(The paper presented at the Fifth World Congress of Bioethics, Imperial College, London, U.K., September 22, 2000. "{ }" signifies the revision which dropped from the copies distributed at the congress.)


Takashi Tsuchiya
Associate Professor, Department of Philosophy
Osaka City University, Osaka 558-8585, JAPAN
Email address: tsuchiya@lit.osaka-cu.ac.jp

In this paper I would try to describe the whole picture of human experimentation by Japanese doctors in China from 1933 to 1945(1). Then I will examine validity of the Nuremberg Code as a judging standard for it.


From 1933 to 1945, Japanese doctors in China performed thousands of cruel experiments on Chinese, Russians, Mongolians, and Koreans and killed all of them. At Unit 731 alone, at least 3,000 people were tortured and murdered. In addition, similar human experiments and vivisections were done at four branches of Unit 731, four other "Boeki Kyusui Bu" (Anti-Epidemic Water Supply and Purification Bureaus), "Gunju Boeki Sho" (Anti-Epizootic Protection Units) including Unit 100, the Manchuria Medical School, and army hospitals(2). These experiments and vivisections can be classified under the following four categories.

(1) vivisections for training newly employed army surgeons
At army hospitals in China, army surgeons did many vivisections on Chinese prisoners. These doctors performed appendectomies and tracheostomies on the prisoners, shot them and took bullets from their bodies, cut their arms and legs and sewed up the skin around the wounds, and finally killed them. This surgical practice was purportedly part of the training program of newly employed young army surgeons to teach them how to treat wounded soldiers at the front lines.

(2) intentional infection of diseases
At the research faculties of the "Boeki Kyusui Bu," including Unit 731, the doctors infected prisoners with many kinds of diseases, for example, plague, cholera, epidemic (kidney) hemorrhagic fever, tuberculosis, typhoid, tetanus, anthrax, glanders, typhus, and dysentery. The purpose of this intentional infection was to seek the pathogen of the disease (for example in the case of epidemic hemorrhagic fever), to measure the infectiousness of the pathogen, to select more infectious strains, to investigate the effect of bacteriological weapons, and so on. The subjects were dissected after their death or vivisected to death.

(3) trials of nonstandardized treatments
Many prisoners were killed during trials of nonstandardized, unestablished, and unusual "treatments." Many kinds of vaccines in the development stage were tried directly on prisoners, with no prior trials on animals. As another example, searching for treatment for severe frostbite, Dr. Hisato Yoshimura made the prisoners' arms or legs suffer severe frostbite and then warmed them with hot water. When the temperature of the water was over 50 degrees centigrade, the skin and muscles came off. Some other doctors tried horse blood transfusion, which was said to be developed for emergent transfusion to wounded soldiers at the front lines where there is no blood supply.

(4) learning tolerance of the human body
There were deadly experiments with airtight chambers at Unit 731, the same ones as those conducted at the Nazi concentration camps. Some prisoners were forced to breathe poison gas. Others were killed by lowering the air pressure. In addition, there were doctors who only wanted to know how much air could be injected intravenously, how much bleeding brought prisoners to death, how many days prisoners could live with no food or water or only water without food, or how high electric current or voltage human beings could bear. There were also many trials of newly developed weapons with human subjects.


But how could such a mass murder by human experimentation be possible? I think there are at least four explanations.

First, it cannot be denied that it was wartime, although Japan did not formally declare war against China. Since 1931, Japan invaded and militarily ruled parts of China. Japan's rule was known to be very cruel. Chinese people who were forced to work for the Japanese factories or suspected spies and resisters were treated violently or murdered routinely. In addition, since victory in the war (especially over the United States and the United Kingdom) had become a supreme goal, Japanese people believed everything was justifiable if it was done for the sake of the country and "Tenno Heika" (the emperor).

Second, at the time Japanese people looked down upon people of other ethnicities. In addition, eugenic and racist ideologies were prevalent in Japan, as well as in the Western countries. Consequently, then most Japanese had prejudice against people in other Asian and European countries and discriminated against them. They thought Chinese, Korean, Mongolian, Russian, American, English, etc. were beings that need not be treated humanely, especially in wartime.

