656 POISONS : THEIR EFFECTS AND DETECTION. [§ 836 . 
That is to say, that, neglecting altogether foods artificially contaminated 
with copper, each of us eats daily about 1 mgrm. of copper (0-015 grain). 
In the animal kingdom it is a constant and natural constituent of 
the blood of the cephalopods, Crustacea, and gasteropods, and is nearly 
always present in the liver and kidneys of domestic animals, as well 
as in men. Dr Dupre 1 found *035 to -029 grain (1*8 to 2 mgrms.) 
in human livers, or about 1 part in 500,000. Bergeron and L. L. Hote’s 
researches on fourteen bodies, specially examined for copper, fully 
substantiate those of Dr Dupre : in twelve the copper was found in 
quantities of from -7 to 1-5 mgrm. ; in the remaining two the amount of 
copper was very minute, and was not estimated. 2 Copper is also found 
normally in the kidneys, and Dupre 3 detected in human kidneys about 
1 in 100,000 parts ; it is also found in the bile, and in minute traces in 
the blood. 4 
In the kidneys and livers of the ruminants copper may always 
be found, a sheep’s liver containing about 1 part in 20,000. 5 Church 
found copper in the feathers of the wings of the turaco and in 
the feathers of a parroquet ( Melopsittacus undulatus ). 6 In these cases 
the copper enters into the composition of the colouring-matter to which 
the name of “ turacin ” has been given. Turacin contains 7 per cent, of 
copper, and gives to analysis numbers which agree with the formula 
of C 82 H 81 Cu 2 N 9 0 32 . 
Copper has been discovered in aerated waters, its presence being due 
to the use of copper cylinders, the tin lining of which had been rendered 
defective by corrosion. 7 
Accidents may also occur from the use of copper boilers. Mr W. 
Thompson found in one case 8 no less than 3-575 grains per gallon 
(51 mgrms. per litre) in water drawn from a kitchen boiler. 
At Roubaix, in France, sulphide of copper had been deposited on the 
roof, as a consequence of the use of copper flues ; the sulphide was 
changed into sulphate by the action of the air, and washed by the rain 
into the water-tank. 9 
That preserved vegetables are made of a bright and attractive green 
colour by impregnation with copper, from the deliberate use of copper 
vessels for this purpose, is a fact long known. Green peas especially 
have been coloured in this way, and a number of convictions for this 
offence have taken place in England. 
§ 836. The “ Coppering ” of Vegetables. —The fact that green 
1 Analyst, No. 13, 1877. 
2 Compt. Rend., vol. lxxx. p. 268. 3 Op. cit. 
4 Hoppe-Seyler, Handbuch der physiologisch. Analyse, p. 415. 
6 Dupre, op. cit. 6 Chem. News, xxviii. 212. 
7 “ On the Presence of Lead and Copper in Aerated Waters,” by Dr Janies Milne, 
Chem. News, xxxi. 77. 
8 Chem. News, xxxi. No. 801. 
8 Blyth, Dictionary of Hygiene, p. 167. 
