Page 116 - Unit 731 Testimony

back to Japan and assigned by the Ministry of Education to teach
bacteriology at the Yamanashi Prefectural University of Medicine.

At one stage, I worked at an important post in Yokohama studying the
control of viruses in a range of temperatures. We worked on strengthening
viruses that become weak in high temperatures and lose their virulence. The
method involved dehydrating the viruses by reducing air pressure and
lowering temperature, and our job was developing the machinery to
accomplish this.

The water filtration system that Ishii developed in Pingfang was used
in Kyoto in the Fushimi district for treating water in saké brewing. The
bacteria filter was checked at the army school, and after it passed the

checks, it was sent to Manchuria. The checking was done by Naito Ryoichi.
I began working at Pingfang in the spring of 1939. Since Japan is an
island country with no borders with other countries, Japanese would be
especially susceptible to bacteria and might be expected to succumb readily
to pathogens encountered in foreign lands. Although researchers were

conducting experiments, many did not think that a bacteriological war could
or would really be prosecuted.
Smallpox is endemic to Manchuria, but Manchurians have a degree of

natural immunity to the disease. Even without vaccination, the death rate of
those afflicted is below thirty percent, while the Japanese death rate was
about eighty percent. The disease was epidemic in China and we had to
develop a method of preventing it among members of the Japanese army.
Test subjects were available in Manchuria. One could see the faces of those
scarred by the disease. It was not necessary to use maruta for this purpose.
Maruta were sent in by the kenpeitai in Harbin, but we did not have to use

them for this disease.

At that time, the general thinking at the unit was that it was necessary
to sacrifice three maruta in order to save one hundred Japanese soldiers. For
a technician though, if a maruta is sacrificed without a real reason, it is
folly. Technicians have to go into animal cages and work in a dirty
environment, but we get accustomed to this. There was much more
resistance to going into cells with people.

We worked in the city of Mudanjiang. It is the custom in China that
when someone has smallpox a red curtain is hung in the window of the