The Soldier at the Western Front – The Use of Poisonous Gas
Source 1: Fritz Haber: Five speeches from 1920-1923

The chemist Fritz Haber (1868-1934) is considered the spiritual father of the use of poisonous gas in the First World War. His wife Clara Immerwahr (1870-1915) – a doctor of chemistry herself, who rejected chemical warfare as “perversion of science” – shot herself shortly after the chlorine gas attack in Ypres with the service weapon of her husband. Haber received the Nobel Prize for Chemistry in 1919, even though not for his participation in the chemical warfare but for the Haber-Bosch process for the artificial production of ammonia, the fundament for the fabrication of nitrogen fertilizer and explosives. He justified the use of poisonous gas after the war.


„The aversion that is feed by the strangeness of the weapon, is further enhanced by the imagination of extreme cruelty and the doubt if it isn’t harming the fundaments of international law, that have to be keept sacrosanct in the interest of the whole humanity even in war. […] Gas as a weapon is not in the least more cruel than flying pieces of metal, to the contrary the partition of fatal diseases is comparable small, there are no mutilations and concerning the illnesses that might occur afterwards naturally statistical material can’t be provided yet, but nothing is known to us that would indicate a high frequency. Based on these objective arguments one would not easily ban gas warfare. […] In the case of gas as a warfare agent everything is the other way around. It is essential to them that their physiological impact on the human being and the sensation they evocate change thousandfold. With every change in the impression that nose and mouth are feeling the soul is trembled by a new and unknown impact and it is a new challenge to the moral strength of the soldier in the moment when the whole performance of his soul is needed for the fight.”

Fritz Haber: The chemistry in the war (speech, delivered to officers the Ministry of the Reichswehr 11th November 1920), in: Fünf Vorträge aus den Jahren 1920–1923, Berlin 1924, pp. 25-41, here pp. 34 f. and 37.


“The event at Ypers which departs the phase of development from the specific gas war time was the rebirth of an ancient military technology with modern tools […] The development of the chemical industry made the effective renewal of this form of combat obvious. According to an historical rule that can be applied to all new effective means of warfare, the physical effect of the chlorine cloud has been profoundly exaggerated. I wouldn’t stand here if it would kill everyone it captures and put him out of action. Because I myself was caught during a large scale field test by my own carelessness and without any protection in such a cloud, I couldn’t find my way out and I escaped with severe but after a couple of days complete disappeared phenomena.”

Fritz Haber: On the history of gas warfare (speech, delivered to the parliamentary inquiry of the German Reichstag on the 1st October 1923), in: Fünf Vorträge aus den Jahren 1920–1923, Berlin 1924, pp. 76-92, here p. 88.

Fritz Haber: The chemistry in the war (in German)

Fritz Haber: On the history of gas warfare (in German)


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