As revealed by Osler's diary, Halsted developed a high level of drug tolerance for morphine.

[9] William S. Halsted's family was of English heritage and was very wealthy with two homes in the state of New York.

Halsted was educated at home by tutors until 1862, when he was sent to boarding school in Monson, Massachusetts at age ten.

[9][12] One of his social setbacks was in his senior year when he wasn't accepted into the prestigious Skull and Bones secret society.

[12] Physicians central to his emergence as a medical scholar include Henry B Sands, a well-known surgeon, who was Halsted's tutor during this time.

[12][13] He then took a competitive exam to apply for an internship at Bellevue Hospital in New York even though this program was only open to students with medical degrees.

[13] The conditions in the hospital were very unsanitary; bleeding patients was a common practice during this time, and surgical tools weren't as well cared for as they are modernly.

It was at New York Hospital that Halsted met the pathologist William H. Welch, who would become his closest friend.

He reformed the classroom by creating a more hands-on experience coupled with theory for his students who were generally at the top of their classes.

[12][13] In 1884, Halsted read a report by the Austrian ophthalmologist Karl Koller, describing the anesthetic power of cocaine when instilled on the surface of the eye.

[16] Halsted, his students, and fellow physicians experimented on each other, and demonstrated that cocaine could produce safe and effective local anesthesia when applied topically and when injected.

[13][16] His close friend Harvey Firestone recognized the gravity of the situation, and arranged for Halsted to be abducted and put aboard a steamer headed for Europe.

[10] Following his discharge from Butler in 1886, Halsted moved to Baltimore, Maryland, to join his friend William Welch in organizing and launching the new Johns Hopkins Hospital.

Halsted began working in Welch's experimental laboratory, and he presented a paper at Harvard Medical School.

These lesser positions alluded to the fact that the administration was still worried about Halsted's past cocaine addiction.

[12][13] In 1892, Halsted joined Welch, William Osler, and Howard Kelly in founding the Johns Hopkins School of Medicine, and was appointed its first Professor of Surgery.

[9] Halsted was credited with starting the first formal surgical residency training program in the United States at Johns Hopkins.

[9][13] Many prominent figures in medical surgery were affected and influenced by his new system of training, and it has had a profound impact on American medicine.

[14] An English surgeon, Charles Moore, believed that even more breast tissue should be removed and doctors who were trying to save women from disfigurement were doing them a disservice.

[14] Halsted presented his findings at the American Surgical Association conference in New Orleans in 1898, concluding that the procedure significantly decreased the percentage of local reoccurrence.

[14] Halsted created multiple techniques for surgery so damage to tissues and blood supply would be minimized.

[9] Besides working on breast cancer, Halsted also contributed to the surgical treatment for other diseases including vascular aneurysm, inguinal hernia, and a certain kind of primary carcinoma of the ampulla of Vater.

[9] As one of the first proponents of hemostasis and investigators of wound healing, Halsted pioneered Halsted's principles, modern surgical principles of control of bleeding, accurate anatomical dissection, complete sterility, exact approximation of tissue in wound closures without excessive tightness, and gentle handling of tissues.

[25] The main reason for the introduction of rubber gloves was to protect the hands of scrub nurse Caroline Hampton.

[25][9][11] Other achievements included advances in thyroid, biliary tract, hernia,[26] intestinal and arterial aneurysm surgery.

Antisepsis and asepsis, coming in when he was young, had turned the attention of surgeons to external and often extraneous things.

[27] Though, like most men of his craft, he had no religion, he yet revived and reinforced the ancient saying of Ambroise Paré: 'God cured him; I assisted.'

The young men who went out from his operating room were magnificently trained, and are among the great ornaments of American surgery today.

[9][29] He died on September 7, 1922, 16 days short of his 70th birthday, from bronchopneumonia as a complication of surgery for gallstones and cholangitis.