Unit 731: Ignored History and Lost Lessons in Medical Education 

I cut him open from the chest to the stomach, and he screamed terribly, and his face was all twisted in agony. He made this unimaginable sound, he was screaming so horribly. But then finally he stopped. This was all in a day's work for the surgeons, but it really left an impression on me because it was my first time.” [2]

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Just three thousand kilometres north of Hong Kong lies the grave of Maruta (丸太). Maruta in Japanese means ‘logs’, but in this case, Maruta means people, three hundred thousand people, to be exact, who were brutally tortured and killed in the Kwantung Army’s ‘Epidemic Prevention and Water Supply Department’, more commonly known as Unit 731, between 1933 and the end of World War II in the name of medical research [4, 10]. The victims consisted predominantly of detained Chinese, Koreans, Mongolians, Russians and Allied POWs, including the young, the old and the pregnant, and were unwillingly subject to incessant exposure to malevolently engineered pathogens, including anthrax, plague, cholera and glanders, vivisections without anaesthesia, and other horrific experiments. These inhumane activities were justified as research into the explanation of diseases, development of therapies, or development of biological and chemical warfare [1, 9]. Despite the diabolical nature of these events, Unit 731 and related moral atrocities that occurred in the Pacific War are seldom remembered and much less included in any medical school curriculum. As a prime example of unethical research, it is a bewilderment that the crimes that occurred in Unit 731 are not studied by medical students, especially in Hong Kong.

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Approval and financial support from Emperor Hirohito, who was also avidly intrigued by human anatomy, was swiftly obtained as he was swayed by the promises of the new knowledge and technology obtained from Unit 731 to strengthen Japan as a nation. The wartime biological warfare research programme was coordinated by Lieutenant General Ishii Shirō, who graduated from the Kyoto Imperial University Medical Department. Perhaps akin to many colleagues in medical school, he was rumoured to have a photographic memory and demonstrated academic excellence, which catapulted his success in military medicine. After enlisting as an army surgeon in 1921 and being commissioned surgeon-first lieutenant in under half a year, he continued his studies in 1924 bacteriology, serology, pathology, and preventative medicine. He then pursued a doctorate in microbiology in 1926 and was posted to the Army Medical Hospital, where he came across a report on chemical and biological warfare prepared for the Geneva Conference in 1925, which fostered his fascination for its potential. Under the guidance of his university mentor, he went on a two-year research tour to 25 countries to learn about biological warfare research. In the face of the prohibition of the use of chemical and biological weapons by the Geneva Protocol following World War I, his belief of Japan’s need to engage in this field solidified in fear that they would fall behind the other powerful nations. Following his return, he was appointed professor of immunology in the Department of Epidemic Prevention at the Army Medical College, in which he was able to covertly conduct research. He was finally able to gain the support and attention of his superior officers and saw the puppet state of Manchukuo as a chance to establish a research agenda under the protection of the military without being constrained by space, security, and safety. His two laboratories in Harbin and Beiyinhe, for ‘defensive’ and ‘offensive’ research respectively were quickly established and his human subjects were conveniently provided by the Kempeitai (憲兵隊), the Imperial Japanese Army with police powers like those of the Nazi Gestapo, who had the ability to arrest anyone accused of being a spy, communist sympathiser, or anti-Japanese saboteur.

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None of the prisoners assigned to Unit 731 made it out of their confinement alive [7]. Inhumane practices such as vivisection were performed without anaesthesia due to the belief that research data after anaesthesia became untrue [4]. Experiments were also conducted to test the firing range of weapons, with analysis into wound patterns and penetration deaths to test the endurance of human life. Other research included crush injury studies, whereby heavy objects were dropped onto bound prisoners, and human survival studies, in which civilians were locked up, deprived of food and water until they died. There were also experiments studying transfusions and the clotting process, in which victims were only allowed to drink seawater or were given injections of mismatched human or animal blood. There were also studies conducted for the advancement of battlefield treatment techniques. For example, the effects of high G-forces on pilots and falling paratroopers were studied by loading prisoners, including young children, into large centrifuges and spinning them at progressing speeds until they lost consciousness or died. Sexually transmitted diseases, such as syphilis, were studied by ordering patients to rape both female and male captives, who were later observed to identify the onset of the disease. Female captives of childbearing age were also forcibly impregnated and infected with various diseases, exposed to chemical weapons, or subject to crush injuries, bullet wounds, or shrapnel injuries, and were then dissected to investigate the impact on the foetuses. 

