NEW RESEARCHES ON OPIUM. 
75 
ceine. Thus, if a current of dry hydrochloric acid gas is 
passed through narceine, this substance will absorb the acid, 
and become of an orange yellow colour; if a little water be 
added it will assume a beautiful blue tint; a larger quantity of 
water will dissolve it, and the colour will disappear, and if the 
acid be now saturated with a few drops of ammonia, the nar- 
ceine will be precipitated in an unaltered state. 
Iodine combines with narceine; this combination is of so deep 
a blue that it appears black, but if it be mixed with some inert 
white substance, it becomes of a magnificent shade of blue. 
It is a real combination; if water be added and the mixture 
boiled, it dissolves without colouring the liquid; on filtering it 
promptly, the narceine separates of either a blue or a rose co- 
lour, in the latter case retaining less iodine. Finally, if the 
boiling be continued, the narceine crystallises of its original 
colour, retaining no iodine, which remains in the fluid. The 
rose coloured combination, which may be termed a sub-ioduret 
of narceine, may be procured by taking the blue ioduret, and 
macerating it in a solution of bicarbonate of potash. If the 
carbonate or caustic potash be employed, the whole of the 
iodine will be taken up. Hitherto starch was the only sub- 
stance which struck a blue colour with iodine. It is remark- 
able that a substance so different from starch in its nature and 
properties, should produce an analogous result. This fact 
should induce us not to place exclusive reliance on the use of 
reagents in determining the nature of a substance. 
The action of bromine, and especially of chlorine on nar- 
ceine, is more complicated; and I shall refrain from speaking 
of it, until I shall be enabled to publish the researches I have 
undertaken on the actions of halogene bodies on vegetable 
substances, and particularly on the vegetable alkalies. 
IX. 
Note on pseudo-morphia , followed by some considerations 
on the detection of morphia by reagents. 
I give the name of pseudo-morphia to a singular substance 
I obtained from opium, treated on a large scale, without my 
