Walter Schiller studied the causes of diseases in the US and Austria in the early twentieth century and in 1928, invented the Schiller test, or a way to diagnose early cervical cancer in women. Cervical cancer is the uncontrollable division of cells in the cervix, or lower part of the uterus. While living in Austria until his emigration to escape the Nazis in 1937, Schiller concluded that there was a form of cervical cancer, later named carcinoma in situ, that physicians could detect earlier than when tumors start to appear. To determine whether women exhibited that early form of cancer, Schiller stained women’s cervixes with a type of iodine that would stain healthy cervical tissue and not cancerous cervical tissue. Cervical cancer is more deadly to women when it is caught later in its progression, and was difficult to detect in Schiller's time. Schiller’s research enabled physicians to diagnose cervical cancer early, helping women receive treatment quicker and ultimately helping to popularize annual diagnostic exams in the US.