Short answers, pulled from the story.
Nazi Germany conducted medical experiments on prisoners in its concentration camps mainly between 1942 and 1945. The true number of victims is believed to be higher than the documented figure of 15,754.
Eduard Wirths directed selected inmates at Auschwitz and other camps to undergo various experiments designed to help German military personnel in combat situations. Josef Mengele led twin experiments to advance Nazi racial ideology and eugenics while Aribert Heim conducted similar medical experiments at Mauthausen.
Prisoners at Dachau concentration camp were used by SS doctor Sigmund Rascher in experiments to aid German pilots who had to eject at high altitudes. Of the 200 subjects placed in a low-pressure chamber simulating conditions up to 18,000 meters, 80 died outright and the others were murdered.
On the 19th of August 1947, doctors captured by Allied forces were put on trial in USA vs. Karl Brandt et al., commonly known as the Doctors' Trial. This legal proceeding addressed the lack of international law regarding medical experimentation at that time.
Drs. Leo Alexander and Andrew Conway Ivy, representing the American Medical Association at the Doctors' Trial, drafted a ten-point memorandum entitled Permissible Medical Experiment. It went on to be known as the Nuremberg Code which calls for voluntary consent of patients and avoidance of unnecessary pain and suffering.