in 1886 a 28-year-old physician opened a medical practice at Friedrichstrasse 10 in Berlin including an outpatient clinic with its own laboratory; his sign read: "Specialist for Stomach and Intestinal disease".

This was indeed a controversial initiative. The authorities of the day feared a split within the field of internal medicine and swore to preserve unity. At first Boasʼ mentor, Carl Anton Ewald, who had early on shown great interest in digestive illnesses vehemently refused to be involved. The new discipline emerged for the first time anywhere in the world as a result of  Boasʼ 'Berlin Initiative'. It was not until ten years later in 1896, in a short announcement by John C. Hemmeters in the digestive and metabolic diseases archive, that the term 'gastroenterology' was coined.

Born to a Jewish family in 1858 near the former Posen / West Prussia, Boas earned his secondary school diploma and then began his medical studies at the University of Berlin. There, inspired by lectures given by Carl Anton Ewald he soon became interested in digestive physiology and pathology. Boas studied medicine at a time when medicine itself was experiencing a sweeping paradigm shift. The phenomenology of diseases no longer stood in the foreground, scientists now sought to understand pathomechanisms and organ function. As a student of Th. F. v. Frerichs at the Medical Clinic of the Charité, Ewald supported the 'Berlin School' of thought. This approach was based on a strong scientific orientation and sought to apply the knowledge of basic subjects such as chemistry, physics, physiology and physiological chemistry to the medical research endeavors of the time.

Buchtitel Ismar Boas wissenschaftskritische Schrift "Therapie und Therapeutik", 1930, © Privatsammlung Harro Jenss
Wissenschaftskritische Schrift "Therapie und Therapeutik", 1930, © Privatsammlung Harro Jenss
Letter to the Jewish community, April 1933, © Private property David Alkan, Karmei Yosef, Israel.
Letter to the Jewish community, April 1933, © Private property David Alkan, Karmei Yosef, Israel.

Boas continued his studies in Halle under Theodor Weber and earned his doctorate with a thesis on hemoglobinuria. In his spare time he improved his financial situation by proofreading medical papers for professional journals. He completed his state examination in Leipzig and immediately settled in Berlin as a private practitioner in one of the city's southern districts. He reestablished contacts with Ewald, and in addition his medical practice duties he simultaneously worked in Ewald's laboratory for stomach physiology between 1882 and 1886; it was here that so-called 'Ewald - Boas test breakfast meal' was first introduced, a standardized analysis of the secretions of the stomach. In collaboration with Ewald, in 1885 he published a pioneering paper in its day in Virchow's Archive entitled 'Investigations of the physiology and pathology of digestion'. According to Boas, these essays 'led me to believe that I should now dedicate all my efforts to studying digestive diseases'. Boas who had no hospital training, having acquired all his basic knowledge on his own was essentially an outsider. Independent, a critical thinker and not committed to any ideology, he took the step towards specialization very early on in his career. This was indeed the kind of differentiate between the various disciplines that would eventually permeate the scientific landscape in the late 1800s. He also foresaw a trend, which 38 years later in 1924 became reality with the introduction of the designation 'specialist in gastrointestinal diseases'.

Abbildung: Buchtitel Ismar Boas Lehrbuch Magenkrankheiten 3. Aufl. 1897, 1. Aufl. 1890
Lehrbuch Magenkrankheiten, 1890, © Privatsammlung Harro Jenss
Buchtitel Ismar Boas "Lehre von den okkulten Blutungen", 1911, © Privatsammlung Harro Jenss
"Die Lehre von den okkulten Blutungen", 1911, © Privatsammlung Harro Jenss

In addition to his research activities and extensive medical practice, Boas sought to provide training in this new medical specialty in Berlin. Up to 1906, approximately 1000 German and foreign physicians had participated in his courses. By 1910, there were already 214 physicians specializing in gastrointestinal diseases.

During this period, the scientific and organizational advancement of the specialist discipline was very much influenced by Boas. In 1895/96, he established the first gastroenterological professional journal, the 'Archive for Digestive Diseases including Metabolic Pathology and Dietetics', which soon gained broad national and international recognition. As co-publisher he actively recruited working researchers and the publication's advisory board also included non-Germans.

