Vivisection is surgery conducted for experimental purposes on a living organism, typically animals with a central nervous system, to view living internal structure. The word is, more broadly, used as
An anesthetized pig used for training a surgeon
Pro-vivisection cartoon in 1911
Prior to vivisection for educational purposes, chloroform was administered as an anesthetic to this common sand frog.
Josef Mengele, often dubbed the "Angel of Death", was a German military officer and physician during World War II at the Soviet front and then at Auschwitz during the Holocaust. He conducted research
Vivisection
…the Japanese, in many cases without anesthesia. Nazi human experimentation involved many medical experiments on live subjects, such as vivisections by Josef Mengele, usually without anesthesia. Alternatives to animal testing…
Mengele at Solahütte in 1944
Selection of Hungarian Jews on the ramp at Birkenau, May/June 1944
(from l. to r.) Richard Baer, Josef Mengele, and Rudolf Höss at Solahütte in 1944 (Höcker Album)
Jewish children kept alive in Auschwitz for use in Mengele's research. They were liberated in January 1945.