1881-1970

American cytologist who improved tissue-culture methodology. Lewis was Thomas H. Morgan's research assistant before she accepted a position at the Carnegie Institution. Scientists adopted Lewis's tissue-culture techniques. With her husband, Warren H. Lewis, she developed what was called the Lewis-Locke Solution, a clear, non-salty fluid. Lewis observed cells' physiological activity and demonstrated that monocytes and macrophages represent varying physiological stages instead of separate cell types. She also experimented with dye for use in chemotherapy.