3. With diseases the leading cause of soldier fatality, Japanese researchers began testing vaccines on deliberately infected prisoners to determine their effects on humans
In the course of the Sino-Japanese War (1937-1945), the Japanese discovered a horrid truth about modern warfare: that the overwhelming majority, in fact as high as 89 percent, of battlefield fatalities were caused not by the fighting but from diseases. In an attempt to better understand these illnesses, in addition to synthesizing vaccinations and cures, researchers at Unit 731 deliberately infected POWs. Forming one of the eight core divisions of Unit 731, this division, numbering approximately 300 researchers, focused on bacteriological diseases, notably cholera, anthrax, typhoid, tuberculosis, and the plague.
Some of the findings of researchers from Unit 731 were published contemporaneously in peer-reviewed journals, disguising that the research had been conducted on non-human primates. Subjects, for example, Chinese prisoners, were referred to as “Manchurian monkeys” or “long-tailed monkeys”, reflecting the sub-human nature in which POWs were viewed by the Japanese Empire. Their corpses were subsequently incinerated to eliminate evidence of wrongdoing by the Japanese military. The consequences of these methods can be seen in Indonesia on August 6, 1944, where an estimated 900 men were injected with an experimental vaccine. This vaccine, designed to combat tetanus, instead induced a fatal reaction to those administered; in total, it is believed nearly 1,000 people were killed by this failed test.