Dichlorodiphenyl-trichloro-ethene (DDT) was synthesized as early as 1874 by Austrian chemist Othmar Zeidler (1859–1911); it was the Swiss chemist Paul Müller (1899–1965) who recognized its insecticidal properties in 1939. He was awarded the 1948 Nobel Prize in Physiology or Medicine for his development of DDT. Unlike the arsenic-based compounds then in use, DDT was effective in killing insects and seemed not to harm plants and animals. In the following twenty years, it proved to be effective in controlling disease-carrying insects (mosquitoes that carry malaria and yellow fever and lice that carry typhus) and in killing many plant crop destroyers. Publication of Rachel Carson’s book Silent Spring in 1962 alerted scientists to the detrimental effects of DDT. Increasingly DDT-resistant insect species and the accumulative hazardous effects of DDT on plant and animal life cycles led to its disuse in many countries during the 1970s. In fact, DDT and PCBs have been added to the list of chemicals known as estrogenic compounds—that is, synthetic substances in the environment that cause the mammalian body to respond as if to estrogen.