Green Colour in certain kinds of Oysters. 177 
green colour, which injects it and renders it very easy to be 
traced, because it is thereby very distinctly defined on the 
white bed formed for it by the fatty matter. The liver is of a 
blackish-green colour instead of its usual reddish tint. But 
neither the great attaching muscle, nor the muscular fibres 
of the mouth, nor the cirri which surround it, nor the heart, 
blood, nerves, nor fatty substance, have undergone any change 
of colour. 
This colouring substance, existing only in the organs named, 
presents nothing remarkable when examined by the micros- 
cope, but it possesses the following properties :— 
It is insoluble, whether cold or warm, in distilled water, in 
alcohol, and in sulphuric ether. These three reactives pro- 
duce no change on its shade of colour. 
All the acids change it into blue, slowly when cold, rapidly 
when warm. Weak sulphuric, hydrochloric and citric acids, 
as well as vinegar, produce this change equally well. 
Ammonia reproduces the green colour. 
Nitric acid, when weak and cold, colours the matter blue : 
when warm it destroys it, and communicates that yellow colour 
which so often appears from the action of nitric acid on animal 
substances, 
Chlorine rapidly discolours the green matter and leaves the 
branchial leaflets entirely white. 
Sulphuretted hydrogen does not discolour it. 
Ammonia, after a long time, destroys the colour by chang- 
ing it into a very faint impure olive. 
Caustic potass dissolves the branchial leaflets and produces 
d brown liquid, from which acetic acid precipitates impure 
green flakes. 
These changes of colour take place in the intestinal canal 
in the same manner as in the branchial leaflets. 
Our accomplished fellow-member, M. Dumas, has made 
some experiments to ascertain whether the green matter does 
hot acquire a part of its colour from Prussian blue. They af- 
forded negative results. 
I made thesé observations on large oysters, of the kind named 
Green Marennes oysters, the branchiz of which, and portions 
of the intestinal canal subjected to the different agents above- 
VOL, XXXII. NO, LXII.— January 1842. M 
