He reportedly mastered twelve languages—in addition to the fifteen he already spoke[1]—and made multiple significant contributions to improving conditions at Stateville Penitentiary. These included reorganizing the prison library, revamping the schooling system and teaching its students, and volunteer work in the prison hospital. In 1944, Leopold volunteered for the Stateville Penitentiary Malaria Study; he was deliberately inoculated with malaria pathogens and then subjected to multiple experimental malaria treatments.[55]