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chromosome, the change of permeability of the cell membrane, the
suppression of cell-division, the decrease of leucocyte, the induction
of the boil, death, etc,
One of the most important facts about the biological effect of
radiation is known as the law of Tribondeau-Bergony which asserts that
the cell is most sensitive to the radiation when it is young and has
the tendency of cell-division.
For instance, in the human body, blood-
producing organs(bone, spleen, lymphatic, etc.) and genital cells are
most likely to be injured by radiation.
The injury of radiation from outside of the body may be classified
into two categories, One is caused by the B- ray of fission products
adhered to the skin. In this case, the skin turns to black, gives rise
to bleb or fester, and the hair may be lost from the head.
In fact,
Fig. 3.
Depariment of Energy
hands and faces of two patients who entered the Tokyo University Hospital
on March 15 were black and had festers at some places.
It was found by
a Geiger counter that the redioactivity wes strong at the head, ears,
neck, armpits, ebdomen, sole, parts of hands or feet between the fingers
or toes,
The result of measurement by the miliroentgenometer (distance
S cm) is given in Table h. The redioautograph of the hair is shown in
;
.
;
iictorian’s Gite?
dcwn maeny fishermen felt
ck
a
mw
om
0
I
3
a
a
t
i
t20n on MWaerch 2 from th
han that of Merch 17.
mu Oo
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n
wt
to riace in the co
noo
oo
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c
au
In Table 5, it iss
mong
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1
As is well-known, we are incessantly exposed to the cosmic-ray from
and the rediation of natural radioactive substances like radium
x= from the earth, Nevertheless, we are not injured by these
1S, not to a visible extent at leest. This is due to the fact
the exposure on successive days hes no dexage if the amount
Ciation is less than a certéin limit. The maximum amunt which
ody cén tolerete is celled the permissible dose. The intercievy of radiology determined that the permissible dose is
Feorie living on 2 Doat are exposed to the
nvgen per week.
any time so that the permissicl e Gose is 1.6 mcr
per hour.
cf radiétion on the Pukurre Maru
10~ 100 mr per hour which wes 5~50
e
¢
Molwom
Opp
os
y
oO
Myon O ct wv
Cm
The other is caused by the y- rays of radioactive substance
WES
adhered to the deck, cabin, fishing implezents, clothes, etc. sire Yhe”
{- ray hes a large penetrating power, it will irradiate the whole body am
cause the change of blood (decreese of leucocyte), recurrent enenta,
depilation, injury to the genital cells, hereditary change, etc.