Paul Weindling is an expert on medicine in Nazi Germany and is author of Health, Race and German Politics, Epidemics and Genocide in Eastern Europe, and Nazi Medicine and the Nuremberg Trials.
According to Weindling, there were four main phases in the atrocities performed during Nazi Germany. The first phase (1939-41) is called the neurological which was linked to the euthanasia program, but it was actually a testing ground for killing techniques. He estimates that more than 70,000 adult patients were killed in mental institutions.
The second phase (1939-1944) was a large scale experiment on sterilization and human reproduction were 400,000 people with inherited disorders were presumably sterilized without their consent under the Nazi regime.
The third phase was of military experimentation, which included studies of people’s reactions to high altitudes, freezing temperatures, exposure to incendiary bombs, mustard gas, poisons, and other highly disturbing practices. Prisoners were also exposed to infections of typhus, malaria, and epidemic jaundice in order to develop vaccines and other treatments.
The fourth phase was experiments on children, such as studies on the inheritance of racial characteristics.
Weindling also writes about the Nuremberg medical trial which took place after the international military trial, where the concept of medical war crime was first introduced.