The same man also invented the modern training method for doctors, residency.
Did he develop it as a way to cover up his morphine and cocaine addictions? Possibly. Is working 100-120 hours a week easier on cocaine? Also possibly.
This play is so good. I've used that monologue to audition and it never fails to elicit a smile or some other reaction. The person speaking is reasoning away why he cheated on his wife but still.
He also pioneered the "Halsted" radical mastectomy treatment for breast cancer, basically a full mastectomy including pectoral muscles and armpit lymph nodes.