Scientijic Intelligence. 
ration of the different alcoholic solutions, a red and apparently 
fatty matter was obtained. This matter has no smell, or sensi- 
ble taste ; is insoluble in cold or boiling water, but soluble in 
sulphuric ether, and pure cold alcohol. This solution is of a 
scarlet colour. It is not disturbed by the addition of distilled 
water, which shews that it is not of a fatty nature. Its natural 
colour is not changed by potash, soda or ammonia. The mineral 
acids have no action upon it, when diluted with water ; but, 
when concentrated, they destroy it, by changing it to a dirty 
yellow. The salts of lead, tin, iron, and copper, do not precipi- 
tate this colouring matter from an alcoholic solution diluted with 
water.— t/owm. de Pharmacies tom. vi. p. 174,-175. 
34. On the colouring matter the memhra/ne which lines the 
shell of the Crab. — M. Lassaigne also examined the membrane, 
which, in young crabs, adheres strongly to the shell, but which 
may be easily separated from it in large crabs. It is extremely 
fine, and of a violet colour by reflected light, and a purple violet 
by transmitted light. When put in water it does not lose its 
colour ; but in cold alcohol it gives out a great quantity of red 
colouring matter, similar to that which is extracted from the 
shell. Though treated successively with several doses of alco- 
hol this membrane retains a little of its red violet colour, which 
cannot be taken away from it by other solvents without destroy- 
ing the membrane itself. The colouring matter has the same 
properties as that of the shell. 
M. Lassaigne has found the same principle in the shells of 
lobsters, and other animals of the same order, and he con- 
cludes, 
1. That crabs, &c. contain a red colouring principle, which may 
be extracted by means of cold alcohol. 
% That this colour is not formed by the action of heat, but 
that it is developed or distributed in the shell by the impulsion 
of that fluid. 
3. That there exists a highly coloured membrane, which ap- 
pears to be the source of the colouring matter in that class of 
animals; and, 
4. That this colouring matter differs in its chemical properties 
from others obtained from the mineral and vegetable kingdom. 
—See Journ. de Pharm. tom. vi. p. 175, L76. 
