IRON AND COPPER IN OYSTERS. 
25 
It is evident from the last table tiiat both the gills and the rest of the body of 
oysters contain normally (as would naturally be expected) a small quantity of iron, 
the gills having a somewhat larger amount in proportion to the total quantity of mineral 
matter present, but quite irrespective of the colour of the gills. 
II.— Determination of the Copper. 
Harless and Bibra* first showed that phosphate of copper was present in the 
blood of Molluscs (Cephalopoda), and Fredericq subsequently extended the ob.servation f 
and proved that a certain small amount of copper is found normally in the blood of 
various Shellfish (both Crustaceans and Mollu.scs). It is apparently in comliination with 
a proteid, to which Fredericq gave the name " hdmocyanine." 
The quantity thus i^resent in oysters of different origin is fairly constant, as shown 
in the following table: it varies from 0.25 to 0.66 mgrme. per oyster, or from 0.30 to 
1. 1 8 per cent, on the ash: — - 
Kind of Oyster. 
Number 
Analyzed. 
Total 
Copper. 
Grille. 
Weight 
of Ash. 
Copper 
per 
Oyster. 
Mgrme. 
Percent- 
age 
Copper 
on Asli. 
Huitres de Marennes 
6 
0.0024 
0.7860 
0.^0 
0.30 
Dutch 
6 
0.0015 
0.1393 
0.. 
1.08 
American 
5 
0.0033 
0.2791 
o.C-6 
1. 18 
Colne River 
10 
0.0036 
1.0938 
0.36 
0.33 
Deep Sea (very large) ... 
0.0069 
I.5017 
0-34 
0.46 
For copper, then, 0.4 mgrme. per oyster may be taken as an a\'erage, a quantity 
slightly greater than the average iron (0.26 mgrme.). The calculated percentages on the ash 
.show greater variations, due to the very considerable differences in the total quantities 
of mineral salts present ; and it is very possibly to this last factor that the well-known 
differences in taste of the various kinds of oysters is at any rate in part due. Certainly 
the minute quantities of copper and iron present cannot account for the flavour, as has 
been sometimes suggested. 
The copper was also determined in the gill.s, and in the bodies minus gills, of 
French, Dutch, and American oysters, with the following results : — 
Si.x Oysters. 
French 
•'• Huitres de Marennes " 
(green). 
Dutch 
(slightly green). 
American 
(white). 
Gills only 
Bodies minus gills 
Trace. 
2.4 mgrme. 
0.8 
..4 
1-7 
3.3 
* Mullet's Archiv, 1847. + J<ech. s. 1. Physiologie du Poulpe, Arch. Zool. Exper., t. VII. (1878). 
c 
