Internal medicine, which deals with the entire patient rather than a particular organ system, is in effect the parent of other medical specialties such as cardiology, dermatology, and gastroenterology. An advanced practitioner of internal medicine is called an internist in the United States and many other countries. In 1936 the American Board of Internal Medicine was established in the United States, with the object of formally certifying specialists in internal medicine. Professional qualifications for certification include graduation from an approved medical school, followed by an internship of not less than one year and, further, a prolonged program of intensified training and experience. The core of this program consists of two to three years of full-time residency training in a hospital