WHEN GERM WARFARE HAPPENED. “These attacks, orchestrated by Japan’s infamous Unit 731 between 1932 and 1945, are the only documented mass use of germ weapons in modern times. Scholars say that we will never know exactly how many were killed. Sheldon H. Harris, the late American historian, estimated in a pioneering work that between 10,000 and 12,000 Chinese prisoners perished in the bloodcurdling experiments that Unit 731 performed in Japanese-occupied Manchuria. Another 300,000 to 500,000 civilians died, he wrote, as a result of Japan’s massive germ assaults on more than 70 Chinese cities and towns.”