A genus of small, gram-positive, rods, Listeria was first isolated by Murray in 1924 as Bacterium monocytogenes. In 1927, Pirie proposed the genus Listerella in honor of British surgeon Sir Joseph Lister (1827–1912), an early advocate of antiseptic surgery. It was not until 1939 that Pirie realized that this genus had already been taken by a slime mold (also named in honor of Lister, by Jahn in 1906). In 1940, he proposed the alternative name Listeria. The mouthwash Listerine was also named after Lister, in 1979 by Lawrence and Bosch, when it was marketed as a surgical antiseptic.