Paul Hermann Müller

1.1. Childhood and Family

Müller was born on January 12, 1899, in Olten, Solothurn, Switzerland. He was the eldest of four children to Gottlieb and Fanny (née Leypoldt) Müller. His father was employed by the Swiss Federal Railways, which led the family to relocate first to Lenzburg in Aargau and later to Basel. From a young age, Müller displayed a strong interest in science and technology. He maintained a small home laboratory where he indulged in elementary experiments, developing photographic plates and assembling radio equipment. During his high school years, he was an average student, often distracted from his studies by his passion for laboratory work. His thin and pale appearance sometimes led his peers to mockingly refer to him as "The Ghost."

1.2. Academic Background

Müller attended the local primary school (Volksschule_{elementary school}^German) before progressing to the lower and upper Realschule_{secondary school}^German. In 1916, he briefly left school due to poor grades and took on a position as a laboratory assistant at Dreyfus. The following year, he became an assistant chemist at the scientific-industrial laboratory of Lonza A.G. He returned to school in 1918, successfully obtaining his secondary school diploma in 1919, the same year he enrolled at University of Basel. At the University of Basel, Müller pursued studies in chemistry, minoring in botany and physics. He initially focused on inorganic chemistry under Friedrich Fichter, then continued his studies in the organic chemistry laboratory of Hans Rupe in 1922, for whom he also worked as an assistant. In 1925, he earned his PhD with a dissertation titled Die chemische und elektrochemische Oxidation des as. m-Xylidins und seines Mono- und Di-Methylderivates (The Chemical and Electrochemical Oxidation of Asymmetrical m-Xylidine and its Mono- and Di-methyl Derivatives), graduating summa cum laude_{with highest honors}^Latin.

2.1. Early Work at Geigy

On May 25, 1925, Müller joined J. R. Geigy AG (now Novartis) in Basel as a research chemist within the dye division. His initial research at Geigy concentrated on synthetic and plant-derived dyes, as well as natural tanning agents. This work led to the successful production of synthetic tanning agents such as Irgatan G, Irgatan FL, and Irgatan FLT. In 1930, he developed Irgatan, a synthetic softening agent for leather. Müller also contributed to the development of disinfectants; notably, he created Graminone, a seed disinfectant considered safer than the mercury-based disinfectants commonly used at the time.

2.2. Initiation of Insecticide Research

In 1935, Geigy expanded its research into moth and plant-protection agents, a field that particularly appealed to Müller. His long-standing interest in botany, which he had pursued as a minor subject during his university studies, naturally drew him to the challenges of plant protection. He expressed a desire to synthesize chemical plant protection agents himself. Following his successes with tanning agents and disinfectants, Müller was tasked with developing a new insecticide.

At the time, the available insecticides were either costly natural products, synthetic compounds that were largely ineffective against insects, or arsenic-based compounds that were highly poisonous to both insects and mammals. Müller observed that insects absorbed chemicals differently from mammals, leading him to believe it was possible to find chemicals selectively toxic to insects. His ambitious goal was to "synthesize the ideal contact insecticide"-one that would possess a rapid and powerful toxic effect on the widest possible range of insect species while causing minimal or no harm to plants and warm-blooded animals. He also aimed for a compound that would be long-lasting, inexpensive to produce, and possess a high degree of chemical stability.

Müller's shift to insecticide research was significantly motivated by two pressing issues of his era: a severe food shortage in Switzerland, which highlighted the urgent need for more effective control of crop infestations, and the devastating typhus epidemic in Russia, which was historically extensive and lethal. He began his dedicated search for this ideal insecticide in 1935.

3.1. Synthesis and Discovery of Properties

Müller's systematic and determined research spanned four years, involving 349 unsuccessful attempts to find the perfect compound. His breakthrough occurred in September 1939. He placed a fly in a cage coated with a particular compound, and shortly thereafter, the fly died. The compound he had discovered was dichlorodiphenyltrichloroethane, commonly known as DDT, or more precisely, 1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane.

It was later recognized that Othmar Zeidler, a Viennese pharmacologist, had first synthesized DDT in 1874. However, Zeidler, while publishing a paper on his synthesis, had not investigated the compound's properties and thus failed to realize its extraordinary value as an insecticide. Müller's methodology focused on finding a contact poison that would permeate the chitin layer of insects, leading him to specifically investigate hydrophobic substances, which proved key to DDT's efficacy. Müller quickly recognized that DDT was the chemical he had been diligently searching for, noting its remarkable potency against numerous arthropods.

3.2. Efficacy Testing and Patent Registration

Extensive tests conducted by the Swiss government and the U.S. Department of Agriculture confirmed DDT's astonishing effectiveness. It proved potent against a wide array of pests, including the Colorado potato beetle, mosquitoes (which spread malaria and yellow fever), lice (carriers of typhus), fleas (responsible for the bubonic plague), and sandflies (vectors for various tropical diseases). The compound also exhibited low toxicity to humans, livestock, and crops, was stable, odorless, and suitable for wide-scale dispersal.

Following these successful tests, Geigy secured a Swiss patent for DDT in 1940. This was followed by a United Kingdom patent in 1942, and patents in the United States and Australia in 1943. The name "DDT" itself was first officially adopted by the British Ministry of Supply in 1943.

3.3. Global Application and Impact

After its patenting, Geigy began to market two DDT-based products: Gesarol, a 5% dust insecticide for spraying, and Neocid, a 3% dust insecticide. In May 1943, DDT was added to the United States Army's supply lists. The first practical tests of DDT as a residual insecticide against adult vector mosquitoes were conducted in 1943. A pivotal moment for DDT's application occurred in 1944 in Naples, Italy, during the Italian campaign of World War II. With typhus epidemics rampant and threatening to disrupt Allied military operations, mass spraying of DDT on the city's inhabitants successfully eradicated the lice population. This unprecedented intervention was the first instance in history where an epidemic of this scale was controlled through chemical means.

