Dr. John Warren, one of the most respected surgeons of his day, was present in the operating theater at Massachusetts General Hospital when William Morton first demonstrated the power of ether. Warren later described what happened: Morton's "apparatus . . . consisted of a tube connected with a glass globe. This apparatus he then proceeded to apply, and after four or five minutes the patient appeared to be asleep, and the operation was performed."

Dr. Warren and the other men present were astonished that the patient did not shrink or cry out; he did move his limbs and speak unintelligibly, which seemed to indicate the existence of pain. On regaining consciousness, the patient reported that he had experienced no pain. As the man was carried from the operating theater, Dr. Warren turned to the stunned audience and said, "Gentlemen, this is no humbug."

Fifty years later, an elderly Boston physician could still vividly remember the awful scenes of surgery in the days before anesthesia: "Yells and screams, most horrible in my memory now, after an interval of so many years." Doctors had tried many techniques to dull pain. They had used plants like marijuana, hypnosis, even causing pain elsewhere on the body. It was not unheard of for a patient to be knocked unconscious with a blow to the jaw. Opium and alcohol were the only effective analgesics, but to be strong enough for surgery, they had to be given in doses that could be lethal.

Ether made brought about such a dramatic improvement that in 1868 a Boston businessman commissioned a monument "to commemorate the discovery that the inhaling of ether causes insensibility to pain. First proved at the Mass. General Hospital in Boston." The 40-foot granite fountain still stands in the Public Garden. The operating theater at MGH where the experiment took place, renamed the "Ether Dome," is now a National Historic Landmark.