Before the mid-19th century patients dreaded the anticipation of surgery and the intense pain that was surely to come. In 1846 ether was used for painless tooth extraction and a surgical procedure. Many other gases used have been chloroform, nitrous oxide, ethylene, cyclopropane, ethyl chloride, vinethene, trichloroethylene, and xenon. These gases affect only the nerve center in the brain and not the rest of the body are are temporary or transient in nature. Intravenous barbiturates can also be used, and have the benefit of reducing nausea upon awakening. Local anesthetics can be used in some surgeries. A film of an actual surgery performed at the Johns Hopkins Medical Center with modern anesthetic procedures is shown.