Ismar Isidor Boas was a German gastroenterologist who was born in the town of Exin

Kcynia

Kcynia is a town in Nakło County, Kuyavian-Pomeranian Voivodeship, Poland, with 4,712 inhabitants .Kcynia is the birthplace of Jan Czochralski....

. He studied medicine in Berlin

Berlin

Berlin is the capital city of Germany and is one of the 16 states of Germany. With a population of 3.45 million people, Berlin is Germany's largest city. It is the second most populous city proper and the seventh most populous urban area in the European Union...

, Halle

Halle, Saxony-Anhalt

Halle is the largest city in the German state of Saxony-Anhalt. It is also called Halle an der Saale in order to distinguish it from the town of Halle in North Rhine-Westphalia...

 and Leipzig

Leipzig

Leipzig Leipzig has always been a trade city, situated during the time of the Holy Roman Empire at the intersection of the Via Regia and Via Imperii, two important trade routes. At one time, Leipzig was one of the major European centres of learning and culture in fields such as music and publishing...

, and subsequently became an assistant to Carl Anton Ewald

Carl Anton Ewald

Carl Anton Ewald was a German gastroenterologist who was a native of Berlin. In 1870 he earned his medical doctorate in Berlin, and subsequently became an assistant to pathologist Friedrich Theodor von Frerichs...

 (1845-1915) at the Augusta Hospital in Berlin. In 1886 he became a licensed specialist of gastro-intestinal diseases in Berlin.

Boas was one of the leading authorities on gastroenterology

Gastroenterology

Gastroenterology is the branch of medicine whereby the digestive system and its disorders are studied. The name is a combination of three Ancient Greek words gaster , enteron , and logos...

 in Europe. Alone, and with Professor Ewald, he made several contributions regarding the pathology

Pathology

Pathology is the precise study and diagnosis of disease. The word pathology is from Ancient Greek , pathos, "feeling, suffering"; and , -logia, "the study of". Pathologization, to pathologize, refers to the process of defining a condition or behavior as pathological, e.g. pathological gambling....

 and physiology

Physiology

Physiology is the science of the function of living systems. This includes how organisms, organ systems, organs, cells, and bio-molecules carry out the chemical or physical functions that exist in a living system. The highest honor awarded in physiology is the Nobel Prize in Physiology or...

 of digestion

Digestion

Digestion is the mechanical and chemical breakdown of food into smaller components that are more easily absorbed into a blood stream, for instance. Digestion is a form of catabolism: a breakdown of large food molecules to smaller ones....

. He described lactobacillus acidophilus

Lactobacillus acidophilus

Lactobacillus acidophilus is a species in the genus Lactobacillus. L. acidophilus is a homofermentative species, fermenting sugars into lactic acid, which grows readily at rather low pH values and has an optimum growth temperature of 37 °C . L...

, a bacillus

Bacillus

Bacillus is a genus of Gram-positive, rod-shaped bacteria and a member of the division Firmicutes. Bacillus species can be obligate aerobes or facultative anaerobes, and test positive for the enzyme catalase. Ubiquitous in nature, Bacillus includes both free-living and pathogenic species...

 found in the gastric juice of individuals with stomach carcinoma

Carcinoma

Carcinoma is the medical term for the most common type of cancer occurring in humans. Put simply, a carcinoma is a cancer that begins in a tissue that lines the inner or outer surfaces of the body, and that generally arises from cells originating in the endodermal or ectodermal germ layer during...

. This bacterium is sometimes referred to as the Boas-Oppler bacillus.

In 1895 he founded the Archiv für Verdauungs-Krankheiten, the first medical journal dedicated to gastroenterological topics, and in 1920 established the German gastroenterological society. He also has a handful of eponyms named in his honor, including:

• Boas' algesimeter
  Dolorimeter
  A dolorimeter is an instrument used to measure pain threshold and pain tolerance. Dolorimetry has been defined as "the measurement of pain sensitivity or pain intensity." There are several kinds of dolorimeter that have been developed...
  
  : an instrument used for determining the sensitiveness over the epigastrium
  Epigastrium
  The epigastrium is the upper central region of the abdomen. It is located between the costal margins and the subcostal plane....
  
  .
• Boas' point: a tender spot to the left of the twelfth thoracic vertebra in individuals with gastric ulcer.