Senn, Nicholas (1844-1908)  Nicholas Senn was born in Switzerland and immigrated to the United States at an early age.  He earned a medical degree from the Chicago Medical School and worked as an intern at Cook County Hospital.  He was a respected teacher of clinical surgery, an accomplished writer on medical topics, and a specialist in the field of abdominal surgery.  In 1891, he founded the Association of Military Surgeons of the United States.