chemical he had been searching for. Tests of DDT by the Swiss government and the U.S. Department of Agriculture confirmed its effectiveness against the Colorado potato beetle. Further tests demonstrated its astonishing effectiveness against a wide range of pests, including the mosquito, louse, flea, and sandfly, which, respectively, spread malaria, typhus, the plague, and various tropical diseases. Application of DDT After taking out a Swiss patent on DDT in 1940 (a U.K. patent followed in 1942 and patents in the U.S. and Australia in 1943), Geigy began to market two DDT-based products, a 5% dust called Gesarol spray insecticide and a 3% dust called Neocid dust insecticide. The name DDT was first employed by the British Ministry of Supply in 1943, and the product was added to U.S. Army supply lists in May of the same year. It was also in 1943 that the first practical tests of DDT as a residual insecticide against adult vector mosquitoes were carried out. The next year, in Italy, tests were performed in which residual DDT was applied to the interior surfaces of all habitations and outbuildings of a community to test its effect on Anopheles vectors and malaria incidence. DDT saved the lives of millions during World War II. Between the 1950s and 1970s, DDT helped eradicate malaria entirely from many countries, the U.S. included. Later scientific career Müller became Geigy's Deputy Director of Scientific Research on Substances for Plant Protection in 1946. In 1948 he was awarded the Nobel Prize in Physiology and Medicine, "for his discovery of the high efficiency of DDT as a contact poison against several arthropods." The fact that he was accorded this honour even though he was neither a physician nor a medical researcher reflected the immense impact that DDT had had in the fight against human disease. The Nobel Committee said: "DDT has been used in large quantities in the evacuation of concentration camps, of prisons and deportees. Without any doubt, the material has already preserved the life and health of hundreds of thousands." In 1951, Müller was one of seven Nobel Laureates who attended the 1st Lindau Nobel Laureate Meeting. In addition to the 1948 Nobel Prize in physiology or medicine, Müller received an honorary doctorate from the University of Thessalonica in Greece in recognition of DDT's impact on the Mediterranean region. He retired from Geigy in 1961, continuing his research in a home laboratory.