Burrill Bernard Crohn 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
Burrill Bernard Crohn 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 credence with the arrival of more sophisticated methods of identifying MAP bacteria. Crohn noted that it can be difficult for physicians to correctly differentiate neuroses from diseases of the organs.