One of the first scientists to study the physical processes of immunity. He is best known for his identification and characterization of the human blood groups, A, B, and O and recipient of the 1930 Nobel Prize. TLS signed “K. Landsteiner,” one page, 5.5 x 8.5, Rockefeller Institute for Medical Research letterhead, February 9, 1934. Letter to Dr. Ernst Witebsky, informing him that he has already contacted the Jewish Relief Committee but is doubtful his efforts will be successful. In fine condition, with expected folds. R&R COA.