Hayward's case report of the first major operation performed under ether anesthesia, which he performed at the Massachusetts General Hospital on November 7, 1846, three weeks after Warren's first operation using ether on October 16, 1846. For the first experiment with ether as a surgical anesthetic Warren chose a minor operation-- the removal of a small vascular tumor. Hayward followed Warren's initial experiment the following day with second minor operation using ether for removal of a small lipoma of the arm on October 17, 1846.

Though both operations were successful, Morton was initially unwilling to disclose the nature of his new anesthetic agent, as he wished to patent it, and no further public trials were permitted for a period of three weeks. In early November Henry Jacob Bigelow informed Morton that his initial demonstrations would be unconvincing to the surgical establishment unless his anesthetic agent could be used successfully during the performance of a "capital" or major operation, after which Morton asked Hayward if he might use his anesthetic agent during an amputation of the thigh that Hayward was schedule to perform. Hayward wrote:

"The patient was a girl of 20 years of age, named Alice Mohan, who had suffered for two years from a disease of the knee, which terminated in suppuration of the joint and caries of the bones. For some months before the operation her constitutional symptoms had become threatening, and the removal of the limb seemed to be the only chance for her life. The ether was administered by Dr. Morton. In a little more than three minutes she was brought under the influence of it; the limb was removed and all the vessels were tied but the last, which was the sixth, before she gave any indication of consciousness or suffering. She then groaned and cried out faintly. She afterwards said that she was totally unconscious, and insensible up to that time, and she seemed to be much surprised when she was told that her limb was off. She recovered rapidly, suffering less than patients usually do after amputation of the thigh, regained her strength and flesh, and was discharged well on the 22nd of December."

Digital facsimile from the Internet Archive at this link. Hayward's paper was published from a different setting of type in the Boston Medical and Surgical Journal on April 21, 1847.