tached and probably of foreign origin.
The nodules did not
appear to be part of the coral but were so well attached that
when one of them- was removed for counting it could not be
arated from the coral without being broken.
low sphere weighing 1 mg yielded 100,000 d/m.
sep-
This unashed hol-
It is possible
that these bodies were cystg produced by the coral itself,
either. for the purpose of walling off irritating, highly radioactive particles,
or that they were rapidly-growing neoplastic
growths which had concentrated a great amount of radioactivity
since the time of the blast.
See Figure 22c.
Photographs and autorediographs of Heliopora and of the
above samples of Acropora collected at Bogallua are shown in
Figure 22a and b.
The specific activity of the Acropora was
7,000,000 d/m/g and of the nodule 100,000,000 d/m/g, i.e.,
100,000 d/m/mg.
After the autoradiographs were made another
piece from the same
sample of Heliopora was used in an attempt
to complement the results with quantitative data.
outer layer,
about one millimeter thick,
The thin
the dense median por-
tion corresponding to the least dense portion in the autoradio-
greph, and the relatively porous central portion were separated
from one another and ashed for counting.
The resulting spec-
ific activities were 3,400,000 d/m/g, 160,000 d/m/g and 1,000,000
a/n/zg respectively.
It seems likely that the radioactivity
found in the median portion lined small cavities which are present in the skeleton rather than actually being incorporated
in the coralline material.
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