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ascertain by other reagents which of the metals is present. 
Very numerous tests were made with the blood obtained 
from white Oysters, and micro-chemical reactions revealed 
in some instances faint traces of copper. Hemocyanin 
has been described in the blood of Molluscs and apparently 
in the blood of the Oyster. We have examined numerous 
samples of blood taken from the white Oyster, but have 
failed to get any blue colouration on exposure to air. In 
the green Oysters a very faint blue colour has been noticed 
in some cases on exposing the blood to air.” 
I quote the following conclusion from the Royal Society 
paper :— 
‘Our results demonstrated the presence of copper in 
comparatively large quantity in the green leucocytes, 
chiefly in the American Oyster, but also in the ‘‘ natives ”’ 
from Falmouth and other localities. We have shown 
that the colour was in proportion to the amount of copper 
present, and that the colourless leucocytes contained only 
traces of that metal. The deposition of the copper in this 
large quantity appears to us to represent a degenerative 
condition. It was accompanied by a most striking 
increase of leucocytes, which tended to distend the vessels 
and to collect in clumps, phenomena which are abnormal 
in our experience in the Oyster. The presence of the 
copper in the leucocytes in these cases might be compared 
to that of the iron which is met with, in man, in some of 
the leucocytes in cases of old hemorrhages, pernicious 
anemia, or in other cases where iron is set free. We 
are not prepared to state whether copper in the food can 
bring about this condition, but certainly we have abundant 
evidence to show that it can occur where no copper mines 
or other evident sources of copper are present. 
‘We are inclined to suggest that the increase in copper 
may be due to a disturbed metabolism, whereby the 
