The twins were a particular interest to Mengele. This interest was in the deep influences instilled by Otmar von Verschuer and Ferdinand Sauerbruch the Kaiser Wilhelm Institute of Genetics and Eugenics, where he imbibed the concepts of inheritance and pure race and the Jewish problem was the core of the discussions. Mengele, in the footsteps of Von Verschuer had developed a strong interest in twins as a source of information about these pseudo-scientific concepts, therefore, when he knew that Auschwitz was their destination, could not hide his satisfaction, because the field concentration was for him a lab full of rats Jewish. Since 1943, the twins were selected and placed in special barracks. When the selection ramp localized twins, for they constituted a longer life expectancy belonging to that condition. The twins were placed in a special area and were treated better than other inmates. Almost all of Mengele's experiments had no scientific value, but were funded by the Nazi government. Including, for example, attempts to change eye color by injecting chemicals into children's eyes, various amputations and other brutal surgeries, and at least once in a while, an attempt to create artificially conjoined veins joining of twins (the operation was a failure and the only result was that the hands of children severely infected). Persons subject to Mengele's experiments, if surviving the experiment were almost always killed for dissection.
Mengele drew the eyes of his victims and placed them on a wall as a display the varieties of heterochromic that existed. He also attempted to chemically change the hair color of inmates by applying painful subcutaneous injections and in some cases performed castrations and experiments on the spinal cord paralyzed leaving the surgery.