where hallstead connected some of his greatest work. thank you, doctor, so much for doing this. >> thanks for having me. >> what was the connection between sigmund freud and william hallstead. >> they both were contemporaries. they never met or at least i can't find any evidence. but their lives were braided together. they were bound together by a fascination with cocaine. and several medical papers that some they each wrote or some they read about the latest, newest miracle drug of their era, 1884. >> so here we are the medical library of william hallstead at johns hopkins university, one of the greatest medical centers in the world. what did he do? >> most of the modern safety procedures we take of how to cut open a body, how to handle the tissue very delicately and gently so that it heals well, how to suture it correctly, this was all william hallstead. he was also fascinated with aseptic surgery, not introducing germs into the surgical wound. >> at this point in medical history, cocaine was found to do what, that would allow hallste