his first book-length publication was "synopsis nosologiae methodicae" (1769), cullen's very influential nosology, or classification of diseases. his next publication was also a medical textbook, and it dealt with the institutions of medicine, i.e. medical theory. its full title was "institutions of medicine. part i. physiology" (1772) because it focused on physiology, which was traditionally only one part of the institutions (pathology and therapeutics were also essential parts of medical theory). it went through two more editions (1777 & 1785).