Institute of Technology and Environmental Health, University of California, Davis, One Davis Road, Davis, California 95616
Received September 3, 1999; accepted September 30, 1999
Fritz Haber was not a toxicologist; he was a physical chemist. And yet he profoundly influenced the science of toxicology. "Haber's law" is well known to inhalation toxicologists. It is usually interpreted to mean that identical products of the concentration of an airborne agent and duration of exposure will yield similar biological responses (C x T = constant). The "Haber-Weiss reaction" is a fundamental mechanism in free-radical toxicology. However, to most toxicologists it comes as a surprise to learn that Fritz Haber's biggest contribution to science was the invention of a practical way to synthesize ammonia from nitrogen in the air (the Haber-Bosch nitrogen-fixation process), and that he was a Nobel Prize winner and a foreign member of the U.S. National Academy of Sciences.
Fritz Haber had a complex personality, and until recently, he was almost a forgotten man, but his scientific accomplishments were never disputed. Before World War I, he first directed what reportedly was the finest and best-equipped laboratory in physical chemistry at the Technical University of Karlsruhe. In 1911, he became the first director of the Kaiser Wilhelm Institute for physical chemistry in Berlin. After the war, this institute became renowned worldwide, and among his colleagues were luminaries such as Albert Einstein, Lise Meitner, and Otto Hahn. Yet he was also demonized for the active role he played during the war in the successful development and application of war gases.
Fritz Haber was born and raised in the then Prussian town of Breslau, now Wroclaw, in Poland. After high school and military service, he studied physical chemistry at the universities of Berlin and Heidelberg. What he himself later called "the 17 best working years of my life" were then spent in Karlsruhe, where he developed, in close collaboration with industry, the process of nitrogen fixation. He also designed several analytical instruments such as (together with Loewe) a gas interferometer, and also an instrument that could be used to warn against dangerous accumulation of methane gas in coalmines ("Schlagwetterpfeife"). At the comparatively young age of 37, he became a full professor.
In 1911, at 43, he moved to Berlin, and shortly thereafter he was called to The Kaiser Wilhelm Institute for Physikalische and Elektrochemie, located in the Berlin suburb of Dahlem. When World War I started in the fall of 1914, Fritz Haber was soon called upon to make his and his institute's talents available to the war effort. He assembled a large team, consisting eventually of more than 150 scientists and 1300 technical personnel. Their task was to develop the tools of gas warfare and, at the same time, to design countermeasures such as efficient gas masks. Ferdinand Flury, later to become a leader in industrial hygiene and toxicology at the University of Wuerzburg, directed department "E." Together with a staff of 10 scientists and 15 assistants, he was responsible for studies on the toxicity of war gases, animal experiments, and industrial hygiene. The group conducted experiments with rats, mice, guinea pigs, dogs, monkeys, and even horses. The acute inhalation toxicity of numerous agents, thought to be useful in gas warfare, was thoroughly explored. The work on the mechanisms of toxicity of gases used in warfare led to the development of effective methods of treatment and countermeasures against gas toxicity. Fritz Haber himself was not only active in directing research, but traveled repeatedly to the western and eastern front where, often under enemy fire, he personally supervised the deployment of the equipment necessary to conduct gas warfare. He was tireless and highly motivated by his patriotism. It was those activities that, in the eyes of Germany's enemies, made him a war criminal. For some time after the war, he was afraid that charges would be pressed against him.
It is also notable that Haber's work was not only helpful at the war front, but that, without his invention, the nitrogen fixation process, Germany would not have been able to conduct war for as long as it eventually did. Nitrogen was needed for the production of fertilizer; Haber's accomplishment at one time was said "to make bread available out of the air." Nitrogen also was essential for the manufacturing of explosives. Since at the outbreak of war, the allies had immediately imposed a naval blockade on Germany, it no longer had access to nitrogen sources coming from abroad. Therefore, it was Haber's process that enabled the German war economy to carry on for as long as it did.
