After receiving his M.D. degree from the University of Michigan in 1883, Dr. William J. Mayo returned to Rochester to join his father, Dr. William Worrall Mayo, in the elder Dr. Mayo's successful practice in southeast Minnesota. In 1888, Dr. Charles H. Mayo obtained his M.D. degree from Northwestern University and returned home to join his father and older brother in the growing Mayo family practice.

	Dr. Will stepped in and successfully removed a tumor that completely filled a washtub.

In late 1888, Dr. Will performed his first surgery for a large ovarian tumor at the Carpenter House, one of several sites used by his father for operative procedures. Dr. Will's surgery was originally scheduled to be done by his father, but the elder Mayo was delayed in returning to Rochester, and Dr. Will stepped in and successfully removed a tumor that completely filled a washtub.