Burrill Bernard Crohn (June 13, 1884 – July 29, 1983) was an American gastroenterologist who made the first major advance to identify the disease that now bears his name. Although the description of Crohn's disease is by far his most famous accomplishment, Crohn had a long career both as a clinician and as a researcher who contributed to modern understanding of many gastrointestinal conditions. Early life Crohn was born on June 13, 1884 in New York City to Theodore and Leah Crohn, who were Jewish emigrants from Europe. He was one of 12 children. Education and work Crohn received his bachelor's degree from City College of New York in 1902. He received a medical degree from Columbia University College of Physicians and Surgeons in 1907. Crohn first became an intern at Mount Sinai Hospital in 1907. He was promoted to head of gastroenterology in 1920, the same year he joined the staff of Columbia University. Working with colleagues at Mount Sinai Hospital, Crohn identified fourteen patients whose symptoms and intestinal abnormalities discovered at surgery, while consistent with each other, did not fit any previously identified disease. Crohn, along with Leon Ginzburg and Gordon Oppenheimer, prepared the classic paper describing this new condition. This paper was read at a professional meeting in May 1932 and published in the Journal of the American Medical Association in October 1932. The title of the published paper was "Regional Ileitis: A Pathologic and Clinical Entity". Crohn's work helped correct the thinking that the ailment was actually a form of tuberculosis rather than an inflammatory disease of the gastrointestinal tract. Crohn's work built on the work of Dr. Kennedy Dalziel of Glasgow into regional enteritis twenty years earlier. Crohn always preferred the medically descriptive terms "regional ileitis" and "regional enteritis" to "Crohn's disease", but he was not able to prevent the appropriation of his name for the disease. Some of Crohn's initial research into the causes of the Crohn's disease was centered around his personal conviction that it was caused by the same pathogen, a bacterium called Mycobacterium paratuberculosis (MAP), responsible for the similar condition that afflicts cattle called Johne's disease. However, he was unable to isolate the pathogen—most likely because M. paratuberculosis sheds its cellular wall in humans and takes the form of a spheroplast, making it virtually undetectable under an optical microscope. This theory has resurfaced in recent years and has been lent more