Nicholas Senn (October 31, 1844 – January 2, 1908) was a Swiss born American surgeon, instructor, and founder of the Association of Military Surgeons of the United States.[1][2] He served as the president of the American Medical Association in 1897–98 and as chief surgeon of the Sixth Army Corps in 1898, seeing service in Cuba during the Spanish–American War.[2][3][4][5] He was involved in experimental research, particularly of acute pancreatitis,[5] plastic surgery, head and neck oncology, the intestinal tract,[6] and the treatment of leukaemia with x-rays.[2]