Warren Harmon Lewis

Warren Harmon Lewis (June 17, 1870 – July 3, 1964) was an American embryologist and cell biologist. In 1901, Lewis worked with Charles R. Bardeen on muscles in Franklin P. Mall's lab. In 1902, he went to Bonn and worked with Moritz Nussbaum on the eye. He returned to Baltimore in 1903 and became an associate in the department of anatomy. In 1904, he became an associate professor.

He married Margaret Reed in 1910 and they later researched and published together. After the death of Mall in 1917, the couple was invited by George L. Streeter to the Carnegie Institute's embryology laboratory at Washington. Among their pioneering work was the use of time-lapse films to study embryology. They identified the process that they called as pinocytosis which was differentiated from phagocytosis.

He was an elected member of the National Academy of Sciences and the American Philosophical Society. He served as the 21st president of the Association of American Anatomists from 1934 to 1936, and the International Society for Experimental Cytology, and held honorary memberships in the Royal Microscopical Society in London and Accademia Nazionale dei Lincei in Rome.