Moreover, the Japanese militarist government at the time feared communism. Therefore, persons who were suspected and arrested as spies of the USSR or communist resisters were tortured to death. This happened sometimes even in the Japanese homeland, but much oftener in China.

Third, those who were arrested by the Kwantung Army Military Police as suspected spies or resisters were usually executed without trial. They were beings that must be killed. So the doctors justified the murders by human experiments and vivisection with the excuse that it was better to utilize them for research and getting precious data than merely to execute them.

Fourth, since the human experimentation was performed strictly behind closed doors, the doctors tended to lose a common sense of humanity. The leaders of the Japanese Army knew that if such barbarity became widely known, the Japanese government would be severely condemned by international society. Therefore, experiments and vivisections with human subjects became "secrets of secrets." This made the laboratories completely hidden from the public, and the doctors did not need to be worried about the constraints of medical ethics.


The "factories of death" were run by army surgeons following Lt. Surgeon General Shiro Ishii. However, except at army hospitals, most of the doctors who performed human experiments and vivisections were academic researchers who had been lecturers or associate professors at leading Japanese medical schools and were temporarily employed by the Japanese Army. Why did they join these "factories" and become murderers? I have found three explanations for the lack of opposition by medical professionals.

First, in Japan then there was prevailing pressure for their participation. As it was in wartime and they lived in a fascist nation, it was very common to cooperate with the military. Those who refused to participate were blamed as "Hikokumin" (traitors). So the doctors accepted their fate without trying to resist it, even when they knew what they would be assigned to do in China [cf. Yoshikai (1981), p.65ff.].

Second, they were ordered to go to China by their academic superiors. In Japanese medial schools head professors exercise supreme power over their staff. Usually, there is only one professor in each "Ikyoku" (department), which is at the same time an office of clinical practice, a faculty for graduate education, and a research laboratory. Even after earning a doctoral degree, the doctors devote themselves to the Ikyoku, hoping to be nominated by the head professor as his successor. They cannot oppose their professors because rejection of the professor's order, for example to go to a certain facility, would result in excommunication from the Ikyoku, in effect forcing them to abandon their academic careers.

In that wartime, being in short supply of research facilities at Universities, professors were willing to be cooperative with the army and Lt. Surgeon General Ishii. The professors promised Ishii to send their best disciples to his factories, and, in return, Ishii and the army supplied enough research equipment (and sometimes even the data and chances of human experimentation) to the professors [cf. Tsuneishi (1994), Chapter 3].

Third, even for the reluctant doctors from the Universities, Ishii's factories were luxurious places. For example, the annual budget of Unit 731 was 10 million yen (about 9 billion yen in the modern currency, or about 86 million dollars, at present value). Half of this budget was for research, and the other half was for labor costs for about 3,000 employees(3). The salary was considerably high, and the food served there was wonderful. Unit 731 had the most luxurious laboratories of Japan then. In addition, there were patients with diseases that they could hardly ever observe in the Japanese homeland, for example, epidemic hemorrhagic fever, plague, typhus, and severe frostbite. They could produce brilliant scientific achievements for Japanese medicine. With these achievements, they could gain good positions in the Japanese medical establishment after the war.


After the war the U.S. government made deals with Ishii and his colleagues. It did not tried any of them as a war criminal. In return, Ishii and his colleagues surrendered the data of their human experiments with vivisection. In order to monopolize the data for biological warfare, the U.S. covered up the brutal deed of the Japanese doctors, though it accused and judged the Nazi doctors in Nuremberg. This fact casts doubt upon sincerity of the U.S., the organizer of the Nuremberg Doctors' Trial and the producer of the Nuremberg Code.

Nevertheless, even though its producer was insincere, I believe the principles declared in the Nuremberg Code themselves are valid as a universal standard for nontherapeutic human experimentation. It can cover the deed of the Japanese doctors. But I would argue on the priority among these ten principles, above all of the principle of the subject's informed consent.

