He joined the faculty of Johns Hopkins Medical School in 1946, and the next year he was appointed head of the newly formed Division of Hematology. He was appointed a full professor in 1956 and a Distinguished Professor of Medicine in 1976. He remained at Hopkins until his retirement in 1980. He then was appointed distinguished senior clinician at the
U.S. Public Health Service Hospital in Baltimore, where he established a teaching program for medical students. He retired from that position in 1987. His hematology research included important work on blood coagulation, blood platelets, hemorrhagic diseases, and hemoglobins. He made significant contributions to developing a therapy for
vitamin B-12 deficiency. In 1953 he and a research fellow, Ernest W. Smith, described a simple method of separating the components of
hemoglobin on filter paper using
electrophoresis, which made hemoglobin analysis far more widely available and facilitated the study and treatment of
sickle cell anemia. In his studies of sickle cell anemia he followed some patients for 40 years. ==Personal==