Boas’ textbook on 'Diseases of the Stomach - General Diagnostics and Therapies' was published in 1890 and republished in many edition, as well as in English translation. He later authored a textbook on diseases of the intestines. Of particular scientific importance were his publications on the identification of occult blood in the stools, the more so as this made it possible to detect tumor diseases of the gastrointestinal tract at an early stage. His 'Treatise on Occult Hemorrhaging' was published in 1911. Boas also contributed substantially to research on gastric ulcers and gastric carcinoma. It was he who introduced the term 'colitis ulcerosa' in Germany. Early on, he understood the enormous potential of both X-ray diagnostics and endoscopic examinations.

Boas was one of the key initiators of the first-ever 'Conference on Digestive and Metabolic Diseases' in 1913 and its modern counterpart the 'German Society for Digestive and Metabolic Diseases' (DGVS). His goals: to maintain high scientific standards and to promote interdisciplinarity and international contacts. In 1910 Boas was made an honorary member of the American Gastroenterological Association for his contributions to the field of gastroenterology. In Berlin he was made an honorary professor.

In his works "Basic Tenets of Therapeutic Methodology in Internal Medicine" and "Therapy and Therapeutics" (1909 and 1930) he also voiced criticism of certain medical practices of his day. Among other things he called for an independent institute to assess drugs and was an early supporter of evidence-based medicine.

The year 1933 signaled the end of his work and collapse of the life he had known. The 'Editorial Law' introduced by the National Socialists in October of 1933 forced Boas to terminate his work for the Archive. In 1936 he emigrated to Vienna with his wife thanks to support from the Rockefeller Foundation and one of his students, Walter Zweig. In 1938, Ismar Boas took his own life after the German invasion of Austria. He was buried in the Jewish Cemetery in Berlin Weissensee. His wife Sophie Boas emigrated to Holland in 1938; in March 1943 she was deported to the Sobibor death camp and murdered. One daughter was able to escape to the United States in January of 1939. Because of his Jewish ancestry, one son, a dermatologist in Saxony, was detained at the Sachsenburg concentration camp near Chemnitz during 1935 and 1936. He was last heard from in 1938 and is thought to have emigrated to Colombia.

In his monodrama entitled "The Doctor from Vienna", Franz Werfel penned a literary memorial to Boas, a piece that features a fictitious dialogue between Ismar Boas and Hermann Nothnagel on the subject of anti-Semitism; even as cries of 'Sieg Heil' waft through the window and Vienna is falling to Nazi occupation Boas asks: "The hate…why all this hate..? What did we ever do to you?"

(Harro Jenss. Lecture on the occasion of re-installing the Ismar Boas Memorial Plaque in the Medical Clinic of Gastroenterology and Hepatology, Charité Mitte Campus, Virchowweg 10, on 15 May 2013)


  • Kleeberg J. On the 100th Commemoration of the Birth of Professor Dr. I. Boas (Berlin). Gastroenterologia 1958; 89: 359 – 363.
  • Eichmann A.  Ismar Boas ( 1858 – 1938 ) and the Emergence of Gastroenterology as a Specialist Field of Medicine. Med. Diss. , Zurich 1970.
  • Hoenig L J, Boyle J D. The life and death of Ismar Boas. J Clin Gastroenterol 1988; 10: 16 – 24.
  • Teichmann W. Ismar Boas, A Biographical Sketch. Freiburg 1992.
  • Jenss H. Ismar Boas. First Specialist for Gastric and Intestinal Diseases. The Father of Gastroenterology. Jüdische Miniaturen, Volume 96. Berlin 2010.

Dr. med. Harro Jenss

Studied medicine in Marburg/Lahn and in London. 1977 to 1993, University Hospital I, Eberhard-Karls University Tübingen. Internist and Gastroenterologist. 1994 to 2011 Medical Director of the Department of Internal Medicine at Waldshut/Südbaden Hospital. He has spent many years in scholarly analysis of the history of gastroenterology.