Very often the Nuremberg Code is admired for its first principle, "The voluntary consent of the human subject is absolutely essential," as the definite articulation of the importance of informed consent in experimentation with human subjects. By contrast, the other nine principles have not been paid much attention. But, from the reflections on the Japanese deadly experiments, these nine principles seem to be more important than the first principle.

As these nine principles set the conditions researchers must observe, these principles order researchers something directly ("The experiment should be...," "No experiment should be conducted...," etc.). On the other hand, as the first principle requires to respect for the subject's autonomy, it orders researchers indirectly in a sense that, not the principle itself, but autonomous subjects, order or permit to do. However, we can imagine that researchers might be asked to perform killing experiments by truly free and voluntary subjects with the intention of suicide or fanatic devotion. Therefore the principle of informed consent is not sufficient guard to prevent deadly experiments. Murderous experiments must be directly prohibited, according not to the subject's decision via the first principle, but to the fifth principle of the Nuremberg Code, "No experiment should be conducted where there is an a priori reason to believe that death or disabling injury will occur." (I believe the latter phrase of this principle, "except, perhaps, in those experiments where the experimental physicians also serve as subjects," should be deleted, because in wartime or fanatic society physician-researchers could devote themselves to killing experiments.)

In fact, subjects come to understand the nature of the experiment only by being explained by researchers. Experiment is always planned by researchers, not by subjects. Researchers know the purpose and nature of experiments. A researcher may recognize that the experiment brings the subject's death, but the subject never comes to know it without being explained. Therefore, at least of killing experiments, absolute prohibition must be laid upon researchers. We should not rely on subjects' autonomous decision to prevent them from being murdered. Probably that is why Jay Katz and Victor Sidel regard the principle of informed consent as a necessary but not sufficient condition [Katz (1996), p.1664; Sidel (1996), pp.1680-1681] . Requirement of subject's truly free, voluntary, and informed consent alone cannot stop researchers from performing deadly experiments in an extraordinary situation.


Japanese doctors performed experiments and vivisection only to kill the subjects. In order to keep secrets, they killed all the subject-prisoners. At their evacuation from China, they killed even prisoners who had not yet been experimented upon at all. Their attitude resembled that of the Japanese soldiers in Nanking who killed their rape victims for fear of being reported to the military police.

Based on the reflection on the Japanese murderous experimentation, absolute prohibition of killing experiments must come first. This means, of the Nuremberg Code, the fifth principle, together with the seventh (requirements of protection of the subject) and tenth (termination in case of possible injury, disability, or death), should precede over the first principle of informed consent.

I wonder why absolute prohibition of deadly experiments did not come first in the Nuremberg Code, since most of the Nazi experiments and eugenic programs were also murderous. Did the U.S. judges consider the informed consent principle sufficient to prevent deadly experiments? The answer is probably "No," since they articulated the other nine principles too. However, a question remains, if they really regarded the principle of informed consent as necessary but not sufficient, why did they declare it as the first principle and "absolutely essential?" Probably because, I would say, the idea of informed consent itself is so central to the modern western way of thinking{, and because medical science needed it to continue human experimentation after the war}.


(1) Sections 1, 2, and 3 of this paper are excerpted from my paper "Why Japanese doctors performed human experiments in China 1933-1945," Eubios Journal of Asian and International Bioethics 10 (6) [November 2000], pp.179-180. Its draft was read at the Fifth International Tsukuba Bioethics Roundtable (TRT5), Tsukuba, JAPAN, in November 1999. I am grateful to the participants in the meeting for precious comments.

(2) For more detailed description, see Harris (1994). This is so far the most comprehensive English-written book on this issue, although it does not mention experiments and vivisections performed at the Manchuria Medical School and army hospitals. On these experiments and vivisections, see Honda (1972), Chinese Central Archive et al. (1991), and Yoshikai (1981).

