Suspension of many civil rights and violations of international accords are characteristic of declared and undeclared wartime conditions, during which captured enemy forces, citizens of occupied countries or political prisoners may be used for scientific and unscientific experimentation.
The physician Celsus of the first century AD approved the vivisection of condemned criminals by his Egyptian predecessors, Heoophilus and Erasistratus. His defence was that the suffering of the few is justified by the benefit of the multitude. By the late 1930s, the professional clinical investigator was established on the medical scene and research had become an integral part of hospital practice in the UK and the US. During World War II, Nazi Germany conducted infamous experiments in the concentration camps. During the Korean War and recently in Northern Ireland, medical-psychological experimentation has been reported as an aspect of torture.