After the war, Haber's institute was greatly reduced in size and barely survived; most of his colleagues left. Throughout the entire country, German science was in dire straits. Haber, deeply concerned, became actively involved in helping to create the "Notgemeinschaft der Deutschen Wissenschaft" (Emergency Association of German Science). The society still survives today, under the name of "Deutsche Forschungsgemeinschaft." Technically, the new organization was to be a scientific society, its members drawn from universities, research institutions, academies of science, and scientific associations. The society was founded on March 13, 1920. Its goal was to unify all sciences, including technical sciences, into one alliance. Haber's role in creating the society and setting its goal was pivotal. He was convinced that science should govern itself. This was in contrast to the views of the president of the new society, Friedrich Schmidt-Ott, a high functionary in the Prussian government, who essentially wished to make all decisions about the allocation of funds by himself. Haber strongly advocated the institution of committees, who would decide how to allocate funds. "It is not possible for the association to foresee the needs of the individual scientific disciplines; rather we must learn from them what their needs are," he said. "Individual committees need to show discipline and recognize general goals from special interests, and they should be able to set priorities for the distribution of funds. The entire concept of science governing itself depends upon the fact that the members in the different committees act reasonably and fairly." Individual committee members were to be elected by secret ballot by the entire membership of the society. Haber's views on how the society should work prevailed against the resistance put up by Schmidt-Ott.
At the ceremonial opening of the society, Haber delivered an address that revealed yet another aspect of his vision of science and the future. Having learned some bitter lessons during the war, he recognized that raw materials were not available in unlimited amounts. He suggested using circular processes and also very strongly advocated that rare raw materials be replaced, wherever possible, by more readily available and cheaper materials. Throughout his life, Fritz Haber never separated "basic science" from "applied science." He was fully convinced that basic science produces the facts that eventually lead to applied technologies. This would justify the investment of large sums of money, much of it from public sources, in basic science. This was in contrast to the thinking that technologies would not arise from the cognitive core of science, but from other technologies devised for quite different purposes.
Haber became engaged not only in science policy and politics, but for a time spent much effort in an attempt to isolate gold from seawater, hoping that this eventually would help to reduce the debts Germany had incurred as a consequence of the lost war. During the same years, his institute became a focus for excellence in research. He also traveled widely, to the United States and then to Japan, where he initiated collaborative efforts between his country and Japan.
Haber had been born to Jewish parents. However, in time he began to resent his religion; it prevented him from advancement, both in academia (where on more than one occasion, less-qualified, but non-Jewish competitors had advanced) and in the military. Eventually he converted to Protestantism. In the spring of 1933, the new National Socialist government in Germany advised him that he was to dismiss from his institute all employees who were of Jewish origin. Haber resisted, believing that his colleagues should be evaluated not by their origins but rather by their professional competence. He made his point in no uncertain terms, but to no avail. He resigned, writing in his resignation letter, "You cannot expect that a man of 65 years will change the way he thinks, a way that guided him so well during the past 39 years in his academic life, and you will understand that the pride with which he served Germany, his country, during his entire life, now requires him to ask to be relieved from his duties."
He spent the last few months of his life trying to help his former colleagues to build a new existence. His health was failing; he was tired, and he suffered repeatedly from attacks of angina, but he continued to travel widely throughout Europe. A trip was planned to what was later to become Israel, at the instigation of his friend Chaim Weizman, but on his way to a quiet place in Switzerland where he hoped to regain some of his health, he died on January 29, 1934.
NOTES
1 To whom correspondence should be addressed. Fax: (530) 752-5300. E-mail: hrwitschi{at}ucdavis.edu.
SUGGESTED FURTHER READING
Stoltzenberg, D. (1994). Fritz Haber: Chemiker, Nobelpreistraeger, Deutscher, Jude. VCH, Weinheim.
Szollosi-Janze, M. (1998). Fritz Haber 18681934. Eine Biographie. Oscar Beck, Munchen.
Witschi, H. (1997). The story of the man who gave us "Haber's Law." Inhal. Toxicol. 9, 199207[ISI]
Witschi, H. P. (1999). Some notes on the history of Haber's law. Toxicol. Sci. 50, 164168.