Milton Winternitz led the Yale Medical School as its dean from 1920 to 1935. Dedicated to the new scientific medicine established in Germany, he was equally fervent about "social medicine" and the study of humans in their culture and environment. He established the "Yale System" of teaching, with few lectures and fewer exams, and strengthened the full-time faculty system; he also created the graduate-level Yale School of Nursing and the Psychiatry Department, and built numerous new buildings. Progress toward his plans for an Institute of Human Relations, envisioned as a refuge where social scientists would collaborate with biological scientists in a holistic study of humankind, unfortunately lasted for only a few years before the opposition of resentful anti-Semitic colleagues drove him to resign.

Answer this question, if possible (if impossible, reply "unanswerable"): What wasn't the driving force behind Milton Winternitz's research?
unanswerable