(3) According to the testimony of Major Genaral Kiyoshi Kawashima at the Khabarovsk Trial, December 25, 1949, in Materials on the Trial of Former Servicemen of the Japanese Army Charged with Manufacturing and Employing Bacteriological Weapons (1950).


Chinese Central Archive et al. (eds.). (1991) Seitai Kaibo: Kyu Nihongun no Senso Hanzai (Vivisection: Japanese Army's War Crime). Japanese translation, Dobunkan.

Harris, Sheldon H. (1994) Factories of Death: Japanese Biological Warfare, 1932-45, and the American Cover-Up. Routledge.

Honda, Katsuichi (1972) Chugoku e no Tabi (A Journey to China). Asahi Shimbun Sha (reprinted in Asahi Bunko, 1981).

Katz, Jay. (1996) The Nuremberg Code and the Nuremberg Trial: A Reappraisal. JAMA 276 (20) [November 27, 1996], pp.1662-1666.

Materials on the Trial of Former Servicemen of the Japanese Army Charged with Manufacturing and Employing Bacteriological Weapons (1950) Moscow: Foreign Languages Publishing House.

Sidel, Victor W. (1996) Commentary: The Social Responsibilities of Health Professionals----Lessons From Their Role in Germany. JAMA 276 (20) [November 27, 1996], pp.1679-1681.

Tsuneishi, Kei'ichi (1994) Igakusha Tachi no Soshiki Hanzai (The Conspiracy of Medical Researchers). Asahi Shimbun Sha (reprinted in Asahi Bunko, 1999).

Yoshikai, Natsuko (1981) Kesenai Kioku: Yuasa Gun'i Seitaikaibo no Kiroku (Unforgettable Memory: A Document of Army Surgion Yuasa's Vivisection). Nitchu Shuppan.


1. The voluntary consent of the human subject is absolutely essential.
This means that the person involved should have legal capacity to give consent; should be so situated as to be able to exercise free power of choice, without the intervention of any element of force, fraud, deceit, duress, over-reaching, or other ulterior form of constraint or coercion; and should have sufficient knowledge and comprehension of the elements of the subject matter involved as to enable him to make an understanding and enlightened decision. This latter element requires that before the acceptance of an affirmative decision by the experimental subject there should be made known to him the nature, duration, and purpose of the experiment; the method and means by which it is to be conducted; all inconveniences and hazards reasonably to be expected; and the effects upon his health or person which may possibly come from his participation in the experiment.

The duty and responsibility for ascertaining the quality of the consent rests upon each individual who initiates, directs or engages in the experiment. It is a personal duty and responsibility which may not be delegated to another with impunity.

2. The experiment should be such as to yield fruitful results for the good of society, unprocurable by other methods or means of study, and not random and unnecessary in nature.

3. The experiment should be so designed and based on the results of animal experimentation and a knowledge of the natural history of the disease or other problem under study that the anticipated results will justify the performance of the experiment.

4. The experiment should be so conducted as to avoid all unnecessary physical and mental suffering and injury.

5. No experiment should be conducted where there is an a priori reason to believe that death or disabling injury will occur; except, perhaps, in those experiments where the experimental physicians also serve as subjects.

6. The degree of risk to be taken should never exceed that determined by the humanitarian importance of the problem to be solved by the experiment.

7. Proper preparations should be made and adequate facilities provided to protect the experimental subject against even remote possibilities of injury, disability, or death.

8. The experiment should be conducted only by scientifically qualified persons. The highest degree of skill and care should be required through all stages of the experiment of those who conduct or engage in the experiment.

9. During the course of the experiment the human subject should be at liberty to bring the experiment to an end if he has reached the physical or mental state where continuation of the experiment seems to him to be impossible.

10. During the course of the experiment the scientist in charge must be prepared to terminate the experiment at any stage, if he has probable cause to believe, in the exercise of the good faith, superior skill and careful judgment required of him that a continuation of the experiment is likely to result in injury, disability, or death to the experimental subject.