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Beyond the research facilities, large quantities of rats and fleas infected with extremely lethal pathogens were released to villages and towns in Manchuria resulting in thousands of casualties of innocent human subjects, whilst doctors monitored the onset of symptoms and progression to breed the most deadly strain possible. This was in preparation for Ishii’s ‘Operation Cherry Blossoms at Night’, which was a biological weapon intended for use against the United States. Before this plan came to fruition, the USA’s atomic bombings occurred and the war ended, prompting the order to destroy all documentation of Unit 731. Regardless, Shirō kept a proportion of his lab notes out of the facility before going into hiding. Meanwhile, the perpetrators of atrocities committed in the interest of medical science in the Western theatre of World War II were prosecuted in the now-famous Doctors’ Trial in Nuremberg. The vague reports from China about unusual outbreaks and plague bombs garnered the vested interest of the Americans in the research conducted by General Ishii, who promptly revealed most of his data to the United States in exchange for immunity and protection. As a result, Shiro Ishii never had to face justice and died a free man in 1959 [3]. 

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In spite of such barbaric methodology, some researchers have recently contended to the scientific community that the data from the grotesque Japanese experiments should be available to the international medical community and used to gain insight into the management and pathophysiology of COVID-19 and pathogens that may cause future pandemics [8]. It is clear that the wartime medical atrocities utterly defied the moral imperative of medicine as the art of humanity, a Confucius percept that confers that it is a moral commitment to love people and free them from suffering through personal caring and medical treatment. As such, medical students must critically explore the question of whether we should use or entertain the option of using data gained through measures and practices that are blatantly unethical, and as future clinicians, biomedical research, or simply consumers of biomedical research, reflect on the past and future of research ethics in tandem with the necessity of addressing moral and ethical considerations in applying associated data, touching on the notion of informed consent, whether unethically obtained data should be used, and whether the ends really justify the means. 

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Acknowledgement

I would like to extend my heartfelt gratitude to Professor Arthur Caplan for generously dedicating his time to provide a brief commentary on my work

References

1. Harbin, Matthew Forney, and Velisarios Kattoulas. “Black Death.” Time, 2 September 2002, https://content.time.com/time/subscriber/article/0,33009,346284,00.html.

2. Kristof, Nicholas D. “Unmasking Horror -- A special report.; Japan Confronting Gruesome War Atrocity (Published 1995).” The New York Times, 17 March 1995, https://www.nytimes.com/1995/03/17/world/unmasking-horror-a-special-report-japan-confronting-gruesome-war-atrocity.html. Accessed 4 September 2023.

3. Lenoir, Andrew. “How Shiro Ishii Became World War 2 Japan's Most Barbaric War Criminal.” All That's Interesting, 24 November 2020, https://allthatsinteresting.com/shiro-ishii-unit-731. Accessed 23 August 2023.

4. Liang, Jiashuo. “A History of Japan’s Unit 731 and Implications for Modern Biological Warfare.” Advances in Social Science, Education and Humanities Research, vol. Proceedings of the 2022 3rd International Conference on Language, Art and Cultural Exchange（ICLACE 2022), no. 673, 2022, pp. 522-526. Atlantic Press, https://doi.org/10.2991/assehr.k.220706.099.

5. Nie, Jing Bao, editor. Japan's Wartime Medical Atrocities: Comparative Inquiries in Science, History, and Ethics. Taylor & Francis, 2010. Accessed 23 August 2023.

6. Pawlowicz, Rachel, and Walter E. Grunden. “Teaching Atrocities: The Holocaust and Unit 731 in the Secondary School Curriculum.” The History Teacher, vol. 48, no. 2, 2015, pp. 271-294. ERIC, https://eric.ed.gov/?redir=http%3a%2f%2fwww.societyforhistoryeducation.org%2fpdfs%2fF15_Pawlowicz_and_Grunden.pdf.

7. Stockton, Richard. “Unit 731: Inside World War II Japan's Sickening Human Experiments Lab.” All That's Interesting, 14 May 2023, https://allthatsinteresting.com/unit-731. Accessed 23 August 2023.

8. Su, Zhaohui, et al. “The promise and perils of Unit 731 data to advance COVID-19 research.” BMJ Global Health, vol. 6, 2021, p. e004772. BMJ Global Health, doi:10.1136/bmjgh-2020-004772.

9. Tsuchiya, Takashi. “The Imperial Japanese Experiments in China.” The Oxford Textbook of Clinical Research Ethics, edited by Ezekiel J. Emanuel, et al., Oxford University Press, USA, 2011, pp. 31-45.

10. Tsuneishi, Keiichi, and John Junkerman. “Unit 731 and the Japanese Imperial Army’s biological warfare program.” Japan's Wartime Medical Atrocities: Comparative Inquiries in Science, History, and Ethics, edited by Jing Bao Nie, Taylor & Francis, 2010, pp. 21-31. Accessed 27 July 2023.