Vankirk was a dentist practicing in 1850s Baltimore. He was an early adopter of chloroform during the extraction of teeth. In 1851 Vankirk treated William Legrand. Legrand was sceptical about the effectiveness of chloroform but agreed to have his bicuspid extracted. When Vankirk applied a rag soaked in chloroform to Legrand's mouth and nose, he lost consciousness almost immediately.