DDT is credited with saving the lives of millions during World War II by preventing widespread outbreaks of typhus and other vector-borne diseases. Beyond the war, between the 1950s and 1970s, DDT played a crucial role in global disease eradication campaigns, helping to eliminate malaria entirely from many countries, including the United States. Following the war, DDT also found extensive use as an agricultural pesticide, significantly boosting crop yields by protecting them from insect infestations.

4.1. Nobel Prize Award

In 1946, Paul Müller was appointed Geigy's Deputy Director of Scientific Research on Substances for Plant Protection. His most significant recognition came in 1948 when he was awarded the Nobel Prize in Physiology or Medicine. The award citation commended him "for his discovery of the high efficiency of DDT as a contact poison against several arthropods." This award was particularly notable as Müller was neither a physician nor a medical researcher, highlighting the extraordinary and immediate impact of DDT on human health and disease prevention. The Nobel Committee specifically praised DDT's use in the evacuation of concentration camps, prisons, and among deportees, stating that the substance had "without any doubt, already preserved the life and health of hundreds of thousands." In 1951, Müller was one of only seven Nobel laureates who attended the inaugural Lindau Nobel Laureate Meetings.

4.2. Other Awards and Positions

Beyond the Nobel Prize, Müller received numerous other accolades and held significant positions. In recognition of DDT's profound impact on controlling malaria and other epidemiological problems in the Mediterranean region, particularly its near elimination in Greece, he was invited to Greece in 1963 and received an honorary doctorate from the Aristotle University of Thessaloniki, along with the Golden Medal of the city of Thessaloniki. He was also awarded an honorary doctorate from the Universidad Nacional Eva Perón and an honorary professorship at the Escuela Superior Tecnica e Investigacion Cientifica in Buenos Aires.

Müller became an honorary member of several distinguished scientific societies, including the Swiss Nature Research Society (1949), the Paris Society of Industrial Chemistry (1949), the Reale Accademia Internazionale del Parnaso in Naples (1951), and the Academia Brasileira de Medicina Militar in Rio de Janeiro (1954). In 1952, he received the Medal of Honour from the Congrèss Internationale de Phytopharmacie et Phytiatrie in Paris.

4.3. Activities After Retirement

Müller retired from Geigy in 1961. Despite his retirement, his passion for scientific inquiry continued. He maintained a home laboratory where he pursued further research activities, demonstrating his lifelong dedication to chemistry and pest control.

5.1. Family and Personality

In 1927, Paul Müller married Friedel Rüegsegger. Together, they had two sons, Heinrich (born 1929) and Niklaus (born 1933), and one daughter, Margaretha (born 1934). Friedel played a crucial role in managing their household and raising their children, which allowed Müller to fully dedicate himself to his chemical research. He was known for his independent and somewhat solitary nature; his daughter, Margaretha, described him as an Eigenbrötler_{one who makes his own bread}^German, signifying someone self-reliant and individualistic. Müller was highly determined and persistent in all aspects of his life, traits he often attributed to lessons learned from his college mentor, Friedrich Fichter.

5.2. Hobbies and Interests

Müller held a profound love for nature, often seeking relaxation and inspiration in the Swiss Alps and the Swiss Jura, where he owned a small holiday home. This allowed him to rekindle his long-standing interest in botany. He also maintained a small fruit farm that he diligently tended to. His leisure activities included gardening, photographing mountain wildflowers, and taking early morning nature walks with his children. A lover of music, Müller and his wife frequently enjoyed playing flute and piano duets, particularly from Gluck's opera Orfeo ed Euridice. His weekend readings, which often delved into the science of plant protection and pest control while in the mountains, fueled his professional fascination and ultimately led to his pivotal research on pesticides at Geigy and the discovery of DDT's insecticidal properties.

7.1. Positive Contributions

The discovery of DDT by Paul Müller in 1939 represented a revolutionary advancement in the fields of public health and agriculture. Its powerful and broad-spectrum insecticidal properties enabled unprecedented control over insect-borne diseases. DDT is credited with saving countless lives, particularly during and after World War II, by preventing widespread epidemics of diseases such as typhus and malaria. Its application was instrumental in the near eradication of malaria from many countries and significantly reduced the incidence of other vector-borne illnesses, leading to a dramatic improvement in global public health. In agriculture, DDT's effectiveness in protecting crops from pests led to increased food production, contributing to food security worldwide. The Nobel Committee's decision to award Müller the Nobel Prize, a rare honor for a non-medical researcher, underscored the immense and immediate humanitarian impact of his discovery.

7.2. DDT Criticism and Controversy

Despite its initial successes, DDT later became a focal point of widespread criticism and controversy due to its adverse environmental effects. Its high chemical stability and environmental persistence meant that it did not break down easily, remaining in the environment for many years. This led to its bioaccumulation in the food chain, affecting wildlife, particularly predatory birds, and raising concerns about potential human health impacts. Furthermore, the widespread and indiscriminate use of DDT led to the rapid development of pesticide resistance in many insect populations, diminishing its long-term effectiveness. These environmental and biological concerns, famously highlighted in Rachel Carson's 1962 book Silent Spring, led to growing public outcry and eventually resulted in global bans or severe restrictions on DDT's use. For instance, Japan prohibited its use in 1970. While these bans aimed to protect ecosystems and human health, they also inadvertently removed a powerful and inexpensive tool against disease vectors, leading to a resurgence of diseases like malaria in some regions where effective alternatives were not readily available.