74 FISH—CULTURAL ASSOCIATION. 
where an unusual greenish material was found in the follicles 
of liver, the living cells of which were also affected, would in- 
dicate that the color was probably absorbed from tke food of 
the animal, which, as we know, consists largely of living vege- 
table matter. It is not improbable that the tinged nutritive 
juices transuded through the walls of the alimentary canal, ac- 
quired the color of the food which had been dissolved by the 
digestive juices. | 
How to account for the accumulation of the green cells in the 
heart and in cysts in the mantle is not, however, an easy matter, 
unless one be permitted to suppose that the acquisition of the 
green color by the blood-cells is in reality a more or less de- 
cidedly diseased condition, for which we have no ground in fact, 
since the green oysters are in apparently as good health as the 
white ones. They are found “fat” or “poor,” just as it may 
have happened that their food was abundant or the reverse. 
They are also found in all stages of the “greened” condition. 
Sometimes they have only a very faint tinge of the gills, or they 
may be so deeply tinged as to appear unpalatable, with the heart 
of a deep green, or with green cysts developed in the mantle or 
with clouds of this color shading the latter organ in certain 
places. A vastly greater proportion of green oysters are eaten 
in this country, at all events, than is generally supposed, espec- 
ially of those just faintly tinged in the gills. 
If it be objected that the green color indicates an unhealthful 
condition of the animal, it may be stated that other color varia- 
tions of the flesh have fallen under my observation recently. 
What is now alluded to is the yellowish, verging toward a red- 
dish cast, which is sometimes noticed in the gills and mantle of 
both the American and European species. This,.in all proba- 
bility, like the green color, is due to the reddish-brown matter 
which is contained in much of the diatomaceous food of the 
animal. 
Mr. B. J. M. Carley has also called my attention to these vari- 
ations, and was inclined to attribute them to the soil in the 
vicinity of the beds. But if the classical writers are to be trust- 
ed, to the green, yellow and white-fleshed sorts we must add red, 
tawny and black-fleshed ones. Pliny tells us of red oysters 
