The Pap smear was introduced as a method of diagnosing carcinomas in the female genital tract by George Papanicolaou.1
1Papanicolaou, G.N. and Traut, H.F. "The Diagnostic Value of Vaginal Smears in Carcinoma of the Uterus." American Journal of Obstetrics and Gynecology. 42 (1941): 193-206. [PUBMED]