Crawford Long is credited with the discovery of what important medical advancement?

Crawford Long is credited with the discovery of anesthesia, specifically the use of ether as a surgical anesthetic. In 1842, he performed an operation on a patient while they were under the influence of ether, which allowed the patient to endure the surgery without pain. This marked a significant advancement in surgical practices, transitioning from procedures performed without pain relief to ones that could utilize anesthesia, greatly improving patient comfort and outcomes during surgical operations.

The other options represent different medical advancements not associated with Crawford Long. Vaccination refers to the process of providing immunity against diseases, which was pioneered by Edward Jenner in the late 18th century. Antiseptics are substances that prevent infection, largely popularized by Joseph Lister in the 19th century. Radiation therapy is a treatment for cancer that involves the use of ionizing radiation, developed much later in the 20th century. Each of these advancements has made monumental contributions to medicine, but it is Crawford Long who is recognized for his foundational role in anesthesia.