Statement of Significance (as of designation - January 12, 1965):
This skylit operating theater on the top floor of Charles Bullfinch's Massachusetts General Hospital building derives its name and its significance from an event that took place on October 16, 1846, that revolutionized the practice of medicine. Here ether gas was first successfully used in public to anesthetize a patient prior to surgery. When the patient recovered and reported he had felt no pain, the chief surgeon announced, "Gentlemen, this is no humbug!" The room served as the hospital's operating room from its 1821 opening until 1867. Classes and lectures are still held here, and it may be visited when not in active use.