Clausen and Bradford Bios Dr. Samuel W. Clausen (1924-1952) Dr. Clausen was the department’s first chairman, serving from 1924 until 1952, a distinguished investigator, teacher, and scholar. He possessed an unusual knowledge of mathematics and chemistry (his chosen field) and was particularly known for his investigations of the absorption and storage of vitamin A. Dr. William L. Bradford (1952-1964) Dr. Bradford, the department's second chair, a distinguished investigator in infectious diseases. Dr. Bradford established a solid foundation for research within Pediatrics. He led by example, making important contributions to our knowledge of the causes and treatment for pertussis. Together with Dr. Kaiser, he was among the first to explore measles (or the prevention of measles). Another research effort resulted in Dr. Bradford's breakthrough discovery of ballisus parapertusis, the causative organism for a condition that closely resembles whooping cough.