Preeminent among the early physicians who joined the practice was Henry Plummer, M.D. A specialist in thyroid disease, he made milestone contributions to the treatment of goiter. In terms of organizational development, he collaborated with the Mayo brothers in coordinating the introduction of specialties that expanded the scope of the Mayo practice beyond its origins in surgery. A polymath whose interests included architecture, engineering, and art, Dr. Plummer also created many of the systems and procedures that remain central to Mayo Clinic today, such as the integrated "dossier" medical record. In fact, Dr. Will said that hiring Dr. Plummer was the best day's work he ever did.